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产品型号LTC2942CDCBTRMPBF的Datasheet PDF文件预览

LTC2942  
Battery Gas Gauge  
with Temperature,  
Voltage Measurement  
FEATURES  
DESCRIPTION  
The LTC®2942 measures battery charge state, battery  
voltage and chip temperature in handheld PC and portable  
productapplications.Itsoperatingrangeisperfectlysuited  
for single cell Li-Ion batteries. A precision coulomb coun-  
ter integrates current through a sense resistor between  
the battery’s positive terminal and the load or charger.  
Battery voltage and on-chip temperature are measured  
with an internal 14-bit No Latency ΔΣ™ ADC. The three  
measured quantities (charge, voltage and temperature)  
are stored in internal registers accessible via the onboard  
n
Indicates Accumulated Battery Charge and  
Discharge  
n
High Accuracy Analog Integration  
n
ADC Measures Battery Voltage and Temperature  
n
Integrated Temperature Sensor  
n
High Side Sense  
n
1% Voltage and Charge Accuracy  
n
±±5mꢀ Sense ꢀoltage Range  
2
n
SMBus/I C Interface  
n
Configurable Alert Output/Charge Complete Input  
2
n
2.7ꢀ to ±.±ꢀ Operating Range  
SMBus/I C interface.  
n
Quiescent Current Less than 155μA  
TheLTC2942featuresprogrammablehighandlowthresh-  
olds for all three measured quantities. If a programmed  
threshold is exceeded, the device communicates an alert  
using either the SMBus alert protocol or by setting a flag  
in the internal status register.  
n
Small 6-Pin 2mm × 3mm DFN package  
APPLICATIONS  
n
Low Power Handheld Products  
n
n
n
n
The LTC2942 requires only a single low value sense resis-  
tor to set the measured current range.  
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear  
Technology Corporation. No Latency ΔΣ is a trademark of Linear Technology Corporation.  
All other trademarks are the property of their respective owners.  
Cellular Phones  
MP3 Players  
Cameras  
GPS  
TYPICAL APPLICATION  
Total Charge Error vs  
Differential Sense Voltage  
2.5  
+ = 3.6ꢀ  
SENSE  
1.±  
1.5  
CHARGER  
LOAD  
5.1μF  
+
SENSE  
LTC2942  
AL/CC  
5.±  
R
SENSE  
155mΩ  
2
I C/SMBus  
5
SDA  
SCL  
SENSE  
TO HOST  
–5.±  
–1.5  
–1.±  
–2.5  
+
1-CELL  
Li-Ion  
GND  
2942 TA51a  
5.1  
1
15  
155  
(mꢀ)  
SENSE  
2942 TA51b  
2942f  
1
LTC2942  
ABSOLUTE MAXIMUM RATINGS  
PIN CONFIGURATION  
(Notes 1, 2)  
+
TOP ꢀIEW  
Supply ꢀoltage (SENSE )............................. –5.3ꢀ to 6ꢀ  
SCL, SDA, AL/CC ......................................... –5.3ꢀ to 6ꢀ  
+
6
±
4
SENSE  
AL/CC  
SDA  
SENSE  
GND  
1
2
3
+
SENSE .................................. –5.3ꢀ to (ꢀ  
Operating Ambient Temperature Range  
+ 5.3ꢀ)  
SENSE  
7
GND  
SCL  
LTC2942C ................................................ 5°C to 75°C  
LTC2942I.............................................. –45°C to 8±°C  
Storage Temperature Range................... –6±°C to 1±5°C  
DCB PACKAGE  
6-LEAD (2mm × 3mm) PLASTIC DFN  
T
JMAX  
= 1±5°C, θ = 125°C/W  
JA  
EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB OR LEFT FLOATING  
ORDER INFORMATION  
Lead Free Finish  
TAPE AND REEL (MINI)  
LTC2942CDCB#TRMPBF  
LTC2942IDCB#TRMPBF  
TAPE AND REEL  
PART MARKING*  
LDꢀN  
PACKAGE DESCRIPTION  
TEMPERATURE RANGE  
5°C to 75°C  
LTC2942CDCB#TRPBF  
LTC2942IDCB#TRPBF  
6-Lead (2mm × 3mm) Plastic DFN  
6-Lead (2mm × 3mm) Plastic DFN  
LDꢀN  
–45°C to 8±°C  
TRM = ±55 pieces. *Temperature grades are identified by a label on the shipping container.  
Consult LTC Marketing for parts specified with wider operating temperature ranges.  
Consult LTC Marketing for information on lead based finish parts.  
For more information on lead free part marking, go to: http://www.linear.com/leadfree/  
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/  
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating  
temperature range, otherwise specifications are at TA = 25°C. (Note 2)  
SYMBOL  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
Power Requirements  
+
Supply ꢀoltage  
2.7  
±.±  
155  
3±5  
425  
2.±  
1
μA  
μA  
μA  
μA  
μA  
SENSE  
l
l
l
l
I
Supply Current (Note 3)  
Battery Gas Gauge On, ADC Sleep  
Battery Gas Gauge On, ADC Converting ꢀoltage  
Battery Gas Gauge On, ADC Converting Temperature  
Shutdown  
75  
SUPPLY  
355  
3±5  
Shutdown, ꢀ  
+ ≤ 4.2ꢀ  
SENSE  
l
l
Undervoltage Lockout Threshold  
+ Falling  
2.±  
2.6  
2.7  
UꢀLO  
SENSE  
Coulomb Counter  
SENSE  
Sense ꢀoltage Differential Input  
Range  
+ – ꢀ  
±±5  
mꢀ  
kΩ  
SENSE  
SENSE  
R
Differential Input Resistance,  
455  
IDR  
+
Across SENSE and SENSE  
(Note 8)  
q
Charge LSB (Note 4)  
Total Charge Error (Note ±)  
Prescaler M = 128 (Default), R  
= ±5mΩ  
5.58±  
mAh  
%
LSB  
SENSE  
TCE  
15mꢀ ≤ |ꢀ  
15mꢀ ≤ |ꢀ  
| ≤ ±5mꢀ DC  
±1  
SENSE  
l
l
| ≤ ±5mꢀ DC, ꢀ  
SENSE  
+ ≤ 4.2ꢀ  
±1.±  
±3.±  
%
SENSE  
1mꢀ ≤ |ꢀ  
| < ±5mꢀ DC (Note 8)  
SENSE  
%
2942f  
2
LTC2942  
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating  
temperature range, otherwise specifications are at TA = 25°C. (Note 2)  
SYMBOL  
Voltage Measurement ADC  
Resolution (No Missing Codes)  
Full-Scale ꢀoltage  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
l
l
(Note 8)  
14  
Bits  
FS  
6
Quantization Step of 14-Bit  
ꢀoltage ADC  
(Note 6)  
366.2  
μꢀ  
Δꢀ  
LSB  
TUE  
ꢀoltage Total Unadjusted Error  
1
%
%
l
l
1.3  
Gain  
Gain Accuracy  
Offset  
1.3  
±15  
±4  
%
LSB  
LSB  
ms  
Extrapolated from Measurements at ±.±ꢀ and 2.7ꢀ  
±1  
±1  
OS  
l
l
INL  
Integral Nonlinearity  
Conversion Time  
t
1±  
CONꢀ  
Temperature Measurement ADC  
Resolution (No Missing Code)  
Full-Scale Temperature  
(Note 8)  
(Note 6)  
15  
Bits  
K
l
T
FS  
655  
Quantization Step of 15-Bit  
Temperature ADC  
5.±86  
K
ΔT  
LSB  
l
l
TUE  
Temperature Total Unadjusted  
Error  
+ ≥ 2.8ꢀ (Note 8)  
SENSE  
±±  
±3  
K
K
T
t
Conversion Time  
1±  
ms  
CONꢀ  
Digital Inputs and Digital Outputs  
l
l
Logic Input Threshold, AL/CC,  
5.3 • ꢀ  
+
5.7 • ꢀ  
+
SENSE  
ITH  
SENSE  
SCL, SDA  
OL  
Low Level Output ꢀoltage, AL/CC, I = 3mA  
SDA  
5.4  
l
l
I
Input Leakage, AL/CC, SCL, SDA  
= ꢀ  
+/2  
SENSE  
1
μA  
pF  
IN  
IN  
C
Input Capacitance, AL/CC, SCL,  
SDA  
(Note 8)  
15  
IN  
t
Minimum Charge Complete (CC)  
Pulse Width  
1
μs  
PCC  
2
I C Timing Characteristics  
l
l
l
f
t
t
Maximum SCL Clock Frequency  
Bus Free Time Between Stop/Start  
455  
955  
kHz  
μs  
SCL(MAX)  
BUF(MIN)  
1.3  
Minimum Repeated Start Set-Up  
Time  
655  
ns  
SU,STA(MIN)  
l
l
l
t
t
t
Minimum Hold Time (Repeated)  
Start Condition  
655  
655  
155  
ns  
ns  
ns  
HD,STA(MIN)  
SU,STO(MIN)  
SU,DAT(MIN)  
Minimum Set-Up Time for Stop  
Condition  
Minimum Data Setup Time Input  
2942f  
3
LTC2942  
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating  
temperature range, otherwise specifications are at TA = 25°C. (Note 2)  
SYMBOL  
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
5
UNITS  
μs  
l
l
l
t
t
t
Minimum Data Hold Time Input  
Data Hold Time Output  
Data Output Fall Time  
HD,DATI(MIN)  
HD,DATO  
of  
5.3  
5.9  
355  
μs  
(Notes 7, 8)  
25 + 5.1 • C  
ns  
B
Note 5: Deviation of q  
Note 6: The quantization step of the 14-bit ADC in voltage mode and  
15-bit ADC in temperature mode is not to be mistaken with the LSB of the  
combined 16-bit voltage registers (I, J) and 16-bit temperature registers  
(M, N).  
from its nominal value.  
Note 1: Stresses beyond those listed under Absolute Maximum Ratings  
may cause permanent damage to the device. Exposure to any Absolute  
Maximum Rating condition for extended periods may affect device  
reliability and lifetime.  
LSB  
Note 2: All currents into pins are positive, all voltages are referenced to  
GND unless otherwise specified  
Note 7: C = Capacitance of one bus line in pF (15pF ≤ C ≤ 455pF). See  
B
B
ꢀoltage and Temperature Registers section for more information.  
Note 3: I  
= I  
+ + I  
SUPPLY  
SENSE SENSE  
Note 8: Guaranteed by design, not subject to test.  
Note 4: The equivalent charge of an LSB in the accumulated charge  
register depends on the value of R  
prescaling factor M:  
and the setting of the internal  
SENSE  
50mΩ  
RSENSE 128  
M
qLSB =0.085mAh•  
See Choosing R  
and Choosing Coulomb Counter Prescaler M section  
SENSE  
for more information. 1mAh = 3.6C (Coulombs).  
TIMING DIAGRAM  
t
of  
SDA  
t
t
SU,STA  
t
SU, DAT  
t
t
BUF  
HD, DATO,  
HD, DATI  
t
HD, STA  
t
SU, STO  
2942 F01  
SCL  
t
HD, STA  
START  
CONDITION  
REPEATED START  
CONDITION  
STOP  
CONDITION  
START  
CONDITION  
Figure 1. Definition of Timing on I2C Bus  
2942f  
4
LTC2942  
TYPICAL PERFORMANCE CHARACTERISTICS  
Total Charge Error vs Differential  
Sense Voltage  
Total Charge Error vs Supply  
Voltage  
Total Charge Error vs Temperature  
3
2
1.55  
5.7±  
5.±5  
5.2±  
5
1.55  
5.7±  
5.±5  
5.2±  
5
1
5
–5.2±  
–5.±5  
–5.7±  
–1.55  
–5.2±  
–5.±5  
–5.7±  
–1.55  
–1  
–2  
–3  
= –±5mꢀ  
= –15mꢀ  
+ = 2.7ꢀ  
+ = 4.2ꢀ  
SENSE  
SENSE  
= –±5mꢀ  
SENSE  
SENSE  
SENSE  
SENSE  
= –15mꢀ  
–±5  
2±  
7±  
–2±  
5
±5  
155  
5.1  
1
15  
155  
2.±  
3.± 4.5 4.±  
+
±.5 ±.± 6.5  
3.5  
TEMPERATURE (°C)  
(ꢀ)  
(mꢀ)  
SENSE  
SENSE  
2942 G51  
2942 G53  
2942 G52  
Shutdown Supply Current vs  
Supply Voltage  
Voltage Measurement ADC  
Total Unadjusted Error  
Supply Current vs Supply Voltage  
155  
95  
2.5  
1.±  
1.5  
15  
8
T
A
T
A
T
A
= 2±°C  
= –45°C  
= 8±°C  
6
T
A
= 8±°C  
4
85  
2
75  
5
T
A
= –4±°C  
–2  
–4  
–6  
–8  
–15  
65  
±5  
45  
5.±  
5
T
= 2±°C  
T
T
T
= 2±°C  
= –45°C  
= 8±°C  
A
A
A
A
4.±  
+
±.±  
6.5  
2.± 3.5  
3.± 4.5  
±.5  
2.±  
3.± 4.5 4.±  
+
±.5 ±.± 6.5  
3.5  
2.±  
3.± 4.5 4.±  
±.5 ±.± 6.5  
3.5  
(ꢀ)  
(ꢀ)  
(ꢀ)  
SENSE  
SENSE  
SENSE  
2942 G54  
2942 G5±  
2942 G56  
Voltage Measurement ADC  
Integral Nonlinearity  
Temperature Error vs Temperature  
1.5  
5.±  
3
2
T
= 8±°C  
A
1
5
5
T
= –45°C  
A
–1  
–2  
–3  
T
A
= 2±°C  
–5.±  
–1.5  
–±5 –2±  
5
2±  
±5  
7±  
155  
3.5  
3.±  
4.± ±.5 ±.± 6.5  
2.±  
4.5  
TEMPERATURE (°C)  
(ꢀ)  
SENSE  
2942 G58  
2942 G57  
2942f  
5
LTC2942  
PIN FUNCTIONS  
+
SENSE (Pin 1): Positive Current Sense Input and Power  
the pin defaults to alert mode conforming to the SMBus  
alert response protocol. It behaves as an open-drain logic  
outputthatpullstoGNDwhenanythresholdregistervalue  
isexceeded. Whenconfiguredasachargecompleteinput,  
connect to the charge complete output from the battery  
charger circuit. A high level at CC sets the value of the  
accumulated charge (registers C, D) to FFFFh.  
Supply. Connect to the load/charger side of the sense  
+
resistor. ꢀ  
operating range is 2.7ꢀ to ±.±.  
SENSE  
GND (Pin 2, Exposed Pad Pin 7): Device Ground. Connect  
directly to the negative battery terminal. Exposed pad may  
be left open or connected to device ground.  
SCL (Pin 3): Serial Bus Clock Input.  
SENSE (Pin 6): Negative Current Sense Input. Connect  
SDA (Pin 4): Serial Bus Data Input and Output.  
SENSE to the positive battery terminal side of the sense  
+
resistor. The voltage between SENSE and SENSE must  
AL/CC (Pin 5): Alert Output or Charge Complete Input.  
Configured either as an SMBus alert output or charge  
completeinputbycontrolregisterbitsB[2:1].Atpower-up,  
remain within ±±5mꢀ in normal operation. SENSE is also  
the input for the ADC in voltage measurement mode.  
BLOCK DIAGRAM  
LTC2942  
SUPPLY  
+
SENSE  
1
CC  
ACCUMULATED  
COULOMB COUNTER  
CHARGE  
REGISTER  
REF  
CLK  
AL  
AL/CC  
SCL  
±
3
4
TEMPERATURE  
SENSOR  
REFERENCE  
GENERATOR  
2
OSCILLATOR  
I C/  
SMBus  
SDA  
+
REF  
CLK  
DATA AND  
CONTROL  
REGISTERS  
MUX  
IN  
ADC  
SENSE  
GND  
6
2
REF  
2942 BD  
2942f  
6
LTC2942  
OPERATION  
Overview  
Aprogrammableprescalereffectivelyincreasesintegration  
time by a factor M programmable from 1 to 128. At each  
underflow or overflow of the prescaler, the accumulated  
chargeregister(ACR)valueisincrementedordecremented  
one count. The value of accumulated charge is read via  
The LTC2942 is a battery gas gauge device designed for  
use with single Li-Ion cells and other battery types with a  
terminalvoltageat2.7to±.Itmeasuresbatterycharge  
and discharge, battery voltage and chip temperature.  
2
the I C interface.  
A precision coulomb counter integrates current through a  
sense resistor between the battery’s positive terminal and  
theloadorcharger.Batteryvoltageandon-chiptemperature  
are measured with an internal 14-bit/15-bit ADC.  
Voltage and Temperature ADC  
The LTC2942 includes a 14-bit No Latency ΔΣ analog-to-  
digital converter, with internal clock and voltage reference  
circuits.  
Coulomb Counter  
The ADC can either be used to monitor the battery voltage  
Charge is the time integral of current. The LTC2942 mea-  
suresbatterycurrentbymonitoringthevoltagedeveloped  
acrossasenseresistorandthenintegratesthisinformation  
atSENSE ortoconverttheoutputoftheon-chiptempera-  
turesensor.Thesensorgeneratesavoltageproportionalto  
temperature with a slope of 2.±mꢀ/K resulting in a voltage  
of 7±5mꢀ at 27°C.  
+
to infer charge. The differential voltage between SENSE  
andSENSE isappliedtoanauto-zeroeddifferentialanalog  
integrator to convert the measured current to charge.  
Conversion of either temperature or voltage is triggered  
2
by setting the control register via the I C interface. The  
When the integrator output ramps to REFHI or REFLO  
levels, switches S1, S2, S3 and S4 toggle to reverse the  
rampdirection. Byobservingtheconditionoftheswitches  
and the ramp direction, polarity is determined.  
LTC2942 features an automatic mode where a voltage and  
atemperatureconversionareexecutedeverytwoseconds.  
At the end of each conversion the corresponding registers  
are updated and the converter goes to sleep to minimize  
quiescent current.  
CHARGER  
LOAD  
REFHI  
+
CC  
CONTROL  
LOGIC  
+
SENSE  
S1  
1
+
S2  
S3  
M
ACR  
R
SENSE  
PRESCALER  
SENSE  
+
I
6
2
BAT  
S4  
POLARITY  
DETECTION  
+
REFLO  
GND  
BATTERY  
2942 F52  
Figure 2. Coulomb Counter Section of the LTC2942  
2942f  
7
LTC2942  
OPERATION  
Power-Up Sequence  
accumulated charge register is set to mid-scale (7FFFh),  
all low threshold registers are set to 5555h and all high  
threshold registers are set to FFFFh. The alert mode is  
enabled and the coulomb counter pre-scaling factor M  
is set to 128.  
+
When SENSE rises above a threshold of approximately  
2.±, the LTC2942 generates an internal power-on reset  
(POR) signal and sets all registers to their default state.  
In the default state, the coulomb counter is active while  
the voltage and temperature ADC is switched off. The  
APPLICATIONS INFORMATION  
I C/SMBus Interface  
2
The sixteen internal registers are organized as shown in  
Table 1.  
The LTC2942 communicates with a bus master using a  
2
2-wireinterfacecompatiblewithI CandSMBus. The7-bit  
Table 1. Register Map  
2
hard-coded I C address of the LTC2942 is 1100100.  
ADDRESS NAME REGISTER DESCRIPTION  
R/W DEFAULT  
55h  
51h  
52h  
53h  
54h  
5±h  
56h  
57h  
58h  
59h  
5Ah  
5Bh  
5Ch  
5Dh  
5Eh  
5Fh  
A
B
C
D
E
Status  
R
See Below  
3Ch  
7Fh  
The LTC2942 is a slave-only device. Therefore the serial  
clock line (SCL) is an input only while the serial data line  
Control  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R
2
Accumulated Charge MSB  
Accumulated Charge LSB  
Charge Threshold High MSB  
Charge Threshold High LSB  
Charge Threshold Low MSB  
Charge Threshold Low LSB  
ꢀoltage MSB  
(SDA) is bidirectional. The device supports I C standard  
2
FFh  
and fast mode. For more details refer to the I C Protocol  
FFh  
section.  
F
FFh  
Internal Registers  
G
H
I
55h  
55h  
The LTC2942 integrates current through a sense resistor,  
measures battery voltage and temperature and stores the  
XXh  
XXh  
FFh  
2
J
ꢀoltage LSB  
R
results in internal 16-bit registers accessible via I C. High  
K
L
ꢀoltage Threshold High  
ꢀoltage Threshold Low  
Temperature MSB  
R/W  
R/W  
R
and low limits can be programmed for each measurement  
quantity. The LTC2942 continuously monitors these limits  
and sets a flag in the onboard status register when a limit  
is exceeded. If the alert mode is enabled, the AL/CC pin  
pulls low.  
55h  
M
N
O
P
XXh  
XXh  
FFh  
Temperature LSB  
R
Temperature Threshold High  
Temperature Threshold Low  
R/W  
R/W  
55h  
R = Read, W = Write, XX = unknown  
2942f  
8
LTC2942  
APPLICATIONS INFORMATION  
Status Register (A)  
The hard-coded bit A[7] of the status register enables the  
host to distinguish the LTC2942 from the pin compatible  
LTC2941, allowing the same software to be used with  
both devices.  
The status of the charge, voltage and temperature alerts  
is reported in the status register shown in Table 2.  
Table 2. Status Register A (Read only)  
Control Register (B)  
BIT NAME  
OPERATION  
DEFAULT  
A[7] Chip Identification  
5: LTC2942  
1: LTC2941  
5
The operation of the LTC2942 is controlled by program-  
ming the control register. Table 3 shows the organization  
of the 8-bit control register B[7:5].  
A[6] Reserved  
5
5
A[±] Accumulated Charge Indicates that the value of the  
Overflow/Underflow ACR hit either top or bottom.  
Table 3. Control Register B  
A[4] Temperature Alert  
A[3] Charge Alert High  
A[2] Charge Alert Low  
A[1] ꢀoltage Alert  
Indicates one of the  
temperature limits was  
exceeded.  
5
5
5
BIT  
NAME  
OPERATION  
Default  
B[7:6] ADC Mode  
[11] Automatic Mode.  
[55]  
Performs voltage and temperature  
conversion every second.  
[15] Manual ꢀoltage Mode.  
Performs single voltage  
conversion, then sleeps.  
[51] Manual Temperature Mode.  
Performs single temperature  
conversion, then sleeps.  
Indicates that the ACR value  
exceeded the charge threshold  
high limit.  
Indicates that the ACR value  
dropped below the charge  
threshold low limit.  
Indicates one of the battery  
voltage limits was exceeded.  
5
[55] Sleep.  
A[5] Undervoltage  
Lockout Alert  
Indicates recovery from  
undervoltage. If set to 1, a  
UꢀLO has occurred and the  
contents of the registers are  
uncertain.  
X
B[±:3] Prescaler M  
Sets coulomb counter prescaling  
factor M between 1 and 128.  
[111]  
[15]  
Default is 128.  
(4 • B[±] + 2 • B[4] + B[3])  
M = 2  
B[2:1] AL/CC Configure Configures the AL/CC pin.  
All status register bits except A[7] are cleared after being  
read by the host, if the conditions which set these bits  
have been removed.  
[15] Alert Mode.  
Alert functionality enabled.  
Pin becomes logic output.  
[51] Charge Complete Mode.  
Pin becomes logic input and  
accepts “charge complete” signal  
(e.g., from a charger) to set  
accumulated charge register (C,D)  
to FFFFh.  
As soon as one of the three measured quantities exceeds  
the programmed limits, the corresponding bit A[4], A[3],  
A[2] or A[1] in the status register is set.  
[55] AL/CC pin disabled.  
[11] Not allowed.  
BitA]issetiftheLTC2942’saccumulatedchargeregisters  
(ACR) overflows or underflows. In these cases, the ACR  
stays at FFFFh or 5555h and does not roll over.  
B[5] Shutdown  
Shut down analog section to  
reduce I  
[5]  
.
SUPPLY  
The undervoltage lockout (UꢀLO) bit of the status register  
+
Power Down B[0]  
A[5] is set if, during operation, the voltage on SENSE  
pin drops below 2.7ꢀ without reaching the POR level.  
The analog parts of the coulomb counter are switched off  
while the digital register values are retained. After recov-  
ery of the supply voltage the coulomb counter resumes  
integrating with the stored value in the accumulated  
charge registers but it has missed any charge flowing  
Setting B[5] to 1 shuts down the analog parts of the  
LTC2942, reducing the current consumption to less than  
1μA. All analog circuits are inoperative while the values  
in the registers are retained. Note that any charge flowing  
whileB[5]is1isnotmeasuredandthechargeinformation  
below 1LSB of the accumulated charge register is lost.  
+
while SENSE < 2.7.  
2942f  
9
LTC2942  
APPLICATIONS INFORMATION  
Alert/Charge Complete Configuration B[2:1]  
coulombcounting.Thustheamountofchargerepresented  
bytheleastsignificantbit(q )oftheaccumulatedcharge  
LSB  
The AL/CC pin is a dual function pin configured by the  
control register. By setting bits B[2:1] to [15] (default)  
the AL/CC pin is configured as an alert pin following the  
SMBus protocol. In this configuration the AL/CC pin is a  
digital output and is pulled low if one of the three mea-  
sured quantities (charge, voltage, temperature) exceeds  
its high or low threshold or if the value of the accumulated  
chargeregisteroverflowsorunderflows.Analertresponse  
procedure started by the master resets the alert at the  
AL/CC pin. For further information see the Alert Response  
Protocol section.  
(registers C, D) is equal to:  
50mΩ  
RSENSE 128  
M
qLSB =0.085mAh•  
or  
50mΩ  
RSENSE  
qLSB =0.085mAh•  
when the prescaler is set to its default value of M = 128.  
Note that 1mAh = 3.6C (coulomb).  
SettingthecontrolbitsB[2:1]to[51]configurestheAL/CC  
pin as a digital input. In this mode, a high input on the  
AL/CC pin communicates to the LTC2942 that the battery  
is full and the accumulated charge register is set to its  
maximum value FFFFh. The AL/CC pin would typically  
be connected to the “charge complete” output from the  
battery charger circuitry.  
Choosing R  
= ±5mꢀ/I  
is not sufficient in ap-  
MAX  
SENSE  
plications where the battery capacity (Q ) is very large  
BAT  
compared to the maximum current (I  
):  
MAX  
Q
BAT  
> I  
• ±.± Hours  
MAX  
For such low current applications with a large battery,  
choosing R  
according to R  
smaller than Q /2 and the 16-bit accu-  
= ±5mꢀ/I  
can  
SENSE  
SENSE  
MAX  
16  
lead to a q  
LSB  
BAT  
If neither the alert nor the charge complete functionality  
is desired, bits B[2:1] should be set to [55]. The AL/CC  
pin is then disabled and should be tied to GND.  
mulated charge register may underflow before the battery  
is exhausted or overflow during charge. Choose, in this  
case, a maximum R  
of:  
SENSE  
Avoid setting B[2:1] to [11] as it enables the alert and the  
charge complete modes simultaneously.  
0.085mAh216  
QBAT  
RSENSE  
50mΩ  
Choosing R  
SENSE  
In an example application where the maximum current is  
= 155mA, calculating R = ±5mꢀ/I would  
To achieve the specified precision of the coulomb counter,  
+
I
MAX  
SENSE  
MAX  
thedifferentialvoltagebetweenSENSE andSENSE must  
stay within ±±5m. For differential input signals up to  
±355mꢀ the LTC2942 will remain functional but the preci-  
sion of the coulomb counter is not guaranteed.  
lead to a sense resistor of ±55mΩ. This gives a q  
of  
LSB  
8.±μAhandtheaccumulatedchargeregistercanrepresent  
a maximum battery capacity of Q = 8.±μAh • 6±±3± =  
BAT  
±±7mAh. If the battery capacity is larger, R  
must be  
SENSE  
The required value of the external sense resistor, R  
,
SENSE  
lowered. For example, R  
must be reduced to 1±5mΩ  
SENSE  
is determined by the maximum input range of ꢀ  
the maximum current of the application:  
and  
SENSE  
if a battery with a capacity of 1855mAh is used.  
Choosing Coulomb Counter Prescaler M B[5:3]  
50mV  
IMAX  
RSENSE  
If the battery capacity (Q ) is very small compared to  
BAT  
the maximum current (I  
) (Q  
MAX  
< I  
• 5.1 Hours)  
BAT  
MAX  
The choice of the external sense resistor value influences  
the gain of the coulomb counter. A larger sense resistor  
gives a larger differential voltage between SENSE and  
SENSE forthesamecurrentwhichresultsinmoreprecise  
the prescaler value M should be changed from its default  
value (128).  
+
In these applications with a small battery but a high  
maximum current, q  
can get quite large with respect  
LSB  
2942f  
10  
LTC2942  
APPLICATIONS INFORMATION  
to the battery capacity. For example, if the battery capacity  
is 155mAh and the maximum current is 1A, the standard  
equation leads to choosing a sense resistor value of  
±5mΩ, resulting in:  
The ADC has four different modes of operation as shown  
in Table 3. These modes are controlled by bits B[7:6] of  
the control register. At power-up, bits B[7:6] are set to  
[55] and the ADC is in sleep mode.  
q
= 5.58±mAh = 356mC  
A single voltage conversion is initiated by setting the bits  
B[7:6] to [15]. A single temperature conversion is started  
by setting bits B[7:6] to [51]. After a single voltage or  
temperature conversion, the ADC resets B[7:6] to [55]  
and goes to sleep.  
LSB  
The battery capacity then corresponds to only 1176 q  
and less than 2% of the accumulated charge register is  
utilized.  
s
LSB  
To preserve digital resolution in this case, the LTC2942  
includes a programmable prescaler. Lowering the pres-  
caler factor M allows reducing q  
accumulated charge register to the capacity of the battery.  
The prescaling factor M can be chosen between 1 and its  
default value 128. The charge LSB then becomes:  
The LTC2942 also offers an automatic scan mode where  
the ADC converts voltage, then temperature, then sleeps  
forapproximatelytwosecondsbeforerepeatingthevoltage  
and temperature conversions. The LTC2942 is set to this  
automatic mode by setting B[7:6] to [11] and stays in this  
mode until B[7:6] are reprogrammed by the host.  
to better match the  
LSB  
50mΩ  
RSENSE 128  
M
q
LSB =0.085mAh•  
Programming B[7:6] to [55] puts the ADC to sleep. If  
control bits B[7:6] change within a conversion, the ADC  
will complete the current conversion before entering the  
newly selected mode.  
To use as much of the range of the accumulated charge  
register as possible the prescaler factor M should be  
chosen for a given battery capacity Q  
resistor R  
Aconversionofeithervoltageortemperaturerequires15ms  
conversion time (typical). At the end of each conversion,  
the corresponding registers are updated. If the converted  
quantity exceeds the values programmed in the threshold  
registers, a flag is set in the status register and the AL/CC  
pin is pulled low (if alert mode is enabled).  
and a sense  
BAT  
as:  
SENSE  
RSENSE  
50mΩ  
QBAT  
216 0.085mAh  
M128 •  
Mcanbesetto1, 2, 4, 8, 128byprogrammingB[±:3]of  
(4B]+2•B[4]+B[3])  
During a voltage conversion, the SENSE pin is connected  
thecontrolregisterasM=2  
.Thedefault  
7
through a small resistor to a sampling circuit with an  
value after power up is M = 128 = 2 (B[±:3] = 111).  
equivalent resistance of 2MΩ, leading to a mean input  
In the above example of a 155mAh battery and an R  
SENSE  
current of I = ꢀ  
/2MΩ.  
SENSE  
of ±5mΩ, the prescaler should be programmed to M = 4.  
Theq thenbecomes2.6±6μAhandthebatterycapacity  
LSB  
Accumulated Charge Register (C,D)  
corresponds to roughly 376±5 q s.  
LSB  
The coulomb counter of the LTC2942 integrates current  
through the sense resistor. The result of this charge inte-  
gration is stored in the 16-bit accumulated charge register  
(registers C, D). As the LTC2942 does not know the actual  
batterystatusatpower-up,theaccumulatedchargeregister  
(ACR) is set to mid-scale (7FFFh). If the host knows the  
statusofthebattery,theaccumulatedcharge(C[7:5]D[7:5])  
Note that the internal digital resolution of the coulomb  
counter is higher than indicated by q . The digitized  
LSB  
chargeq  
isM•8timessmallerthanq .q  
is typically 299μAs for a ±5mΩ sense resistor.  
INTERNAL  
LSB INTERNAL  
ADC Mode B[7:6]  
2
can be either programmed to the correct value via I C or  
The LTC2942 features an ADC which measures either  
it can be set after charging to FFFFh (full) by pulling the  
AL/CC pin high if charge complete mode is enabled via  
bits B[2:1]. Before writing the accumulated charge regis-  
voltage on SENSE (battery voltage) or temperature via  
an internal temperature sensor. The reference voltage and  
clock for the ADC are generated internally.  
2942f  
11  
LTC2942  
APPLICATIONS INFORMATION  
ters, the analog section should be shut down by setting  
B[5] to 1. In order to avoid a change in the accumulated  
charge registers between reading MSBs C[7:5] and LSBs  
D[7:5], it is recommended to read them sequentially as  
shown in Figure 15.  
sets the corresponding flag in the status register and  
pulls the AL/CC pin low if alert mode is enabled via bits  
B[2:1]. Note that the voltage and temperature threshold  
registers are single byte registers and only the 8 MSBs of  
the corresponding quantity are checked. To set a low level  
threshold for the battery voltage of 3, register L should  
be programmed to 85h; a high temperature limit of 65°C  
is programmed by setting register O to 8Eh.  
Voltage and Temperature Registers (I, J),(M, N)  
The result of the 14-bit ADC conversion of the voltage at  
SENSE is stored in the voltage registers (I, J), whereas  
2
I C Protocol  
the temperature measurement result is stored in the tem-  
perature registers (M, N). The voltage and temperature  
registers are read only.  
2
TheLTC2942usesanI C/SMBuscompatible2-wireopen-  
drain interface supporting multiple devices and masters  
on a single bus. The connected devices can only pull the  
bus wires low and they never drive the bus high. The bus  
wires must be externally connected to a positive supply  
voltage via a current source or pull-up resistor. When the  
As the ADC resolution is 14-bit in voltage mode and 15-bit  
in temperature mode, the lowest two bits of the combined  
voltage registers (I, J) and the lowest six bits of the  
combined temperature registers (M, N) are always zero.  
From the result of the 16-bit voltage registers I[7:5]J[7:5]  
the measured voltage can be calculated as:  
2
busisidle, bothSDAandSCLarehigh. DataontheI Cbus  
can be transferred at rates of up to 155kbit/s in standard  
mode and up to 455kbit/s in fast mode.  
RESULTDEC  
65535  
RESULTh  
FFFFh  
2
VSENSE =6V •  
=6V •  
Each device on the I C/SMbus is recognized by a unique  
address stored in that device and can operate as either a  
transmitter or receiver, depending on the function of the  
device. In addition to transmitters and receivers, devices  
can also be classified as masters or slaves when perform-  
ing data transfers. A master is the device which initiates a  
data transfer on the bus and generates the clock signals  
to permit that transfer. At the same time any device ad-  
dressed is considered a slave. The LTC2942 always acts  
as a slave.  
Example: a register value of I[7:5] = B5 and J[7:5] = 1C  
h
h
corresponds to a voltage on SENSE of:  
45084DEC  
65535  
B01C  
h =6V •  
FFFFh  
VSENSE =6V •  
4.1276V  
The actual temperature can be obtained from the two byte  
register C[7:5]D[7:5] by:  
Figure 3 shows an overview of the data transmission for  
RESULTDEC  
65535  
RESULTh  
FFFFh  
T = 600K •  
= 600K •  
2
fast and standard mode on the I C bus.  
Start and Stop Conditions  
Example: a register value of C[7:5] = 85 D[7:5] = 55  
h
h
corresponds to 355K or 27°C.  
When the bus is idle, both SCL and SDA must be high. A  
bus master signals the beginning of a transmission with  
a START condition by transitioning SDA from high to low  
while SCL is high. When the master has finished com-  
municating with the slave, it issues a STOP condition by  
transitioning SDA from low to high while SCL is high. The  
bus is then free for another transmission. When the bus is  
in use, it stays busy if a repeated START (Sr) is generated  
instead of a STOP condition. The repeated START (Sr)  
conditions are functionally identical to the START (S).  
2942f  
Threshold Registers (E, F, G, H, K, L, O, P)  
For each of the measured quantities (battery charge, volt-  
age and temperature) the LTC2942 features a high and a  
low threshold registers. At power-up, the high thresholds  
are set to FFFFh while the low thresholds are set to 5555h.  
All thresholds can be programmed to a desired value via  
2
I C. As soon as a measured quantity exceeds the high  
threshold or falls below the low threshold, the LTC2942  
12  
LTC2942  
APPLICATIONS INFORMATION  
Data Transmission  
the master sends a command byte which indicates which  
internal register the master is to write. The LTC2942 ac-  
knowledgesandlatchesthecommandbyteintoitsinternal  
registeraddresspointer.Themasterdeliversthedatabyte,  
the LTC2942 acknowledges once more and latches the  
data into the desired register. The transmission is ended  
when the master sends a STOP condition. If the master  
continues by sending a second data byte instead of a stop,  
the LTC2942 acknowledges again, increments its address  
pointer and latches the second data byte in the following  
register, as shown in Figure ±.  
2
After a START condition, the I C bus is considered busy  
and data transfer begins between a master and a slave. As  
2
data is transferred over I C in groups of nine bits (eight  
data bits followed by an acknowledge bit), each group  
takes nine SCL cycles. The transmitter releases the SDA  
line during the acknowledge clock pulse and the receiver  
issuesanacknowledge(ACK)bypullingSDAloworleaves  
SDA high to indicate a not acknowledge (NAK) condition.  
Change of data state can only happen while SCL is low.  
Write Protocol  
Read Protocol  
The master begins a write operation with a START condi-  
tion followed by the seven bit slave address 1100100  
and the R/W bit set to zero, as shown in Figure 4. The  
LTC2942 acknowledges this by pulling SDA low and then  
ThemasterbeginsareadoperationwithaSTARTcondition  
followed by the seven bit slave address 1100100 and the  
R/W bit set to zero, as shown in Figure 6. The LTC2942  
SDA  
SCL  
a6 - a5  
b7 - b5  
b7 - b5  
1 - 7  
8
9
1 - 7  
8
9
1 - 7  
8
9
S
P
ADDRESS  
R/W  
ACK  
DATA  
ACK  
DATA  
ACK  
START  
CONDITION  
STOP  
CONDITION  
2942 F53  
Figure 3. Data Transfer Over I2C or SMBus  
S
ADDRESS  
1155155  
W
A
5
REGISTER  
51h  
A
5
DATA  
FCh  
A
5
P
5
2942 F54  
FROM MASTER TO SLAꢀE  
FROM SLAꢀE TO MASTER  
A: ACKNOWLEDGE (LOW)  
A: NOT ACKNOWLEDGE (HIGH)  
S: START CONDITION  
P: STOP CONDITION  
R: READ BIT (HIGH)  
W: WRITE BIT (LOW)  
Figure 4. Writing FCh to the LTC2942 Control Register (B)  
S
ADDRESS  
1155155  
W
A
5
REGISTER  
52h  
A
5
DATA  
F5h  
A
5
DATA  
51h  
A
5
P
S
ADDRESS  
1155155  
W
A
5
REGISTER  
55h  
A
S
ADDRESS  
1155155  
R
1
A
5
DATA  
51h  
A
P
5
5
5
1
2942 F5±  
2942 F56  
Figure 5. Writing F001h to the LTC2942  
Accumulated Charge Register (C, D)  
Figure 6. Reading the LTC2942 Status Register (A)  
S
ADDRESS  
1155155  
W
A
5
REGISTER  
58h  
A
5
S
ADDRESS  
1155155  
R
1
A
5
DATA  
F1h  
A
5
DATA  
24h  
A
P
5
1
2942 F57  
Figure 7. Reading the LTC2942 Voltage Register (I, J)  
2942f  
13  
LTC2942  
APPLICATIONS INFORMATION  
acknowledges and then the master sends a command  
byte which indicates which internal register the master is  
to read. The LTC2942 acknowledges and then latches the  
commandbyteintoitsinternalregisteraddresspointer.The  
master then sends a repeated START condition followed  
by the same seven bit address with the R/W bit now set  
to one. The LTC2942 acknowledges and sends the con-  
tents of the requested register. The transmission is ended  
when the master sends a STOP condition. If the master  
acknowledges the transmitted data byte, the LTC2942  
increments its address pointer and sends the contents of  
the following register as depicted in Figure 7.  
ing a 1 and reads a 5 on the SDA pin on the rising edge of  
SCL, it assumes another device with a lower address is  
sending and the LTC2942 immediately aborts its transfer  
and waits for the next ARA cycle to try again. If transfer  
is successfully completed, the LTC2942 will stop pulling  
down the AL/CC pin and will not respond to further ARA  
requests until a new Alert event occurs.  
PC Board Layout Suggestions  
Keep all traces as short as possible to minimize noise and  
inaccuracy. Use a 4-wire Kelvin sense connection for the  
sense resistor, locating the LTC2942 close to the resistor  
+
with short sense traces to the SENSE and SENSE pins.  
Use wider traces from the resistor to the battery, load  
and/or charger (see Figure 11). Put the bypass capacitor  
Alert Response Protocol  
In a system where several slaves share a common inter-  
rupt line, the master can use the alert response address  
(ARA) to determine which device initiated the interrupt  
(Figure 8).  
+
close to SENSE and GND.  
TO  
R
SENSE  
TO BATTERY  
CHARGER/LOAD  
The master initiates the ARA procedure with a START con-  
dition and the special 7-bit ARA bus address (0001100)  
followed by the read bit (R) = 1. If the LTC2942 is asserting  
theAL/CCpininalertmode,itacknowledgesandresponds  
by sending its 7-bit bus address (1100100) and a 1. While  
it is sending its address, it monitors the SDA pin to see  
if another device is sending an address at the same time  
6
±
4
1
2
3
LTC2942  
C
2942 F15  
Figure 11. Kelvin Connection on Sense Resistor  
2
using standard I C bus arbitration. If the LTC2942 is send-  
S
ALERT RESPONSE ADDRESS  
5551155  
R
1
A
5
DEꢀICE ADDRESS  
11551551  
A
P
1
2942 F58  
Figure 8. LTC2942 Serial Bus SDA Alert Response Protocol  
15ms  
S ADDRESS W A REGISTER A  
1155155 58h  
S
ADDRESS R A DATA  
1155155  
F1h  
A
5
DATA A  
85h 1  
P
S ADDRESS W A REGISTER A DATA P  
5
5
5
1
5
1155155  
5
5
51h  
5
BC  
2942 F59  
Figure 9. Voltage Conversion Sequence  
S
ADDRESS  
1155155  
W
A
5
REGISTER  
52h  
A
5
S
ADDRESS  
1155155  
R
1
A
5
DATA  
85h  
A
5
DATA  
51h  
A
P
5
1
2942 F15  
Figure 10. Reading the LTC2942 Accumulated Charge Registers (C, D)  
2942f  
14  
LTC2942  
PACKAGE DESCRIPTION  
DCB Package  
6-Lead Plastic DFN (2mm × 3mm)  
(Reference LTC DWG # 5±-58-171±)  
0.70 p0.05  
1.65 p0.05  
3.55 p0.05  
(2 SIDES)  
2.15 p0.05  
PACKAGE  
OUTLINE  
0.25 p 0.05  
0.50 BSC  
1.35 p0.05  
(2 SIDES)  
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS  
R = 0.115  
TYP  
2.00 p0.10  
(2 SIDES)  
0.40 p 0.10  
R = 0.05  
TYP  
4
6
3.00 p0.10 1.65 p 0.10  
(2 SIDES)  
(2 SIDES)  
PIN 1 BAR  
TOP MARK  
(SEE NOTE 6)  
PIN 1 NOTCH  
R0.20 OR 0.25  
s 45o CHAMFER  
(DCB6) DFN 0405  
3
1
0.25 p 0.05  
0.50 BSC  
0.75 p0.05  
0.200 REF  
1.35 p0.10  
(2 SIDES)  
BOTTOM VIEW—EXPOSED PAD  
0.00 – 0.05  
NOTE:  
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (TBD)  
2. DRAWING NOT TO SCALE  
3. ALL DIMENSIONS ARE IN MILLIMETERS  
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE  
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE  
5. EXPOSED PAD SHALL BE SOLDER PLATED  
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE  
TOP AND BOTTOM OF PACKAGE  
2942f  
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.  
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-  
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.  
15  
LTC2942  
TYPICAL APPLICATION  
Single Cell Lithium-Ion Coulomb Counter with Battery Charger for Charge and Discharge Currents of up to 500mA  
±55mA  
4
3
1
IN  
BAT  
LOAD  
5.1μF  
CC  
±ꢀ  
3.3ꢀ  
LTC45±7-4.2  
(CHARGER)  
1
6
1μF  
+
SENSE  
SENSE  
2k 2k 2k  
LTC2942  
AL/CC  
SDA  
SCL  
R
SENSE  
±
±
4
3
DD  
PROG SHDN  
155mΩ  
GND  
μP  
2k  
+
2
1-CELL  
Li-Ion  
GND  
2
2942 TA52  
RELATED PARTS  
PART NUMBER  
DESCRIPTION  
COMMENTS  
Battery Gas Gauges  
2
LTC2942-1  
Battery Gas Gauge with I C Interface and ꢀoltage and 2.7ꢀ to ±.±ꢀ Operation, 14-Bit Δ∑-ADC, Pin Compatible with LTC2941-1  
Temperature ADC; Integrated Sense Resistor  
2
LTC2941  
Battery Gas Gauge with I C Interface  
2.7ꢀ to ±.±ꢀ Operation, Pin Compatible with LTC2942  
2.7ꢀ to ±.±ꢀ Operation, Pin Compatible with LTC2942-1  
2
LTC2941-1  
Battery Gas Gauge with I C Interface and Integrated  
±5mΩ Sense Resistor  
LTC41±5  
Coulomb Counter/Battery Gas Gauge  
2.7ꢀ to 8.±ꢀ Operation, 15-Pin MSOP Package  
Battery Chargers  
LTC1734  
Lithium-Ion Battery Charger in ThinSOT™  
Switch Mode Lithium-Ion Battery Charger  
Monolithic Lithium-Ion Battery Pulse Charger  
USB Compatible Monolithic Li-Ion Battery Charger  
Lithium-Ion Linear Battery Charger  
Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed  
LTC4552  
Standalone, 4.7ꢀ ≤ ꢀ ≤ 24, ±55kHz Frequency  
IN  
LTC45±2  
No Blocking Diode or External Power FET Required, ≤1.±A Charge Current  
Standalone Charger with Programmable Timer, Up to 1.2±A Charge Current  
Up to 855mA Charge Current, Thermal Regulation, ThinSOT Package  
C/15 Charge Termination, Battery Kelvin Sensing, ±7% Charge Accuracy  
LTC45±3  
LTC45±7  
LTC45±8  
Standalone 9±5mA Lithium-Ion Charger in DFN  
955mA Linear Lithium-Ion Battery Charger  
LTC45±9  
2mm × 2mm DFN Package, Thermal Regulation, Charge Current Monitor  
Output  
LTC4561  
Standalone Linear Li-Ion Battery Charger with  
Thermistor Input  
4.2, ±5.3±% Float ꢀoltage, Up to 1A Charge Current, 3mm × 3mm DFN  
Package  
LTC4563  
LTC4588  
Li-Ion Charger with Linear Regulator  
Up to 1A Charge Current, 155mA, 12±mꢀ LDO, 3mm × 3mm DFN Package  
High Efficiency Battery Charger/USB Power Manager  
Maximizes Available Power from USB Port, Bat-Track™, Instant-On Operation,  
1.±A Max Charge Current, 185mΩ Ideal Diode with <±5mΩ Option,  
3.3ꢀ/2±mA Always-On LDO, 4mm × 3mm DFN-14 Package  
ThinSOT and Bat-Track are trademarks of Linear Technology Corporation.  
2942f  
LT 0210 • PRINTED IN USA  
LinearTechnology Corporation  
1635 McCarthy Blvd., Milpitas, CA 9±53±-7417  
16  
© LINEAR TECHNOLOGY CORPORATION 2010  
(458) 432-1955 FAX: (458) 434-5±57 www.linear.com  
配单直通车
LTC2942IDCB-1#PBF产品参数
型号:LTC2942IDCB-1#PBF
Brand Name:Linear Technology
是否Rohs认证: 符合
生命周期:Active
零件包装代码:DFN
包装说明:2 X 3 MM, LEAD FREE, PLASTIC, MO-229TBD, DFN-6
针数:6
制造商包装代码:DCB
Reach Compliance Code:compliant
风险等级:5.65
Base Number Matches:1
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