1.8V to 28V Input, PWM Step-Up
Controllers in µMAX
MAX668/MAX669
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..........................................................-0.3V to +30V
PGND to GND....................................................................±0.3V
SYNC/SHDN to GND .............................................-0.3V to +30V
EXT, REF to GND.....................................-0.3V to (V
LDO
+ 0.3V)
LDO, FREQ, FB, CS+ to GND ................................ -0.3V to +6V
LDO Output Current...........................................-1mA to +20mA
REF Output Current..............................................-1mA to +1mA
LDO Short Circuit to GND .........................................Momentary
REF Short Circuit to GND ..........................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ............444mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering,10sec) ..............................+300°C
Soldering Temperature (Reflow) ......................................+300°C
Lead(Pb)-Free Packages..............................................+260°C
Packages Containing Lead(Pb)....................................+240°C
ELECTRICAL CHARACTERISTICS
(V
CC
= V
LDO
= +5V, R
OSC
= 200kΩ, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
PWM Controller
PWM CONTROLLER
Input Voltage Range, V
CC
Input Voltage Range with V
CC
Tied to LDO
FB Threshold
FB Threshold Load Regulation
Typically 0.013% per mV on CS+;
V
CS
+ range is 0 to 100mV for 0 to full
load current.
Typically 0.012% per % duty factor on
EXT; EXT duty factor for a step-up is:
100% (1 – V
IN
/V
OUT
)
V
FB
= 1.30V
85
5
CS+ forced to GND
V
FB
= 1.30V, V
CC
= 3V to 28V
SYNC/SHDN = GND, V
CC
= 28V
5V
≤
V
CC
≤
28V
(includes LDO dropout)
3V
≤
V
CC
≤
28V
(includes LDO dropout)
MAX668
MAX669
3
1.8
2.7
1.225
1.250
0.013
28
28
5.5
1.275
V
V
V
%/mV
CONDITIONS
MIN
TYP
MAX
UNITS
FB Threshold Line Regulation
FB Input Current
Current Limit Threshold
Idle Mode Current-Sense Threshold
CS+ Input Current
V
CC
Supply Current (Note 1)
Shutdown Supply Current (V
CC
)
REFERENCE AND LDO REGULATORS
Reference and LDO Regulators
0.012
1
100
15
0.2
220
3.5
20
115
25
1
350
6
%/%
nA
mV
mV
µA
µA
µA
4.50
2.65
2.40
1.225
1.0
225
425
85
5.00
5.50
V
5.50
LDO Output Voltage
LDO load =
∞
to 400Ω
Undervoltage Lockout Threshold
REF Output Voltage
REF Load Regulation
REF Undervoltage Lockout Threshold
OSCILLATOR
Oscillator
Sensed at LDO, falling edge,
hysteresis = 1%, MAX668 only
No load, C
REF
= 0.22µF
REF load = 0 to 50µA
Rising edge, 1% hysteresis
R
OSC
= 200kΩ ±1%
2.50
1.250
-2
1.1
250
500
100
2.60
1.275
-10
1.2
275
575
115
V
V
mV
V
Oscillator Frequency
R
OSC
= 100kΩ ±1%
R
OSC
= 500kΩ ±1%
kHz
2
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