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产品型号MAX931CSA的概述

MAX931CSA芯片概述 MAX931CSA是一款集成化的高性能电压比较器，属于Maxim Integrated公司生产的系列产品。此芯片因其灵活的输入范围、快速的响应时间和低功耗特性，广泛应用于各类电子设备和电路设计中。MAX931CSA 的设计初衷是满足高精度和高速度的信号处理需求，适合于速度敏感型应用。 MAX931CSA的详细参数 MAX931CSA的核心参数包括： - 工作电压范围：通常为2.5V到6V，适用于多种供电场景。 - 输入偏置电流：最大值为5nA，这意味着在应用中，输入信号的影响最小化，提高了系统的精度。 - 响应时间：典型值为10ns，适合高速信号检测。 - 增益带宽产品：在最小配置下，增益带宽约为10MHz，这为其在高频应用中提供了足够的性能。 - 功耗：工作时的功耗相对较低，典型功耗为1.6mA，减少了能源消耗，延长了电池寿命。此外，MAX931CSA具...

产品型号MAX931CSA的Datasheet PDF文件预览

19-0194; Rev 1; 2/97

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

1-MAX934

_______________Ge n e ra l De s c rip t io n

____________________________Fe a t u re s

The MAX931-MAX934 single, dual, and quad micropower,

low-voltage comparators plus an on-board 2% accurate

reference feature the lowest power consumption available.

These comparators draw less than 4µA supply current

ove r te mp e ra ture (MAX931), a nd inc lud e a n inte rna l

1.182V ±2% voltage reference, programmable hysteresis,

and TTL/CMOS outputs that sink and source current.

♦ Ultra-Low 4µA Max Quiescent Current

Over Extended Temp. Range (MAX931)

♦ Power Supplies:

Single +2.5V to +11V

Dual ±1.25V to ±5.5V

♦ Input Voltage Range Includes Negative Supply

♦ Internal 1.182V ±2% Bandgap Reference

♦ Adjustable Hysteresis

Id e a l for 3V or 5V s ing le -s up p ly a p p lic a tions , the

MAX931-MAX934 operate from a single +2.5V to +11V

s up p ly (or a ± 1.25V to ± 5V d ua l s up p ly), a nd e a c h

c omp a ra tor’s inp ut volta g e ra ng e e xte nd s from the

negative supply rail to within 1.3V of the positive supply.

♦ TTL-/CMOS-Compatible Outputs

♦ 12µs Propagation Delay (10mV Overdrive)

♦ No Switching Crowbar Current

The MAX931-MAX934’s unique output stage continuously

sources as much as 40mA. And by eliminating power-

supply glitches that commonly occur when comparators

c ha ng e log ic s ta te s , the MAX931-MAX934 minimize

parasitic feedback, which makes them easier to use.

♦ 40mA Continuous Source Current

♦ Available in Space-Saving µMAX Package

The single MAX931 and dual MAX932/MAX933 provide a

unique and simple method for adding hysteresis without

feedback and complicated equations, using the HYST pin

and two resistors.

______________Ord e rin g In fo rm a t io n

PART

TEMP. RANGE

0°C to +70°C

-40°C to +85°C

PIN-PACKAGE

8 Plastic DIP

8 SO

MAX931CPA

MAX931CSA

MAX931CUA

MAX931EPA

MAX931ESA

For applications that require increased precision with

similar power requirements, see the MAX921-MAX924 data

sheet. These devices include a 1% precision reference.

8 µMAX

8 Plastic DIP

8 SO

INTERNAL COMPARATORS

INTERNAL

HYSTERESIS

PACK-

AGE

Ordering Information continued on last page.

PART

PER

For similar devices guaranteed over the military temp. range, see

the MAX921-MAX924 data sheet. The MAX931, MAX933, and

MAX934 are pin-compatible with the 1% accurate MAX921,

MAX923, and MAX924, respectively. The MAX932 and

MAX922 are not pin-compatible.

REFERENCE

PACKAGE

8-Pin

DIP/SO/

µMAX

MAX931

MAX932

Yes

8-Pin

DIP/SO/

µMAX

__________Typ ic a l Op e ra t in g Circ u it

8-Pin

DIP/SO/

µMAX

MAX933

MAX934

Yes

V+

IN+

16-Pin

DIP/SO

OUT

IN-

________________________Ap p lic a t io n s

Battery-Powered Systems

Threshold Detectors

HYST

REF

MAX931

Window Comparators

V-

GND

Oscillator Circuits

Alarm Circuits

THRESHOLD DETECTOR

________________________________________________________________ Maxim Integrated Products

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

ABSOLUTE MAXIMUM RATINGS

V+ to V-, V+ to GND, GND to V-................................-0.3V, +12V

Inputs

Continuous Power Dissipation (T = +70°C)

8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ...727mW

Current, IN_+, IN_-, HYST...............................................20mA

Voltage, IN_+, IN_-, HYST................(V+ + 0.3V) to (V- – 0.3V)

Outputs

Current, REF....................................................................20mA

Current, OUT_.................................................................50mA

Voltage, REF ....................................(V+ + 0.3V) to (V- – 0.3V)

Voltage, OUT_ (MAX931/934) .....(V+ + 0.3V) to (GND – 0.3V)

Voltage, OUT_ (MAX932/933)..........(V+ + 0.3V) to (V- – 0.3V)

OUT_ Short-Circuit Duration (V+ ≤ 5.5V) ...............Continuous

8-Pin SO (derate 5.88mW/°C above +70°C)................471mW

8-Pin µMAX (derate 4.1mW/°C above +70°C) .............330mW

16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)..842mW

16-Pin SO (derate 8.70mW/°C above +70°C) ................696mW

Operating Temperature Ranges:

MAX93_C_ _ .......................................................0°C to +70°C

MAX93_E_ _.....................................................-40°C to +85°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10sec) .............................+300°C

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional

operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to

absolute maximum rating conditions for extended periods may affect device reliability.

1-MAX934

ELECTRICAL CHARACTERISTICS—5V Operation

(V+ = 5V, V- = GND = 0V, T = T

to T , unless otherwise noted.)

MAX

MIN

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

POWER REQUIREMENTS

Supply Voltage Range

(Note 1)

2.5

= +25°C

2.5

3.1

5.5

3.2

MAX931,

HYST = REF

C/E temp. ranges

= +25°C

4.5

MAX932,

HYST = REF

C/E temp. ranges

= +25°C

Supply Current

IN+ = IN- + 100mV

µA

4.5

MAX933,

HYST = REF

C/E temp. ranges

= +25°C

6.5

8.5

MAX934

C/E temp. ranges

COMPARATOR

Input Offset Voltage

= 2.5V

±10

±5

Input Leakage Current (IN-, IN+)

Input Leakage Current (HYST)

IN+ = IN- = 2.5V, C/E temp. ranges

MAX931, MAX932, MAX933

±0.01

±0.02

Input Common-Mode Voltage Range

Common-Mode Rejection Ratio

Power-Supply Rejection Ratio

Voltage Noise

V-

V+ – 1.3

1.0

V- to (V+ – 1.3V)

0.1

mV/V

V+ = 2.5V to 11V

1.0

100Hz to 100kHz

µV

RMS

Hysteresis Input Voltage Range

MAX931, MAX932, MAX933

REF – 0.05

REF

Overdrive = 10mV

Overdrive = 100mV

Response Time

= +25°C, 100pF load

µs

_______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

1-MAX934

ELECTRICAL CHARACTERISTICS—5V Operation (continued)

(V+ = 5V, V- = GND = 0V, T = T

to T , unless otherwise noted.)

MAX

MIN

PARAMETER

CONDITIONS

= 17mA

MIN

TYP

MAX UNITS

Output High Voltage

C/E temp. ranges, I

V+ – 0.4

OUT

MAX932,

MAX933

V- + 0.4

GND + 0.4

C/E temp. ranges,

Output Low Voltage

= 1.8mA

OUT

MAX931,

MAX934

XREFERENCE

C temp. range

E temp. range

1.158

1.182

1.206

1.217

Reference Voltage

1.147

= +25°C

Source Current

µA

C/E temp. ranges

= +25°C

Sink Current

C/E temp. ranges

100Hz to 100kHz

Voltage Noise

100

µV

RMS

Note 1: MAX934 comparators work below 2.5V, see Low-Voltage Operation section for more details.

ELECTRICAL CHARACTERISTICS—3V Operation

(V+ = 3V, V- = GND = 0V, T = T

to T , unless otherwise noted.)

MAX

MIN

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

POWER REQUIREMENTS

= +25°C

2.4

3.4

5.2

3.0

3.8

4.3

5.8

4.3

5.8

6.2

8.0

MAX931,

HYST = REF

C/E temp. ranges

= +25°C

MAX932,

HYST = REF

C/E temp. ranges

= +25°C

Supply Current

IN+ = (IN- + 100mV)

µA

MAX933,

HYST = REF

C/E temp. ranges

= +25°C

MAX934

C/E temp. ranges

COMPARATOR

Input Offset Voltage

= 1.5V

±10

±1

Input Leakage Current (IN-, IN+)

Input Leakage Current (HYST)

IN+ = IN- = 1.5V, C/E temp. ranges

MAX931, MAX932, MAX933

±0.01

±0.02

_______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

ELECTRICAL CHARACTERISTICS—3V Operation (continued)

(V+ = 3V, V- = GND = 0V, T = T

to T , unless otherwise noted.)

MAX

MIN

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Input Common-Mode Voltage Range

Common-Mode Rejection Ratio

Power-Supply Rejection Ratio

Voltage Noise

V-

V+ – 1.3

V- to (V+ – 1.3V)

V+ = 2.5V to 11V

100Hz to 100kHz

0.2

0.1

mV/V

µV

RMS

Hysteresis Input Voltage Range

MAX931, MAX932, MAX933

REF – 0.05

V+ – 0.4

REF

Overdrive = 10mV

Overdrive = 100mV

Response Time

= +25°C, 100pF load

µs

Output High Voltage

C/E temp. ranges, I

= 10mA

OUT

MAX932,

MAX933

V- + 0.4

1-MAX934

Output Low Voltage

C/E temp. ranges, I

= 0.8mA

OUT

MAX931

GND + 0.4

REFERENCE

C temp. range

E temp. range

1.158

1.182

1.206

1.217

Reference Voltage

1.147

= +25°C

Source Current

µA

C/E temp. ranges

= +25°C

Sink Current

C/E temp. ranges

100Hz to 100kHz

Voltage Noise

100

µV

RMS

_______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

1-MAX934

__________________________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s

(V+ = 5V, V- = GND, T = +25°C, unless otherwise noted.)

OUTPUT VOLTAGE LOW

vs. LOAD CURRENT

OUTPUT VOLTAGE HIGH vs.

LOAD CURRENT

REFERENCE OUTPUT VOLTAGE vs.

OUTPUT LOAD CURRENT

2.5

2.0

5.0

1.190

V+ = 5V

SINK

V+ = 5V

4.5

4.0

1.185

1.180

V+ = 3V

SOURCE

1.5

1.0

3.5

3.0

2.5

2.0

1.5

1.175

1.170

1.165

1.160

1.155

V+ = 3V

V+ = 5V

0.5

0.0

V+ = 3V

LOAD CURRENT (mA)

OUTPUT LOAD CURRENT (µA)

REFERENCE VOLTAGE

vs. TEMPERATURE

MAX931

MAX932

SUPPLY CURRENT vs. TEMPERATURE

1.22

1.21

4.5

5.0

4.5

IN+ = IN- + 100mV

IN+ = IN- +100mV

4.0

3.5

3.0

EXTENDED TEMP. RANGE

1.20

1.19

4.0

3.5

3.0

2.5

2.0

V+ = 5V, V- = - 5V

COMMERCIAL

TEMP. RANGE

V+ = 5V, V- = 0V

1.18

1.17

V+ = 3V, V- = 0V

1.16

1.15

2.5

2.0

V+ = 3V, V- = 0V

20 60

V+ = 5V, V- = 0V

-20 20

1.14

-60

100

140

-60

-20

100

140

-60 -40 -20

20 40 60 80 100 120 140

TEMPERATURE (°C)

MAX934

MAX933

SUPPLY CURRENT vs.

SUPPLY CURRENT vs. TEMPERATURE

LOW SUPPLY VOLTAGES

5.0

IN+ = (IN- + 100mV)

IN+ = IN- +100mV

4.5

4.0

V+ = 5V, V- = 0V

V+ = 5V, V- = -5V

3.5

3.0

2.5

2.0

0.1

V+ = 5V, V- = 0V

V+ = 3V, V- = 0V

0.01

-60

-20

100

140

-60

-20

100

140

1.0

1.5

2.0

2.5

TEMPERATURE (°C)

SINGLE-SUPPLY VOLTAGE (V)

_______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

____________________________Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )

(V+ = 5V, V- = GND, T = +25°C, unless otherwise noted.)

RESPONSE TIME vs.

LOAD CAPACITANCE

HYSTERESIS CONTROL

TRANSFER FUNCTION

5.0

4.5

100k

OUTPUT HIGH

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

10µF

OHL

NO CHANGE

-20

OLH

-40

-60

OUTPUT LOW

1-MAX934

-80

-V

(mV)

-0.3

-0.1

0.1

0.2

0.3

-0.2

100

IN+ INPUT VOLTAGE (mV)

REF HYST

LOAD CAPACITANCE (nF)

RESPONSE TIME FOR VARIOUS

INPUT OVERDRIVES

RESPONSE TIME FOR VARIOUS

INPUT OVERDRIVES

MAX934 RESPONSE TIME

AT LOW SUPPLY VOLTAGES

100mV

10mV

20mV

100mV

50mV

20mV

50mV

10mV

100

±20mV OVERDRIVE

0.1

±100mV

OVERDRIVE

100

0.01

-2

1.0

1.5

2.0

2.5

-2

RESPONSE TIME (µs)

SINGLE-SUPPLY VOLTAGE (V)

RESPONSE TIME (µs)

SHORT-CIRCUIT SOURCE CURRENT

vs. SUPPLY VOLTAGE

SHORT-CIRCUIT SINK CURRENT

vs. SUPPLY VOLTAGE

MAX934 OUTPUT DRIVE

AT LOW SUPPLY VOLTAGES

200

100

OUT CONNECTED TO V+

GND CONNECTED TO V-

180

160

140

120

100

OUT CONNECTED TO V-

SOURCE CURRENT INTO 0.75V LOAD

SINK CURRENT AT V

= 0.4V

2.0

OUT

0.1

1.0

2.0

3.0

4.0

5.0

1.0

1.5

2.5

TOTAL SUPPLY VOLTAGE (V)

SINGLE-SUPPLY VOLTAGE (V)

_______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

1-MAX934

____________________________________________________________P in De s c rip t io n s

NAME

FUNCTION

MAX931 MAX932 MAX933

–

GND

OUTA

V-

Ground. Connect to V- for single-supply operation. Output swings from V+ to GND.

–

Comparator A output. Sinks and sources current. Swings from V+ to V-.

Negative supply. Connect to ground for single-supply operation (MAX931).

Noninverting comparator input

–

IN+

INA+

IN-

Noninverting input of comparator A

Inverting comparator input

INB+

INB-

Noninverting input of comparator B

Inverting input of comparator B

Hysteresis input. Connect to REF if not used. Input voltage range is from

HYST

to V

- 50mV.

REF

–

REF

V+

Reference output. 1.182V with respect to V-.

Positive supply

OUT

OUTB

Comparator output. Sinks and sources current. Swings from V+ to GND.

Comparator B output. Sinks and sources current. Swings from V+ to V-.

NAME

FUNCTION

MAX934

OUTB

OUTA

V+

Comparator B output. Sinks and sources current. Swings from V+ to GND.

Comparator A output. Sinks and sources current. Swings from V+ to GND.

Positive supply

INA-

INA+

INB-

INB+

REF

Inverting input of comparator A

Noninverting input of comparator A

Inverting input of comparator B

Noninverting input of comparator B

Reference output. 1.182V with respect to V-.

Negative supply. Connect to ground for single-supply operation.

Inverting input of comparator C

V-

INC-

INC+

IND-

IND+

GND

OUTD

OUTC

Noninverting input of comparator C

Inverting input of comparator D

Noninverting input of comparator D

Ground. Connect to V- for single-supply operation.

Comparator D output. Sinks and sources current. Swings from V+ to GND.

Comparator C output. Sinks and sources current. Swings from V+ to GND.

_______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

a s e p a ra te g round for the outp ut d rive r, a llowing

_______________De t a ile d De s c rip t io n

operation with dual supplies ranging from ±1.25V to

± 5.5V. Conne c t V- to GND whe n op e ra ting the

MAX931 and the MAX934 from a single supply. The

maximum supply voltage in this case is still 11V.

The MAX931-MAX934 comprise various combinations

of a micropower 1.182V reference and a micropower

comparator. The Typical Operating Circuit shows the

MAX931 configuration, and Figures 1a-1c show the

MAX932/MAX933/MAX934 configurations.

For proper comparator operation, the input signal can

be driven from the negative supply (V-) to within one

volt of the positive supply (V+ - 1V). The guaranteed

c ommon-mod e inp ut volta g e ra ng e e xte nd s from

V- to (V+ - 1.3V). The inputs can be taken above and

below the supply rails by up to 300mV without damage.

Each comparator continuously sources up to 40mA, and

the unique output stage eliminates crowbar glitches

during output transitions. This makes them immune to

parasitic feedback (which can cause instability) and

provides excellent performance, even when circuit-

board layout is not optimal.

Operating the MAX931 and MAX934 at ±5V provides

TTL/CMOS compatibility when monitoring bipolar input

signals. TTL compatibility for the MAX932 and MAX933

is achieved by operation from a single +5V supply.

Internal hysteresis in the MAX931/MAX932/MAX933

p rovid e s the e a s ie s t me thod for imp le me nting

hysteresis. It also produces faster hysteresis action

and consumes much less current than circuits using

external positive feedback.

1-MAX934

Lo w -Vo lt a g e Op e ra t io n : V+ = 1 V

(MAX9 3 4 On ly)

P o w e r-S u p p ly a n d In p u t S ig n a l Ra n g e s

This family of devices operates from a single +2.5V to

+11V power supply. The MAX931 and MAX934 have

The guaranteed minimum operating voltage is 2.5V (or

±1.25V). As the total supply voltage is reduced below

2.5V, the p e rforma nc e d e g ra d e s a nd the s up p ly

MAX932

OUTB

V+

OUTA

V-

MAX934

OUTB

OUTA

OUTC

OUTD

REF

INA+

INB+

HYST

V+

GND 14

V-

INA-

INA+

IND+

Figure 1a. MAX932 Functional Diagram

IND-

MAX933

OUTB

V+

OUTA

INC+

INB-

INB+

REF

V-

INC-

REF

INA+

INB-

V-

HYST

V-

Figure 1c. MAX934 Functional Diagram

Figure 1b. MAX933 Functional Diagram

_______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

1-MAX934

current falls. The reference will not function below

As the inp ut volta g e a p p roa c he s the c omp a ra tor's

offset, the output begins to bounce back and forth; this

about 2.2V, although the comparators will continue to

operate with a total supply voltage as low as 1V. While

the MAX934 has comparators that may be used at

supply voltages below 2V, the MAX931, MAX932, and

MAX933 ma y not b e us e d with s up p ly volta g e s

significantly below 2.5V.

peaks when

= V_OS. (The lowpass filter shown on

the g ra p h a ve ra g e s out the b ounc ing , ma king the

transfer function easy to observe.) Consequently, the

comparator has an effective wideband peak-to-peak

nois e of a round 0.3mV. The volta g e re fe re nc e ha s

peak-to peak noise approaching 1mV. Thus, when a

comparator is used with the reference, the combined

peak-to-peak noise is about 1mV. This, of course, is

muc h hig he r tha n the RMS nois e of the ind ivid ua l

components. Care should be taken in the layout to

a void c a p a c itive c oup ling from a ny outp ut to the

reference pin. Crosstalk can significantly increase the

actual noise of the reference.

At low supply voltages, the comparators’ output drive is

reduced and the propagation delay increases (see

Typical Operating Characteristics ). The useful input

voltage range extends from the negative supply to a

little und e r 1V b e low the p os itive s up p ly, whic h is

s lig htly c los e r to the p os itive ra il tha n the d e vic e

op e ra ting from hig he r s up p ly volta g e s . Te s t your

prototype over the full temperature and supply-voltage

range if operation below 2.5V is anticipated.

__________Ap p lic a t io n s In fo rm a t io n

Co m p a ra t o r Ou t p u t

With 100mV of overdrive, propagation delay is typically

3µs. The Typical Operating Characteristics show the

propagation delay for various overdrive levels.

Hys t e re s is

Hysteresis increases the comparators’ noise margin by

increasing the upper threshold and decreasing the

lower threshold (see Figure 2).

The MAX931 and MAX934 output swings from V+ to

GND, s o TTL c omp a tib ility is a s s ure d b y us ing a

+5V ±10% supply. The negative supply does not affect

the output swing, and can range from 0V to -5V ±10%.

Hysteresis (MAX931/MAX932/MAX933)

To add hysteresis to the MAX931/MAX932/MAX933,

c onne c t re s is tor R1 b e twe e n REF a nd HYST, a nd

connect resistor R2 between HYST and V- (Figure 3). If

no hysteresis is required, connect HYST to REF. When

hysteresis is added, the upper threshold increases by

the same amount that the lower threshold decreases.

The hysteresis band (the difference between the upper

and lower thresholds, V_HB) is approximately equal to

twice the voltage between REF and HYST. The HYST

input can be adjusted to a maximum voltage of REF

a nd to a minimum volta g e of (REF - 50mV). The

The MAX932 and MAX933 do not have a GND pin, and

their outputs swing from V+ to V-. Connect V- to ground

and V+ to a +5V supply to achieve TTL compatibility.

The MAX931-MAX934’s unique design achieves an

outp ut s ourc e c urre nt of more tha n 40mA a nd a

s ink c urre nt of ove r 5mA, while ke e p ing q uie s c e nt

currents in the microampere range. The output can

source 100mA (at V+ = 5V) for short pulses, as long as

the p a c ka g e 's ma ximum p owe r d is s ip a tion is not

exceeded. The output stage does not generate crowbar

switching currents during transitions, which minimizes

feedback through the supplies and helps ensure stability

without bypassing.

THRESHOLDS

IN+

Vo lt a g e Re fe re n c e

The internal bandgap voltage reference has an output

of 1.182V a b ove V-. Note tha t the REF volta g e is

referenced to V-, not to GND. Its accuracy is ±2% in

the range 0°C to +70°C. The REF output is typically

capable of sourcing 15µA and sinking 8µA. Do not

bypass the REF output. For applications that require a

1% p re c is ion re fe re nc e , s e e the MAX921-MAX924

data sheet.

HYSTERESIS

IN-

BAND

VREF - VHYST

OUT

No is e Co n s id e ra t io n s

Although the comparators have a very high gain, useful

gain is limited by noise. This is shown in the Transfer

Function graph (see Typical Operating Characteristics).

Figure 2. Threshold Hysteresis Band

_______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

maximum difference between REF and HYST (50mV)

will therefore produce a 100mV max hysteresis band.

Use the following equations to determine R1 and R2:

2. Choose the hysteresis voltage (V_HB), the voltage

between the upper and lower thresholds. In this

example, choose V_HB= 50mV.

3. Calculate R1.

R1 =

2 × I

(

)

REF

R1 = R3 ×

V +

1.182 –

0.05

= 10M ×

R2 =

REF

= 100kΩ

Whe re I_REF(the c urre nt s ourc e d b y the re fe re nc e )

s hould not e xc e e d the REF s ourc e c a p a b ility, a nd

s hould b e s ig nific a ntly la rg e r tha n the HYST inp ut

c urre nt. I_REFva lue s b e twe e n 0.1µA a nd 4µA a re

us ua lly a p p rop ria te . If 2.4MΩ is c hos e n for

R2 (I_REF= 0.5µA), the equation for R1 and V_HBcan be

approximated as:

4. Choose the threshold voltage for V_INrising (V_THR). In

this example, choose V_THR= 3V.

5. Calculate R2.

R2 =

THR

1-MAX934

−

R1 R3

REF × R1)

R1 (kΩ) = V (mV)

Whe n hys te re s is is ob ta ine d in this ma nne r for

the MAX932/MAX933, the same hysteresis applies to

both comparators.

−

(1.182 × 100k)

100k 10M

Hysteresis (MAX934)

Hysteresis can be set with two resistors using positive

feedback, as shown in Figure 4. This circuit generally

draws more current than the circuits using the HYST

pin on the MAX931/MAX932/MAX933, and the high

feedback impedance slows hysteresis. The design

procedure is as follows:

= 65.44kΩ

A 1% preferred value is 64.9kΩ.

6. Verify the threshold voltages with these formulas:

rising :

= V

× R1 ×

THR

REF

1. Choose R3. The leakage current of IN+ is under 1nA

(up to +85°C), so the current through R3 can be

around 100nA and still maintain good accuracy.

The current through R3 at the trip point is V_REF/R3,

or 100nA for R3 = 11.8MΩ. 10MΩ is a g ood

practical value.

falling :

R1 × V +

(

−

THR

)

= V

THF

2.5V TO 11V

V+

REF

V+

REF

MAX931

MAX932

MAX933

OUT

V+

V-

MAX934

GND

HYST

V-

REF

Figure 4. External Hysteresis

Figure 3. Programming the HYST Pin

10 ______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

1-MAX934

For example: 2MΩ x 10µF x 4.6 = 92sec. The actual

time will va ry with b oth the le a ka g e c urre nt of the

capacitor and the voltage applied to the circuit.

Bo a rd La yo u t a n d Byp a s s in g

Power-supply bypass capacitors are not needed if the

supply impedance is low, but 100nF bypass capacitors

should be used when the supply impedance is high or

when the supply leads are long. Minimize signal lead

lengths to reduce stray capacitance between the input

and output that might cause instability. Do not bypass

the reference output.

Win d o w De t e c t o r

The MAX933 is id e a l for ma king wind ow d e te c tors

(undervoltage/overvoltage detectors). The schematic

is shown in Figure 6, with component values selected

for a n 4.5V und e rvolta g e thre s hold , a nd a 5.5V

overvoltage threshold. Choose different thresholds by

changing the values of R1, R2, and R3. To prevent

chatter at the output when the supply voltage is close

to a threshold, hysteresis has been added using R4

and R5. OUTA provides an active-low undervoltage

indication, and OUTB gives an active-low overvoltage

indication. ANDing the two outputs provides an active-

high, power-good signal.

_______________Typ ic a l Ap p lic a t io n s

Au t o -Off P o w e r S o u rc e

Figure 5 shows the schematic for a 40mA power supply

tha t ha s a time d a uto p owe r-off func tion. The

comparator output is the switched power-supply output.

With a 10mA load, it typically provides a voltage of

(V_BATT- 0.12V), but draws only 3.5µA quiescent current.

This circuit takes advantage of the four key features of

the MAX931: 2.5µA s up p ly c urre nt, a n inte rna l

reference, hysteresis, and high current output. Using

the component values shown, the three-resistor voltage

divider programs the maximum ±50mV of hysteresis

and sets the IN- voltage at 100mV. This gives an IN+

trip threshold of approximately 50mV for IN+ falling.

The design procedure is as follows:

1. Choose the required hysteresis level and calculate

values for R4 and R5 according to the formulas in

the Hysteresis (MAX931/MAX932/MAX933) section.

In this example, ±5mV of hysteresis has been added

at the comparator input (V_H= V_HB/2). This means

that the hysteresis apparent at V_INwill be larger

because of the input resistor divider.

The RC time constant determines the maximum power-

on time of the OUT pin before power-down occurs.

This period can be approximated by:

2. Select R1. The leakage current into INB- is normally

under 1nA, so the current through R1 should exceed

R x C x 4.6sec

MOMENTARY SWITCH

+5V

V+

UTH

= 5.5V

= 4.5V

OTH

4.5V TO 6.0V

V+

INA+

UNDERVOLTAGE

POWER GOOD

OVERVOLTAGE

OUTA

OUTB

MAX931

IN+

REF

HYST

47k

10k

HYST

IN-

REF

INB-

OUT

1.1M

100k

VBATT -0.15V

10mA

V-

GND

2.4M

MAX933

V-

Figure 6. Window Detector

Figure 5. Auto-off power switch operates on 2.5µA quiescent

current.

______________________________________________________________________________________ 11

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

100nA for the thresholds to be accurate. R1 values

up to about 10MΩ can be used, but values in the

100kΩ to 1MΩ range are usually easier to deal with.

In this example, choose R1 = 294kΩ.

The full-s c a le thre s hold (a ll LEDs on) is g ive n b y

= (R1 + R2)/R1 volts. The other thresholds are at

3/4 full scale, 1/2 full scale, and 1/4 full scale. The

output resistors limit the current into the LEDs.

3. Ca lc ula te R2 + R3. The ove rvolta g e thre s hold

s hould b e 5.5V whe n V_INis ris ing . The d e s ig n

equation is as follows:

Le ve l S h ift e r

Figure 8 shows a circuit to shift from bipolar ±5V inputs

to TTL s ig na ls . The 10kΩ re s is tors p rote c t the

comparator inputs, and do not materially affect the

operation of the circuit.

OTH

R2 + R3 = R1 ×

− 1

+ V

REF

Tw o -S t a g e Lo w -Vo lt a g e De t e c t o r

Fig ure 9 s hows the MAX932 monitoring a n inp ut

5.5

(1.182 + 0.005)

= 294k ×

− 1

volta g e in two s te p s . Whe n V is hig he r tha n the

LOW and FAIL thresholds, outputs are high. Threshold

c a lc ula tions a re s imila r to thos e for the wind ow-

detector application.

= 1.068MΩ

4. Calculate R2. The undervoltage threshold should

be 4.5V when V is falling. The design equation is

1-MAX934

as follows:

− V )

REF

R2 = (R1 + R2 + R3) ×

− R1

UTH

+5V

(1.182 − 0.005)

= (294k + 1.068M) ×

= 62.2kΩ

− 294k

V+

4.5

MAX934

1.182V

Choose R2 = 61.9kΩ (1% standard value).

REF

5. Calculate R3.

V-

R3 = (R2 + R3) − R2

= 1.068M − 61.9k

182k

250k

INA+

INA-

OUTA

= 1.006MΩ

330Ω

Choose R3 = 1MΩ (1% standard value).

INB+

INB-

6. Verify the resistor values. The equations are as

follows, evaluated for the above example.

OUTB

750mV

Overvoltage threshold :

(R1 + R2 + R3)

= (V

+ V ) ×

OTH

REF H

INC+

= 5.474V.

Undervoltage threshold :

OUTC

OUTD

500mV

250mV

10 INC-

(R1 + R2 + R3)

= (V

− V ) ×

UTH

REF H

(R1 + R2)

IND+

250k

= 4.484V,

12 IND-

where the hysteresis voltage V = V

REF

GND

Ba r-Gra p h Le ve l Ga u g e

The high output source capability of the MAX931 series

is useful for driving LEDs. An example of this is the

simple four-stage level detector shown in Figure 7.

Figure 7. Bar-Graph Level Gauge

12 ______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

1-MAX934

+5V

V+

MAX934

10k

INA+

INA-

0 FOR V < 0V

+5V

V+

INA

1 FOR V > 0V

INB

OUTA

OUTB

OUTC

INA+

REF

INPUT VOLTAGE FAIL

INPUT VOLTAGE LOW

INB+

INB-

INB

HYST

INB+

10k

INC+

INC-

INC

MAX932

V-

IND+

IND-

IND

OUTD

REF

N.C.

V-

GND

-5V

Figure 8. Level Shifter: ±5V Input to CMOS Output

Figure 9. Two-Stage Low-Voltage Detector

______________________________________________________________________________________ 13

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

_________________P in Co n fig u ra t io n s

_Ord e rin g In fo rm a t io n (c o n t in u e d )

PART

TEMP. RANGE

0°C to +70°C

-40°C to +85°C

0°C to +70°C

-40°C to +85°C

0°C to +70°C

-40°C to +85°C

PIN-PACKAGE

8 Plastic DIP

8 SO

TOP VIEW

MAX932CPA

MAX932CSA

MAX932CUA

MAX932EPA

MAX932ESA

MAX933CPA

MAX933CSA

MAX933CUA

MAX933EPA

MAX933ESA

MAX934CPE

MAX934CSE

MAX934EPE

MAX934ESE

GND

V-

OUT

V+

8 µMAX

8 Plastic DIP

8 SO

MAX931

REF

IN+

IN-

8 Plastic DIP

8 SO

HYST

DIP/SO/µMAX

8 µMAX

8 Plastic DIP

8 SO

OUTA

V-

OUTB

V+

16 Plastic DIP

16 Narrow SO

16 Plastic DIP

16 Narrow SO

1-MAX934

MAX932

REF

INA+

INB+

HYST

For similar devices guaranteed over the military temp. range, see

the MAX921-MAX924 data sheet. The MAX931, MAX933, and

MAX934 are pin-compatible with the 1% accurate MAX921,

MAX923, and MAX924, respectively. The MAX932 and

MAX922 are not pin-compatible.

DIP/SO/µMAX

OUTA

V-

OUTB

V+

MAX933

REF

INA+

INB-

HYST

DIP/SO/µMAX

OUTB

OUTA

V+

OUTC

OUTD

GND

IND+

IND-

INC+

INC-

V-

INA-

MAX934

INA+

INB-

INB+

REF

DIP/Narrow SO

14 ______________________________________________________________________________________

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

1-MAX934

________________________________________________________P a c k a g e In fo rm a t io n

______________________________________________________________________________________ 15

Ult ra Lo w -P o w e r, Lo w -Co s t

Co m p a ra t o rs w it h 2 % Re fe re n c e

__________________________________________P a c k a g e In fo rm a t io n (c o n t in u e d )

1-MAX934

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

16 __________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 (4 0 8 ) 7 3 7 -7 6 0 0

Printed USA

is a registered trademark of Maxim Integrated Products.

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MAX931CSA产品参数

型号:	MAX931CSA
是否无铅：	含铅
是否Rohs认证：	不符合
生命周期：	Obsolete
零件包装代码：	SOIC
包装说明：	0.150 INCH, MS-012A, SOIC-8
针数：	8
Reach Compliance Code：	not_compliant
ECCN代码：	EAR99
HTS代码：	8542.39.00.01
风险等级：	5
Is Samacsys：	N
模拟集成电路 - 其他类型：	ANALOG CIRCUIT
JESD-30 代码：	R-PDSO-G8
JESD-609代码：	e0
长度：	4.9 mm
湿度敏感等级：	1
功能数量：	1
端子数量：	8
最高工作温度：	70 °C
最低工作温度：
封装主体材料：	PLASTIC/EPOXY
封装代码：	SOP
封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE
峰值回流温度（摄氏度）：	245
认证状态：	Not Qualified
座面最大高度：	1.75 mm
最大供电电压 (Vsup)：	11 V
最小供电电压 (Vsup)：	2.5 V
标称供电电压 (Vsup)：	5 V
表面贴装：	YES
温度等级：	COMMERCIAL
端子面层：	Tin/Lead (Sn/Pb)
端子形式：	GULL WING
端子节距：	1.27 mm
端子位置：	DUAL
处于峰值回流温度下的最长时间：	NOT SPECIFIED
宽度：	3.9 mm
Base Number Matches：	1

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