Rainbow Electronics MAX977 User Manual

General Description

The MAX975/MAX977 single/dual comparators feature
three different operating modes, and are optimized for
+3V and +5V single-supply applications. The operating
modes are as follows: high speed, high speed with
auto-standby, and low power. Propagation delay is 28ns
in high-speed mode, while supply current is only 250µA.
Supply current is reduced to 3µA in low-power mode.

The auto-standby feature allows the comparator to
automatically change from low-power mode to high­speed mode upon receipt of an input signal. In the
absence of an input signal, the comparator reverts
back to low-power mode after an adjustable timeout
period. The timeout period for the MAX975 to enter
standby is set by a single capacitor. The dual MAX977
features independently adjustable timeout periods for
each comparator using separate capacitors.

The MAX975/MAX977’s inputs have a common-mode
voltage range of -0.2V to (VCC- 1.2V). The differential
input voltage range extends rail to rail. The outputs are
capable of rail-to-rail operation without external pull-up
circuitry, making these devices ideal for interface with
CMOS/TTL logic. All inputs and outputs can tolerate a
continuous short-circuit fault condition to either rail. The
comparator’s internal hysteresis in high-speed mode
ensures clean output switching, even with slow-moving
input signals.

The single MAX975 is available in 8-pin SO and 8-pin
µMAX packages, while the dual MAX977 is available in
14-pin SO and 16-pin QSOP packages.

________________________Applications

Battery-Powered Systems
RF ID Tags
Keyless Entry
Threshold Detectors/Discriminators
3V Systems
IR Receivers
Digital-Line Receivers

____________________________Features

♦ Three Operating Modes:

High Speed
High Speed with Auto-Standby
Low Power

♦ 28ns Propagation Delay (high-speed mode)
♦ 5µA Max Supply Current in Low-Power/

Auto-Standby Modes

♦ +3V/+5V Single-Supply Operation
♦ Rail-to-Rail Outputs
♦ Ground-Sensing Input
♦ Internal Hysteresis (high-speed mode)
♦ Adjustable Timeout Period
♦ µMAX Package (MAX975)

QSOP-16 Package (MAX977)

MAX975/MAX977

Single/Dual, +3V/+5V Dual-Speed

Comparators with Auto-Standby

________________________________________________________________

Maxim Integrated Products

1

Functional Diagram

19-1141; Rev 1; 11/98

PART

MAX975ESA

MAX975EUA
MAX977ESD

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

TEMP. RANGE PIN-PACKAGE

8 SO
8 µMAX
14 SO

Ordering Information

Pin Configurations appear at end of data sheet.

MAX977EEE -40°C to +85°C

16 QSOP

MAX975

V

CC

IN+

LP

OUT

GND

STO

HIGH SPEED

LOW POWER

ENABLE

IN-

STAT

TIMING

CIRCUIT

ENABLE

TRANSITION

MONITOR

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

MAX975/MAX977

Single/Dual, +3V/+5V Dual-Speed
Comparators with Auto-Standby

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +2.7V to +5.25V, specifications are for high-speed mode, TA= -40°C to +85°C, unless otherwise noted. Typical values are at
T

A

= +25°C.) (Note 1)

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.

Supply Voltage (V

CC

)

............................................................+6V

All Other Pins..............................................-0.3V to (V

CC

+ 0.3V)

Duration of Output Short Circuit to GND_ or V

CC

......Continuous

Continuous Power Dissipation (T

A

= +70°C)

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

8-Pin µMAX (derate 4.10mW/°C above +70°C).............330mW

14-Pin SO (derate 8.33mW/°C above +70°C)................667mW

16-Pin QSOP (derate 8.33mW/°C above +70°C)...........667mW

Operating Temperature Range ...........................-40°C to +85°C

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

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

250 500

µA

36

I

CC

Supply Current
Per Comparator

35

dB

77

PSRR

Power-Supply
Rejection Ratio

63 90

V2.7 5.25V

CC

Supply-Voltage
Operating Range

UNITSMIN TYP MAXSYMBOLPARAMETER

High-speed mode

µMAX/QSOP

SO

CONDITIONS

Low-power mode

High-speed mode

Auto-standby/low-power modes

VCM= 1V,

2.7V ≤ VCC≤ 5.25V

Common-Mode
Voltage Range

V

CMR

(Note 2) -0.2 VCC- 1.2 V

High-speed mode, TA= +25°C +0.2 ±2

±3High-speed mode, TA= T

MIN

to T

MAX

±1 ±5

Input Offset Voltage
(Note 3)

VCM= 1V,
VCC= 5V

Auto-standby/
low-power modes,
TA= T

MIN

to T

MAX

mV

SO 0.5 2 4

Input-Referred Hysteresis V

HYS

VCM= 1V, VCC= 5V (Note 4)

µMAX/QSOP 0.3 2 4

mV

I

B

SO -100 -300

High-speed mode

µMAX/QSOP -100 -400Input Bias Current

Auto-standby/low-power modes -5

nA

Input Offset Current I

OS

±20 ±100 nA

Input Capacitance C

IN

3 pF

SO 66 90

High-speed mode

µMAX/QSOP 54

Common-Mode
Rejection Ratio

CMRR

-0.2V ≤ V

CM

≤ VCC- 1.2V

Low-power mode 82

dB

SO

V

OS

POWER SUPPLY

COMPARATOR INPUTS

±1 ±7

µMAX/QSOP

MAX975/MAX977

Single/Dual, +3V/+5V Dual-Speed

Comparators with Auto-Standby

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +2.7V to +5.25V, specifications are for high-speed mode, TA= -40°C to +85°C, unless otherwise noted. Typical values are at
T

A

= +25°C.) (Note 1)

C

LOAD

= 10pF,

VCC= 5V

I

SINK

= 2mA, all modes

High-speed mode,
overdrive = 5mV

Low-power mode,
overdrive = 10mV

I

SOURCE

= 2mA, all modes

CONDITIONS

µs0.82 1.6

ns28 50

t

PD+

Propagation Delay, Low to High
(Note 6)

V0.1 0.4V

OL

OUT_ Output Voltage Low

V0.7xVCCVCC/2V

LPIH

LP Input Voltage High

VVCC- 0.4 VCC- 0.1V

OH

OUT_ Output Voltage High

UNITSMIN TYP MAXSYMBOLPARAMETER

VVCC/ 2 0.3xV

CC

V

LPIL

LP Input Voltage Low

µA

(Note 5)

0.01 ±1I

LPB

LP Input Current

µs10t

LP

LP Fall Time

V

CC

= 3V µA0.15I

STO

STO_ Source Current

VVCC/ 2 0.3 x V

CC

V

CIL

STO_ Input Voltage Low

C

LOAD

= 10pF,

VCC= 5V

High-speed mode,
overdrive = 5mV

Low-power mode,
overdrive = 10mV

µs0.48 1.6

ns28 50

t

PD-

Propagation Delay, High to Low
(Note 6)

C

LOAD

= 10pF ns2t

SKEW

Propagation-Delay Skew (Note 6)

MAX977 only, C

LOAD

= 10pF ns1

∆t

PD

Propagation-Delay Matching

C

LOAD

= 10pF,

VCC= 5.0V

High-speed mode
Low-power mode 1.6

ns

1.6

Rise/Fall Time

I

SOURCE

= 3mA, all modes VV

CC

- 0.4V

SH

STAT_ Output Voltage High

I

SINK

= 400µA, all modes V0.4V

SL

STAT_ Output Voltage Low

DIGITAL INPUTS

DIGITAL OUTPUTS

Note 1: The MAX975EUA is 100% production tested at TA= +25°C; all temperature specifications are guaranteed by design.
Note 2: Inferred by CMRR. Either input can be driven to the absolute maximum limit without false output inversion, as long as the

other input is within the specified common-mode input voltage range.

Note 3: V

OS

is defined as the mean of trip points. The trip points are the extremities of the differential input voltage required to make

the comparator output change state (Figure 1).

Note 4: The difference between the upper and lower trip points is equal to the width of the input-referred hysteresis zone (Figure 1).
Note 5: Guaranteed by design. The LP pin is sensitive to noise. If fall times larger than 10µs are expected, bypass LP to ground

using a 0.1µF capacitor.

Note 6: Propagation delay is guaranteed by design. For low-overdrive conditions, V

OS

is added to the overdrive. The following

equation defines propagation-delay skew: t

SKEW

= t

PD+

- t

PD-.

MAX975/MAX977

Single/Dual, +3V/+5V Dual-Speed
Comparators with Auto-Standby

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +2.7V to +5.25V, specifications are for high-speed mode, TA= -40°C to +85°C, unless otherwise noted. Typical values are at
T

A

= +25°C.) (Note 1)

CONDITIONS

(Note 9)
10mV overdrive (Note 10)

µs

(Note 8)

3

t

ASB

Auto-Standby Timeout

t

ASBE

UNITSMIN TYP MAXSYMBOLPARAMETER

Auto-Standby Enable Time

µs24t

ASD

Auto-Standby Wake-Up Time

10mV overdrive (Note 11)

(Note 12)

µs1.6t

PWD

Auto-Standby Wake-Up Input
or LP Pulse Width

µs0.8t

ASCD

Auto-Standby Comparator
Disable

(Note 13) µs3t

LPE

Low-Power Enable Time

(Note 14) µs1.1 4t

HSE

High-Speed Enable Time

(Note 15) µs0.7t

LPCD

Low-Power Comparator Disable

(Note 16) ns20t

LPSH

Low-Power STAT_ High

AUTO-STANDBY/LOW-POWER TIMING (Note 7; Figure 2)

Note 7: Timing specifications are guaranteed by design.
Note 8: Set by 1000pF external capacitor at the STO_ pin. t

ASB

is defined as the time from last input transition to STAT_ = high.

Does not include time to go into standby condition (t

ASBE)

.

Note 9: t

ASBE

is defined as the time from when STAT_ goes high to when the supply current drops to 5µA.

Note 10: t

ASD

is defined as the time from the last input transition to when STAT_ goes low. The comparator is in high-speed mode

before STAT_ is low.

Note 11: t

PWD

is defined as the minimum input or LP pulse width to trigger fast-mode operation from auto-standby.

Note 12: t

ASCD

is defined as the time from the last input transition to when the supply current increases to 300µA.

Note 13: t

LPE

is defined as the time from when LP is driven high to when the supply current drops to 5µA.

Note 14: t

HSE

is defined as the time from when LP goes low to when STAT goes low. The comparator is in high-speed mode before

STAT_ is low.

Note 15: t

LPCD

is defined as the time from when LP goes low to when the supply current increases to 300µA.

Note 16: t

LPSH

is defined as the time from when LP goes high to when STAT_ goes high.

ms51016

MAX975/MAX977

Single/Dual, +3V/+5V Dual-Speed

Comparators with Auto-Standby

_______________________________________________________________________________________

5

-1.20

-1.15

-1.10

-1.05

-1.00

-0.95

-0.90

-0.85

-0.80

-0.75

-0.70

-0.65

-0.60

-60 -40 -20 0 20 40 60 80 100

LOW-POWER OFFSET VOLTAGE

vs. TEMPERATURE

MAX977-01

TEMPERATURE (°C)

OFFSET VOLTAGE (mV)

VCC = 3V

1

0.01k 10k1k0.1k 100k 1M 10M 100M

SUPPLY CURRENT PER COMPARATOR

vs. OUTPUT TRANSITION FREQUENCY

10

MAX977-02

TRANSITION FREQUENCY (kHz)

SUPPLY CURRENT

PER COMPARATOR (µA)

100

1000

10000

HIGH-SPEED MODE

LOW-POWER MODE

-170

-150

-130

-110

-90

-70

-50

-60 -40 -20 0 20 40 60 80 100

HIGH-SPEED INPUT BIAS CURRENT

vs. TEMPERATURE

MAX977-03

TEMPERATURE (°C)

INPUT BIAS CURRENT (nA)

VCC = 3V

VCC = 5V

7.0

6.5

6.0

5.5

5.0

4.5

4.0

3.0

3.5

-60 -40 -20 0 20 40 60 80 100

LOW-POWER INPUT BIAS CURRENT

vs. TEMPERATURE

MAX977-04

TEMPERATURE (°C)

INPUT BIAS CURRENT (nA)

VCC = 3V

VCC = 5V

200

250

300

350

400

450

500

550

600

0 50 100 150 200 250

LOW-POWER PROPAGATION DELAY

vs. CAPACITIVE LOAD

MAX977-07

CAPACITIVE LOAD (pF)

PROPAGATION DELAY (ns)

VCC = 3V

VCC = 3V

VCC = 5V

VCC = 5V

t

PD-

50mV OVERDRIVE

tPD+

-1.0

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1.0

-60 -40 -20 0 20 40 60 80 100

HIGH-SPEED VOLTAGE TRIP POINTS/INPUT

OFFSET VOLTAGE vs. TEMPERATURE

MAX977-05

TEMPERATURE (°C)

TRIP POINTS/OFFSET VOLTAGE (mV)

VCC = 5V

V

TRIP+

V

TRIP-

V

OS

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1.0

1.2

-60 -40 -20 0 20 40 60 80 100

HIGH-SPEED VOLTAGE TRIP POINTS/INPUT

OFFSET VOLTAGE vs. TEMPERATURE

MAX977-06

TEMPERATURE (°C)

TRIP POINTS/OFFSET VOLTAGE (mV)

V

TRIP-

V

OS

V

TRIP+

VCC = 3V

200
150

250

300

350

400

450

500

550

600

650

700

0 40 80 120 160 240200

LOW-POWER PROPAGATION DELAY

vs. INPUT OVERDRIVE

MAX977-08

INPUT OVERDRIVE (mV)

PROPAGATION DELAY (ns)

VCC = 3V

VCC = 3V

VCC = 5V

VCC = 5V

C

LOAD

=15pF

t

PD-

t

PD+

10.2

10.1

10.0

9.9

9.8

9.7

9.6

9.5

9.4

9.3

-60 -40 -20 0 20 40 60 80 100

AUTO-STANDBY TIMEOUT

vs. TEMPERATURE

MAX977-09

TEMPERATURE (°C)

TIMEOUT (ms)

VCC = 3V

VCC = 5V

__________________________________________Typical Operating Characteristics

(VCC= 3.0V, TA = +25°C, unless otherwise noted.)