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Pin description functional diagrams, Detailed description, Input stage circuitry – Rainbow Electronics MAX920 User Manual

Page 9

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MAX917–MAX920

SOT23, 1.8V, Nanopower, Beyond-the-Rails

Comparators With/Without Reference

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9

Pin Description

Functional Diagrams

MAX917
MAX918

IN+

OUT

V

CC

V

EE

REF

REF

1.245V

MAX919
MAX920

IN+

OUT

V

CC

V

EE

IN-

MAX917/MAX918

SO

PIN

SOT23-5

MAX919/MAX920

SOT23-5

SO

N.C.

V

CC

V

EE

IN-

REF

IN+

OUT

1, 5, 8

7

4

2

3

6

5

2

4

3

1

1, 5, 8

No Connection. Not internally connected.

5

7

Positive Supply Voltage

2

4

Negative Supply Voltage

Comparator Inverting Input

4

2

1.245V Reference Output and Comparator Inverting Input

3

3

Comparator Noninverting Input

1

6

Comparator Output

NAME

FUNCTION

Detailed Description

The MAX917/MAX918 feature an on-board 1.245V
±1.5% reference, yet draw an ultra-low supply current
of 750nA. The MAX919/MAX920 (without reference)
consume just 380nA of supply current. All four devices
are guaranteed to operate down to +1.8V. Their com-
mon-mode input voltage range extends 200mV
beyond-the-rails. Internal hysteresis ensures clean out-
put switching, even with slow-moving input signals.
Large internal output drivers allow rail-to-rail output
swing with up to ±8mA loads.

The output stage employs a unique design that mini-
mizes supply-current surges while switching, virtually
eliminating the supply glitches typical of many other
comparators. The MAX917/MAX919 have a push/pull

output stage that sinks as well as sources current. The
MAX918/MAX920 have an open-drain output stage that
can be pulled beyond V

CC

to an absolute maximum of

6V above V

EE

. These open-drain versions are ideal for

implementing wire-Or output logic functions.

Input Stage Circuitry

The input common-mode voltage range extends from
V

EE

- 0.2V to V

CC

+ 0.2V. These comparators operate

at any differential input voltage within these limits. Input
bias current is typically ±0.15nA if the input voltage is
between the supply rails. Comparator inputs are pro-
tected from overvoltage by internal ESD protection
diodes connected to the supply rails. As the input volt-
age exceeds the supply rails, these ESD protection
diodes become forward biased and begin to conduct.