_______________Detailed Description

The MAX951–MAX954 are combinations of a micropow-

er op amp, comparator, and reference in an 8-pin pack-

age, as shown in Figure 1. In the MAX951/MAX952, the

comparator’s negative input is connected to a 1.20V

±2% bandgap reference. All four devices are optimized

to operate from a single supply. Supply current is less

than 10µA (7µA typical) for the MAX951/MAX952 and

less than 8µA (5µA typical) for the MAX953/MAX954.

Op Amp

The op amps in the MAX951/MAX953 are internally

compensated to be unity-gain stable, while the op

amps in the MAX952/MAX954 feature 125kHz typical

gain bandwidth, 66V/ms slew rate, and stability for

gains of 10V/V or greater. All these op amps feature

high-impedance differential inputs and a common-

mode input voltage range that extends from the nega-

tive supply rail to within 1.6V of the positive rail. They

have a CMOS output stage that swings rail to rail and is

driven by a proprietary high gain stage, which enables

them to operate with an ultra-low supply current while

maintaining linearity under loaded conditions. Careful

design results in good DC characteristics over their

entire operating temperature range, minimizing input

referred errors.

Comparator

The comparator in the MAX951–MAX954 has a high-

impedance differential input stage with a common-

mode input voltage range that extends from the

negative supply rail to within 1.6V of the positive rail.

Their CMOS output stage swings rail to rail and can

Ultra-Low-Power, Single-Supply

Op Amp + Comparator + Reference

8

_______________________________________________________________________________________

______________________________________________________________Pin Description

COMPIN-

6

—

COMPOUT

7

7

8

8

AMPIN+

3

3

4

4

COMPIN+

5

5

REF

—

6

AMPIN-

2

2

AMPOUT

1

1

NAME

MAX953

MAX954

MAX951

MAX952

PIN

Inverting Comparator Input

Comparator Output

Positive Supply

Noninverting Op-Amp Input

Negative Supply or Ground

Noninverting Comparator Input

1.200V Reference Output. Also connected to inverting comparator input.

Inverting Op-Amp Input

Op-Amp Output

FUNCTION

Figure 1. MAX951–MAX954 Functional Diagrams

MAX951

MAX952

4

8

COMPOUT

7

x1

REF

6

COMPIN+

5

1.20V

3

AMPIN+

2

AMPIN-

1

AMPOUT

OP AMP

COMP

MAX953

MAX954

4

8

COMPOUT

7

COMPIN-

6

COMPIN+

5

3

AMPIN+

2

AMPIN-

1

AMPOUT

OP AMP

COMP