OUT

+

-

V+

V+

GND

2.048 V

GND

INP

INN

HYSTP

HYSTN

LMP7300

SNOSAT7G – AUGUST 2007 – REVISED OCTOBER 2015

www.ti.com

7 Detailed Description

7.1 Overview

The LMP7300 device is a unique combination of micropower and precision. The open collector comparator has

low offset, high CMRR, high PSRR, programmable hysteresis and microamp supply current. The precision 2.048-

V reference provides a DAC or ADC with an accurate binary divisible voltage. The comparator and reference

combination forms an ideal single IC solution for low power sensor or portable applications.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Voltage Reference

The reference output voltage is a band gap derived 2.048 V that is trimmed to achieve typically 0.2% accuracy

over the full operating temperature range of

−40°C to 125°C. The trim procedure employs a curvature correction

algorithm to compensate for the base emitter thermal nonlinearity inherent in band gap design topologies. The

reference accuracy and the set resistor tolerance determine the magnitude and precision of the programmable

hysteresis. In situations where reference noise filtering is required, TI recommends a 5-µF capacitor in series

with a 190-

Ω resistor to ground.

7.3.2 Comparator

7.3.2.1 Output Stage

The comparator employs an open collector output stage that can switch microamp loads for micropower

precision threshold detection to applications requiring activating a solenoid, a lamp, or an LED. The wired-OR

type output easily interfaces to TTL, CMOS, or multiple outputs, as in a window comparator application, over a

range of 0.5 V to 12 V. The output is capable of driving greater than 10-mA output current and yet maintaining a

saturation voltage less than 0.4 V over temperature. The supply current increases linearly when driving heavy

loads, so TI recommends a pullup resistor of 100 k

Ω or greater for micropower applications.

7.3.2.2 Fault Detection Rate

The user’s choice of a pullup resistor and capacitive load determines the minimum response time and the event

detection rate. By optimizing overdrive, the pullup resistor and capactive load fault update rates of 200 kHz to

250 kHz or greater can be achieved.

10

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