INVERTERS

+

-

+

-

OUTPUT

GND

VCC

INP

INN

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14

LPV7215

SNOSAI6J – SEPTEMBER 2005 – REVISED AUGUST 2016

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Copyright © 2005–2016, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The LPV7215 is a single-channel comparator with a push-pull output stage. This comparator is optimized for low-

power consumption and single-supply operation with greater than rail-to-rail input operation. The push-pull output

of the LPV7215 supports rail-to-rail output swing and interfaces with TTL/CMOS logic.

7.2 Functional Block Diagram

7.3 Feature Description

Low supply current and fast propagation delay distinguish the LPV7215 from other low-power comparators.

7.3.1 Input Stage

The LPV7215 has rail-to-rail input common-mode voltage range. It can operate at any differential input voltage

within this limit as long as the differential voltage is greater than zero. A differential input of zero volts may result

in oscillation.

The differential input stage of the comparator is a pair of PMOS and NMOS transistors, therefore, no current

flows into the device. The input bias current measured is the leakage current in the MOS transistors and input

protection diodes. This low bias current allows the comparator to interface with a variety of circuitry and devices

with minimal concern about matching the input resistances.

The input to the comparator is protected from excessive voltage by internal ESD diodes connected to both supply

rails. This protects the circuit from both ESD events, as well as signals that significantly exceed the supply

voltages. When this occurs the ESD protection diodes becomes forward-biased and draws current into these

structures, resulting in no input current to the terminals of the comparator. Until this occurs, there is essentially

no input current to the diodes. As a result, placing a large resistor in series with an input that may be exposed to

large voltages, limits the input current but have no other noticeable effect.