90E21 datasheet(11/57 Pages) IDT

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90E21/22/23/24

SINGLE-PHASE HIGH-PERFORMANCE WIDE-SPAN ENERGY METERING IC

Pin Description

January 10, 2012

OSCI

LVTTL

OSCI: External Crystal Input

An 8.192 MHz crystal is connected between OSCI and OSCO. There is an on-chip 10pF

capacitor, therefore no need of external capacitors.

OSCO

LVTTL

OSCO: External Crystal Output

An 8.192 MHz crystal is connected between OSCI and OSCO. There is an on-chip 10pF

capacitor, therefore no need of external capacitors.

CF1

CF2

LVTTL

CF1: Active Energy Pulse Output

CF2: Reactive Energy Pulse Output

These pins output active/reactive energy pulses.

Note: CF2 is dedicated for the 90E22/24. It should be left open for the 90E21/23.

LVTTL

ZX: Voltage Zero-Crossing Output

This pin is asserted when voltage crosses zero. Zero-crossing mode can be configured to

positive zero-crossing, negative zero-crossing or all zero-crossing by the Zxcon[1:0] bits

(MMode, 2BH).

IRQ

LVTTL

IRQ: Interrupt Output

This pin is asserted when one or more events in the SysStatus register (01H) occur. It is

deasserted when there is no bit set in the SysStatus register (01H).

WarnOut

LVTTL

WarnOut: Fatal Error Warning

This pin is asserted when there is metering parameter calibration error or voltage sag. Refer

to section 4.2.

Note 1: All digital inputs are 5V tolerant except for the OSCI pin.

Table-2 Pin Description (Continued)

Name

Pin No.

I/O

note 1

Type

Description

90E21 Datasheet(PDF) 11 Page - Integrated Device Technology

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