ADE7755

Rev. A | Page 7 of 20

Pin No.

Mnemonic

Description

17

CLKIN

An external clock can be provided at this logic input. Alternatively, a parallel resonant AT crystal can be

connected across CLKIN and CLKOUT to provide a clock source for the ADE7755. The clock frequency for

specified operation is 3.579545 MHz. Crystal load capacitance of between 22 pF and 33 pF (ceramic) should

be used with the gate oscillator circuit.

18

CLKOUT

A crystal can be connected across this pin and CLKIN to provide a clock source for the ADE7755. The CLKOUT

pin can drive one CMOS load when an external clock is supplied at CLKIN or by the gate oscillator circuit.

20

REVP

This logic output goes logic high when negative power is detected, that is, when the phase angle between

the voltage and current signals is greater than 90°. This output is not latched and is reset when positive power

is detected again. The output goes high or low at the same time that a pulse is issued on CF.

21

DGND

This pin provides the ground reference for digital circuitry in the ADE7755, that is, the multiplier, filters, and

digital-to-frequency converter. This pin should be tied to the digital ground plane of the PCB. The digital ground

plane is the ground reference for all digital circuitry, for example, counters (mechanical and digital), MCUs, and

indicator LEDs. For good noise suppression, the analog ground plane should be connected to the digital ground

plane at one point only, for example, a star ground.

22

CF

Calibration Frequency Logic Output. The CF logic output gives instantaneous active power information.

This output is intended to be used for calibration purposes. Also, see the SCF pin description.

23, 24

F2, F1

Low Frequency Logic Outputs. F1 and F2 supply average active power information. The logic outputs can

be used to directly drive electromechanical counters and 2-phase stepper motors. See the Transfer Function

section.