PRELIMINARY TECHNICAL DATA

REV. PrC.

–5–

ADE7757

PIN FUNCTION DESCRIPTIONS

Pin No.

Mnemonic

Description

Power Supply. This pin provides the supply voltage for the circuitry in the ADE7757. The

supply voltage should be maintained at 5 V ± 5% for specified operation. This pin should be

decoupled with a 10 µF capacitor in parallel with a ceramic 100 nF capacitor.

2,3

V2P, V2N

Analog Inputs for Channel V2 (voltage channel). These inputs provide a fully differential

input pair. The maximum differential input voltage is ±165 mV for specified operation. The

maximum signal level at these pins is ±165 mV with respect to AGND. Both inputs have

internal ESD protection circuitry and an overvoltage of ±6 V can also be sustained on these

inputs without risk of permanent damage.

4, 5

V1N, V1P

Analog Inputs for Channel V1 (current channel). These inputs are fully differential voltage

inputs with a maximum signal level of ±30 mV with respect to pin V1N for specified opera-

tion. The maximum signal level at this pin is ±165 mV with respect to AGND. Both inputs

have internal ESD protection circuitry and in addition an overvoltage of ±6 V can be sus-

tained on these inputs without risk of permanent damage.

6

AGND

This provides the ground reference for the analog circuitry in the ADE7757, i.e., ADCs and

reference. This pin should be tied to the analog ground plane of the PCB. The analog ground

plane is the ground reference for all analog circuitry, e.g., antialiasing filters, current and

voltage sensors, etc. For accurate noise suppression, the analog ground plane should only be

connected to the digital ground plane at one point. A star ground configuration will help to

keep noisy digital currents away from the analog circuits.

7

This pin provides access to the on-chip voltage reference. The on-chip reference has a nomi-

nal value of 2.5 V ± 8% and a typical temperature coefficient of 30 ppm/°C. An external

reference source may also be connected at this pin. In either case this pin should be

decoupled to AGND with a 1 µF tantalum capacitor and 100 nF ceramic capacitor.

8

S C F

Select Calibration Frequency. This logic input is used to select the frequency on the calibra-

tion output CF. Table III shows calibration frequencies selection.

9,10

S1, S0

These logic inputs are used to select one of four possible frequencies for the digital-to-fre-

quency conversion. With this logic input, designers have greater flexibility when designing an

energy meter. See Selecting a Frequency for an Energy Meter Application.

Selecting a Frequency for an Energy Meter Application.

Selecting a Frequency for an Energy Meter Application.

Selecting a Frequency for an Energy Meter Application.

Selecting a Frequency for an Energy Meter Application.

11

RCLKIN

To enable the internal oscillator as a clock source to the chip, a precise 5 k

Ω resistor must be

connected from this pin to DGND.

12

RESERVED

Reserved pin. No load should be connected to this pin.

13

DGND

This provides the ground reference for the digital circuitry in the ADE7757, i.e., 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, e.g.,

counters (mechanical and digital), MCUs and indicator LEDs. For accurate noise suppres-

sion the analog ground plane should only be connected to the digital ground plane at one

point only, e.g., a star ground.

14

C F

Calibration Frequency Logic Output. The CF logic output provides instantaneous real power

information. This output is intended for calibration purposes. Also see SCF pin description.

15,16

F2,F1

Low Frequency Logic Outputs. F1 and F2 supply average real power information. The logic

outputs can be used to directly drive electromechanical counters and two phase stepper mo-

tors. See Transfer Function.

Transfer Function.

Transfer Function.

Transfer Function.

Transfer Function.

PIN CONFIGURATION

SOIC-16nb Package

TOP VIEW

(Not to Scale)

ADE7757

V2P

V2N

V1N

F1

V1P

AGND

SCF

F2

CF

DGND

RESERVED

RCLKIN

S0

S1

1

4

7

3

2

6

5

14

11

15

16

12

13

8

9

10