REV. A

ADE7757

–5–

PIN CONFIGURATION

1

ADE7757

V2P

V2N

V1N

V1P

F1

F2

CF

DGND

REVP

2

3

4

5

16

15

14

13

12

TOP VIEW

(Not to Scale)

AGND

SCF

RCLKIN

S0

S1

6

7

8

11

10

9

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. Both inputs have internal ESD

protection circuitry; an overvoltage of

±6 V can 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 the V1N pin for specified operation. Both inputs have

internal ESD protection circuitry and, in addition, an overvoltage of

±6 V can be sustained 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, and so forth. For

accurate noise suppression, the analog ground plane should be connected to the digital ground plane at

only 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 nominal value

of 2.5 V and a typical temperature coefficient of 20 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 tanta-

lum capacitor and a 100 nF ceramic capacitor. The internal reference cannot be used to drive an

external load.

8

SCF

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

sion. With this logic input, designers have greater flexibility when designing an energy meter. See the

Selecting a Frequency for an Energy Meter Application section.

11

RCLKIN

To enable the internal oscillator as a clock source to the chip, a precise low temperature drift resistor at a

nominal value of 6.2 k

Ω must be connected from this pin to DGND.

12

REVP

This logic output will go high when negative power is detected, i.e., when the phase angle between the

voltage and current signals is greater than 90

°. This output is not latched and will be reset when positive

power is once again detected. The output will go high or low at the same time that a pulse is issued on CF.

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 digi-

tal ground plane is the ground reference for all digital circuitry, e.g., counters (mechanical and digital),

MCUs, and indicator LEDs. For accurate noise suppression, the analog ground plane should be con-

nected to the digital ground plane at one point only, i.e., a star ground.

14

CF

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

tion. 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 2-phase stepper motors. See the Transfer Func-

tion section.