Three Phase Power / Energy IC with SPI
Interface
SA9904B
FEATURES
+
Bi-directional
+
+
+
+
active and reactive power/energy
sames
+
+
+
+
+
+
Meets the IEC 61268 Specification requirements for
Class 2 VAR hour meters
Protected against ESD
Total power consumption rating below 60mW
Uses current transformers for current sensing
Operates over a wide temperature range
Precision on-chip voltage reference
measurement
RMS Voltage and frequency measurement
Individual Phase information
SPI communication bus
Meets the IEC 61036 Specification requirements for Class 1
AC Watt hour meters
DESCRIPTION
The SAMES SA9904B is a three phase bi-directional
energy/power metering integrated circuit that has been
designed to measure active and reactive energy, RMS mains
voltage and frequency. The SA9904B has an integrated SPI
serial interface for communication with a micro-controller.
Measured values for active and reactive energy, the mains
voltage and frequency for each phase are accessible through
the SPI interface from 24 bit registers. The SA9904B active and
reactive energy registers are capable of holding at least 52
seconds of accumulated energy at full load. A mains voltage
zero crossover is available on the F50 output.
The SA9904B includes all the required functions for three-
phase power and energy measurement such as oversampling
A/D converters for the voltage and current sense inputs, power
calculation and energy integration. This innovative universal
three phase power/energy metering integrated circuit is ideally
suited for energy calculations in applications such as electricity
dispensing systems, residential metering and factory energy
metering and control.
The SA9904B integrated circuit is available in 20 pin dual-in-
line plastic (PDIP20), as well as 20 pin small outline (SOIC20)
package types.
VDD
VSS
IIP1
IIN2
IIP2
IIN2
IIP3
IIN3
IVP1
IVP2
IVP3
ACTIVE
CURRENT
ADC
DI
REACTIVE
SPI
RMS
VOLTAGE
VOLTAGE
ADC
MAINS
FREQ.
F50
DO
SCK
CS
GND
VOLTAGE
REF.
OSC
DR-01641
VREF
OSC1
OSC2
Figure 1: Block diagram
SPEC-0447 (REV. 6)
1/12
04-07-03