Datasheet SA9603CPA, SA9603CSA Datasheet (SAMES)

sames

OSC2

6

OSC1

DR-01088

7

VR E F

IIP

TEST

DD

V

IIN

25431

SIN

IVP

TP12

SS

FM O

13V101112

GND

14

SINGLE PHASE BIDIRECTIONAL POWER/ENERGY

METERING IC WITH SERIAL INTERFACE

FEATURES

■ Performs bidirectional active and

reactive power/energy, frequency and
voltage measurement

■ Meets the IEC 521/1036 Specification

requirements for Class 1 AC Watt hour
meters

■ Protected against ESD

■ Total power consumption rating below

25mW

DESCRIPTION

The SAMES SA9603C bidirectional single
phase power/energy metering integrated
circuit has a serial interface with a RS232
protocol, ideal for use with a µ-Controller.
The SA9603C performs the calculation for
active and reactive power.

The SA9603C is a direct replacement for
the SA9103C with additional features for
the fast reading of all register values.

The integrated values for active and
reactive energy as well as the mains
frequency and voltage information are
accessable through the serial interface as
16 bit values.

This universal single phase power/energy
metering integrated circuit is ideally suited
for energy calculations in applications such
as electricity dispensing systems (ED's),
residential municipal metering and factory
energy metering and control.

The SA9603C integrated circuit is available
in both 14 and 20 pin dual-in-line plastic

7133

sames

SA9603C

PRELIMINARY

SA9603C

■ Adaptable to different current sensor

technologies

■ Operates over a wide temperature

range

■ Serial interface having a RS232

protocol

■ Precision voltage reference on-chip

■ Tri-state output to allow parallel

connection of devices

(DIP-14/DIP-20), as well as 20 pin small
outline (SOIC-20) package types.

PIN CONNECTIONS

9
8

SO U T

Package: DIP-14

1/18

PDS039-SA9603C-001 REV. A 19-09-97

1/16

SA9603C

TP6

OSC 2

TP9DDV

D R-00829

789

10

VREF

IIN

TP5

TP4

124

635

SS

OSC 1

SOUT

14

V

111213

IV P

GND

TP17

2019151617

18

OSC1

OSC

REF.

ACTIVE

REACTIVE

FREQUENCY

SIG NAL

SSING

D R-00830

TEST

TIMING

FM O

INTERFACE

V

SOU T

PIN CONNECTIONS

BLOCK DIAGRAM

IIP

TP18

TP16
FMO

SIN

Package: DIP-20

SOIC-20

2/18

IIP

IIN

IVP

GND

ANALOG

PR O CE-

sames

VREF

ENERGY

ENERGY

VOLTAGE

VOLTAGE

OSC2

V

DD

SERIAL

SS

SIN

SA9603C

ABSOLUTE MAXIMUM RATINGS*

Parameter Symbol Min Max Unit

Supply Voltage VDD -V
Current on any pin I

Storage Temperature T
Operating Temperature T

PIN

STG

O

SS

-0.3 6.0 V

-150 +150 mA

-40 +125 °C

-10 +70 °C

* Stresses above those listed under “Absolute Maximum Ratings” may cause permanent

damage to the device. This is a stress rating only. Functional operation of the device
at these or any other condition above those indicated in the operational sections of this
specification, is not implied. Exposure to Absolute Maximum Ratings for extended
periods may affect device reliability.

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3/18

SA9603C

ELECTRICAL CHARACTERISTICS

(VDD = 2.5V, VSS = -2.5V, over the temperature range -10°C to +70°C#, unless otherwise
specified.)

Parameter Symbol Min Typ Max Unit Condition

Supply Voltage: Positive V
Supply Voltage: Negative V
Supply Current: Positive I
Supply Current: Negative I

DD

SS

2.25 2.75 V

DD

-2.75 -2.25 V

SS

56mA

56mA
Current Sensor Inputs (Differential)
Input Current Range I

-25 +25 µA Peak value

II

Voltage Sensor Input (Asymetrical)
Input Current Range I

IV

-25 +25 µA Peak value

Pin FMO

Output Low Voltage V
Output High Voltage V

OL

VDD-1 V IOH = -2mA

OH

VSS+1 V IOL = 5mA

Pin SIN

Input High Voltage V
Input Low Voltage V
Pull-up Current -I

VDD-1 V

IH
IL

50 150 µA VIN = V

I

VSS+1 V

SS

Pin SOUT Tri-state
Output Low Voltage V
Output High Voltage V

OL

VDD-1 V

OH

VSS+1 V

Oscillator Recommended crystal:

TV colour burst crystal f = 3.5795 MHz

Pin VREF With R = 24kΩ

Ref. Current -I
Ref. Voltage V

#

Extended Operating Temperature Range available on request.

4/18

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R
R

45 50 55 µA connected to V

1.1 1.3 V Referred to V

SS

SS

PIN DESCRIPTION

SA9603C

14 Pin

14

5
10
13

1

2

7

6

8

9

3

4
11

12

20 Pin

20

8
14
19

1

2
11
10
12
13

3

7
15

4

5

6

9

16
17
18

Designation

GND

V

DD

V

SS

IVP

IIN

IIP
OSC1
OSC2
SOUT

SIN

VREF

TEST

FMO

TP4
TP5
TP6

TP9
TP12
TP16
TP17
TP18

Description

Ground
Positive Supply Voltage
Negative Supply Voltage
Analog input for mains voltage
Inputs for current sensor

Connections for crystal or ceramic resonator
(OSC1 = Input ; OSC2 = Output)
Serial Interface Out
Serial Interface In
Connection for current setting resistor
Test Pin. Must be connected to V

SS

Mains frequency zero-crossing indication
Test Pins (Leave unconnected)

FUNCTIONAL DESCRIPTION

The SA9603C is a CMOS mixed signal Analog/Digital integrated circuit, which performs
power/energy calculations across a power range of 1000:1, to an overall accurancy of
better than Class 1.

The integrated circuit includes all the required functions for 1-phase power and energy
measurement, such as two oversampling A/D converters for the voltage and current
sense inputs, power calculation and energy integration. Internal offsets are eliminated
through the use of cancellation procedures. The SA9603C integrates the measured
active and reactive power consumption into 22 bit integrators, which are accessable via
a serial port having a RS232 protocol. Two additional on-chip registers exist: one register
contains the mains frequency information; and the other the voltage information.

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5/18

SA9603C

D R -00831

IV P

VOLTAGE

SENSOR

IN P U T

V

IIP

IIN

CURRENT

SENSOR

IN P U TS

VDDVSSVDDVDDV

A

GND

VAI

1. Power Calculation

In the Application Circuit (Figure 1), the voltage drop across the shunt will be
between 0 and 16mV
is converted to a current of between 0 and 16µA

(0 to 80A through a shunt resistor of 200µΩ). This voltage

RMS

, by means of resistors R1 and

RMS

R2.
The current sense input saturates at an input current of ±25µA peak.
For the voltage sensor input, the mains voltage (230V AC) is divided down through

a divider to 14V

. The resulting current into the A/D converter input is 14µA

RMS

at nominal voltage, via resistor R4 (1MΩ).
In this configuration, with a mains voltage of 230V and a current of 80A, the

SA9603C functions at its optimum conditions, having a margin of 3dB for overload
available.

2. Analog Input Configuration

The input circuitry of the current and voltage sensor inputs are illustrated below.
These inputs are protected against electrostatic discharge through clamping
diodes.

The feedback loops from the outputs of the amplifiers AI and AV generate virtual
shorts on the signal inputs. Exact duplications of the input currents are generated
for the analog signal processing circuitry.

RMS

6/18

SS

SS

sames

3. Electrostatic Discharge (ESD) Protection

The SA9603C integrated circuit's inputs/outputs are protected against ESD .

4. Power Consumption

The power consumption rating of the SA9603C integrated circuit is less than
25mW.

5. Serial Interface

Reading and resetting of the SA9603C's on-chip integrators, is performed via the
serial interface.

The settings are: 19 200 Baud

1 Start bit (S)
1 Stop bit (E)
No parity bits

The serial interface, having a RS232 protocol, has been designed to operate directly
with a PC (Personal Computer).

The serial interface allows for the following operations:
Read Integrator (RD): The SA9603C integrated circuit transmits the integrator

status to the controller, after the current measurement cycle has been completed
(8 mains periods maximum).

The register containing the mains frequency information is read only.
Reset Integrator (RES): The SA9603C integrator is reset, without transmitting the

integrator status.
Read/Reset Integrator (RD/RES): The SA9603C transmits the integrator status

and resets the integrator after the current measurement cycle has been completed.
In a typical application, the system controller monitors the status of the SA9603C's

integrator using the "Read" command. At rated load conditions, the capacity of the
22 bit integrator allows for an integration time of 2 seconds, prior to integrator
overflow.

If after a "Read" command, the integrator value is sufficently high, a "Read/Reset"
command from the controller causes the SA9603C integrated circuit to complete
the existing measurement cycle, transmit the most significant bits of the 22 bit
integrator via the Serial Output (SOUT) to the controller and restart the integrator.

In order to ensure correct measurements, the integrator commands ("Read" and
"Read/Reset") are only executed after completion of the internal offset calibration
cycle. The cycle length is 8 mains periods.

Thus, for power calculations, the time value should be taken from the difference in
time from the previously received energy value to the currently received value.

By adapting the "Read/Reset" rate to the line current, the accuracy of the
measurement can be achieved down to lowest signal levels.

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SA9603C

7/18

SA9603C

RESRDDUMP

RES

RD

STA RT

BIT

DR-0 08 33

RD/

RES

DUM P

RES

RD

RESRDRESRDSTOP

RDRDSTART

BIT

DR-00834

DUMP

DUMP

BIT

Dump register values: The content of the individual registers are transmitted
sequentially, at the 'Dump' command. Transmission of the first register value will
start with the completion of the current measurement cycle (Maximum 8 mains
cycles). The sequence of the registers is always as follows: Mains voltage, mains
frequency, reactive energy register followed by the active energy register value. By
specifying the register in the DUMP command, register values are transmitted
starting with the specified register and stopping with the active energy register.

Commands for the active energy integrator

RD

RES

RD/
RES

DUMP

DR -00832

START

BIT

STOP

BIT

Commands for the reactive energy integrator

DUM P

Commands for the frequency register

8/18

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BIT

STOP

Commands for the voltage integrator

891011121314

15

1

234

DUMP

START

DR-01362

RD/

RES

DUMPRDRESRDRESRDRES

STOP

SA9603C

BIT

BIT

The register access codes which may be written to the SA9603C via the serial
communications port, are shown in the table below:

REGISTER READ RESET READ-RESET DUMP

ACTIVE $01 $02 $03 $05

#

<

<

<

RE-ACTIVE $81 $82 $83 $84
FREQUENCY $41 - - $44
VOLTAGE $C1 $C2 $C3 $C4

#

Note: The Dump Active ($04) and Read Active ($01) commands have the same

effect.

Data on SOUT

567

DR-00835

FIRST BYTE

0

SECOND BYTE

From the two bytes of data output by the device, the value for the register can
be derived as shown:

Register value = (First Byte * 256) + Second Byte

The register value is represented in two's compliment in order to provide for
positive and negative register values.
The most significant bit of the 16 bit energy register (active or reactive) may be
used as an indication of the direction of the energy flow (0 = positive, 1 =
negative).

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9/18

SA9603C

6. Register Values

a. The active and reactive energy measured per count, may be calculated by

applying the following formula:
Energy per Count =

V * I

K

Watt seconds

Where V = Rated Voltage

I = Rated Current
K = 9281 for Active Energy

9281 * 2

for Reactive Energy

π

b. The mains frequency may be calculated as follows:

Frequency =

Crystal frequency
Register Value * 8

c. To calculate the measured voltage, the following formula may be used:

Vmeasured =

V * n

14000 * t

Where V = rated mains voltage

t = time difference between successive reads
n = difference in register values between

successive reads

7. Software Flow

The SA9603C is able to execute code written for the SA9103C without any
modifications. (Ensure that only bits of the serial command to the device is set that
need to be set.)

It is suggested that the DUMP command is used in cases where more than one
register is continuously read. The DUMP command initiates a serial transmission
of successive register values, starting with the specified register. The Dump
command does not reset the register values.

New software should be developed in such a way that registers are never resettled
and must allow for register overflow. Register overflow is easily taken into account
by software running on a controlling microcontroller. The software subtracts the
previous register value from the current register value in order to determine the
actual change in register value. Note that the mains frequency register value only
needs to be scaled, in order to calculate the true mains frequency in Hertz.

The SA9603C integrated circuit only transmits the register values after completion
of the current measurement cycle (8 mains periods maximum).

The delay of 8 mains periods may be calculated from the period value of the
frequency returned by the initial read, and updated with each subsequent frequency
reading.

10/18

sames

8. Calibration

For calibration of the SA9603C, the following procedure is recommended:

a. Establish the calibration factor for active energy (Ka) at power factor (PF)

close to 1.

Active (Measured) = register_value (Active) * Ka. 1

b. The factor for reactive (Kr) is typically Ka * PI/2.

For higher accuracy of Kr, establish Kr at PF close to 0.

Reactive (Measured) = register_value (Reactive) * Kr 2

c. At PF close to 1, establish error for reactive (Er)

Er = (Reactive (Measured) - Reactive (True)) / Active ( Measured) 3

Reactive (Corrected) = Reactive (Measured) - Er * Active (Measured) 3b

Measurement

SA9603C

Having determined the scaling factors (Ka & Kr) and error correction constant (Er)
the measurement cycle consists of the following steps:

Step 1 Read active register

∨∨

∨

∨∨

⇒⇒

⇒

Step 2 Calculate Active (Measured) as per 1 Active energy

∨∨

∨

∨∨

⇒⇒

Step 3 Read reactive register

∨∨

∨

∨∨

Step 4 Calculate Reactive (Measured) as per 2

∨∨

∨

∨∨

Step 5 Perform error correction

⇒⇒

⇒

Calculate Reactive (Corrected) as per 3b Reactive energy

⇒⇒

The above five steps must be performed for each measurement cycle.

sames

11/18

SA9603C

TYPICAL APPLICATIONS

In the Application Circuits (Figures 1 and 2), the components required for power metering
applications, are shown.

In Figure 1, a shunt resistor is used for current sensing. In this application, the circuitry
requires a +2.5V, 0V, -2.5V DC supply.

In the case of Figure 2, when using a current transformer for current sensing, a +5V, 0V
DC supply is sufficient for the circuit.

R1, R2 and RSH are the resistors defining the current level into the current sense input.
The values should be selected for an input current of 16µA

into the SA9603C at rated

RMS

line current.
Values for RSH of less than 200µΩ should be avoided.
R1 = R2 = (IL/16µA
Where I

L

) * RSH/2

RMS

= Line current

RSH = Shunt resistor/termination resistor

R3, R6 and R4 set the current for the voltage sense input. The values should be selected
so that the input current into the voltage sense input (virtual ground) is set to 14µA

RMS

R7 defines all on-chip bias and reference currents. With R7 = 24kΩ, optimum conditions
are set.

XTAL is a colour burst TV crystal (f = 3.5795MHz) for the oscillator. The oscillator
frequency is divided down to 1.7897MHz on-chip to supply the A/D converters and digital
circuitry.

.

12/18

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SA9603C

Figure 1: Application Circuit using a Shunt Resistor for current sensing,

having a PC (Personal Computer) Interface.

TXD

GN D

D3

3

2

SERIAL

R1 2

1

DT R

RX D

RT S

INTE RFA CE

DS R

R1 3

R1 4

4

6

5

IC-2

6

4

5

ISOLATED PC INTERFACE

R6

R4

19

20

1

18

17

2

3

4

16

5

13

14

15

12

11

IC-1

8

9

7

6

10

R7

R1 5

XTA L

IC-3

2

3

1

C1 2

C1 0

C1 5

C9

ZD1

ZD2

D1

R9

C1 3

+

R1 0

C1 4

+

D2

C1 1

R5

DR-00836

RS H

LOAD

sames

SUPPLY

13/18

SA9603C

Part List for Application Circuit: Figure 1

Item Symbol Description Detail

1 IC-1 SA9603C DIP-20/SOIC-20
2 IC-2 Opto Coupler 4N35 DIP-6
3 IC-3 Opto Coupler 4N35 DIP-6
4 D1 Diode, Silicon, 1N4148
5 D2 Diode, Silicon, 1N4148
6 D3 Diode, Silicon, 1N4148
7 ZD1 Diode, Zener, 2.4V, 200mW
8 ZD2 Diode, Zener, 2.4V, 200mW

9 XTAL Crystal, 3.5795MHz Colour burst TV
10 R1 Resistor, 1% metal Note 1
11 R2 Resistor, 1% metal Note 1
12 R3 Resistor, 390k, (230VAC), 1% metal
13 R4 Resistor, 1M, 1/4W, 1% metal
14 R5 Resitor, 470Ω, 2W, 5%, carbon
15 R6 Resistor, 24k, 1/4W, 1%, metal
16 R7 Resistor, 24k, 1/4W, 1%, metal
17 R8 Resistor, 680Ω, 1/4W, 5%
18 R9 Resistor, 680Ω, 1/4W, 5%
19 R10 Resistor, 680Ω, 1/4W, 5%
20 R11 Resistor, 100k, 1/4W, 5%
21 R12 Resistor, 120Ω, 1/4W, 5%
22 R13 Resistor, 1/4W, 5%, 47k
23 R14 Resistor, 1/4W, 5%, 1.6k
24 R15 Resistor, 120Ω, 1/4W, 5%
25 C9 Capacitor, 100nF
26 C10 Capacitor, 100nF
27 C11 Capacitor, 0.47µF, 250VAC, polyester
28 C12 Capacitor, 100nF
29 C13 Capacitor, 100µF
30 C14 Capacitor, 100µF
31 C15 Capacitor, 820nF
32 RSH Shunt Resistor Note 2

Note 1: Resistor (R1 and R2) values are dependant upon the selected value of RSH.
Note 2: See TYPICAL APPLICATIONS when selecting the value for RSH.

14/18

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SA9603C

Figure 2: Application Circuit using a Current Transformer for current sensing.

SERIAL INT ERFACE

SOUT

FM 0

R6

SIN

C1 1

R4

0V

18

19

16

17

20

1

2

R1

RSH

R3

CT

LOAD

R2

15

IC-1

4

3

6

5

14

7

13

8

12

9

11

10

R7

XTAL

C9

5V

R8

C1 0

R9

DR-00837

L

N

SUPPLY

sames

15/18

SA9603C

Parts List for Application Circuit: Figure 2

Item Symbol Description Detail

1 IC-1 SA9603C DIP-20/SOIC-20
2 XTAL Crystal, 3.5795MHz Colour burst TV
3 RSH Resistor Note 1
4 R1 Resistor, 1%, metal Note 2
5 R2 Resistor, 1%, metal Note 2
6 R3 Resistor, 390k, (230VAC) 1%, metal
7 R4 Resistor, 1M, 1/4W, metal
8 R6 Resistor, 24k, 1/4W, metal

9 R7 Resistor, 24k, 1/4W, metal
10 R8 Resistor, 2.2k, 1/4W, 5%
11 R9 Resistor, 2.2k, 1/4W, 5%
12 C9 Capacitor, 820nF Note 3
13 C10 Capacitor, 100nF
14 C11 Capacitor Note 4
15 CT Current Transformer

Note 1: See TYPICAL APPLICATIONS when selecting the value of RSH.
Note 2: Resistor (R1and R2) values are dependant upon the selected value of

RSH.
Note 3: Capacitor (C9) to be positioned as close to IC-1, as possible.
Note 4: Capacitor (C11) selected for DC blocking and to minimize phase error

introduced by the current transformer.

Part Number Package

SA9603CPA DIP-14
SA9603CPA DIP-20

SA9603CSA SOIC-20

Note: When ordering, the package option must be specified along with the part

number.

16/18

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Note:

SA9603C

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17/18

SA9603C

Disclaimer: The information contained in this document is confidential and proprietary to South African Micro-

Electronic Systems (Pty) Ltd ("SAMES") and may not be copied or disclosed to a third party, in whole or in part,
without the express written consent of SAMES. The information contained herein is current as of the date of
publication; however, delivery of this document shall not under any circumstances create any implication that the
information contained herein is correct as of any time subsequent to such date. SAMES does not undertake to inform
any recipient of this document of any changes in the information contained herein, and SAMES expressly reserves
the right to make changes in such information, without notification,even if such changes would render information
contained herein inaccurate or incomplete. SAMES makes no representation or warranty that any circuit designed
by reference to the information contained herein, will function without errors and as intended by the designer.

Any Sales or technical questions may be posted to our e-mail address below:
[e-mail]

For the latest updates on datasheets, please visit out web site:
http://www.sames.co.za

South African Micro-Electronic Systems (Pty) Ltd

P O Box 15888, 33 Eland Street,
Lynn East, Koedoespoort Industrial Area,
0039 Pretoria,
Republic of South Africa, Republic of South Africa

Tel: [phone] Tel: Int [phone]
Fax: [phone] Fax: Int [phone]

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