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FEATURES
SA9103E
SINGLE PHASE BIDIRECTIONAL POWER/ENERGY
METERING IC WITH SERIAL INTERFACE
n Performs bidirectional active power/
energy measurement
n Meets the IEC 521/1036 Specification
requirements for Class 1 AC Watt hour
meters
n Protected against ESD
n Power consumption rating below 25mW
n Adaptable to different current sensor
technologies
DESCRIPTION
The SAMES SA9103E Single Phase
bidirectional Power/Energy metering
integrated circuit has a serial interface with
a RS232 protocol, ideal for use with a µController. The SA9103E performs the
calculation for active power.
The integrated value for active energy is
accessable through the RS232-Interface
as a 16 bit value.
This innovative universal single phase
power/energy metering integrated circuit
is ideally suited for energy calculations in
applications such as electricitydispensing
systems (ED's), residential municipal
metering and factory energy metering and
control.
The SA9103E integrated circuit is available
in both 20 pin dual-in-line plastic (DIP-20),
as well as 20 pin small outline (SOIC-20)
package types.
n Operates over a wide temperature
range
n Serial interface having a RS232
protocol
n Precision voltage reference on-chip
n Tri-state output to allow parallel
connection of devices.
PIN CONNECTIONS
IIN
IIP
VREF
CPON
CPOP
CPIN
CPIP
V
DD
TP9
OSC2
1
2
3
4
5
6
7
8
9
10
DR-00917
20
19
18
17
16
15
14
13
12
11
GND
IVP
CON
COP
CIN
CIP
V
SS
SIN
SOUT
OSC1
Package: DIP-20
SOIC-20
4353
PDS039-SA9103E-001 REV. B 14-11-1996
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SA9103E
BLOCK DIAGRAM
V V
DD
SS
IIP
IIN
ANALOG
SIGNAL
ACTIVE
ENERGY
SERIAL
INTERFACE
SIN
SOUT
PROCE-
VOLTAGE
REF.
OSC
OSC1
TIMING
OSC2
IVP
GND
DR-00918
SSING
VREF
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
-40 +85 °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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SA9103E
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
2.25 2.75 V
DD
-2.75 -2.25 V
SS
DD
SS
56mA
56mA
Current Sensor Inputs (Differential)
Input Current Range I
II
-25 +25 µA Peak value
Voltage Sensor Input (Asymetrical)
Input Current Range I
IV
-25 +25 µA Peak value
Pin SOUT
Output Low Voltage V
Output High Voltage V
OL
VDD-1 V IOH = -2mA
OH
Pin SIN
High Voltage V
Low Voltage V
Pull-up Current -I
VDD-1 V
IH
IL
50 150 µA VIN = V
I
Oscillator Recommended crystal:
TV colour burst crystal f = 3.5795 MHz
VSS+1 V IOL = 5mA
VSS+1 V
SS
Pin VREF With R = 24kΩ
Ref. Current -I
Ref. Voltage V
#
Extended Operating Temperature Range available on request.
R
R
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45 50 55 µA connected to V
1.1 1.3 V Referred to V
SS
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SA9103E
PIN DESCRIPTION
Pin Designation Description
20 GND Ground
8 V
14 V
DD
SS
Positive Supply Voltage
Negative Supply Voltage
19 I V P Analog input for Voltage
1 IIN Inputs for current sensor
2 IIP
11 OSC1 Connections for crystal or ceramic resonator
10 OSC2 (OSC1 = Input ; OSC2 = Output)
12 SOUT Serial Interface Out
13 S IN Serial Interface In
4 CPON Connections for outer loop capacitors of
5 CPOP A/D converter (Voltage)
6 CPIN Connections for inner loop capacitors of
7 CPIP A/D converter (Voltage)
15 C I P Connections for inner loop capacitors of
16 CI N A/D converter (Current)
17 C O P Connections for outer loop capacitors of
18 CO N A/D converter (Current)
3 VREF Connection for current setting resistor
9 TP9 Test Pin. Connect to V
SS
FUNCTIONAL DESCRIPTION
The SA9103E 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 of 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 SA9103E integrates the measured
active power consumption into a 22 bit integrator, which is accessable via a serial port
having a RS232 protocol.
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1. Power calculation
In the Application Circuit (Figure 1), the voltage drop across the shunt will be
between 0 and 16mV (0 to 80A through a shunt resistor of 200µ Ω). This voltage is
converted to a current of between 0 and 16µA, by means of resistors R1 and R2.
The current sense input saturates at an input current of ±25µA peak.
For the voltage sense input, the mains voltage (230VAC) is divided down through
a divider to 14V. The resulting current into the A/D converter input is set at 14µA
at nominal mains voltage,via resistor R4 (1MΩ).
In this configuration, with a mains voltage of 230V and a current of 80A, the SA9103E
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.
V
DD
SA9103E
CURRENT
SENSOR
INPUTS
VOLTAGE
SENSOR
INPUT
DR-00919
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IIP
IIN
IVP
V
SS
V
DD
V
SS
V
DD
V
SS
GND
A
A
I
V
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SA9103E
3. Electrostatic Discharge (ESD) Protection
The SA9103E integrated circuit's inputs/outputs are protected against ESD.
4. Power Consumption
The power consumption rating of the SA9103E integrated circuit is less than
25mW.
5. Serial Interface
Reading and resetting of the SA9103E's on-chip integrator, 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 allows for the following operations:
Read Integrator: The SA9103E integrated circuit transmits the integrator status
to the controller, after the current measurement cycle has been completed (8 mains
periods maximum).
Reset Integrator: The SA9103E integrator is reset, without transmitting the
integrator status.
Read/Reset Integrator): The SA9103E 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 SA9103E'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 SA9103E integrated circuit to complete
the existing measurement cycle, transmit the 16 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.
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SA9103E
By adapting the "Read/Reset" rate to the line current the accuracy of the measurement
can be achieved down to lowest signal levels.
Read, Reset and Read/Reset of integrator for active energy
BI T
RD
RD
RE S
RE S
STOP
BI T
RD
RE S
RD/
RE S
DR-00920
ST ART
The register access codes which can be written to the SA9103E via the serial
communications port are shown in the table below:
REGISTER READ RESET READ-RESET
Active $01 $02 $03
From the two bytes of data output by the device, the value for the register may be
derived as shown:
Register value = (first byte * 256) + second byte
The most significant bit of the 16 bit energy register is an indication fo the direction
of the energy flow (0 = positive, 1 = negative)
Data on SOUT
8 9 10 11 12 13 14 15
FIRST BYTE
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10 234567
SECOND BYTE
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SA9103E
6. Register Values
The active energy measured per count, may be calculated by applying the following
formula:
Energy per Count =
When
V
= Rated Voltage
I
= Rated Current
K
= 9281 for Active Energy
VI
K
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.
The most important external components for the SA9103E integrated circuit are:
C1 and C2 are the outer loop capacitors for the two integrated oversampling A/D
converters. The value of these capacitors is 560pF. The actual values determine the
signal to noise and stability performance. The tolerances should be within ±10%.
C3 and C4 are the inner loop capacitors of the A/D converters. The optimum value is 3.3nF.
The actual values are uncritical. Values smaller than 0.5nF and larger than 5nF should
be avoided.
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 SA9103E at maximum
line current.
Values for RSH of less than 200µΩ should be avoided.
R1 = R2 = (IL/16µA) * RSH/2
Where IL= 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.
R7 defines all on-chip bias and reference currents. With R7 = 24kΩ, optimum conditions
are set.
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SA9103E
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.
Figure 1: Application Circuit using a Shunt Resistor for Current Sensing, having
a PC (Personal Computer) Interface.
Note: The Serial Interface having a RS232 protocol, has been designed to operate
directly with a PC (Personal Computer).
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SA9103E
Part List for Application Circuit: Figure 1
Item Symbol Description Detail
1 IC-1 SA9103E 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, 680 Ω, 1/4W, 5%
18 R9 Resistor, 680 Ω, 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, 120k, 1/4W, 5%
23 R14 Resistor, 3.9k, 1/4W, 5%
24 R15 Resistor, 120Ω, 1/4W, 5%
25 C1 Capacitor, 560pF
26 C2 Capacitor, 560pF
27 C3 Capacitor, 3.3nF
28 C4 Capacitor, 3.3nF
29 C9 Capacitor, 100nF
30 C10 Capacitor, 100nF
31 C11 Capacitor, 0.47µF, 250VAC, polyester
32 C12 Capacitor, 100nF
33 C13 Capacitor, 100µF
34 C14 Capacitor, 100µF
35 C15 Capacitor, 820nF
36 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.
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SA9103E
Figure 2: Application Circuit using a Current Transformer for Current Sensing.
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SA9103E
Parts List for Application Circuit: Figure 2
Item Symbol Description Detail
1 IC-1 SA9103E 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 C1 Capacitor, 560pF
13 C2 Capacitor, 560pF
14 C3 Capacitor, 3.3nF
15 C4 Capacitor, 3.3nF,
16 C9 Capacitor, 820nF Note 3
17 C10 Capacitor, 100nF
18 C11 Capacitor Note 4
19 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.
ORDERING INFORMATION
Part Number Package
SA9103EPA DIP-20
SA9103ESA SOIC-20
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NOTES:
SA9103E
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SA9103E
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:
[email protected]
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: 012 333-6021 Tel: Int +27 12 333-6021
Fax: 012 333-8071 Fax: Int +27 12 333-8071
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