Datasheet SA9108FFA, SA9108FPA Datasheet (SAMES)

DESCRIPTION

The SAMES SA9108F Two Phase bidirec­tional Power/Energy metering integrated
circuit generates pulse rate outputs for
positive and negative energy directions,
the frequency of which is proportional to the
power consumption. The SA9108F
performs the calculation for active power.

The method of calculation takes the power
factor into account.

Energy consumption is determined by the
power measurement being integrated over
time.

The output of this innovative universal two
phase power/energy metering integrated
circuit is ideally suited for applications such
as residential and industrial energy metering
and control.

The SA9108F integrated circuit is available
in 40 pin dual-in-line plastic (DIP-40), as
well as 44 pin plastic leaded chip carrier
(PLCC-44) package types.

SA9108F

TWO PHASE BIDIRECTIONAL POWER/ENERGY

METERING IC WITH INSTANTANEOUS PULSE OUTPUT

Package: DIP-40

1/12

PIN CONNECTIONS

4364 PDS039-SA9108F-001 Rev. B 09-01-97

sames

FEATURES

n Performs bidirectional one or two phase

power and energy measurement

n Meets the IEC 521/1036 Specification

requirements for Class 1 AC Watt hour
meters

n Operates over a wide temperature

range

n Adaptable to different types of current

sensors

n Excellent long term stability
n Easily adaptable to different signal

levels

n Precision voltage reference on-chip
n Two pulse rate output formats available
n Protected against ESD

DR-00940

TP11

11

COPP
CONP

OSC2

OSC1

TP18

TP17

SS

CIPP
CINP

V

16
17
18
19
20

12
13
14
15

CIN1

1

CIP2
CIN2

TP10

IIN1
IIP1

IIN2
IIP2

TP4
TP5

6
7
8
9

10

3

5

4

2

TP30

30

TP24

FOUT1

25

21

22

23

24

TP22

FOUT2

DIR

V
TP27

TP26

DD

29
28
27
26

VREF

CIP1

40

GND

35

IVP1
IVP2

TP32
TP31

34

31

32

33

COP1
CON1
CON2
COP2

36

37

38

39

SA9108F

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BLOCK DIAGRAM

PIN CONNECTIONS

Package: PLCC-44

N.C.

N.C.

12

34

3

TP32

DR-00941

IVP2
IVP1
GND

CON2

COP2

5

4

6

7

CON1

COP1

CIP1

109811

TP27
V

DD

N.C.
TP30
TP31

VREF

TP26

TP24

FOUT1

FOUT2

TP22

38

41

42
43
44
1
2

40

39

DIR

37 3536

IIP2

21

TP4

16

CIN1

CIP2

CIN2

151413

TP5

18

19

17

20

IIN1

IIP1

IIN2

OSC2

OSC1

TP18

TP17

SS

3033 32 31

27

22

24

25

26

23

28

V

29

CIPP

TP10

TP11

COPP

CONP

N.C.

CINP

INTEG.

&

AVERAGE

TIMING & CONTROL

GND

DR-00942

VREF

REF

12 CONNECTIONS

FOR LOOPCAPS

IVP2

IVP1

IIP2
IIN2

IIP1
IIN1

ANALOG

SIGNAL

PRO-

CESSING

OSC

OSC1
OSC2

SS

VV

DD

POWER

TO

PULSERATE

FOUT1
FOUT2
DIR

SA9108F

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ABSOLUTE MAXIMUM RATINGS *

Parameter Symbol Min Max Unit

Supply Voltage VDD-V

SS

-0.3 6.0 V

Current on any Pin I

PIN

-150 +150 mA

Storage Temperature T

STG

-40 +125 °C

Operating Temperature T

O

-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 conditions above those indicated in the operation sections of this
specification, is not implied. Exposure to Absolute Maximum Ratings for extended
periods may affect device reliability.

ELECTRICAL CHARACTERISTICS

(VDD = 5V over the temperature range -10°C to +70°C#, unless otherwise specified.)

Parameter Symbol Min Typ Max Unit Con dition

Supply Voltage VDD-V

SS

4.5 5.5 V

Supply Current I

DD

10 mA

Nonlinearity of
Power Calculation -0.3 +0.3 % 1% -100% of rated

power
Current Sensor Inputs (Differential)
Input Current Range I

II

-25 +25 µA Peak value
Voltage Sensor Inputs (Asymmetric)
Input Current Range I

IV

-25 +25 µA Peak value
Digital Outputs:

Output Low Voltage V

OL

VSS+1 V IOL = 5mA

Output High Voltage V

OH

VDD-1 V IOH = -2mA

Pulse Rate: FOUT1, FOUT2 f

p

0 64 Hz Specified linearity
0 180 Hz Min and max limits

Oscillator Recommended crystal:

TV colour burst crystal, f = 3.5795 MHz

Pin VREF With R = 24 kΩ

Ref. Current -I

R

45 50 55 µA connected to V

SS

Ref. Voltage V

R

1.1 1.3 V Referred to V

SS

Extended Operating Temperature Range available on request.

#

SA9108F

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PIN DESCRIPTION

Pin Pin

PLCC-44 DIP-40

6 35 GND Ground

42 28 V

DD

Positive Supply Voltage

29 16 V

SS

Negative Suply Voltage
5 34 IVP1 Analog input for Voltage : Phase 1
4 33 IVP2 Analog input for Voltage : Phase 2

18 6 IIN1 Inputs for current sensor : Phase 1
19 7 IIP1
20 8 IIN2 Inputs for current sensor : Phase 2
21 9 IIP2
32 19 OSC1 Connections for crystal or ceramic resonator
33 20 OSC2 (OSC1 = Input; OSC2 = Output)
35 21 FOUT1 Pulse rate outputs
37 23 FOUT2
39 25 DIR Direction indication

9 38 CON1 Connections for outer loop capacitors of A/D

10 39 COP1 converters

8 37 CON2
7 36 COP2

26 13 CONP
25 12 COPP
13 1 CIN1 Connections for inner loop capacitors of A/D
11 40 CIP1 converters
15 3 CIN2
14 2 CIP2
28 15 CINP
27 14 CIPP
43 29 VREF Connection for current setting resistor
41 27 TP27 Test Pin. Connect to V

SS

16 4 TP4 Manufacturer's test pins (Leave unconnected)
17 5 TP5
22 10 TP10
23 11 TP11
30 17 TP17
31 18 TP18
36 22 TP22
38 24 TP24
40 26 TP26

1 30 TP30
2 31 TP31
3 32 TP32

Designation Description

SA9108F

sames

5/12

PIN DESCRIPTION (Continued)

Pin Pin

PLCC-44 DIP-40

12 NC Not connected
24 NC
34 NC
44 NC

FUNCTIONAL DESCRIPTION

The SAMES SA9108F is a CMOS mixed signal Analog/Digital integrated circuit, which
performs two phase power/energy calculations over a dynamic range of greater than
1000:1, to an overall accuracy of better than Class 1.

The integrated circuit includes all the required functions for 2-phase power and energy
measurement such as 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 SA9108F generates pulses, the frequency of which is proportional to the power
consumption. The pulse rate follows the instantenous power measured. Direction
information is also provided.

1. Power Calculation

In the Application Circuit (Figure 1), the mains voltages from Line 1 and Line 2, are
converted to currents and applied to the voltage sense inputs IVP1 and IVP2. The
mains voltage (2 x 115 V) is divided down through voltage dividers to 14V. The
resulting input currents into the A/D converters are 14 µA

RMS

through the resistors R

9

and R10.
For the current sense inputs the voltage drop across the current transformers'

terminating resistors are converted to currents of 16µA

RMS

for rated conditions, by

means of resistors R5, R6, (Phase 1) and R7, R8 (Phase 2).
The signals providing the current information are applied to the current sensor inputs

IIN1, IIP1 and IIN2, IIP2.
In this configuration, with the mains voltage of 2 x 115 VAC and rated currents of

80A, the output frequency of the SA9108F energy metering integrated circuit at
FOUT1 is 64Hz. In this case 1 pulse will correspond to an energy consumption of
2 x 9.2 kW/64Hz = 287.5 Ws.

Designation Description

SA9108F

sames

6/12

2. Analog Input Configuration

The current and voltage sensor inputs are illustrated below.
These inputs are protected against electrostatic discharge through clamping

diodes, in conjunction with the amplifiers input configuration.
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 processing circuitry.

3. Electrostatic Discharge (ESD) Protection

The SA9108F integrated circuit's inputs/outputs are protected against ESD .

4. Power Consumption

The overall power consumption rating of the SA9108F integrated circuit is less than
40mW having a 5V supply.

VOLTAGE
SENSOR
INPUT

DR-00943

IVP

GND

SS

V

DD

V

CURRENT
SENSOR
INPUTS

II N

II P

DD

V

SS

V

SS

V

V

DD

A

V

I

A

SA9108F

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5. Pulse Output Signals

The calculated power is divided down to a pulse rate 64Hz, for rated conditions on
FOUT1 and FOUT2.

Two formats of pulse output signals are available which provide both power/energy
and direction information.
The direction of the energy flow is defined by the mark/space ratio on FOUT1 while
the pulse width defines the direction on FOUT2.

An integrated anticreep function ensures no metering at zero line currents.

The formula for calculating the Output Frequency (f) is given below:
f = 11.16

*

FOUTX

*

FOSC * (II1 IV1) + (II2 IV2)

3.58MHz 2 * I

R

2

Where FOUTX = Nominal rated frequency (64Hz)

FOSC = Oscillator frequency (2MHz ...... 4MHz)

II1, I

I2

= Input currents for current sensor inputs (16µA at rated line current)

IV1, I

V2

= Input currents for voltage sensor inputs (14µA at rated line voltage)

I

R

= Reference current (typically 50µA)

DR-00944

Wave form on DIR

mm

Wave form on FOUT1

Wave form on FOUT2

Positive Energy Flow

pp = 1.1ms

pp

t

t

mm

pp

t

mm

t

mm

pn = 3.4ms

Negative Energy Flow

pn

t

t

pn

SA9108F

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TYPICAL APPLICATION

In the Application Circuit (Figure 1), the components required for a two phase power
metering application, are shown. Terminated current transformers are used for current
sensing.

The most important external components for the SA9108F integrated circuit are:
C2, C6 and C7 are the outer loop capacitors for the integrated oversampling A/D

converters. The typical value of C2 is 2.2nF and the value of C6 and C7 is 560µF.
The actual values determine the signal to noise and stability performance. The

tolerances should be within ± 10%.
C1, C3 and C4 are the inner loop capacitors for the integrated oversampling A/D

converters. The typical value of C1, C3 and C4 is 3.3nF. Values smaller than 0.5nF and
larger than 5nF should be avoided.

Terminated current sensors (current transformers) are connected to the current sensor
inputs of the SA9108F through current setting resistors (R5, R6 and R7, R8).

The resistor values should be selected for an input current of 16µA

RMS

into the SA9108F,

at the rated line current.
The values of these resistors should be calculated as follows:
Phase 1:
R5 = R6 = (IL1/16µA

RMS

) * R3/2
Phase 2:
R7 = R8 = (IL2/16µA

RMS

) * R4/2
Where I

LX

= Secondary CT current at rated conditions.

R3 and R

4

= Current transformer termination resistors for the two phases.

R1 + R1A, R

13

and R9 set the current for the phase 1 voltage sense input. R2 + R2A, R12 +
P2 and R10 set the currents for phase 2. The values should be selected so that the input
currents into the voltage sense inputs (virtual ground) are set to 14µ A

RMS

for nominal line

voltage. Capacitors C8 and C9 are for decoupling and phase compensation.
R11 and P1 defines all on-chip bias and reference currents. With a total resistance of

24kΩ, optimum conditions are set. R

11

+ P1 may be varied within ± 10% for calibration
purposes. Any change in resistance will affect the output quadratically (i.e: ∆ R = +5%,
∆f = +10%).

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

SA9108F

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Figure 1: Application Circuit for Two Phase Power/Energy Measurement.

S A9108F

IC - 1

10

0V

C5

DR-00 945

16

XTAL

18

17

19

20

11
12

15

14

13

C3

C2

FROM CTs

VI1P
VI1N
VI2P
VI2N

N

R4

R3

0V

M AINS VOLTAGES

LINE 2

LINE 1

4
5
6

7
8
9

R6
R7

R8

R5

1
2
3

C1

C4

R2

R1

R2A

R1A

31

R1 1

P1

0V

25
24

23

22
21

30
29
28
27
26

FOUT1

DIR
FOUT2

0V

0V

+

C10

0V

P2

0V

C11

R10

R9

37

C7

36
35
34
33
32

40
39

38

C6

+
+C8C9

R15

R14

R12 R13

5V

SA9108F

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10/12

Parts List for Application Circuit: Figure 1

Item Symbol Description Detail

1 IC-1 SA9108FPA DIP-40
2 XTAL Crystal, 3.5795 MHz Colour burst TV
3 R1 Resistor, 120k, 1%, 1/4W
4 R1A Resistor, 82k, 1%, 1/4W
5 R2 Resistor, 120k, 1%, 1/4W
6 R2A Resistor, 82k, 1%, 1/4W
7 R13 Resistor, 24k, 1%, 1/4W
8 R12 Resistor, 22k, 1%, 1/4W

9 R14 Resistor, 820Ω, 1%, 1/4W
10 R5 Resistor Note 1
11 R6 Resistor Note 1
12 R7 Resistor Note 1
13 R8 Resistor Note 1
14 R11 Resistor, 22k, 1%, 1/4W
15 R9 Resistor, 1M, 1%, 1/4W
16 R10 Resistor, 1M, 1%, 1/4W
17 R3 Resistor Note 1
18 R4 Resistor Note 1
19 R15 Resistor, 820Ω, 1%, 1/4W
20 P2 Potentiometer, 4.7k Multi turn
21 P1 Potentiometer, 4.7k Multi turn
22 C8 Capacitor, electrolytic, 1µF, 16V Note 2
23 C9 Capacitor, electrolytic, 1µF, 16V Note 2
24 C4 Capacitor, 3.3nF
25 C1 Capacitor, 3.3nF
26 C2 Capacitor, 2.2nF
27 C3 Capacitor, 3.3nF
28 C6 Capacitor, 560pF
29 C7 Capacitor, 560pF
30 C5 Capacitor, 820nF Note 3
31 C10 Capacitor, 100nF
32 C11 Capacitor, 100nF

Note 1: Resistor (R5, R6, R7 and R8) values are dependant upon the selected values of

the current transformer termination resistors R3 and R4.

Note 2: Capacitor values may be selected for DC blocking and to compensate for phase

errors caused by the current transformers.

Note 3: Capacitor (C5) to be positioned as close to Supply Pins (VDD & VSS) of IC-1, as

possible.

SA9108F

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11/12

ORDERING INFORMATION

Part Number Package

SA9108FPA DIP-40

SA9108FFA PLCC-44

SA9108F

sames

12/12

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Disclaimer: The information contained in this document is confidential and proprietary to South African Micro­Electronic 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.