Datasheet SA2002EPA Datasheet (SAMES)

Single Phase Uni-directional Power / Energy
Metering IC with Instantaneous Pulse Output

SA2002E

+ FEATURES

+ Functionally compatible with the SA9602E with reduced

external components

+ Uni-directional power and energy measurement

+ Meets the IEC 521/1036 Specification requirements for

Class 1 AC Watt hour meters

+ Protected against ESD

DESCRIPTION

The SAMES SA2002E is an enhancement of the SA9602E, as
the circuit contains the oscillator on chip.

The SAMES SA2002E single phase uni-directional
power/energy metering integrated circuit generates a pulse
rate output with a frequency proportional to the power
consumption.

The SA2002E performs a calculation for active power. The
method of calculation takes the power factor into account.
Energy consumption can be determined by the power
measurement being integrated over time.

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+ Total power consumption rating below 25mW

+ Adaptable to different types of current sensors

+ Operates over a wide temperature range

+ Precision voltage reference on-chip

+ Precision oscillator on-chip

This innovative universal single-phase power/energy metering
integrated circuit is ideally suited for energy calculations in
applications such as residential municipal metering and factory
energy metering and control.

The SA2002E integrated circuit is available in 8, 14 and 20 pin
dual-in-line plastic (DIP) as well as 16 and 20 pin small outline
(SOIC) package types.

IIP

IIN

IVP

GND

DR-01586

ANALOG

SIGNAL

PROCESSING

POWER

INTEGRATOR

VOLTAGE

REF.

VREF

Figure 1: Block diagram

V

DD

POWER

TO

FREQUENCY

TIMINGOSC

V

SS

FOUT

SA2002E (REV. 5)

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SA2002E

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ELECTRICAL CHARACTERISTICS

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

DD SS

Parameter

Operating temp. Range

Supply Voltage: Positive

Supply Voltage: Negative

Supply Current: Positive

Supply Current: Negative

Symbol

T

O

V

DD

V

SS

I

DD

I

SS

Min

-25

2.25

-2.75 -2.25

#

Typ

Max

+85

2.75

3

3

5

5

Current Sensor Inputs (Diffferential)

Input Current Range

I

II

-25

+25

Voltage Sensor Input (Asymmetrical)

Input Current Range

Pin FOUT
Output High Voltage
Output Low Voltage

Pulse Rate FOUT

Pin VREF
Ref. Current
Ref. Voltage

I

IV

V

OL

V

OH

f

p

-I

R

V

R

-25

V-1

DD

5
0

45

1.1

1360

50

+25

V+1

SS

1600
3000

55

1.3

# Extended Operating Temperature Range available on request.

Unit

°C

V

V

mA

mA

µA

µA

V
V

Hz
Hz
Hz

µA

V

Condition

Peak value

Peak value

At rated input conditions
Specified linearity
Min and Max frequency

With R = 24kW
connected to V
Reference to V

SS

SS

ABSOLUTE MAXIMUM RATINGS*

Parameter Symbol Min Max Unit

Supply Voltage V -V -0.3 6.0 V

Current on any pin I -150 +150 mA

Storage Temperature T -40 +125 °C

Operating Temperature T -25 +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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DD SS

PIN

STG

O

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3

SA2002E

PIN DESCRIPTION

8

Pin

8

4

14

Pin

Pin

14 16 20 GND

5 5 8

16

20

Pin

Designation Description

Analog Ground. The voltage to this pin should be mid-way
between V and V .

Positive supply voltage. The voltage to this pin is typically +2.5V

V

DD

if a shunt resistor is used for current sensing or in the case of a
current transformer a +5V supply can be applied.

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DD SS

6

7

1, 2

10 12 14

13 15 19

1, 2 1, 2 1, 2

3 3 3 3

5

8 6

4 4 4

6 7 5

7 8 6

9 9 7

11 9

10

12 11 10

13 11

14 13

12

15

16

17

18

V

SS

IVP

IIN, IIP

VREF

FOUT

TP1

TP2

TP3

TP4

TP5

TP6

TP7

TP8

TP9

TP10

TP11

TP12

Negative supply voltage. The voltage to this pin is typically -2.5V
if a shunt resistor is used for current sensing or in the case of a
current transformer a 0V supply can be applied.

Analog Input for Voltage. The current into the A/D converter
should be set at 14µA at nominal mains voltage. The

RMS

voltage sense input saturates at an input current of ±25µA peak.

Inputs for current sensor. The shunt resistor voltage from each
channel is converted to a current of 16µA at rated conditions.

RMS

The current sense input saturates at an input current of ±25µA
peak.

This pin provides the connection for the reference current setting
resistor. A 24kW resistor connected to V set the optimum

SS

operating condition.

Pulse rate output. Refer to pulse output format for a description
of the pulse rate.

Leave pins unconnected.

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SA2002E

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IIN

IIP

VREF

V

1

2

3

4

DD

dr-01484

8

GND

IVP

7

6

V

SS

FOUT

5

Figure 2: Pin connections: Package: DIP-8

IIN

1

IIP IVP

2

VREF

FOUT

3

4

TP1

5

V

DD

6 11

7

TP2

TP3

8

16

15

14

13

12

10

GND

TP8

TP7

V

SS

TP6

TP5

TP4

9

IIN

IIP

VREF

TP1

V

TP2

TP3

1

2

3

4

5

DD

6

7

dr-01485

14

13

12

10

GND

IVP

TP6

TP5

11

V

SS

9

TP4

8

FOUT

Figure 3: Pin connections: Package: DIP-14

IIN

1

IIP IVP

2

VREF

3

4

TP1

5

TP2

TP3

6 15

7

TP4

V

8

DD

TP5

9

TP6

10

20

19

18

17

16

14

13

12

GND

TP12

TP11

TP10

TP9

V

SS

TP8

FOUT

TP7

11

DR-01486

Figure 4: Pin connections: Package: SOIC-16

ORDERING INFORMATION

Part Number

SA2002EPA

SA2002EPA

SA2002EPA

SA2002ESA

SA2002ESA

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Package

DIP-8

DIP-14

DIP-20

SOIC-16

SOIC-20

DR-01483

Figure 5: Pin connections: Package: DIP-20, SOIC-20

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SA2002E

GND

V

DD

DR-01148

VOLTA GE
SENSOR
INPUT

IVP

SS

V

IIN

IIP

CURRENT
SENSOR
INPUTS

SS

V

SS

V

V

DD

DD

V

A

V

A

I

FUNCTIONAL DESCRIPTION

The SA2002E is a CMOS mixed signal Analog/Digital
integrated circuit, which performs power/energy calculations
across a power range of 1000:1, to an overall accuracy of
better than Class 1.

The integrated circuit includes all the required functions for 1­phase 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 SA2002E generates pulses, the frequency of
which is proportional to the measured power consumption.
One frequency output (FOUT) is available. The pulse rate
follows the instantaneous power consumption measured.

POWER CALCULATION

In the application circuit (figure 6), the voltage drop across the
shunt will be between 0 and 16mV (0 to 80A through a shunt
resistor of 200µW) The voltage is converted to a current of
between 0 and 16uA , by means of resistors R1 and R2. The

RMS

current sense inputs saturates at an input current of ±25µA
peak.

RMS

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For the voltage sensor input, the mains voltage (230VAC) is
divided down through a divider (R3, R4 and P1) to 14V . The
current into the A/D converter input is set at 14µA at nominal
mains voltage, via resistor R5 (1MW). P1 may be varied for
calibration purposes.

In this configuration, with a mains voltage of 230V and a
current of 80A, the output frequency measured on the FOUT
pin is 1360Hz. In this case one pulse on FOUT correspond to
an energy consumption of 18.4kW/1360Hz = 13.53Ws.

ANALOG INPUT CONFIGURATION

The input circuitry of the current and voltage sensor inputs is
illustrated in figure 7. These inputs are protected against
electrostatic discharge through clamping diodes. The
feedback loops from the outputs of the amplifiers A and A
generate virtual shorts on the signal inputs. Exact duplications
of the input currents are generated for the analog signal
processing circuitry.

RMS

RMS

IV

N

L

N

L

RSH

GND

R3

GND

Figure 6: Application circuit

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R1

R2

R5

R4

P1

Supply

GND

DR-01584

R6

VDD

U1

IIN

IIP

IVP

GND

VREF

VSS

VDD

FOUT

VSS

SA2002E

VSS

VDD

Pulse output

Figure 7: Internal analog input configuration

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SA2002E

POWER

DR-01282

FOUT

V x I

v

MAINS

P

t

t

t

t

71µs min.

71µs

DR-01151

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ELECTROSTATIC DISCHARGE (ESD)
PROTECTION

The SA2002E integrated circuit's inputs/outputs are protected
against ESD.

POWER CONSUMPTION

The power consumption rating of the SA2002E integrated
circuit is less than 25mW.

INPUT SIGNALS

VREF

A bias resistor of 24kW set optimum bias conditions on chip.
Calibration of the SA2002E should be done on the voltage
input as described in Typical Applications.

Current sense input (IIP and IIN)

Figure 6 shows the typical connections for the current sensor
input. The resistor R1 and R2 define the current level into the
current sense inputs of the SA2002E. At maximum rated
current the resistor values should be selected for input currents
of 16µA .

Values for resistors R1 and R2 can be calculated as follows:
R1 = R2 = (I /16µA) x RSH/2
Where I = Line current
RSH = Shunt resistor or termination resistor if a CT is used as
the current sensor.

RMS

L

L

OUTPUT SIGNAL

Pulse output (FOUT)

The output on FOUT is a pulse density signal representing the
instantaneous power/energy measurement as shown in figure

8. The minimum timing characteristics are shown in the figure

9. The output frequency may be calculated using the following
formula:
f = 11.16 x FOUT x ( I x I ) / I

IV R

Where:
FOUT = Typical rated output frequency (1360Hz)
I = Input current on current sense input (16µA at rated

I

conditions)
I = Input current on voltage sense input (16µA at rated

V

conditions)
I = Reference current on VREF typically 50µA

R

An integrated anti-creep function does not allow output pulses
on FOUT if no power is measured by the device.

2

The value of RSH, if used as the CT's termination resistor,
should be less than the DC resistance of the CT's secondary
winding. The voltage drop across RSH should not be less than
16mV at rated currents.

RMS

Voltage Sense Input (IVP)

The current into the A/D converter should be set at 14µA at

RMS

nominal mains voltage. The voltage sense input saturates at
an input current of ±25µA peak. Referring to figure 6 the typical
connections for the voltage sense input is illustrated. Resistors
R3, R4 and R5 set the current for the voltage sense input. The
mains voltage is divided down to 14V . The current into the
A/D converter input is set at 14µA via resistor R5.

RMS

RMS

Figure 8: FOUT instantaneous pulse output

Figure 9: FOUT pulse width

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SA2002E

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TYPICAL APPLICATION

In figure 10, the components required for stand alone power
metering application, is shown. The application uses a shunt
resistor for the mains current sensing. The meter is designed
for 220V/40A I operation. The most important external
components for the SA2002E integrated circuit are the current
sense resistors, the voltage sense resistors as well as the bias
setting resistor.

BIAS RESISTOR

R13 defines all on-chip and reference currents. With
R13=24kW, optimum conditions are set. Device calibration is
done on the voltage input of the device.

SHUNT RESISTOR

The voltage drop across the shunt resistor at rated current
should be at least 20mV. A shunt resistor with a value of 625µW
is chosen. The voltage drop across the shunt resistor is 25mV
at rated conditions (Imax). The power dissipation in the current
sensor is:

P=(40A)² x 625µW = 1W.

CURRENT SENSE RESISTORS

The resistors R6 and R7 define the current level into the
current sense inputs of the device. The resistor values are
selected for an input current of 16µA on the current inputs of
the SA2002E at rated conditions. According to equation
described in the Current Sense inputs section:

MAX

VOLTAGE DIVIDER

The voltage divider is calculated for a voltage drop of 14V +
5%(14.7V). Equations for the voltage divider in figure 9 are:

RA = R1 + R2 + R3
RB = R12 || (R11+P1)

Combining the two equations gives:
(RA + RB) / 220V = RB / 14.7V

A 5k trimpot will be used in the voltage channel for meter
calibration. The center position on the pot is used in the
calculations. P1 = 2.5kW and values for resistors R11 = 22kW
and R12 =1MW is chosen.

Substituting the values will result in:

RB = 23.91kW
RA = RB x (230V/14.7V - 1) = 333kW so the resistor values of
R1, R2 and R3 are chosen to be 110kW.

R6 = R7 = ( I / 16µA ) x RSH / 2
= 40A / 16µA x 625µW / 2
= 781.2W

A resistor with value of 820W is chosen, the 5% deviation from
the calculated value will be compensated for when calculating
resistor values for the voltage path.

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SA2002E

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OE

OC

P1

C2

+2V5

D3

R4

+ C3

D1

C5

C1

D4

+ C4

D2

R11

U2

R12

-2V5

8

7

6

5

IVP

GND

R5

IIN

U1

1

R6

R1 R2 R3

VSS

FOUT

VDD

VREF

IIP

3

2

R7

SA2002E

4

+2V5

R13

R9

+2V5

DR-01585

C6

-2V5

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R8

NEUTRAL

LIVE

R10

LIVE

NEUTRAL

Figure 10: Application circuit using a shunt resistor for current sensing.

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SA2002E

Parts List for Application Circuit: Figure 10

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Symbol

U1
D1
D2
D3

D4
R1
R2
R3
R4
R5
R6
R7
R8
R9

R10
R11

R12
R13

P1

C1

C2
C3
C4

C5

C6

U2

Description

SA2002E
Diode, Silicon, 1N4002

Diode, Silicon, 1N4002
Diode, Zener, 2.4V

Diode, Zener, 2.4V
Resistor, 110k, 1/4W, 1% metal
Resistor, 110k, 1/4W, 1% metal
Resistor, 110k, 1/4W, 1%, metal

Resistor, 680, 1/4W, 1%, metal
Resistor, 680, 1/4W, 1%, metal

Resistor, 820, 1/4W, 1%, metal

Resistor, 820, 1/4W, 1%, metal

Resistor, 47R, 2W, 5%, wire wound

Resistor, 680, 1/4W, 5%, carbon

Shunt resistor

Resistor, 22k 1/4W, 1%, metal

Resistor, 1M, 1/4W, 1%, metal

Resistor, 24k, 1/4W, 1%, metal
Trim pot, 5k, Multi turn

Capacitor, 220nF

Capacitor, 220nF

Capacitor, 100uF, 16V, electrolytic

Capacitor, 100uF, 16V, electrolytic
Capacitor, 330nF, 250VAC

Capacitor, 820nF
4N35, Opto Coupler

Detail

DIP-8

Note 1
Note 1

Note 2

Note 1: Resistor (R6 and R7) values are dependant on the selected shunt resistor (R14) value.
Note 2: Capacitor C6 to be positioned as close as possible to supply pins.

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PM9607AP

SA2002E

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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:

For the latest updates on datasheets, please visit our web site:

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DIVISION OF LABAT TECHNOLOGIES (PTY) LTD

P O BOX 15888

33 ELAND STREET

LYNN EAST 0039

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[e-mail]

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