Datasheet SA2007MPA, SA2007MSA Datasheet (SAMES)

Single Phase Power/Energy Metering IC with
Tamper Detection

SA2007M

FEATURES

+ Provides direct interface to mechanical counters
+ Monitors Live and Neutral for tamper detection
+ Performs bidirectional energy measurement
+ Various setup modes selectable
+ Meets the IEC 521/1036 Specification for Class 1 AC Watt

hour meters

DESCRIPTION

The SAMES SA2007M is a single-phase bidirectional energy
metering integrated circuit. It provides a mono-chip solution for
energy meters with electro-mechanical displays, such as
stepper motors and impulse counters. A precision oscillator,
that replaces an external crystal is integrated on chip.

Two current sensor inputs allow the measurement of energy
consumption on both the live and neutral.

Direction detection of energy flow as well as other common
tamper conditions are flagged.

samessames

+ Total power consumption rating below 30mW
+ Adaptable to different types of sensors
+ Operates over a wide temperature range
+ Precision voltage reference on-chip
+ Precision oscillator on chip

The power consumption on both the live and neutral are
continuously measured and the larger of the two is selected for
energy metering.

The SA2007M drives the calibration LED, the indicator LEDs
and the electro-mechanical counter directly.

The SA2007M integrated circuit is available in 20 pin dual-in­line plastic (DIP-20) and small outline (SOIC-20) package
types.

IIN1

IIP1

IIN2

IIP2

IVP

GND

Dr-01558

ANALOG

SIGNAL

PRO-

CESSING

AND

POWER

CAL-

CULATION

VOLTAGE

REF.

VREF

POWER 1 (DIGITAL)

POWER 2 (DIGITAL)

OSC

TCLK

Figure 1: Block diagram

COM-

PARATOR

POWER

TO

PULSE RATE

MP0MP1

VSSVDD

ELT

SEL1

DIRO

LED

MOP

MON

RATED

SPEC-0075 (REV. 2)

1/10

PRELIMINARY

16-01-01

SA2007M

samessames

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

4.1

4.1

#

Typ

Max

+85

2.75

5.8

5.8

8.2

8.2

Current Sensor Inputs (Differential)

Input Current Range

I

II

-25

+25

Voltage Sensor Input (Asymmetrical)

Input Current Range

Pin VREF
Ref. Current
Ref. Voltage

I

IV

-I

R

V

R

-25

45

1.1

50

+25

55

1.3

Digital I/O

Pins DIRO, LED, MON, MOP
Output High Voltage
Output Low Voltage

V

OH

V

OL

V-1

DD

V+1

SS

Pins MP0, MP1, TCLK, RATED,
SEL1, ELT
Input High Voltage
Input Low Voltage

Pin RATED
Pin scan current**

Pins MP0, MP1, TCLK
Pull down current

V

IH

V

IL

I

IH

-I

IL

I

IH

V-1

DD

3.1
2

48

V+1

SS

7

4.6

110

Unit

°C

V

V

mA

mA

µA

µA

µA

V

V
V

V
V

mA
mA

µA

Condition

Peak value

Peak value

With R = 24kW
connected to V
Reference to V

I = -2mA

OH

I = 5mA

OL

V = V

IDD

V = V

ISS

V = V

IDD

SS

SS

#Extended Operating Temperature Range available on request.
** Switched to pin-scan mode every 1.1 seconds for 71µs.

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.

http://www.sames.co.za

DD SS

PIN

STG

O

2/10

PRELIMINARY

SA2007M

PIN DESCRIPTION

PIN

Designation

samessames

Description

20

8

14

19

1, 2,

3, 4

5

6, 7

9, 12

13

15

16

GND

V

DD

V

SS

IVP

IIN1, IIP1
IIN2, IIP2

VREF

MP0, MP1

MON, MOP

LED

RATED

SEL1

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

DD SS

Positive 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 +5V supply can be applied.

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.

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

RMS

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

Inputs for current sensor - channel 1 and channel 2. The shunt resistor voltage from each
channel is converted to a current of 16µA at rated conditions. The current sense input

RMS

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 sets the optimum operating condition.

SS

Motor pulse rate select inputs. Described under Input Signals.

Motor pulse outputs. These outputs can be used to drive an impulse counter or stepper motor
directly.

Calibration LED output. Refer to section Led Output (LED) for the pulse rate output options.

Rated condition select input. Described under Input Signals.

Current channel select output. This output indicates which channel is been used for kWh
metering.

17

18

11

10

ELT

DIRO

NC

TCLK

1IIN1 GND

IIP1 IVP

2

3

IIN2 DIRO

IIP2

4

VREF

5

MP1

6 15

MP0

7

VDD

8

9

MON

10

Earth loop tamper output. This output indicates an earth loop tamper condition.

Direction output. This output indicates the energy flow direction.

No Connection.

Test input. Connect to V for normal operation.

20

19

18

ELT

17

SEL1

16

RATED

VSS

14

LED

13

MOP

12

11

NCTCLK

DR-01595

Figure 2: Pin connections: Package: DIP-20, SOIC-20

SS

ORDERING INFORMATION

Part Number

SA2007MPA

SA2007MSA

Package

DIP-20

SOIC-20

http://www.sames.co.za

3/10

PRELIMINARY

SA2007M

samessames

FUNCTIONAL DESCRIPTION

The SA2007M 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 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
SA2007M incorporates an anti-tamper scheme by
continuously measuring the power consumption on both LIVE
and NEUTRAL lines. A fault is indicated when these
measurements differ by more than 12.5%. The SA2007M
generates pulses with a frequency proportional to the larger of
the two current measurements. The source (LIVE or
NEUTRAL) for these pulses is indicated on the SEL1 pin.

Frequency outputs (MOP, MON and LED) are available. The
pulse rate on these pins follows the instantaneous active
power consumption measured.

A low voltage stepper may be driven directly from the device by
connecting it between the MOP and MON pins, alternatively an
impulse counter may be driven directly by connecting it
between MOP and V .

SS

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 A and A

IV

generate virtual shorts on the signal inputs. Exact duplications
of the input currents are generated for the analog signal
processing circuitry.

ELECTROSTATIC DISCHARGE (ESD)
PROTECTION

The SA2007M integrated circuit's input's/outputs are protected
against ESD.

POWER CONSUMPTION

The power consumption rating of the SA2007M integrated
circuit is less than 30mW.

V

DD

IIP

POWER CALCULATION

In Figure 6, the voltage drops across the current transformers
terminating resistors are converted to currents for each current
sense input, by means of resistors R and R (channel 1) as
well as R and R (channel 2). The current sense input

12 13.

10 11

saturates at an input current of ±25µA peak.

The mains voltage (230VAC) is divided down through a divider
to 14V . The current into the A/D converter input is set at

RMS

14µA at nominal mains voltage, via resistor R (1MW).

RMS 7

Different pulse rates are available at the MOP and MON pins.
The device may be programmed for a 1 pulse/kWh, 10
pulses/kWh or 100 pulses/kWh output, depending on the
status of the motor pulse rate select pins MP0 and MP1.

The LED pulse rate is fixed at 6400 pulses per kWh. Rated
conditions such as 230V/20A, 230V/40A and 230V/60A may
be chosen with the rated pin. This facility allows meter
manufacturers to cater for a wide range of metering
applications with minimal design changes.

V

CURRENT
SENSOR
INPUTS

IIN

IVP

VOLTAGE
SENSOR
INPUT

DR-01288

SS

V

DD

V

SS

V

DD

V

SS

GND

A

I

A

V

Figure 3: Analog input internal configuration

http://www.sames.co.za

4/10

PRELIMINARY

SA2007M

samessames

INPUT SIGNALS

VREF

A bias resistor of 24kW sets optimum bias and reference
conditions on chip. Calibration of the SA2007M should be
done on the voltage input as described in Typical Application.

Motor pulse rate select (MP1 and MP0)

The pulse rate of the motor driver output of the SA2007M is
selected by the inputs MP1 and MP0. Three pulses rate
options are available as shown in the following table:

Pulse rate selection

Pulse Rate

Selection Input

MP1 MP0

V

SS

V

SS

V

DD

V

DD

V

SS

V

DD

V

SS

V

DD

Please note that the device will not perform metering functions
as described in this document while in test mode.

Motor drive

output

selection

1

10

100

Device test mode

Unit

pulses/kWh

pulses/kWh

pulses/kWh

OUTPUT SIGNALS

Motor output (MOP, MON)

The MON pulse will follow the MOP pulse within 142ms. This
prevents that the motor armature is in the wrong position after a
power failure. Both MOP and MON outputs are active high.
The motor drive wave forms are shown below:

VDD

MOP

VSS

VDD

MON

VSS

t = 142ms

m

DR-01559

t

m

Figure 4: Motor drive on MON and MOP pins

LED output (LED)

The LED output pulse at a fixed rate of 6400 pulses per kWh.
The LED output is active low. The LED waveform is shown
below:

t

t

m

m

Rated condition select (RATED)

The rated condition select pin gives the option of having a 3:2:1
scaling ratio for the rated meter current. This feature is
particularly useful in circumstances where a manufacturer
requires a meter for use in a system rated for two different
conditions, for example 230V/60A and 230V40A. With the
rated condition select the SA2007M allow for the development
of different rated meters requiring minimal changes. The
following table below lists the option available (assuming the
rated condition to be 230V/60A).

Rated condition select (RATED)

Signal Input RATED

V

SS

OPEN

V

DD

Rated Conditions

230V / 20A

230V / 40A

230V / 60A

VDD

LED

VSS

DR-01332

t

LED

Figure 5: LED pulse output

An integrated anti-creep function prevents any output pulses if
the measured power is less than 0.02% of the meters rated
current.

Selected input indicator (SEL1)

The SA2007M continuously compares the power
consumptions on current channel 1 inputs and current channel
2 inputs. The larger of the two measurements are used for
metering. The SEL1 output pin indicates which channel is
currently being used for the pulse output.

Signal

Output

Value

0

Channel 1 selected (IIN1/IIP1)

SEL 1

Channel 2 selected (IIN2/IIP2)

1

Switching between channels will not be faster than once per
second when both channels are balanced.

Description

http://www.sames.co.za

5/10

PRELIMINARY

SA2007M

Earth loop tamper indication (ELT)

If the power measurements from both current channels differ
by more than 12.5%, (indicating a earth loop tamper
condition), the ELT output is set to zero. The SA2007M
continues to generate output pulses from the larger of the two
measured powers in this condition. The ELT output is active
low.

Direction indication (DIRO)

The SA2007M provides information about the energy flow
direction of both current channels on pin DIRO .

A logic 1 on pin DIRO indicates reverse energy flow of both
current channels. Reverse energy flow is defined as the
condition where the voltage sense input and current sense
input are out of phase (greater than 90 degrees).

Positive energy flow, when voltage sense and both current
sense input are in phase, is indicated on pin DIRO as a logic 0.

The DIRO output will toggle between 1 and 0 a rate of 1Hz
when one of the current channels measure positive energy
and the other negative energy. This condition may occur with a
improper installed or tampered meter.

samessames

The DIRO pin may be used to drive a LED in order to indicate
reverse energy.

Signal

Output

DIRO

Value

1

0

1Hz

Reverse energy flow

Forward energy flow

Out of phase current channels

Description

http://www.sames.co.za

6/10

PRELIMINARY

SA2007M

TYPICAL APPLICATION

The analog (metering) interface described in this section is
designed for measuring 230V/60A with precision better than
Class 1.

The most important external components for the SA2007M
integrated circuit are the current sense resistors, the voltage
sense resistors and the bias setting resistor. The resistors
used in the metering section should be of the same type so
temperature effects are minimized.

Current Input IIN1, IIP1, IIN2, IIP2

Two current transformers are used to measure the current in
the live and neutral phases. The output of the current
transformer is terminated with a low impedance resistor. The
voltage drop across the termination resistor is converted to a
current that is fed to the differential current inputs of the
SA2007M.

samessames

at approximately 17µA. At a nominal voltage current of 14µA
allows for 20% overdriving. The mains voltage is divided with a
voltage divider to 14V that is fed to the voltage input pins via a
1MW resistor.

Voltage Divider

The voltage divider is calculated for a voltage drop of 14V.
Equations for the voltage divider are:

RA = R1 + R2 + R3
RB = R7 || (R5 + P1)

A 5k trimpot will be used in the voltage channel for meter
calibration. The center position on the pot is used in the
calibration P1 = 2.5kW.

Combining the two equations gives:

CT Termination Resistor

The voltage drop across the CT termination resistor at rated
current should be at least 20mV. The CTs have low phase shift
and a ratio of 1:2500. The CT is terminated with a 3.6W resistor
giving a voltage drop of 86.4mV across the termination resistor
at rated conditions (I for the meter).

max

The termination resistor on the second current channel is
adjustable by means of P2 to facilitate channel equalization
calibration. The termination resistor is chosen so that a 10W
trimpot in parallel will provide a sufficient channel range.

Current Sensor Input Resistors

The resistors R10, R11 and R12, R13 define the current level
into the current sense inputs of the SA2007M. The resistor
values are selected for an input current of 16µA on the current
inputs of the SA2007M at rated conditions. For a 60A meter at
2500:1 CT the resistor values are calculated as follows:

R10 = R11 = ( I / 16µA ) x R / 2

LSH

= 60A / 2500 / 16µA x 3.6W / 2
= 2.7kW

I =Line current

L

RSH = CT Termination resistor
2500 = CT ratio

The two current channels are identical so R10 = R11 = R12 =
R13.

Voltage Input IVP

The voltage input of the SA2007M (IVP) is driven with a current
of 14µA at nominal mains voltage. The voltage input saturates

( RA + RB ) / 230V = RB / 14V
Values for resistors R5 = 22kW, P1 = 2.5kW and R7 = 1MW is
chosen.

Substituting the values result in:

RB = 23.9kW

RA = RB x ( 230V / 14V – 1 )

RA = 369kW.

Standard resistor values of R1, R2 and R3 are chosen to be
120kW, 120kW and 130kW.

The capacitor C1 is used to compensate for phase shift
between the voltage sense inputs and the current sense inputs
of the device, in cases where CTs with phase errors are used.
The phase shift caused by the CT may be corrected by
inserting a capacitor in the voltage divider circuit. To
compensate for a phase shift of 0.18 degrees the capacitor
value is calculated as follows:

C = 1 / (2 x p x Mains frequency x R5 x tan (Phase shift angle))
C = 1 / ( 2 x p x 50 x 1MW x tan (0.18 degrees ))
C = 1.013µF

Reference Voltage Bias resistor

R6 defines all on chip and reference currents. With R6 = 24kW
optimum conditions are set. Device calibration is done on the
voltage input of the device.

http://www.sames.co.za

7/10

PRELIMINARY

http://www.sames.co.za

SA2007M

NEUTRAL

LIVE

Figure 6: Typical application circuit

8/10

PRELIMINARY

LIVE

NEUTRAL

GND

IVP

DIRO

ELT

SEL1

RATED

VSS

LED

MOP

R18

R19

14V

VDD

20

19

18

17

16

15

14

13

12

11

C2

GND

P1

C3

R5

VDD

VSS

CNT1

VSS

C1

R7

LED2

R14

R15

LED3

VDD

R16

LED1

LED4

R17

.1123456

U1

1

C4

Vin

GND

2

+C5

VSS

10

VSS

R4

L

T1

TZ1

D1

D3

p s

GND

CT2

CT1

D2

R8

P2

R9

D4

R1 R2 R3

R10

R11

R12

R13

R6

3

Vout

+

C6

U2

1

IIN1

2

IIP1

3

IIN2

4

IIP2

5

VREF

6

MP1

7

MP0

8

VDD

9

MON

TCLK

dr-01597

samessames

SA2007M

Parts List for Application Circuit: Figure 6

Item

1
2
3
4
5
6
7
8
9

10

11
12
13
14
15
16
17
18
19
20
21
22
23
24

25
26
27

28
29
30

31
32
33

34
35
36

37
38
39

40
41

42

Symbol

U2
D1
D2
D3
D4
LED1
LED2
LED3
LED4
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11

R12
R13
R14
R15

R16
R17
R18

R19

P1

P2

C1

C2

C3

C4

C5
C6

CT1
CT2
T1

U1
CNT1
TZ1

Description

SA2007M
Diode, Silicon 1N4148
Diode, Silicon 1N4148
Diode, Silicon 1N4148

Diode, Silicon 1N4148

Light emitting diode, Amber
Light emitting diode, Green
Light emitting diode, Red

Light emitting diode, Green
Resistor, 120k, 1/4W, 1%, metal

Resistor, 120k, 1/4W, 1%, metal
Resistor, 130k, 1/4W, 1%, metal

Resistor, 10W, 2W, Wire wound

Resistor, 24k, 1/4W, 1%, metal
Resistor, 22k, 1/4W, 1%, metal
Resistor, 1M, 1/4W, 1%, metal

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

Resistor, 1/4W, 1%, metal

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

Resistor, 1/4W, 1%, metal

Resistor, 1k, 1/4W, 5%
Resistor, 1k, 1/4W, 5%

Resistor, 1k, 1/4W, 5%
Resistor, 1k, 1/4W, 5%
Resistor, 1k, 1/4W, 5%, metal
Resistor, 1k, 1/4W, 5%, metal

Multi-turn, Trim pot, 10k
Multi-turn, Trim pot, 10W

Capacitor
Capacitor, 220nF
Capacitor, 220nF
Capacitor, 820nF

Capacitor, 2200µF, 25V, electrolytic

Capacitor, 100µF, 16V, electrolytic
Current Transformer

Current Transformer

Transformer, 230V/9V

78LC05, Voltage regulator
Bipolar step motor

400V, Metal oxide varistor

samessames

Detail

DIP-20/SOIC-20

or Similar
or Similar

or Similar
or Similar

Note 2

Note 2
Note 1

Note 1

Note 1
Note 1

Note 2

Note 4

Note 3

Note 1: Resistor (R10, R11, R12 and R13) values are dependent upon the selected value of R8 and R9
Note 2: See TYPICAL APPLICATION when selected the value of R8 and R9.
Note 3: Capacitor (C4) to be positioned as closed to Supply Pins (V & V ) of U-1, as possible.
Note 4: Capacitor (C1) selected to minimize phase error introduced by current transformer (typically 1.5µF for normal CTs)

http://www.sames.co.za

9/10

DD SS

PRELIMINARY

PM9607AP

SA2007P

samessames

samessames

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:

SOUTH AFRICAN MICRO-ELECTRONIC SYSTEMS

DIVISION OF LABAT TECHNOLOGIES (PTY) LTD

P O BOX 15888

33 ELAND STREET

LYNN EAST 0039

REPUBLIC OF SOUTH AFRICA

[e-mail]

http://www.sames.co.za.

Tel: [phone]

Tel: Int [phone]

Fax: [phone]

Fax: Int [phone]

33 ELAND STREET

KOEDOESPOORT INDUSTRIAL AREA

PRETORIA

REPUBLIC OF SOUTH AFRICA

http://www.sames.co.za

10/10

PRELIMINARY