SA9106A

sames

DESCRIPTION
The SAMES SA9106A Single Phase Watt
measurement integrated circuit has an
integrated Light Emitting Diode (LED) dis-
play driver for a 5 digit (7 segment) display.
The SA9106A performs the power calcu-
lations for active power.

The method of calculation takes the power
factor into account.

The measured power is displayed in Watts
and is updated approximately every 2 sec-
onds, given an average power reading for
this period.

This innovative universal Watt measure-
ment integrated circuit is ideally suited for
the display of the measured power in in-
dustrial and domestic power measurement
and multi plug sockets.

The SA9106A integrated circuit is avail-
able in 40 pin dual-in-line plastic (DIP-40)
as well as 44 pin plastic leaded chip carrier
(PLCC-44) package types.

FEATURES

Performs bidirectional power measure-
ment and directly drives a 5 digit (7
segment) LED display

Accuracy better than 1% (± 1 count)

Protected against ESD

Total power consumption rating below
50mW

1/14

Adaptable to different types of current
sensors

Operates over a wide temperature
range

Precision voltage reference on-chip

SINGLE PHASE WATT MEASUREMENT IC

WITH INTEGRATED 5 DIGIT LED DISPLAY DRIVER

PIN CONNECTIONS

4008

PDS039-SA9106A-001

REV. D

10-08-1995

Package: DIP-40

CPIN

V DDA

CPIP

IIP

TP15

CPOP

CPON

VREF

DR-00235

SSA

IVP

GND

TP11

IIN

TP8

TP7

CIP

CIN

COP

CON

V SS

TP22

TP39

DIG[0]

OSC1

OSC2

DIG[1]

DIG[4]

DIG[3]
DIG[2]

TP38

DIG[5]

TP40

SA9106A

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BLOCK DIAGRAM

PIN CONNECTIONS

POWER

INTEG-

RATOR

OSC

VOLTAGE

REF.

ANALOG

SIGNAL

PROCE-

SSING

IVP

GND

DR-00236

VREF

OSC1

IIP

IIN

OSC2

TIMING

LED

DISPLAY

DRIVER

OUTPUTS
FOR LED
DISPLAY

SSA

TP12

IIP

DR-00903

TP4
TP5
VREF

CPOP

CPON

TP9

CPIN

CPIP

TP7

TP44

GND

IVP

TP1
IIN

CON

COP

TP38

TP37

CIN

CIP

DDA

TP22

E
D
C

TP40

TP39

DIG[5]

DIG[4]

DIG[2]
DIG[1]
DIG[0]

OSC2
G

OSC1

DIG[3]

SA9106A

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ELECTRICAL CHARACTERISTICS
(V

and V

DDA

= 2.5V, V

and V

SSA

= -2.5V, over the temperature range -10°C to +70°C

unless otherwise specified.)

Parameter

Symbol

Min

Typ

Max

Unit

Condition

Supply Voltage: Positive

2.25

2.75

Supply Voltage: Negative

-2.75

-2.25

Supply Current: Positive

Supply Current: Negative

Current Sensor Inputs (Differential)

Input Current Range

-25

+25

µA

Peak value

Voltage Sensor Input (Asymetric)

Input Current Range

-25

+25

µA

Peak value

Display outputs

Digit Outputs

= V

+ 0.5V

Segment Drivers

= V

- 0.5V

Oscillator

Recommended crystal:
TV colour burst crystal f = 3.5795 MHz

Pin VREF

With R

= 24k

Ref. Current

-I

µA

connected to V

Ref. Voltage

1.1

1.3

Referred to V

Extended Operating Temperature Range available on request.

ABSOLUTE MAXIMUM RATINGS*

Parameter

Symbol

Min

Max

Unit

Supply Voltage

-V

-0.3

6.0

Current on any pin

-150

+150

Storage Temperature

STG

-40

+125

°C

Operating Temperature

-25

+85

°C

* Stresses above those listed under "Absolute Maximum Ratings" may cause perma-

nent 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.

SA9106A

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Pin

Designation

Description

PLCC

DIP

GND

Ground

Positive Supply Voltage

DDA

Negative Supply Voltage

SSA

IVP

Analog input for Voltage

IIN

Inputs for current sensor

IIP

OSC1

Connections for crystal or ceramic resonator

OSC2

(OSC1 = Input ; OSC2 = Output)

Light Emitting Diode (LED) display segment

outputs

DIG [0]

Light Emitting Diode (LED) display digit outputs

DIG [1]

DIG [2]

DIG [3]

DIG [4]

DIG [5]

CPON

Connections for outer loop capacitor of A/D

CPOP

converter (Voltage)

CPIN

Connections for inner loop capacitor of A/D

CPIP

converter (Voltage)

CIP

Connections for inner loop capacitor of A/D

CIN

converter (Current)

COP

Connections for outer loop capacitor of A/D

CON

converter (Current)

VREF

Connection for current setting resistor

TP7

Manufacturer's Test Pins (Leave unconnected)

TP8

TP11

TP15

TP22

TP38

PIN DESCRIPTION

SA9106A

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Pin

Designation

Description

PLCC

DIP

TP39

Manufacturer's Test Pins (Leave unconnected)

TP40

TP1

TP4

TP5

TP9

TP12

TP37

TP38

TP44

PIN DESCRIPTION (Continued)

FUNCTIONAL DESCRIPTION
The SA9106A is a CMOS mixed signal Analog/Digital integrated circuit, which performs
bidirectional power calculations across a power range of 1000:1, to an overall accurancy
of better than 1% (± 1 count). An on-chip LED display driver directly drives a 5 digit (7
segment) LED display. The measured power is displayed in Watts.

The integrated circuit comprises of all the required functions 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.

Power Calculation
In the Application Circuit (Figure 1), the voltage drop across the shunt will be
between 0 and 50mV (0 to 80A through a shunt resistor of 625µ

). This voltage is

converted to a current of between 0 and 16µA, by means of resistors R

and R

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 (1M

In this configuration, with a mains voltage of 230 V and a current of 80A, the
displayed power is 18 400 Watts.

LED Display Driver
The SA9106A has an on-chip LED display driver capable of driving 5 digit (7
segment) common cathode digits as well as a sign LED.

The sign LED is addressed by DIG [5], the most significant digit by DIG [4] and the
least significant digit by DIG [0].

The position of the segments a, b, c, d, e, f and g are shown in the diagram below:

SA9106A

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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

generate virtual

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

GND

DR-00505

VOLTAGE
SENSOR
INPUT

IVP

IIN

CURRENT
SENSOR
INPUTS

IIP

VDD

D R - 0 0 2 3 7

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Electrostatic Discharge (ESD) Protection
The SA9106A integrated circuit inputs/outputs are protected against ESD according
to Mil-Std 883C, method 3015.

Power Consumption
The power consumption rating of the SA9106A integrated circuit is less than 50mW,
excluding the display.

TYPICAL APPLICATIONS
In the Application Circuits (Figures 1 and 2) the components required for power
measurement 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.

The most important external components for the SA9106A integrated circuit are:

and C

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%.

and C

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.

, R

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 SA9106A at maximum
line current.

Values for RSH of less than 200µ

should be avoided.

= R

= (I

/16µA) * RSH/2

Where

Line current

RSH

Shunt resistor/termination resistor

, R

and R

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.

together with the trimpot RT defines all on-chip bias and reference currents. The bias

resistor value (R

= R

+ RT) may be varied within ±10% for calibration purposes. Any

change to R

will affect the displayed value quadratically (i.e.: R

= +5%, Display value

= +10%).

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 digital circuitry and the
A/D converters.

SA9106A

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Parts List for Application Circuit: Figure 1

Item

Symbol

Description

Detail

IC-1

SA9106A

DIP-40/PLCC-44

Light Emitting Diode

XTAL

Crystal, 3.5795 MHz

Colour burst TV

Resistor, 1% metal

Note 1

Resistor, 1% metal

Note 1

Resistor, 390k, (230VAC) 1%, metal

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

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

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

Resistor, (Segment G)

Note 2

Resistor, (Segment F)

Note 2

R10

Resistor, (Segment E)

Note 2

R11

Resistor, (Segment D)

Note 2

R12

Resistor, (Segment C)

Note 2

R13

Resistor, (Segment B)

Note 2

R14

Resistor, (Segment A)

Note 2

Potentiometer 4.7k

Multi turn

Capacitor, 560pF

Capacitor, 3.3nF

Capacitor, 100nF

C10

Capacitor, 100nF

C15

Capacitor, 820nF

Note 3

RSH

Shunt Resistor

Note 4

Note 1: Resistor (R1 and R2) values are dependant upon the selected value of RSH.
Note 2: Resistors (R8 to R14) are current limiting resistors required to set the intensity

of the LED display segments.

Note 3: Capacitor (C15) to be positioned as close to Supply Pins (V

& V

) of IC-1 as

possible.

Note 4: See TYPICAL APPLICATIONS when selecting the value of RSH.

SA9106A

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Parts List for Application Circuit: Figure 2

Item

Symbol

Description

Detail

IC-1

SA9106A

DIP-40/PLCC-44

XTAL

Crystal, 3.5795MHz

Colour burst TV

RSH

Resistor

Note 1

Resistor, 1%, metal

Note 2

Resistor, 1%, metal

Note 2

Resistor, 390k, (230 VAC). 1%, metal

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

Resistor, 24k, 1/4W, metal

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

Resistor

Note 3

Resistor

Note 3

R10

Resistor

Note 3

R11

Resistor

Note 3

R12

Resistor

Note 3

R13

Resistor

Note 3

R14

Resistor

Note 3

R15

Resistor, 820

, 1/4W, 1%

R16

Resistor, 820

, 1/4W, 1%

Light emitting diode

Potentiometer 4.7k

Multi turn

Capacitor, 560pF

Capacitor, 3.3nF

Capacitor, 100nF

C10

Capacitor, 100nF

C11

Capacitor

Note 4

C15

Capacitor, 820nF

Note 5

SA9106A

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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:

Resistors (R10 to R16) are current limiting resistors required to set the
intensity of the LED display segments.

Note 4:

Capacitor (C11) selected to minimize phase error introduced by current
transformer (typically 1.5µF).

Note 5:

Capacitor (C15) to be positioned as close to Supply Pins (V

& V

) of

IC-1, as possible.

ORDERING INFORMATION

Part Number

Package

SA9106APA

DIP-40

SA9106AFA

PLCC-44

SA9106A

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Any Sales or technical questions may be posted to our e-mail address below:
energy@sames.co.za

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, 0039

Koedoespoort Industrial Area,

Republic of South Africa,

Pretoria,

Republic of South Africa

Tel:

012 333-6021

Tel:

Int +27 12 333-6021

Fax:

012 333-8071

Fax:

Int +27 12 333-8071

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.

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