Pin Selectable Three Phase Power / Energy Metering
IC for Stepper Motor / Impulse Counter Applications
with Anti Tamper Features
SA2005M
FEATURES
+
Direct drive for
+
+
+
electro-mechanical counters or stepper
sames
+
+
+
+
+
motors
Selectable dividing ratios for different meter rated
conditions
Per phase energy direction and voltage fail indication
Precision oscillator on chip
Meets the IEC 521/1036 Specification requirements for
Class 1 AC Watt hour meters
Operates over a wide temperature range
Easily adaptable to different signal levels
Precision voltage reference on chip
Protected against ESD
DESCRIPTION
The SAMES SA2005M provides a single chip active energy
metering solution for three phase mechanical counter-based
meter designs. Very few external components are required
and it has direct drive capability for electro-mechanical
counters.
The SAMES SA2005M is a CMOS mixed signal integrated
circuit that performs three phase power/energy calculations
over a range of 1000:1, to an overall accuracy of better than
Class 1.
The integrated circuit includes all the required functions for 3-
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.
VDD VSS
The SA2005M drives a calibration LED directly.
voltage fail and voltage sequence faults as well
direction indication are available as LED outputs.
divider ratios enable various mechanical counter
motor counter resolutions.
Per phase
as energy
Selectable
or stepper
A precision oscillator, that replaces an external crystal, is
integrated on chip. A voltage reference is integrated on chip.
The SA2005M integrated circuit is available in 24-pin dual in
line plastic (DIP-24) and small outline (SOIC-24) package
options.
IIN1
IIP1
IVN1
IIN2
IIP2
IVN2
IIN3
IIP3
IVN3
GND
I1
X
V1
I2
X
V2
I3
X
V3
PROGRAM-
MABLE
ADDER
POWER
TO
PULSE
RATE
LED
MON
MOP
PH1
PH2
PH3
PH / DIR
REF
TIMING & CONTROL
OSC
SELECTOR
INTERFACE
dr-01616
VREF
TEST
RA RE
IM
Figure 1: Block diagram
SPEC-0115 (REV. 3)
1/12
09-05-02
SA2005M
ELECTRICAL CHARACTERISTICS
(V
DD
= 2.5V, V
SS
= -2.5V, over the temperature range -10°C to +70°C
#
, unless otherwise specified.)
Parameter
Operating temp. Range
Supply Voltage: Positive
Supply Voltage: Negative
Supply Current: Positive
Supply Current: Negative
Current Sensor Inputs (Differential)
Input Current Range
Voltage Sensor Inputs (Asymmetrical)
Input Current Range
Pin VREF
Ref. Current
Ref. Voltage
Digital I/O
Pin MOP, MON, LED, PH/DIR,
PH1, PH2, PH3
Output High Voltage
Output Low Voltage
Pins RA, RE, IM, TEST
Input Low Voltage
Input High Voltage
Pins RA, RE, IM
Pin scan current*
Pin TEST
Pull down current
-I
R
V
R
45
1.1
50
55
1.3
µA
V
I
IV
-25
+25
µA
I
II
-25
+25
µA
Symbol
T
O
V
DD
V
SS
I
DD
I
SS
Min
-25
2.25
-2.75
15
15
Typ
Max
+85
2.75
-2.25
Unit
°C
V
V
mA
mA
sames
Condition
Peak value
Peak value
With R = 24kW
connected to V
SS
Reference to V
SS
V
OH
V
OL
V
IH
V
IL
I
IH
-I
IL
I
IH
V
DD
-1
V
SS
+1
V
DD
-1
V
SS
+1
3.1
2
48
7
4.6
110
V
V
V
V
mA
mA
µA
I
OH
= -2mA
I
OL
= 5mA
V
I
= V
DD
V
I
= V
SS
V
I
= V
DD
#Extended Operating Temperature Range available on request.
*Switched to pin scan mode for 71µs.
ABSOLUTE MAXIMUM RATINGS*
Parameter
Supply Voltage
Current on any pin
Storage Temperature
Operating Temperature
Symbol
V
DD
-V
SS
I
PIN
T
STG
T
O
Min
3.6V
-150
-40
-40
Max
6.0
+150
+125
+85
Unit
V
mA
°C
°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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SA2005M
PIN DESCRIPTION
PIN
20
6
18
21, 24,
3
23, 22,
2, 1,
5, 4
19
Designation
GND
V
DD
V
SS
IVN1, IVN2,
IVN3
IIN1, IIP1,
IIN2, IIP2,
IIN3, IIP3
VREF
Description
Analog Ground. The voltage to this pin should be mid-way between V
DD
and V
SS
.
sames
Positive supply voltage. Typically +5V if a current transformer is used for current sensing.
Negative supply voltage. Typically 0V if a current transformer is used for current sensing.
Voltage sense inputs. The current into the A/D converter should be set at 14µA
RMS
at nominal mains
voltage. The voltage sense input saturates at an input current of ±25µA peak.
Inputs for current sensors. The termination resistor voltage from each current transformer is
converted to a current of 16µA
RMS
at rated conditions. 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
SS
sets the optimum operating condition.
Test input. For normal operation connect this pin to V
SS
.
Calibration LED output. Refer to section LED Output (LED) for the pulse rate output options.
Motor pulse outputs. These outputs can be used to drive an impulse counter or stepper motor directly.
Multiplexed Phase or direction driver output.
Multiplexed LED drivers for direction and mains fail indication.
Rated conditions select input.
The RE input selects the calibration LED resolution as well as the summing mode for the
programmable adder.
The IM inputs selects the counter resolution (Motor drive output).
17
10
11, 12
13
14, 15,
16
7
8
9
TEST
LED
MON, MOP
PH / DIR
PH1, PH2,
PH3
RA
RE
IM
ORDERING INFORMATION
IIP2
IIN2
IVN3
IIP3
IIN3
VDD
1
2
3
4
5
6
7
8
9
10
11
12
dr-01617
24
23
22
21
20
19
IVN2
Part Number
IIN1
IIP1
IVN1
GND
VREF
Package
DIP-24
SOIC-24
SA2005MPA
SA2005MSA
RA
RE
IM
LED
MON
MOP
18 VSS
17
16
15
14
13
TEST
PH3
PH2
PH1
PH / DIR
Figure 2: Pin connections: Package: DIP-24, SOIC-24
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SA2005M
FUNCTIONAL DESCRIPTION
The SAMES SA2005M is a CMOS mixed signal analog/digital
integrated circuit that performs three phase 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 3-
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 integrated circuit includes all the required functions for a
three phase mechanical counter-based meter design. A
precision oscillator, that replaces an external crystal, is
integrated on chip providing a temperature stable time base for
the digital circuitry. A temperature stable voltage reference
integrated on chip generates the reference current used by the
analog circuitry.
Voltage and current are sampled simultaneously by means of a
sigma delta modulator type ADC and power is calculated for
each individual phase.
The power is fed to a programmable adder that allows the
representation of the measured energy to be either total or
absolute sum.
The summed power is integrated and divided down to
represent integrated energy. Pulses on the LED output and on
the mechanical counter driver outputs represent measured
amounts of energy. Programmable dividers provide flexible
counter as well as calibration LED resolutions.
Outputs for phase fail and voltage sequence faults and energy
direction are available.
Calibration of the device is done on the voltage sense inputs of
the SA2005M.
The SA2005M may be used in various meter designs by
setting the RE, RA and IM pins to the appropriate state. See
Input Signals section for the configuration settings. These
features enable the meter manufacturer extremely flexible
meter designs from a single integrated circuit.
An integrated anti-creep function ensures that no pulses are
generated at zero line currents.
sames
POWER CONSUMPTION
The overall power consumption rating of the SA2005M
integrated circuit is less than 80mW with a 5V supply.
INPUT SIGNALS
ANALOG INPUT CONFIGURATION
The current and voltage sensor inputs are illustrated in figure 3.
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 A
I
and A
V
generate virtual shorts on the signal inputs.
Exact duplications of the input currents are generated for the
analog processing circuitry. The current and voltage sense
inputs are identical. Both inputs are differential current driven
up to ±25µA peak. One of the voltage sense amplifiers input
terminals is internally connected to GND. This configuration is
possible because the voltage sense input is much less
sensitive to externally induced parasitic signals compared to
the current sense inputs.
Voltage Sense Inputs (IVN1, IVN2, IVN3)
The mains voltages are measured by means of resistor
dividers and the divided voltages are converted to currents.
The current into each voltage sense input (virtual ground)
should be set to 14µA
RMS
at rated voltage conditions. The
individual mains voltages are divided down to 14V
RMS
per
phase. The resistors R12, R13 and R14 (figure 8) set the
current for the voltage sense inputs. The voltage sense inputs
saturate at an input current of ±25µA peak.
V DD
IIP
CURRENT
SENSOR
INPUTS
VSS
VDD
A
I
IIN
VSS
VDD
IVP
VOLTAGE
SENSOR
INPUT
V SS
A
V
ELECTROSTATIC DISCHARGE (ESD) PROTECTION
The SA2005M integrated circuit's inputs/outputs are protected
against ESD.
GND
DR-01288
Figure 3: Analog input internal configuration
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SA2005M
Current Sense Inputs (IIN1, IIP1, IIN2, IIP2, IIN3, IIP3)
The current sense inputs connects to a termination resistor
connected across the terminals of a current transformer. At
rated current the resistor values should be selected for input
currents of 16µA
RMS
. Referring to figure 8, the resistors R1 and
R2 on current channel 1, resistors R3 and R4 on current
channel 2 and resistors R5 and R6 on current channel 3, define
the current level into the current sense inputs of the SA2005M.
The current sense inputs saturates at an input current of
±25µA peak. Resistors R29, R30 and R31 are used as current
transformer termination resistors. The voltage drop across the
termination resistors should be at least 20mV at rated
conditions. Values for the current sense inputs are calculated
as follows:
R
1
= R
2
= ( I
L
/ 16µA
RMS
) x R
29
/ 2
R
3
= R
4
= ( I
L
/ 16µA
RMS
) x R
30
/ 2
R
5
= R
6
= ( I
L
/ 16µA
RMS
) x R
31
/ 2
Where:
I
L
= Line current/CT-ratio
The value of the termination resistors should be less than the
resistance of the CT's secondary winding.
sames
Resolution (RE)
The RE input selects the summing mode for the programmable
adder as well as the dividing ratio for the LED output (LED
resolution). The following table lists the options available:
RE Pin
VSS
PH/DIR
OPEN
VDD
Summing Mode
Total sum
Total sum
Absolute sum
Absolute sum
Dividing Ratio
(LED Resolution)
1
4
1
4
The summing mode is the representation of the measured
energy and can be either of the following types:
Total sum
This represents the total sum of the energy measured on all
three phases flowing through the current sensors. Negative
energy flow is taken into consideration.
Absolute sum
This represents the sum of the energy measured on all three
phases, regardless of the direction of energy flow through the
current sensors.
Voltage Reference Connection (VREF)
A bias resistor of 24kW provides an optimum bias conditions on
chip. Calibration of the SA2005M is done on the voltage sense
inputs as described in the Typical Application.
Impulses (IM)
The IM inputs selects between 1, 10, or 100 dividing ratio for
the motor drive outputs (counter resolution). Please note that
the device will not perform metering functions while in test
mode. Refer to the Using the RA, Re, Im inputs section for
further information.
IM Pin
VSS
PH/DIR
VDD
OPEN
Dividing Ratio (Counter Resolution)
100 (1P/KwH)
10 (10P/KwH)
1 (100P/KwH)
Test Mode
Rated (RA)
The rated condition select pin allows the metering constants
(LED output and Motor Drive output) to remain unchanged for
different rated conditions having a 1:2:3 scaling ratio, for
example 230V/20A, 230V/40A and 230V/60A. This option
allows for the development of different rated meters requiring
minimal changes. The only changes to be implemented is the
selection of the current sense resistors for the expected rated
load currents and the selection of pins RA, RE and IM.
RA Pin
VSS
PH/DIR
VDD
Open
Rated Conditions Multiplying Ratio
1/3
2/3
3/3
Fast LED output. The output is 1252Hz at rated
current and voltage inputs.
Test Inputs (TEST)
The TEST input is the manufacturers test pin and must be
connected to VSS in a metering application.
At a rated condition of 230V/60A (13800W), setting the RA pin
to VDD (ratio set to 3/3) and the RE pin to VSS (LED
resolution) the LED pulse rate will be 3200 pulses/KWh. With a
combination of RA, RE and IM settings various rated condition
can easily be met. Refer to the Using the RA, RE, IM inputs
section for further information.
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