Programmable Three Phase Power / Energy Metering
IC for Stepper Motor / Impulse Counter Applications
SA2005P
FEATURES
+
Direct drive for
+
+
+
+
electro-mechanical counters or stepper
sames
+
+
+
+
+
+
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
Adaptable to different types of sensors
Precision voltage reference on-chip
Protected against ESD
motors
Calibration and setup stored on external EEPROM - no
trim-pots required
Flexible programmable features providing ease of
implementation for meter manufacturers
Per phase energy direction and voltage fail indication
Precision oscillator on chip
DESCRIPTION
The SAMES SA2005P provides a single chip active energy
metering solution for three phase mechanical counter-based
meter designs.
Th SA2005P does not require any external trim-pots or resistor
ladders for meter calibration. Calibration and meter
configuration information is stored on a small external
EEPROM.
Meter setup stored on the EEPROM includes various metering
direction modes (total sum, absolute sum, positive or negative
energy) phase calibration data, rated metering conditions,
LED pulse rate, counter pulse width, counter resolution and
creep current.
A programmable rate pulse output is available for meter
calibration purposes. Per phase voltage fail and voltage
sequence faults as well as energy direction indication are
available as LED outputs. Programmable dividers enable
various mechanical counter or stepper motor counter
resolutions.
A precision oscillator, that replaces an external crystal, is
integrated on chip. A voltage reference is integrated on chip.
The SA2005P integrated circuit is available in 24-pin dual in
line plastic (DIP-24) and small outline (SOIC-24) package
options.
VDD VSS
IIN1
IIP1
IVN1
IIN2
IIP2
IVN2
IIN3
IIP3
IVN3
GND
I1
X
V1
I2
X
V2
I3
X
V3
CHANNEL
BALANCE
PROGRAM-
PROG.
CHANNEL
ADDER
BALANCE
CHANNEL
BALANCE
MABLE
ADDER
POWER
TO
PULSE
RATE
LED
MON
MOP
PH / DIR
PH1
PH2
PH3
REF
TIMING & CONTROL
OSC
INTERFACE
RLOAD
dr-01605
VREF
TEST
SCL
SDA
Figure 1: Block diagram
SPEC-0756 (REV. 4)
1/16
22-03-02
SA2005P
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 Input (Asymmetrical)
Input Current Range
Pin VREF
Ref. Current
Ref. Voltage
Digital I/O
Pins RLOAD, TEST, SDA
Input High Voltage
Input Low Voltage
Pins MOP, MON, LED, SCL,
PH/DIR, PH1, PH2, PH3
Output High Voltage
Output Low Voltage
Pin SDA
Pull up current
Pins TEST, RLOAD
Pull down current
V
IH
V
IL
V
DD
-1
V
SS
+1
V
V
-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
16
16
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
-I
IL
I
IH
V
DD
-1
V
SS
+1
24
48
54
110
V
V
µA
µA
I
OH
= -2mA
I
OL
= 5mA
V
I
= V
SS
V
I
= V
DD
#Extended Operating Temperature Range available on request.
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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SA2005P
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.
Serial clock output. This output is used to strobe data from the external EEPROM.
Serial data. Send and receive data from an external EEPROM.
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.
Triggers a data reload from the external EEPROM.
Multiplexed LED drivers for direction and mains fail indication.
8
9
17
10
11, 12
13
7
14, 15,
16
SCL
SDA
TEST
LED
MON, MOP
PH / DIR
RLOAD
PH1, PH2,
PH3
ORDERING INFORMATION
IIP2
IIN2
IVN3
IIP3
IIN3
VDD
1
2
3
4
5
6
7
8
9
10
11
12
dr-01602
24
23
22
21
20
19
IVN2
Part Number
IIN1
IIP1
IVN1
GND
VREF
Package
DIP-24
SOIC-24
SA2005PPA
SA2005PSA
RLOAD
SCL
SDA
LED
MON
MOP
18 VSS
17
16
TEST
PH3
15 PH2
14 PH1
13 PH / DIR
Figure 2: Pin connections: Package: DIP-24, SOIC-24
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3/16
SA2005P
FUNCTIONAL DESCRIPTION
The SAMES SA2005P 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 currents are sampled simultaneously by means of
a sigma delta modulator type ADC and power is calculated for
each individual phase. A programmable channel balance on
each channel is used for individual channel calibration.
The scaled power is fed to a programmable adder that allows
the representation of the measured energy to be either total
sum 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 outputs represent measured amounts
of energy. The programmable dividers provide flexible counter
and calibration LED resolutions.
Outputs for phase voltage fail and voltage sequence faults and
energy direction are available.
The SA2005P does not require any external trim-pots or
resistor ladders as meter calibration and configuration data is
stored on a small external EEPROM. The SA2005P configures
itself from the EEPROM during power up. These features
enables meter manufacturers flexible meter designs from a
single integrated circuit.
sames
operation of the meter. Every data byte stored in the EEPROM
is protected with a checksum byte to ensure data integrity.
ELECTROSTATIC DISCHARGE (ESD) PROTECTION
The SA2005P integrated circuit's inputs/outputs are protected
against ESD.
POWER CONSUMPTION
The overall power consumption rating of the SA2005P
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.
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
V DD
IIP
CURRENT
SENSOR
INPUTS
VSS
VDD
A
I
IIN
VSS
VDD
IVP
AUTOMATIC DEVICE CONFIGURATION (BOOT UP)
During power up, registers containing configuration and
calibration information is updated from an external EEPROM.
The device itself never writes tot he EEPROM so any write
protect features offered by manufacturer of EEPROM’s may
be used to protect the configuration and calibration constant of
the meter. The device reloads its configuration every 1193
seconds from the external EEPROM in order to ensure correct
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VOLTAGE
SENSOR
INPUT
V SS
A
V
GND
DR-01288
Figure 3: Analog input internal configuration
4/16
SA2005P
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 SA2005P.
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
In case a current transformer is used for current sensing the
value of the termination resistors should be less than the
resistance of the CT's secondary winding.
sames
Reload (RLOAD)
A falling edge on the RLOAD pin will trigger a register update
from the external EEPROM. This feature may be used during
calibration to load updated register data in the SA2005P. For
normal operation of the SA2005P the RLOAD pin may be left
floating.
Test Inputs (TEST)
The TEST input is the manufacturers test pin and must be
connected to VSS in a metering application.
OUTPUT SIGNALS
LED Output (LED)
Four options for the LED output pulse rate are available, 6400,
3200, 1600 pulses per kWh, and a pulse rate of 1252 pulses
per second at rated conditions. At 1252 pulses per second t
LED
is 71µs, for the other options t
LED
is 10ms. The LED output is
active low as shown in figure 4.
VDD
LED
VSS
DR-01332
Voltage Sense Inputs (IVN1, IVN2, IVN3)
The mains voltage are measured by means of a resistor divider
and the divided voltage are converted to a current. The current
into the voltage sense inputs (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 ±25uA peak.
t
LED
Figure 4: LED pulse output
Motor Output (MOP, MON)
The motor pulse width is programmable for 71ms, 142ms and
284ms. The MON pulse will follow the MOP pulse within the
selected pulse width time. This prevents the motor armature
being in the wrong position after a power failure. Both MOP
and MON outputs are active high.
A MOP pulse followed by a
MON pulse represents one energy pulse.
The motor drive
waveforms are shown in figure 5.
VDD
MOP
VSS
VDD
MON
VSS
DR-01559
Voltage Reference Connection (VREF)
A bias resistor of 24k provides an optimum bias conditions on
chip. Calibration of the SA2005P is done by means of divider
ratios stored on an external EEPROM. This is described in the
Device Configuration section.
Serial Data (SDA)
The SDA pin connects directly to the SDA pin of an external
EEPROM. The pin is used to transfer data between the
EEPROM and the SA2005P. An external pull-up resistor in not
needed.
t
m
t
m
t
m
Figure 5: Motor drive on MON and MOP pins of device
Serial Clock (SCL)
The SCL pin connects directly to the SCL of an external
EEPROM. The SCL output is used to strobe data at a rate of
50kHz out of the EEPROM. An external pull up resistor is not
needed. The SCL output uses a soft driver and may be
overdriven by the calibration equipment.
Multiplex Output (PH/ DIR)
The PH/DIR output enables either direction or voltage
information on the phase LED driver outputs (PH1, PH2 and
PH3). This multiplex output switches between logic 1 and 0 at
a frequency of approximately 113Hz. A logic 0 enables energy
direction information on the LED driver outputs and a logic 1
enables voltage information.
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