Single Phase Bidirectional Dual Element
Power/Energy Metering IC with Pulse Output
SA2007H
FEATURES
+
Two current sensor inputs
+
Dual pulse and energy direction outputs
+
No external crystal or resonator required
+
Performs bi-directional power and energy measurement
+
Meets the IEC 521/1036 Specification for Class 1 AC Watt
hour meters
sames
+
+
+
+
+
Protected against ESD
Total power consumption rating below 25mW
Adaptable to different types of sensors
Operates over a wide temperature range
Precision voltage reference on-chip
DESCRIPTION
The SAMES SA2007H is a single phase bidirectional dual
element energy metering integrated circuit. It provides a
simple analog interface to a micro-controller and is specifically
designed for meter manufacturers to have full control over the
meter functionality.
The SA2007H has two current sensor inputs. The power
consumption on both inputs are continuously measured. A
typical application would be to monitor Live and Neutral lines
for tamper detection.
For each current sensor input the SA2007H integrated circuit
has a corresponding pulse output, each generating a pulse
rate with a frequency proportional to the power consumption
measured on the specific channel.
The SA2007H performs active power measurement and takes
the power factor into account. Energy consumption can be
determined by the power measurement being integrated over
time. The energy flow direction information is also available for
each channel.
IIP1
IIN1
CURRENT
CHANNEL 1
X POWER 1
POWER TO
PULSE RATE
P1
D1
OMODE
IVP
VOLTAGE
AGND
OUTPUT
CONTROL
RP
INT
IIP2
IIN2
CURRENT
CHANNEL 2
X POWER 2
POWER TO
PULSE RATE
P2
D2
FMO
VOLTAGE
REF.
OSC
TIMING
dr-01623
V
DD
V
SS
VREF
TCLK
TEST
Figure 1: Block diagram
SPEC-0116 (REV. 1)
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PRELIMINARY
15-01-01
SA2007H
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 P1, P2, D1, D2, FMO, INT
Output High Voltage
Output Low Voltage
Pins TCLK, TEST, OMODE, RP
Input High Voltage
Input Low Voltage
Pulse Rate P1, P2
V
OH
V
OL
V
IH
V
IL
f
p
V
DD
-1
V
V
V
V
Hz
Hz
Hz
µs
µs
µA
I
IV
-I
R
V
R
-25
45
1.1
50
+25
55
1.3
µA
µA
V
I
II
-25
+25
µA
Symbol
T
O
V
DD
V
SS
I
DD
I
SS
Min
-25
2.25
-2.75
5
5
Typ
Max
+85
2.75
-2.25
6
6
Unit
°C
V
V
mA
mA
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Condition
Peak value
Peak value
With R = 24kW
connected to V
SS
Reference to V
SS
V
SS
+1
I
OH
= -2mA
I
OL
= 5mA
V
DD
-1
1360
5
0
71.55
143.1
48
V
SS
+1
1600
3000
At rated input conditions
Specified linearity
Min and Max frequency
Positive energy flow
Negative energy
V
1 =
V
DD
Pulse Width P1, P2
t
pp
t
pn
I
IL
Pins TCLK, TEST, RP, OMODE
Pull down current
110
#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
-0.3
-150
-40
-25
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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PRELIMINARY
SA2007H
PIN DESCRIPTION
PIN
20
8
Designation
AGND
V
DD
Description
sames
Analog Ground. The voltage to this pin should be mid-way between V
DD
and V
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.
Analog Input for Voltage. 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 sensor - Channel 1 and Channel 2. The shunt resistor voltage from each
channel 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.
This logic input is used to select between latched or unlatched condition for the pulse and
direction outputs.
A logic input is used to reset the latched outputs which is required after an interrupt has
occurred.
The zero crossover of the voltage sense input is signaled on this pin.
Configure / Test inputs. For normal operations these pins must be connected to V
SS
.
This logic output will indicate a change in status of the pulse or direction outputs.
Pulse outputs. The P1 and P2 outputs give instantaneous pulse outputs of channel 1 and
channel 2 respectively. The pulse is active low with a pulse width of 71.5µs for positive energy
and doubles for reverse energy.
Direction output. These outputs indicate the energy flow direction of each channel.
No Connection.
14
19
V
SS
IVP
1, 2,
3, 4
IIN1, IIP1
IIN2, IIP2
5
6
7
9
10, 15
12
17, 13
VREF
OMODE
RP
FMO
TCLK, TEST
INT
P1, P2
18, 16
11
D1, D2
NC
ORDERING INFORMATION
IIN1
IIP1
IIN2
IIP2
VREF
OMODE
RP
VDD
FMO
TCLK
1
2
3
4
5
6
7
8
9
10
20
19
AGND
IVP
Part Number
SA2007HPA
SA2007HSA
Package
DIP-20
SOIC-20
18 D1
17
16
15
P1
D2
TEST
14 VSS
13
12
11
P2
INT
NC
DR-01620
Figure 2: Pin connections: Package: DIP-20, SOIC-20
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PRELIMINARY
SA2007H
FUNCTIONAL DESCRIPTION
The SA2007H 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 1-
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.
Referring to the block diagram (figure 1) the SA2007H has two
current sense channels and a voltage sense channel. The
voltage measured is multiplied with the current measured on
the two channels. The multiplied signals from each current
channel is fed to separate power to pulse rate blocks.
The power to pulse rate blocks generate pulses at a frequency
proportional to the instantaneous active power measured.
Pulses on output P1 represent energy measured on current
channel 1. The pulses on output P2 represent energy
measured on current channel 2. Counting the pulses
generated represents the energy measured.
A typical application would be to simultaneous measure
energy/power consumption in both Live and Neutral lines. A
meter tamper condition could be detected when an imbalance
exists between the live and neutral energy/power measured.
Two modes of operation is available on the SA2007H, in one
mode the device is functionally the same as two SA2002H
devices sharing a common voltage channel. Alternatively the
pulse output is latched and an interrupt is generated on any
change of the pulse outputs.
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POWER CALCULATION
In Figure 8, the voltage drops across the current transformers
terminating resistors are converted to currents for each
current sense input, by means of resistors R
10
and R
11
(channel
1) as well as R
12
and R
13.
(channel 2). The current sense input
saturates at an input current of ±25µA peak.
The mains voltage (230VAC) is divided down through a divider
to 14V
RMS
. The current into the A/D converter input is set at
14µA
RMS
at nominal mains voltage, via resistor R
7
(1MW).
In this configuration, with a mains voltage of 230V and a
current of 80A, the output frequency measured on P1 or P2 pin
is 1360Hz. In this case the energy associated with a single
pulse is 18.4kW/1360Hz = 13.5Ws per pulse.
ANALOG INPUT CONFIGURATION
The input circuitry of the current and voltage sensor inputs are
illustrated in figure 3. These inputs are protected against
electrostatic discharge through clamping diodes.
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 signal
processing circuitry.
ELECTROSTATIC DISCHARGE (ESD)
PROTECTION
The SA2007H integrated circuit's input's/outputs are protected
against ESD.
POWER CONSUMPTION
The power consumption rating of the SA2007H integrated
circuit is less than 30mW.
V DD
IIP
CURRENT
SENSOR
INPUTS
VSS
VDD
A
I
IIN
VSS
VDD
IVP
VOLTAGE
SENSOR
INPUT
V SS
A
V
GND
DR-01288
Figure 3: Analog input internal configuration
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PRELIMINARY
SA2007H
INPUT SIGNALS
Voltage reference (VREF)
A bias resistor of 24kW sets optimum bias conditions on chip.
Calibration of the SA2007H should be done in the micro-
controllers software.
Output Mode (OMODE)
The output behavior of the SA2007H is selectable between
fixed width outputs or latched outputs. In fixed width mode the
P1 and P2 output pulses stay at a fixed width. In latched mode
the status of P1 and P2 are cleared with a logic 1 on the RP pin.
Refer to the “Output signals in latched mode” section (Page 6)
for further information.
OMODE
0
1
Description
I
V
Fixed width mode
Latched mode
I
R
=
=
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OUTPUT SIGNALS
Pulse outputs (P1, P2)
The output on P1 and P2 is a pulse density signal representing
the instantaneous power/energy measurement as shown in
figure 4. The pulse width t
p
on P1 and P2 change with the
direction of energy measurement t
p
is 71.5µs for positive
energy and doubles (143µS) if negative energy is measured.
The output frequency may be calculated using the following
formula:
f = 11.16 x FOUT x ( I
I
x I
V
) / I
R2
Where:
FOUT=
I
I
=
Typical rated output frequency (1360Hz)
Input current on current sense input (16µA at rated
conditions)
Input current on voltage sense input (14µA at rated
conditions)
Reference current on VREF typically 50µA
Clear Interrupt (RP)
A logic 1 on the RP input is used to clear the interrupt
generated by the SA2007H when a pulse is generated on P1
or P2, while operating in latched mode. By clearing the
interrupt in latched mode the status of the pulse outputs will
also be cleared.
Test Inputs (TEST, TCLK)
For normal operations these pins must be connected to V
SS
.
An integrated anti-creep function does not allow output pulses
on P1 or P2 if no power is measured by the device.
v
MAINS
t
POWER
VxI
t
FOUT
DR-01282
tP
t
Figure 4: FOUT instantaneous pulse output
Direction indication (D1, D2)
The SA2007H provides information about the energy flow
direction of both current channels separately on pins D1 and
D2.
Logic 0 on pin D1 or D2 indicates reverse energy flow of that
particular channel. 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).
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PRELIMINARY
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