Three Phase Power / Energy IC with SPI
Interface
sames
SA9904B
FEATURES
+ Bi-directional
+
+
+
+
+
active and reactive power/energy
measurement
RMS Voltage and frequency measurement
Individual Phase information
SPI communication bus
Meets the IEC 61036 Specification requirements for Class 1
AC Watt hour meters
Meets the IEC 61268 Specification requirements for
Class 2 VAR hour meters
Protected against ESD
Total power consumption rating below 60mW
Uses current transformers for current sensing
Operates over a wide temperature range
Precision on-chip voltage reference
+
+
+
+
+
DESCRIPTION
The SA9904B includes all the required functions for threephase power and energy measurement such as oversampling
A/D converters for the voltage and current sense inputs, power
calculation and energy integration. This innovative universal
three phase power/energy metering integrated circuit is ideally
suited for energy calculations in applications such as electricity
dispensing systems, residential metering and factory energy
metering and control.
The SAMES SA9904B is a three phase bi-directional
energy/power metering integrated circuit that has been
designed to measure active and reactive energy, RMS mains
voltage and frequency. The SA9904B has an integrated SPI
serial interface for communication with a micro-controller.
Measured values for active and reactive energy, the mains
voltage and frequency for each phase are accessible through
the SPI interface from 24 bit registers. The SA9904B active and
reactive energy registers are capable of holding at least 52
seconds of accumulated energy at full load. A mains voltage
zero crossover is available on the F50 output.
The SA9904B integrated circuit is available in 20 pin dual-inline plastic (PDIP20), as well as 20 pin small outline (SOIC20)
package types.
VDD
VSS
ACTIVE
IIP1
IIN2
IIP2
IIN2
IIP3
IIN3
CURRENT
ADC
DI
DO
REACTIVE
SPI
RMS
VOLTAGE
IVP1
IVP2
IVP3
VOLTAGE
ADC
SCK
CS
MAINS
FREQ.
F50
VOLTAGE
REF.
GND
OSC
DR-01641
VREF
OSC1
OSC2
Figure 1: Block diagram
SPEC-0447 (REV. 6)
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04-07-03
sames
SA9904B
ELECTRICAL CHARACTERISTICS
#
(VDD = 2.5V, VSS = -2.5V, over the temperature range -10°C to +70°C , unless otherwise specified.)
Symbol
Min
Operating temp. Range
TO
Supply Voltage: Positive
Typ
Max
Unit
-25
+85
°C
VDD
2.25
2.75
V
Supply Voltage: Negative
VSS
-2.75
-2.25
V
Supply Current: Positive
IDD
9.5
11
mA
Supply Current: Negative
ISS
9.5
11
mA
Parameter
Condition
Current Sensor Inputs (Differential)
Input Current Range
III
-25
+25
µA
Peak value
IIV
-25
+25
µA
Peak value
VIH
VIL
VDD-1
VSS+1
V
V
Voltage Sensor Input (Asymmetrical)
Input Current Range
Pins SCK
High Voltage
Low Voltage
fSCK
tLO
tHI
Pins CS, DI
High Voltage
Low Voltage
Pins F50, DO
Low Voltage
High Voltage
Oscillator
Pin VREF
Ref. Current
Ref. Voltage
VIH
VIL
800
0.6
0.6
VDD-1
VOL
VOH
kHz
µs
µs
VSS+1
V
V
VSS+1
V
V
VDD-1
IOL = 5mA
IOH = -2mA
Recommended crystal: TV colour burst crystal f = 3.5795 MHz
-IR
VR
25
23
1.1
27
1.3
With R = 47kW
connected to VSS
Reference to VSS
µA
V
ABSOLUTE MAXIMUM RATINGS*
Parameter
Symbol
Min
Max
Unit
Supply Voltage
VDD -VSS
3.6V
6.0
V
Current on any pin
IPIN
-150
+150
mA
Storage Temperature
TSTG
-40
+125
°C
Operating Temperature
TO
-40
+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.
During manufacturing, testing and shipment we take great care to protect our products against potential
external environmental damage such as Electrostatic Discharge (ESD). Although our products have ESD
protection circuitry, permanent damage may occur on products subjected to high-energy electrostatic
discharges accumulated on the human body and test equipment and can discharge without detection.
Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of
functionality during product handling.
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3
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SA9904B
PIN DESCRIPTION
PIN
Designation
Description
16
GND
6
VDD
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.
14
VSS
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.
17, 20, 3
IVP1, IVP2,
IVP3
Analog Ground. The supply voltage to this pin should be mid-way between
VDD and VSS.
Analog Input for Voltage Phase 1, Phase 2 and Phase 3. The current into the
A/D converter should be set at 14µARMS at nominal mains voltage. The voltage
sense input saturates at an input current of ±25µA peak.
IIP1, IIN1, IIP2, IIN2, Inputs for current sensors. The shunt resistor voltage from each channel is
converted to a current of 16µARMS at rated conditions. The current sense input
IIP3, IIN3
saturates at an input current of ±25µA peak.
18, 19, 1, 2, 4, 5
This pin provides the connection for the reference current setting resistor.
A 47kW resistor connected to sets the optimum operating condition.
15
VREF
10, 11
OSC1, OSC2
8
SCK
Serial clock in. This pin is used to strobe data in and out of the SA9904B
9
DO
Serial data out. Data from the SA9904B is strobed out on this pin. DO is
only driven when CS is active.
7
F50
Voltage zero crossover. The F50 output generates a pulse, on every
rising edge of the mains voltage for any one phase.
12
DI
Serial data in. Data is only accepted during an active chip select (CS).
13
CS
Chip select. The CS pin is active high.
Connections for a crystal or ceramic resonator. (OSC1 = input; OSC2 = Output)
IIP2
1
20
IVP2
IIN2
2
19
IIN1
IVP3
3
18 IIP1
IIP3
4
17 IVP1
IIN3
5
16 GND
VDD
6
15 VREF
F50
7
14 VSS
SCK
8
13 CS
DO
9
12
OSC1
10
ORDERING INFORMATION
DI
11 OSC2
Dr-01642
Figure 2: Pin connections: Package: PDIP20, SOIC20
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Part Number
Package
SA9904BPA
PDIP20
SA9904BSA
SOIC20
sames
SA9904B
FUNCTIONAL DESCRIPTION
V DD
The SA9904B is a CMOS mixed signal Analog/Digital integrated
circuit, which performs the measurement of active power,
reactive power, RMS voltage and mains frequency. The
integrated circuit includes all the required functions for threephase power and energy measurement such as oversampling
A/D converters for the voltage and current sense inputs, power
calculation and energy integration.
IIP
VSS
CURRENT
SENSOR
INPUTS
AI
VDD
IIN
VSS
VDD
Current
Sensing
Calibration LED
Voltage
Sensing
Power
Supply
N L1 L2 L3
SA9904B
Active Energy
Reactive Energy
VRMS and
Frequency
Measurements
SPI
MicroController
IVP
VOLTAGE
SENSOR
INPUT
V SS
AV
EEPROM LCD
A micro-controller in addition to communicating
with the SA9904B is used to read/write
parameters to the EEPROM, output pulses for
fast calibration and to display the consumed
active and reactive power, Vrms and mains
frequency information. Other parameters such
as Irms, phase angle etc. can be accurately
calculated.
Dr-01643
Figure 3: Typical architecture of an energy meter using the
SA9904B
The SA9904B integrates instantaneous active and reactive
power into 24 bit registers. RMS voltage and frequency are
continuously measured and stored in the respective registers.
The mains voltage zero crossover is available on the F50 output.
The SPI interface of the SA9904B has a tri-state output that
allows connection of more than one metering device on a single
SPI bus.
GND
DR-01288
Figure 4: Analog input internal configuration
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 levels into the SA9904B current sense inputs. The
current sense inputs saturates at ±25µA peak. Resistors Rsh1,
Rsh2 and Rsh3 are the current transformer termination
resistors. The voltage drop across the termination resistors
should be at least 20mV but not higher than 200mV. The ideal
value should be approximately 100mV at rated conditions.
Values for the current sense inputs are calculated as follows:
R1 = R2 = (IL / 16µARMS) x Rsh / 2
R3 = R4 = (IL / 16µARMS) x Rsh / 2
R5 = R6 = (IL / 16µARMS) x Rsh / 2
Ch3 In
INPUT SIGNALS
CH2 In
Analog Input Configuration
The input circuitry of the current and voltage sensor inputs is
illustrated in figure 4. These inputs are protected against
electrostatic discharge through clamping diodes. The feedback
loops from the outputs of the amplifiers AI and AV generate
virtual shorts on the signal inputs. Exact duplications of the input
currents are generated for the analog signal 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 amplifier input terminals is internally
connected to GND. This is possible because the voltage sense
input is much less sensitive to externally induced parasitic
signals compared to the current sense inputs.
CH1In
IMAX
Neutral
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RMS
IIN1
IMAX
Rsh1
IMAX
> 20mV
RMS
R2
IIP1
GND
16µA
R3
CT2
RMS
IIN2
Rsh2
> 20mV
SA9904B
RMS
R4
IIP2
GND
16µA
R5
CT3
RMS
IIN3
Rsh3
> 20mV
RMS
R6
IIP3
GND
CH3 Out
Current Sense Inputs (IIN1, IIP1, IIN2, IIP2, IIN3, IIP3)
At rated current (IMAX) the resistor values should be selected for
input currents of 16µARMS. Referring to figure 5, the resistors R1
16µA
R1
CT1
GND
Dr-01644
CH2 Out
CH1 Out
Figure 5: Current sense input configuration
sames
SA9904B
Where:
IL = Line current or if a CT is used IL = Line current / CT ratio
Rsh = Shunt resistor or CT termination resistor.
Rsh should be less than the resistance of the CT's secondary
winding.
Voltage Sense Input (IVP1, IVP2, IVP3)
Figure 6 shows the voltage sense (IVP) input configuration for
one phase. The exact circuit is duplicated for the other two
phases. The current into the voltage sense inputs (virtual
ground) should be set to 14µARMS at rated voltage conditions.
The voltage sense inputs saturate at an input current of ±25µA
peak.
14V
R16
Ch1 Voltage
C5
R8
14µA
RMS
IVP1
Chip Select (CS)
The CS input is used to address the SA9904B. An active high
on this pin enables the SA9904B to initiate data exchange.
Serial Data Out (DO)
The DO pin is the serial data output pin for the SA9904B. The
Serial Clock (SCK) determines the data output rate. Data is
only transferred during on active chip select (CS). This output
is tri-state when CS is low.
GND
GND
Figure 6: Voltage sense input configuration
Mains Voltage sense zero crossover (F50)
The individual mains voltages are divided down to 14VRMS per
phase. The resistor R8 sets the current for the voltage sense
input. The voltage divider is calculated for a voltage drop of 14V.
With a phase voltage of 230V the equation for the voltage divider
is:
RA = R16 + R19 + R22
RB = R8 || R13
Combining the two equations gives:
(RA + RB) / 230V = RB / 14V
A 24K resistor is chosen for R13 and a 1M resistor for R8.
Substituting these values results in:
RB = 23.44K
RA = RB x (230V / 14V-1)
RA = 361.6K
Resistor values for R16, R19 and R22 is chosen to be 120K
each.
The capacitor C5 is used to compensate for any phase shift
between the voltage sense and current sense input caused by
the current transformer. As an example 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 50Hz x 1MW x tan (0.18 degrees))
C = 1.013µF
Reference Voltage (VREF)
The VREF pin is the reference for the bias resistor. With a bias
resistor of 47kW connected to Vss optimum conditions are set.
Serial Clock (SCK)
The SCK pin is used to synchronize data interchange between
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Serial Data In (DI)
The DI pin is the serial data input pin for the SA9904B. Data will
be input at a rate determined by the Serial Clock (SCK). Data
will be accepted only during an active chip select (CS).
OUTPUT SIGNALS
RMS
R22
R13
Neutral
Dr-01645
R19
the micro controller and the SA9904B. The clock signal on this
pin is generated by the micro controller and determines the
data transfer rate of the DO and DI pins.
The F50 output generates a signal, which follows the mains
voltage zero crossings, see figure 7. This output generates a
pulse on the rising edge of the mains voltage zero crossing
point. Internal logic ensures that this signal is generated from a
valid phase. Should all three phase be missing but power still
applied to the SA9904B this output will generate a constant
54Hz signal. The micro controller can use the F50 to extract
mains timing.
Phase Voltage
F50
Dr-01646
+5V
1ms to 2ms
0V (Vss)
1ms to 2ms
Figure 7: Mains voltage zero crossover
SPI - INTERFACE
Description
A serial peripheral interface bus (SPI) is a synchronous bus
used for data transfers between a micro controller and the
SA9904B. The pins DO (Serial Data Out), DI (Serial Data In),
CS (Chip Select), and SCK (Serial Clock) are used in the bus
implementation. The SA9904B is the slave device with the
micro controller being bus master. The CS input initiates and
terminates data transfers. A SCK signal (generated by the
micro controller) strobes data between the micro-controller
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SA9904B
and the SCK pin of the SA9904B. The DI and DO pins are the
serial data input and output pins for the SA9904B, respectively.
The 9 bits needed for register addressing can be padded with
leading zeros when the micro-controller requires a 8 bit SPI
word length. The following sequence is valid:
Register Access
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 1 1 0 A5 A4 A3A2A1 A0
Table 1 lists the various register addresses. The SA9904B
contains nine 24 bit- registers representing the active energy,
reactive energy and the mains voltage for each phase. A tenth
24 bit register represents the mains frequency for any valid
phase. To remain compatible with the SA9604A three
addresses have been included. Any of the three addresses can
be used to access the frequency register.
Data format
Figure 8 shows the SPI waveforms and figure 9 the timing
information. After the least significant digit of the address has
been entered on the rising edge of SCK, the output DO goes
low with the falling edge of SCK. Each subsequent falling edge
transition on the SCK pin will validate the next data bit on the
DO pin.
Header
A5 A4 A3 A2 A1 A0
bits
ID
Register
1
Active Phase 1
1
1
0
X
X
0
0
0
0
2
Reactive Phase 1
1
1
0
X
X
0
0
0
1
3
Voltage Phase 1
1
1
0
X
X
0
0
1
0
4
Frequency
1
1
0
X
X
0
0
1
1
5
Active Phase 2
1
1
0
X
X
0
1
0
0
6
Reactive Phase 2
1
1
0
X
X
0
1
0
1
7
Voltage Phase 2
1
1
0
X
X
0
1
1
0
8
Frequency
1
1
0
X
X
0
1
1
1
9
Active Phase 3
1
1
0
X
X
1
0
0
0
10 Reactive Phase 3
1
1
0
X
X
1
0
0
1
11
1
1
0
X
X
1
0
1
0
1
1
0
X
X
1
0
1
1
The content of each register consists of 24 bits of data. The
MSB is shifted out first.
SCK
t3
t4
DI
t2
Voltage Phase 3
12 Frequency
t5
DO
t1
CS
Table 1: Register address
DR-01545
The header bits 110 (0x06) must precede the 6-bit address of the
register being accessed. When CS is HIGH, data on pin DI is
clocked into the SA9904B on the rising edge of SCK. Figure 8
shows the data clocked into DI comprising of 1 1 0 A5 A4 A3 A2
A1 A0. Address locations A5 and A4 are included for
compatibility with future developments.
Parameter Description
Registers may be read individually and in any order. After a
register has been read, the contents of the next register value
will be shifted out on the DO pin with every SCK clock cycle. Data
output on DO will continue until CS is inactive.
Min
Max
t1
SCK rising edge to DO valid
625ns 1.160µs
t3
SCK min high time
625ns
t4
SCK min low time
625ns
t2
Setup time for DI and CS
before the rising edge of SCK 20ns
t5
625ns
DI hold time
Figure 9: SPI Timing diagrams with timing information
SCK
CS
Read command
DI
1
1
Register address
0
A5
A4
A3
A2
A1
A0
Register Data
DO
Next data register
High impedance
0
D23
D22
D21
Dr-01647
Figure 8: SPI waveforms
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D1
D0
D23
D22
D1
D0
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SA9904B
REGISTER DESCRIPTION
Using this delta value will result in incorrect calculations.
Active and reactive registers
The active and reactive power is accumulated in 24 bit registers
for each phase. These registers are 24 bit up/down counters,
that increment or decrement at a rate of 320k samples per
second at rated conditions.
23 22 21 20 19
10 9 8 7 6 5 4 3 2 1 0
Voltage registers
The three voltage registers contain the RMS voltage measured
for each phase.
The RMS voltage measurement is accurate to 1% for a range
of 50% to 115% of the rated mains voltage.
23 22 21 20 19
Active or Reactive Energy Register
The register values will increment for positive energy flow and
decrement for negative energy flow as indicated in figure 10.
Register wrap around
Positive energy flow
H7FFFFF
................ (8388607)
H800000
(8388608)
Voltage Register
Frequency register
The single frequency register contains the measured mains
frequency information for a valid phase. Internal logic ensures
that the frequency information is generated from the same
phase being used for the F50 output. Only bits D0 to D9 are
used for the frequency calculation however the remaining bits
must still be clocked out as additional information can be
derived from these data bits.
Register values
0
HFFFFFF
................ (16777215)
Negative energy flow
Register wrap around
Frequency Register
DR-01590
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Figure 10: Register increment / decrement showing the
register wrap around
The active and reactive registers are not reset after access, so
in order to determine the correct register value, the previous
value read must be subtracted from the current reading. The
data read from the registers represents the active or reactive
power integrated over time. The increase or decrease between
readings represent the measured energy consumption. At rated
conditions, the active and reactive registers will wrap around
every 52 seconds. The micro controller program needs to take
this condition into account when calculating the difference
between register values.
As an example lets assume that with a constant load connected,
the delta value (delta value = present register - previous register
value) is 22260. Because of the constant load, the delta value
should always be 22260 every time the register is read and the
previous value subtracted (assuming the same time period
between reads). However this will not be true when a wrap
around occurs, as the following example will demonstrate:
Description
Present register value
Variable
Decimal
delta_val
Mains Frequency
Not used
Missing phase
Phase sequence
error
Voltage zero
crossover
Bit location Description
0 to 9
10 to 17
18,19,20
Hex
new_val 16767215 0x00FFD8EF
Previous register value old_val
new_val - old_val =
16744955 0x00FF81FB
new_val
The phase error status can be ascertained
from these two bits.
D21 D22 Missing phase
0
0 No phase error
0
1 Phase sequence error.
1
X Missing phase
23
Voltage zero crossover. This bit changes
state with the rising edge of the mains
voltage.
22260 0x000056F4
12259 0x00002FE4
Previous register value old_val
new_val - old_val =
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These bits represent a value that is used
in the frequency calculation
Not used
Missing phase. These bits indicate which
phase is missing during a lost phase
condition.
D18 D19 D20 Missing phase
1 X
X Phase 1
X 1
X Phase 2
X X
1 Phase 3
21,22
The register now wraps around so after the next read
the values are as follows:
Present register value
10 9 8 7 6 5 4 3 2 1 0
16767215 0x00FFD8EF
delta_val -16754956 0x00FFA90B
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SA9904B
POWER CALCULATION
Mains voltage register
Instantaneous power signals are generated by multiplying the
current and voltage signals, for active power = V x I x Cos(ø) and
for reactive power = V x I x Sin(ø). The power signals are
continuously added to the respective energy registers. Positive
power will be added to the energy register contents and
negative energy will be subtracted.
The RMS voltage measurement is accurate to 1% in a range of
50% to 115% of rated mains voltage. The RMS mains voltage
measured by the SA9904B is calculated as follows:
USING THE REGISTER VALUES
Voltage
Where
VRATED
VREGISTER VALUE
=
VRATED x VREGISTER VALUE / 700
=
=
Rated mains voltage of meter
Voltage register value
Active and Reactive energy register
The active and reactive energy measured per count can be
calculated by applying the following formulae:
Energy per count = (VRATED x IRATED)/ 320000
(In watt seconds or var seconds)
Where:
VRATED = Rated mains voltage of meter
= Rated mains current of meter
IRATED
Mains frequency register
The mains frequency measured by the SA9904B is calculated
as follows:
Frequency = FCRYSTAL / 256 / FREGISTER VALUE
where
FCRYSTAL
The external crystal frequency.
=
FREGISTER VALUE
=
Bits D9 to D0 of the frequency
register.
The active and reactive power measured by the SA9904B is
calculated as follows:
Power = VRATED x IRATED x N / INTTIME / 320000
(in Watt or VAR)
Where:
VRATED =
=
IRATED
N
=
INTTIME =
Rated mains voltage of meter
Rated mains current of meter
Difference in register values between
successive reads (delta value)
Time difference between successive
register reads (in seconds)
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SA9904B
TYPICAL APPLICATION
In figure 11, the components required for the three phase
power/energy metering section of a meter, is shown. The
application uses current transformers for current sensing. The 4wire meter section is capable of measuring 3x230V/80A with
precision better than Class 1.
The most important external components for the SA9904B
integrated circuit are the current sense resistors, the voltage
sense resistors as well as the bias setting resistor.
The three current channels are identical so R1 = R2 = R3 = R4
= R5 = R6.
VOLTAGE DIVIDER
The voltage divider is calculated for a voltage drop of 14V.
Equations for the voltage divider in figure 5 are:
RA = R16 + R19 + R22
RB = R8 || R13
Combining the two equations gives:
BIAS RESISTOR
R7 defines all on-chip and reference currents. With R7=47kW,
optimum conditions are set.
( RA + RB ) / 230V = RB / 14V
CT TERMINATION RESISTOR
A 24k resistor is chosen for R13 and a 1M resistor is used for
R8.
The voltage drop across the CT termination resistor at rated
current should be at least 20mV. The CT’s used have low phase
shift and a ratio of 1:2500.The CT is terminated with a 2.7W
resistor giving a voltage drop across the termination resistor
86.4mV at rated conditions (Imax for the meter).
Substituting the values result in:
RB = 23.44k
RA = RB x (230V / 14V - 1)
RA = 361.6k.
CURRENT SENSE RESISTORS
The resistors R1 and R2 define the current level into the current
sense inputs of phase one of the device. The resistor values are
selected for an input current of 16µA on the current inputs at
rated conditions.
According to equation described in the Current Sense inputs
section:
R1 = R2
= (IL / 16µA ) x RSH / 2
= 80A /2500 / 16µA x 2.7W / 2
= 2.7kW
IL = Line current / CT Ratio
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Resistor values of R16, R19 and R22 is chosen to be 120k
each.
The three voltage channels are identical so R14= R15= R16 =
R17 = R18 = R19 and R20 = R21= R22.
CRYSTAL OSCILLATOR
A color burst TV crystal with f = 3.5795MHz is used for the
oscillator. The oscillator frequency is divided down to
1.7897MHz on-chip, to supply the A/D converters as well as
the digital circuitry.
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Figure 11: Typical application circuit
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V1 Out
V2 Out
V3 Out
V1In
V2 In
V3 In
Neutral
GND
CT3
CT2
CT1
R25
GND
R27
GND
R26
GND
VSS
R19
R16
R7
R6
R5
R4
R3
R2
R1
R18
R17
R15
R14
14
15
4
5
1
2
18
19
DR-01600
VSS
VREF
IIP3
IIN3
IIP2
IIN2
IIP1
IIN1
U1
R22
R21
R20
VDD
OSC2
OSC1
F50
SCK
DI
CS
DO
IVP3
IVP2
IVP1
GND
6
11
10
7
8
12
13
9
3
20
17
16
VDD
GND
X1
R10
R9
R8
GND
C3
C4
C5
VSS
R24
R23
SCK
DI
CS
R13
R11
R12
C1
C2
DO
F50
VDD
C6
SA9904B
sames
sames
SA9904B
Parts List for Application Circuit: Figure 11
Symbol
Description
U1
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
SA9904B
Resistor, 2.7k, 1/4W, 1% metal
Resistor, 2.7k, 1/4W, 1% metal
Resistor, 2.7k, 1/4W, 1% metal
Resistor, 2.7k, 1/4W, 1% metal
Resistor, 2.7k, 1/4W, 1% metal
Resistor, 2.7k, 1/4W, 1% metal
Resistor, 47k, 1/4W, 1%, metal
Resistor, 1M, 1/4W, 1%, metal
Resistor, 1M, 1/4W, 1%, metal
Resistor, 1M, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
Resistor, 24k, 1/4W, 1%, metal
R14
R15
R16
R17
R18
R19
R20
Resistor, 120k, 1/4W, 1%, metal
Resistor, 120k, 1/4W, 1%, metal
Resistor, 120k, 1/4W, 1%, metal
R21
R22
R23
R24
R25
R26
R27
C1
C2
C3
C4
C5
C6
CT1
CT2
CT3
X1
Detail
PDIP20 / SOIC20
Note 1
Note 1
Note 1
Note 1
Note 1
Note 1
Resistor, 120k, 1/4W, 1%, metal
Resistor, 120k, 1/4W, 1%, metal
Resistor, 120k, 1/4W, 1%, metal
Resistor, 120k, 1/4W, 1%, metal
Resistor, 120k, 1/4W, 1%, metal
Resistor, 120k, 1/4W, 1%, metal
Resistor, 1k, 1/4W, 1%, metal
Resistor, 1k, 1/4W, 1%, metal
Resistor, 2.7R, 1/4W, 1%, metal
Resistor, 2.7R, 1/4W, 1%, metal
Resistor, 2.7R, 1/4W, 1%, metal
Capacitor, 220nF
Note 1
Note 1
Note 1
Capacitor, 220nF
Capacitor, 820nF
Capacitor, 820nF
Capacitor, 820nF
Capacitor, 820nF
Current Transformer, TZ76
Note 2
Note 2
Note 2
Note 3
Current Transformer, TZ76
Current Transformer, TZ76
Crystal, 3.57954MHz
Note 1: Resistor (R1 to R6) values are dependant on the selection of the termination resistors (R25 to R27) and CT combination.
Note 2: Capacitor values may be selected to compensate for phase errors caused by the current transformers.
Note 3: Capacitor C6 to be positioned as close as possible to supply pins VDD and VSS of U1.
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sames
SA9904B
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:
[email protected]
For the latest updates on datasheets, please visit our web site:
http://www.sames.co.za.
SOUTH AFRICAN MICRO-ELECTRONIC
SYSTEMS (PTY) LTD
Tel: (012) 333-6021
Tel: Int +27 12 333-6021
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