ams AS8118D18 Single phase instantaneous energy metering ic with on-chip calibration, stepper motor drive and led output Datasheet

AS8118
Single Phase Instantaneous Energy Metering IC
with On-Chip Calibration, Stepper Motor Drive and LED Output
-
-
The AS8118 offers three different pulse outputs. A stepper
motor drive output for directly driving a stepper motor
display, a LED output for energy consumption indication
and a dedicated high frequency output for fast single point
system calibration.
The AS8118 is available in either surface mount SOIC-18
or dual-in-line DIP-18 packages.
Block Diagram
PROG
-
The on-chip anti-creep circuit ensures that the AS8118
does not output pulses when the meter is in a no-load
condition and that the IEC1036 anti-creep test
requirements are fully complied with, for both direct or
transformer connection meters.
VSSD
-
VDDD
-
Extremely accurate, surpassing the accuracy
requirements of the IEC 1036 Specification less than
0.1% error over a 600 : 1 dynamic range
On-chip programmable current input gain suitable for
use with low-resistance shunt resistor or current
transformer
On-chip programming for output pulse rate selection
On-chip calibration eliminates the need for an external
resistor network or trim-potentiometer
Programmable on-chip creep prevention under no-load
condition
All on-chip programmable functions may be
reprogrammed a second time
Outputs directly drive an electromechanical counter or
counters with a two phase stepper motor and
consumption LED indicator
Fast calibration pulse output for high speed manual or
automated calibration
On-chip voltage reference and power supply
monitoring
Bi-directional or unidirectional energy measurement,
with direction indication output available
VSSA
-
control block and non-volatile calibration memory for the
on-chip programming. The on-chip programming enables
the setting of the current input gain, the anti-creep
threshold, the output pulse rates and the system
calibration. The high level of integration ensures a
minimum number of non-critical external components are
required.
VDDA
Features
DATA SHEET
Description
Revision 1.8, 15-Feb-05
Σ∆-mod
Digital
Filter
Power
Calculation
IP
IN
Σ∆-mod
Digital
Filter
VREF
XIN
XOUT
CAL
Crystal
Osc
LED
Control
MON
POR
MOP
Figure 1
DIRO
The highly integrated AS8118 design includes all the
required functional blocks. The blocks comprise of analog
to digital converters (ADC) for the voltage and current
channels, digital filters, a digital signal processing block, a
VP
VN
TM
The AS8118 is ideal for use in ‘stand alone’ kWh meter
applications, where the IC directly drives an
electromechanical counter with a two-phase stepper
motor, or for more complex meter applications, the
AS8118 interfaces directly to a micro-controller.
Non-volatile
Calibration
AGND
Buffer
DIRI
The AS8118 is a very accurate single-phase bi-directional
instantaneous energy measurement integrated circuit,
which surpasses all the accuracy requirements for
IEC1036 alternating current static watt-hour meters. The
measured energy is converted into pulses with the number
of output pulses being proportional to the measured
energy.
Block diagram of the AS8118
Page 1 of 30
Data Sheet AS8118
Typical Connection Circuit
Load
VDD (5V)
IP
VDDA VDDD
PROG
Shunt
Calibration
Programming
TM
LED
IN
LED Output
VN
CAL
VP
DIRI
XIN
MOP
MON
XOUT VSSA VSSD
Calibration
Pulse Output
Stepper Motor
Outputs
DIRO
VSS
Voltage
Regulator
VDD (5V)
VSS
N
L
Figure 2
Typical connection circuit for the AS8118
Pin Configuration
1
2
3
4
5
6
7
8
9
Figure 3
VP
IN
VN
IP
TM
DIRI
VSSA
VDDA
PROG
XIN
VSSD
XOUT
DIRO
VDDD
18
17
16
15
14
13
12
11
CAL
LED
MOP
MON
10
Pin configuration of the AS8118
Revision 1.8, 15-Feb-05
Page 2 of 30
Data Sheet AS8118
Pin Description
Pin No.
Pin Name
1
VP
2
VN
3
TM
4
5
VSSA
PROG
6
7
VSSD
DIRO
8
CAL
9
MOP
10
MON
11
LED
12
VDDD
13
XOUT
14
XIN
15
VDDA
16
DIRI
17
IP
18
IN
Revision 1.8, 15-Feb-05
Description
Positive input for the voltage channel. VP is a differential input with VN. The differential voltage
should be set at ±150mV peak for rated voltage conditions. VP is an analog input pin.
Negative input for the voltage channel. VN is a differential input with VP. VN is usually tied to 0V
potential (VSSA). VN is an analog input pin.
On ‘power up’, the test mode input defines the operation mode of the device. Either ‘Normal
Operation’, or ‘Calibration’ modes may be selected. TM has an on-chip pull down resistor and
should be left unconnected during ‘Normal Operation’. TM must be set to logic ‘1’ at ‘power up’ to
set the device in ‘Calibration’ mode.
Negative analog supply. VSSA is the ground reference for the analog circuitry.
Programming pin for calibration procedure. PROG is an analog input pin which must be left
unconnected during normal operation. Note: PROG must not be connected to VSS.
Negative digital supply. VSSD is the ground reference for the digital circuitry.
Direction output provides indication of the direction of current flow through the current sensor.
This digital input/output has an on-chip pull down resistor and provides logic ‘0’ for positive
power and logic ‘1’ for negative power. DIRO is used as an input during the programming cycle.
This output may be directly connected to a LED and is capable of driving 4mA.
Fast energy pulse output for calibration. CAL pulse rate is programmable and dependent upon
the selected MON/MOP frequency.
Positive motor drive signal. MOP and MON are low frequency outputs for directly driving a two
phase stepper motor. The frequency of the MOP/MON outputs is programmable to suite all
industry standards and is capable of driving 10mA.
Negative motor drive signal. MON and MOP are low frequency outputs for directly driving a two
phase stepper motor. The frequency of the MOP/MON outputs is programmable to suite all
industry standards and is capable of driving 10mA.
This output may be connected to an LED to display energy consumption. LED is a digital output,
which is programmable to a desired pulse rate. All the industry standard pulse rates are
available. This output is capable of driving 10mA.
Positive digital supply. VDDD provides the supply voltage for the digital circuitry. The required
supply voltage is 5V ±10%.
See XIN below, for the connection of a crystal or ceramic resonator. When an external clock is
applied to XIN, XOUT is not connected.
A 3.579545 MHz crystal or ceramic resonator may be connected across XIN and XOUT without
the need for external load capacitors. Alternatively, an external clock signal may be applied to
XIN.
Positive analog supply. VDDA provides the supply voltage for the analog circuitry. The required
supply voltage is 5V ±10%.
Direction input pin for selecting unidirectional or bi-directional energy measurement mode. When
DIRI is at logic ‘0’, the IC is set in unidirectional mode. When DIRI is at logic ‘1’ the IC is in bidirectional mode. In default mode, when DIRI is not connected, the IC is in bi-directional mode.
DIRI is a digital input with an on-chip pull-up resistor.
Positive input for the current channel. IP is a differential input with IN. The input gain is
programmable depending on the desired current sensor. The maximum differential voltage is
±150mV peak (Gain = 4). IP is an analog input pin.
Negative input for the current channel. IN is a differential input with IP. The input gain is
programmable depending on the desired current sensor. IN is usually at 0V potential. IN is an
analog input pin.
Page 3 of 30
Data Sheet AS8118
AS8118 Performance Graphs
0,8
0,8
0,6
0,6
0,2
GAIN 16
Error [%]
Error [%]
0,4
0
-0,2
-0,4
GAIN 4
GAIN 20
0,4
- 40°C
0,2
+ 85°C
0
+ 25°C
-0,2
-0,4
-0,6
-0,6
-0,8
0,01
0,1
1
10
-0,8
0,01
100
0,1
I [A]
0,8
0,8
0,6
0,6
- 40°C
0,2
+ 85°C
0
+ 25°C
VDD_5.5V
VDD_5.0V
0,2
0
-0,2
-0,4
-0,4
-0,6
-0,6
0,1
1
10
-0,8
0,01
100
VDD_4.5V
0,1
0,8
0,6
0,6
- 40°C
+ 85°C
+ 25°C
-0,2
0,2
0
-0,4
-0,6
-0,6
0,1
1
10
100
I [A]
Graph 3: Error as a % of reading at temperature limits and PF = 0.8
Revision 1.8, 15-Feb-05
V_MAIN_264.5
V_MAIN_230
-0,2
-0,4
-0,8
0,01
100
0,4
Error [%]
Error [%]
0,8
0,2
10
Graph 5: Error as a % of reading with variation in VDD
Graph 2: Error as a % of reading at temperature limits and PF = 1
0,4
1
I [A]
I [A]
0
100
0,4
-0,2
-0,8
0,01
10
Graph 4: Error as a % of reading at temperature limits and PF = 0.5
Error [%]
Error [%]
Graph 1: Error as a % of reading for gain settings 4, 16 and 20 at 25°°C
0,4
1
I [A]
-0,8
0,01
V_MAIN_184
0,1
1
10
I [A]
Graph 6: Error as a % of reading with mains voltage variation
Page 4 of 30
100
Data Sheet AS8118
0 ,8
0 ,6
Error [%]
0 ,4
0 ,2
0
-0 ,2
-0 ,4
-0 ,6
-0 ,8
45
50
55
60
65
F [H z )
Graph 7: Error as a % of reading with mains frequency variation
Functional Description
The AS8118 is a CMOS mixed signal integrated circuit that measures electrical power over a dynamic range of 600:1, to an
accuracy of better than 0.1%.
The AS8118 comprises of standard functional blocks including two sigma/delta modulators, which convert the analog voltage
and current input signals into digital signals. The voltage and current signals are then digitally filtered, which eliminates
offsets thus enabling a single point calibration cycle. A power calculation block calculates the active energy value. An on-chip
voltage reference (±30ppm/K typical), oscillator and non-volatile calibration registers and control block for programming the
AS8118 completes the core functional elements.
Programming of the AS8118 enables the device to be configured to suite the users specific input and output requirements
and allows for fast and efficient calibration. The AS8118 device provides the user with two complete opportunities to
programme the device. The following parameters may be programmed via the on-chip non-volatile memory:
- Current channel input gain
- Calibration pulse output frequency
- Stepper motor output drive frequency
- LED output frequency
- Anti-creep threshold
- Calibration constant
A detailed description of the versatility of the AS8118 is given below.
Current Inputs for Energy Calculation
The current channel input consisting of inputs IP and IN is differential and connected to a low resistance shunt or current
transformer, in series with the load. The current input signal level may be programmed by means of an on-chip
programmable gain amplifier (PGA). The gain is selected through the programming of 2 bits in the on-chip memory as
follows:
Parameter: Gain
Setting
Voltage
Gain
Input Voltage
Comments
11
10
01
20
-30mVpeak≤VIP≤30mVpeak
Shunt mode
16
-38mVpeak≤VIP≤38mVpeak
CT mode
00
4
-150mVpeak≤VIP≤150mVpeak
CT mode
Revision 1.8, 15-Feb-05
Page 5 of 30
Data Sheet AS8118
For optimum operating conditions, the input signal at the Maximum Current (IMAX) condition should be set at ±30mV peak,
when the input Gain = 20, or ±150mV peak, when the input Gain = 4.
The default gain, namely the AS8118 setting which is available without any programming required, is Gain = 20.
The value of an ideal shunt resistor, may be calculated as follows:
Assuming an IMAX rating of 60A (rms) → 84.85A (peak), then a shunt value of 350µΩ would be suitable.
Rshunt =
30mVpeak
84.85 Apeak
= 350 µΩ
The mains current is sampled at 1.7478kHz, assuming that the recommended crystal oscillator frequency of 3.5795MHz, is
used.
Voltage Input for Energy Calculation
The voltage channel input consists of inputs VP and VN, which are is differential, with VP connected to the tap of a resistor
divider circuit of the line voltage and VN connected to Ground. For optimum operating conditions, the input signal at VP with
respect to VN, should be set at 150mV peak for the rated line voltage condition.
The maximum voltage on VP for the specified operation is 210mV with respect to VSS. The maximum allowed voltage signal
at VP, which ensures that pulses are still provided at the output, is 300mV with respect to VSS. Both VP and VN have
internal ESD protection and an over-voltage of ±7V can be sustained on these pins without risk of permanent damage to the
device.
The resistor values for an ideal voltage divider, may be calculated as follows:
Assuming a Vmains of 230V (rms) → 325V (peak) and according to the voltage divider shown below, the value for
R2 = 820Ω, the value of R1A+R1B may be calculated as follows:
Vmains
R1A+R1B
R2
R1A + R1B = R 2 *
Vin
(Vmains( peak ) − VIP max )
VIP max
= 820Ω *
325V − 150mV
= 1.77MΩ
150mV
The mains voltage is sampled at 1.7478kHz, assuming that the recommended crystal oscillator frequency of 3.5795MHz is
used.
Revision 1.8, 15-Feb-05
Page 6 of 30
Data Sheet AS8118
Digital Filters
The current and voltage channels have been identically implemented with digital high pass filters in both channels, thus
eliminating offsets.
The filters ensure that there are no phase errors introduced between the voltage and current channels, enabling single point
calibration.
Energy to Pulse Output Conversion
The energy value is accumulated in the energy accumulator and compared with the default or programmed threshold level,
following each sample. The threshold represents the pulse equivalent energy value. If the energy value goes above the
threshold, a pulse is generated and presented to the output. Each time a pulse is generated the threshold value is subtracted
from the contents of the energy accumulator.
The remaining energy, namely the energy value above the threshold value is retained in the accumulator. Further measured
energy is added to the retained value in the accumulator and a pulse is again generated and presented to the output, when
the value again exceeds the threshold value. Thus no energy is lost during the energy to pulse output conversion process.
The voltage and current signals are sampled at 1.7478kHz. The sample rate is derived from the main clock (FMCLK) as
follows:
3.57945 MHz / 8*256 =
1.7478 kHz
The number of measured harmonics is defined by the sample rates of the voltage and current input signals. The maximum
bandwidth, which is half the sample frequency, is calculated as follows:
1.7478/2 kHz =
873.9 Hz
Thus, depending on the mains frequency, the measured energy is up to the following harmonics:
50Hz mains = 17th harmonic
60Hz mains = 14th harmonic
Energy Pulse Outputs
The AS8118 has three different pulse outputs. All the outputs are derived directly from the measured energy; thus, the
outputs can be used for energy accumulation and for calibration purposes. The output options include the following:
- CAL: A higher pulse rate output for fast calibration
- MOP/MON: Low pulse rate outputs for directly driving a stepper motor
- LED: A low pulse rate output which may be used to directly drive a LED for displaying power consumption
Calibration Pulse Output (CAL): The CAL output is a high frequency output, the frequency of which is proportional to the real
power measured.
The output pulse rate is programmable via the on-chip memory and allows for 4 pulse rate options:
Parameter: F_cal_sel
Setting CAL Output Pulse Rate
00
MON/MOP x
01
MON/MOP x 16
10
MON/MOP x 32
11
MON/MOP x 64
Revision 1.8, 15-Feb-05
8
Page 7 of 30
Data Sheet AS8118
The default pulse rate of CAL is MON/MOP x 16. The default pulse rate is the pulse rate available at the output, without any
programming required to the AS8118.
(Note: As the default pulse rate of MON/MOP is 400 imp/kWh, the actual CAL default pulse rate is 400 x 16 = 6,400
imp/kWh)
As an example, the maximum selectable pulse rate of CAL is 64 * 800 = 51,200 imp/kWh (See MON/MOP below)
The CAL pulse width is fixed at 1ms and is shown in the Timing Diagram and Timing Parameters that follow.
Stepper Motor Drive Outputs (MON & MOP): The MON and MOP outputs may be used to directly drive an electromechanical
counter or a stepper motor counter. The output frequencies are proportional to the real power measured. The required format
of the signal for driving a mechanical counter, activated by a 2-phase stepper motor is provided by the difference between
the MON and MOP outputs.
The output pulse rate is programmable via the on-chip memory, with 4 pulse rate options being available:
Parameter: F_mon_sel
Setting MON/MOP Output Pulse Rate
00
100 imp/kWh
01
200 imp/kWh
10
400 imp/kWh
11
800 imp/kWh
The default MON/MOP pulse rate is set at 400 imp/kWh. The default pulse rate is the pulse rate available at the output,
without any programming required to the AS8118.
The MON and MOP outputs shown in Figure 4 are capable of driving 10mA at VOH = 4.0V and VOL = 0.4V.
The widths of the MON/MOP pulses are 200ms for all settings up to 800imp/kWh. Above 800imp/kWh, the MON/MOP pulse
widths maintain a constant 50% duty cycle and is shown in the Timing Diagram and Timing Parameters that follows.
LED Driver Pulse Output (LED): The LED output is a low frequency output, the frequency of which is proportional to the real
power measured. The pulse rate is programmable via the on-chip memory the selected pulse rate is independent of the
settings of both the selected CAL and the MON/MOP settings.
Parameter: F_led_sel
Setting LED Output Pulse Rate
000
100 imp/kWh
001
200 imp/kWh
010
400 imp/kWh
011
800 imp/kWh
100
1600 imp/kWh
101
3200 imp/kWh
110
6400 imp/kWh
The default LED pulse rate is set at 3200 imp/kWh. The default frequency is the frequency available at the output, without
any programming required to the AS8118.
The LED output is capable of driving 10mA at VOH = 4.0V and VOL = 0.4V.
The width of the LED pulse is 80 ms for all settings except where the LED stream is shorter than 160ms. In this case, a 50%
duty cycle is maintained. The format of the LED signal is shown in the Timing Diagram and Timing Parameters below.
Revision 1.8, 15-Feb-05
Page 8 of 30
Data Sheet AS8118
Anti-Creep Threshold Setting
The anti-creep threshold is programmable to ensure that the set threshold lies between the anti-creep current, a current level
at which no pulses must be generated and the start current. The programmable threshold levels have been set to
accommodate the various specified base currents (IB) of the meter and if the meter is direct connection (shunt resistor) or
connection is through a current transformer. The formulae for calculating the appropriate thresholds are as follows:
Shunt:
ac _ th =
4 * IB 1
1
* = IStart *
1000 5
5
Current Transformer:
ac _ th =
2 * IB 1
1
* = IStart *
1000 5
5
Parameter: Acreep_sel
(All values are given in mA, unless otherwise specified)
Setting
Ithreshold
IB (A)
00
2.3
1.5
2.3
2.5
7.4
5
20
01
10
11
IMAX(A)
(IB*4)
IMAX(A)
(IB*6)
Ianticreep
Shunt
Istarting
Shunt
Ianticreep
CT
Istarting
CT
6
9
1.2
6
0.6
3
10
15
2
10
1
5
30
4
20
2
10
14.8
10
40
60
8
40
4
20
14.8
15
60
90
12
60
6
30
29.7
20
80
120
16
80
8
40
29.7
30
120
n/a
20
100
10
50
The default Anti-Creep threshold (ac_th) is set at 7.4mA, best suited to a 30A (IB*6) or 20A (IB*4) meter. The default AntiCreep is the programmed threshold setting, without any programming required to the AS8118.
Summary of Programmable Parameters
The AS8118 programming options, along with the default settings have been summarised in the table below:
I Gain
CAL
MON/MOP
LED
Anti-Creep Threshold
20
8
100
100
2.32mA
16
16
200
200
7.43mA
4
32
400
400
14.90mA
64
800
800
29.70mA
1600
3200
6400
Note: The default settings have been highlighted.
Revision 1.8, 15-Feb-05
Page 9 of 30
Data Sheet AS8118
Timing Diagram
t1
MON
t2
MOP
t3
t4
t5
CAL
t6
LED
Figure 4
Timing diagram for AS8118 frequency outputs
Timing Parameters
Parameter
t1
Values
Unit
200
ms
100,200,400 imp/kWh
For all currents up to 120A ; 230V
200
ms
800 imp/kWh
Imax < 97.8 A ; 230 V
50% duty cycle
Pulse rate
800 imp/kWh
t2
Tosc*4
t3
t1+t2
ms
100,200,400,800 imp/kWh
t4
2 * t3
ms
50,100,200,400 imp/kWh
t5
1
ms
t6
ms
Comments
Imax > 97.8 A ; 230 V
Minimum time between MON and MOP
80
ms
100,200,400,800 imp/kWh
For all currents up to 120A ; 230V
80
ms
1600 imp/kWh
For currents below 61.14A ; 230V
1600 imp/kWh
For currents above 61.14A ; 230V
3200 imp/kWh
For currents below 30.57A ; 230V
50% duty cycle
3200 imp/kWh
For currents above 30.57A ; 230V
50% duty cycle
3200 imp/kWh
For currents above 61.14A ; 230V
6400 imp/kWh
For currents below 15.28A ; 230V
50% duty cycle
6400 imp/kWh
For currents above 15.28A ; 230V
50% duty cycle
6400 imp/kWh
For currents above 30.57A ; 230V
50% duty cycle
6400 imp/kWh
For currents above 61.14A ; 230V
50% duty cycle
80
80
Revision 1.8, 15-Feb-05
ms
ms
Page 10 of 30
Data Sheet AS8118
Direction Input (DIRI)
The direction input pin (DIRI) is used to program the AS8118 for either bi-directional energy measurement, or unidirectional
measurement.
Bi-directional measurement mode ensures that all energy is measured regardless of the direction of the current through the
current sensor. In unidirectional energy measurement mode, all negative going energy is suppressed and thus excluded from
the accumulated energy value.
The programming conditions for the DIRI pin are given below:
DIRI Pin
0
1
Mode
Unidirectional
Bi-directional
The default condition, when the DIRI pin is not connected is bi-directional energy measurement, as the DIRI pin has an onchip pull-up resistor.
Direction Output (DIRO)
The Direction Output pin (DIRO) is a logic output providing information on the direction of the current flow through the current
sensor. The DIRO output may be used to directly drive an LED to indicate a reversal in the direction of current flow.
The timing diagram below demonstrates the operation of the DIRO output and the pulse outputs (MOP/MON, CAL and LED)
relative to the sign of the measured energy and the setting of the DIRI input.
For illustration purposes, the timing diagram below only shows the LED output.
1
2
3
4
VP
IP
DIRI
LED
DIRO
Figure 5
Timing diagram for the DIRI and DIRO functions
The timing diagram above demonstrates the state of both the LED and DIRO output pins depending on the input conditions:
1.
The voltage input (VP) and current input (IP) are in phase and the direction input DIRI is set to ‘Unidirectional’ mode.
Pulses are available at the LED output and DIRO indicates a positive energy flow.
Revision 1.8, 15-Feb-05
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Data Sheet AS8118
2.
3.
4.
The voltage input (VP) and current input (IP) are in phase and the direction input DIRI is set to ‘Bidirectional’ mode.
Pulses are available at the LED output and DIRO indicates a positive energy flow.
The voltage input (VP) and current input (IP) are out of phase and the direction input DIRI is set to ’Unidirectional’
mode. Pulses are no longer available at the LED output as negative going energy is not measured. The direction
output DIRO indicates a change in direction of the input current at IP.
The voltage input (VP) and current input (IP) are out of phase. The direction input DIRI is set to ‘Bidirectional’ mode.
Pulses are again available at the LED output and the direction output DIRO indicates a change in direction of the
input current at IP.
Crystal Oscillator
The AS8118 has an on-chip crystal oscillator, with the recommended 3.5795MHz crystal connected to the XIN (Crystal Input)
and XOUT (Crystal Output) pins. The 3.5795MHz crystal is recommended, as it is a standard low cost component.
Alternatively, an external clock signal may be applied to XIN. In this case, XOUT should not be connected.
Test Mode (TM)
On ‘power up’, the test mode input defines the mode of operation of the device. Either ‘Normal Operation’, or ‘Programming’
modes may be selected. TM has an on-chip pull down resistor and should be left unconnected during ‘Normal Operation’. TM
must be set to logic ‘1’ at ‘power up’ to set device in ‘Programming’ mode.
The AS8118 programming procedure is defined in detail in the following paragraphs.
Power Supply Monitor
The AS8118 has an on-chip power supply monitor (PSM) which resets the complete device once the supply voltage drops
below the specified threshold of 3.5V ±5%.
Programming the AS8118
The AS8118 is a programmable device, which uses on-chip zener diodes to permanently program specific data such as
current input channel gain, pulse-level, meter constant settings and system calibration. This programming operation is also
called ‘burn’ which relates to the permanent physical change of the on-chip zener diodes electrical behavior. Another term for
‘permanent programming’ is OTP (One-Time-Programming).
Two banks of zener diodes are available in the AS8118 in order to allow a second calibration. By programming the 2nd bank
of zener diodes, this bank will subsequently be used (bank-select-bit). During power-up of AS8118, a readout of all zener
diodes occurs and the data of the active bank is used.
The AS8118 may also be used with the default operating parameters, which have been defined earlier in this document. If
the user wishes to alter the operating parameters, the AS8118 may simply be programmed to provide the required operating
parameters. Fast meter system calibration may also be carried out as part of the AS8118 programming procedure, providing
long term meter system stability.
The AS8118 can be operated in one of two modes. The two modes are:
- Normal Operation Mode: Normal operation is the mode in which the device operates to perform the kWh metering
function, for which the device is designed.
- Programming Mode: Programming is the mode in which the AS8118 is set to perform the programming operations. When
in Programming mode, two different operations may be carried out:
Revision 1.8, 15-Feb-05
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Data Sheet AS8118
Test Write: Test Write enables the writing of data to a register in the device and for the resultant chip behaviour to be
investigated, before the data is written permanently to the non-volatile PROM (programmable read only memory)
memory.
- Burn: Burn is the programming cycle that ensures that the required data is permanently written to the non-volatile
PROM (programmable read only memory).
During Programming mode all pulse outputs (MOP/MON, CAL and LED) can be accessed.
-
The AS8118 may only be set up in one of these two modes during the ‘power up’ cycle of the device. The mode is selected
by programming the TM and DIRO at ‘power up’ as shown in the table below:
Mode of Operation
TM
DIRO
Normal Operation
0
X
Programming
1
0
Note: Pin DIRO has an on-chip internal pull-down resistor, thus the pin may be left open or tied ‘low’ for both Normal
Operation and Programming modes. The default mode is thus Normal Operation mode, with the AS8118 only being set to
Programming mode when TM is pulled high during power up.
The analog input pin PROG is also required for the programming of the AS8118. During Test-Write PROG is used to transfer
digital data to the internal register. During Burn it is used to change the states of the internal PROM cells.
When in Programming mode, the AS8118 must be powered down before the device can enter Normal Operation mode.
PROM Definition and Contents
The table below provides a definition of the internal PROM cells. As shown, sets of PROM cells form binary words, which
represent, for example, a defined pulse rate.
Parameter
Description
Number
of bits
Register bits
Bank 0
Bank 1
Settings
Default
Gain
Select current
channel gain
2
[34:33]
[67:66]
00 : 4
01 : 16
10 : 16
11 : 20
11
Acreep_sel
Select anti creep
threshold
2
[32:31]
[65:64]
00 : 2.32mA
01 : 7.43mA
10 : 14.9mA
11 : 29.7mA
01
F_mon_sel
Select MOP/MON
pulse rate
[imp/kWh]
2
[30:29]
[63:62]
00 : 100
01 : 200
10 : 400
11 : 800
10
F_cal_sel
Select multiplier for
CAL pulse rate
related to
MOP/MON pulse
rate
2
[28:27]
[61:60]
00 : 8
01 : 16
10 : 32
11 : 64
01
Revision 1.8, 15-Feb-05
Page 13 of 30
Data Sheet AS8118
Parameter
Description
Number
of bits
Register bits
Settings
Default
F_led_sel
Select LED pulse
rate [imp/kWh]
3
[26:24]
[59:57]
000 : 100
001 : 200
010 : 400
011 : 800
100 : 1600
101 : 3200
110 : 6400
101
Pulse_lev
Central pulse_level
value
22
[23:2]
[56:35]
Bank01
Select PROM bank
0 or 1
1
[1]
Sel_def
Select default or
programmed values
1
[0]
Not used
2
[69:68]
Total
70
0x6A6D4
0 : Bank 0
1 : Bank 1
0 : default
1 : programmed
Value
0
0
00
The “Default” values are hard coded on-chip outside the PROM block. Only once the Sel_def bit has been set, are the PROM
parameters selected by the AS8118.
Two PROM banks are defined as ‘Bank 0’ and ‘Bank 1’. This feature allows for a complete reprogramming cycle if necessary.
The required bank is selected with the bit called Bank01.
The calibration of the AS8118 adjusts the specific pulse-level (Pulse_lev), which defines exactly the energy level when a
pulse has to be generated and presented to the output. This pulse-level is used to define a very fast internal pulse rate from
which the external pulse outputs are derived. Therefore, the AS8118 is extremely flexible in defining pulse output rates as
required for a specified kWh meter.
The parameters F_mon_sel, F_cal_sel and F_led_sel are used to define the pulse rates for the pins MOP/MON, CAL and
LED.
The Acreep_sel bit defines the threshold for the current for when no pulses should be transmitted.
Calculations for Calibration
This paragraph describes how to successfully calibrate the AS8118 device. The parameter Pulse_lev is the main parameter
to determine the basic internal (very fast) frequency. This frequency relates to the measured power and is the basis from
which all the output pulse rates namely, MOP/MON, CAL and LED are derived.
Prior to system calibration, the appropriate value for the parameter Pulse_lev must be calculated to produce the required
output pulse rates for MOP/MON, CAL and LED. The calibration exercise must accommodate all system non-idealities that
are present in the meter system.
There are two calibration methods available to find the appropriate value of Pulse_lev, namely:
- Defined current and calibration time method
- Comparison method
It is also possible to perform:
Calibration without on-chip programming
-
Revision 1.8, 15-Feb-05
Page 14 of 30
Data Sheet AS8118
Defined Current and Calibration Time Method
The AS8118 generates a pulse whenever the internal energy accumulator contains a value, which is greater than a
programmed threshold. This threshold is the parameter Pulse_lev. This parameter depends on the basic meter properties,
the mains voltage Vmains and the maximum current to be measured, Imax. Furthermore, it is assumed that through a resistor
divider Vmains is scaled down to match the maximum input range of the VP input.
Firstly, an ideal value for Pulse_lev is calculated. This is the value, which would have to be programmed into the AS8118
device if the meter system was perfect.
The following formula calculates this ideal value of Pulse_lev:
Pulse _ lev ( ideal ) =
230V 20 A
*
* 435924
Vmains I max
A calibration is performed to compensate for system non-idealities like resistor tolerances etc. The effect of these nonidealities is that with the ideal Pulse_lev value the pulse rates will not be correct. In order to calibrate the meter, a new
Pulse_lev value has to be found. Figure 6 shows the basic calibration setup. CAL pulses from a meter built with the AS8118
are counted during a defined time period tc, while an accurately defined calibration current Ical, is being measured.
AS8118
Meter
time
base
Ical
tc
Calboard
Figure 6
Basic calibration setup for defined current and calibration time method
Again, if the system was perfect we would expect a certain number of pulses to be counted, the ideal number of pulses, Ni:
Ni =
PR * tc * Vmains * Ical
3600 * 1000
where tc is in seconds.
PR is the pulse rate on pin CAL, which can be calculated from the PROM parameters F_mon_sel and F_cal_sel:
PR = Fmon * Fcal
where Fmon [imp/kWh] is the pulse rate selected by F_mon_sel and Fcal is the multiplier selected by F_cal_sel.
If pin LED is used for calibration then PR is the pulse rate on pin LED (selected by F_led_sel).
The corrected value for Pulse_lev can now be calculated using the following formula:
Pulse _ lev ( corrected ) = Pulse _ lev ( ideal ) *
Nr
Ni
,
where Nr is the real number of pulses, i.e. the number of pulses counted during tc.
Revision 1.8, 15-Feb-05
Page 15 of 30
Data Sheet AS8118
A logical flow of the described calculations, is shown below:
System Properties
Vmains
ideal Pulse_lev
Imax
Calibration Setup
Number of pulses to
expect (ideal), Ni
Ical
tc
Correction
Pulse _ lev = Pulselev(ideal ) *
Nr
Ni
Pulse Counting
real number of
pulses, Nr
System Nonidealities
Example
Calibrate a meter with Vmains = 230V, Imax = 40A and Ical = 10A. Calibration time is 20 seconds, the PROM settings for the
pulse rates are: Fmon: 200 imp/kWh, Fcal: 64
Pulse _ lev ( ideal ) =
230V 20 A
*
* 435924 = 217962
230V 40 A
The ideal number of pulses during 20 seconds of calibration is:
Ni =
200imp / kWh * 64 * 20s * 230V * 10 A
= 163.56imp ≈ 164imp
3600 * 1000
Thus 164 pulses are expected during the 20 seconds calibration time. (For this example it is not important what error is
introduced with this setting!).
Assuming that 170 pulses were actually counted. The real pulse level may then be calculated:
Pulse _ lev ( real ) = 217962 *
170
= 225936 .2 ≈ 225936
164
This pulse level must then be written to the PROM so that Nr equals Ni.
Comparison Method
Most common, is the comparison of energy reading of the meter under test against a standard or reference meter. Normally,
the standard, or reference meter has a considerably higher pulse rate than the meter under calibration. In this case, the
absolute calibration time is not important for the calculations. The basic calibration setup is shown below:
Revision 1.8, 15-Feb-05
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Data Sheet AS8118
Reference
Meter
AS8118
Meter
Calboard
I
Figure 7
Basic calibration setup for comparison calibration method
The standard or reference meter pulses are counted between two or more pulses from the meter to be calibrated. Ideally the
sum of the pulses would exactly be the ratio between standard meter pulse rate and the pulse rate of the meter under test.
From the deviation the corrected Pulse_lev may be calculated.
Pulse _ lev ( corrected ) = Pulse _ lev ( ideal ) *
Ni
,
Nr
Where Nr is the number of pulses counted from the standard or reference meter and Ni is the ratio between the pulse rates,
which is always >1. The formula for Ni is as follows:
Ni =
PR( ref )
,
Fmon * Fcal
This is assuming that the CAL pulse output is used for calibration. If the LED pulse output is used for calibration, the following
formula should be used:
Ni =
PR( ref )
Fled
The Pulse_lev (ideal) is calculated using the following formula:
Pulse _ lev ( ideal ) =
230V 20 A
*
* 435924
Vmains I max
It is important to note that the formula for Pulse_lev (corrected) above should not be confused with the formula in the
previous method of calibration for ‘Defined Current and Calibration Time’ method, where Ni and Nr are reversed.
Example
The reference meter has a pulse rate, which is 10,000 times greater than the pulse rate of the AS8118 CAL output. During a
calibration cycle we measure 11,000 pulses between two CAL pulses. Therefore the ideal pulse-level has to be changed by a
factor of 10,000/11,000 = 0.909.
Revision 1.8, 15-Feb-05
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Data Sheet AS8118
Calibration without On-Chip Programming
It is also possible to calibrate a kWh meter using the AS8118 by means of an external resistor network or trim-potentiometer.
In this case, the parameters for the required pulse outputs are programmed into the device, along with the ideal value for
Pulse_lev as defined in the formula above. A resistor network may then be used in the voltage divider for the voltage input
setting, which is then trimmed until the measured pulse rate matches the ideal pulse rate.
In the case for kWh meter designs, which include a µ-controller and non-volatile memory, again, the parameters for the
required pulse outputs are programmed into the device, along with the ideal value for Pulse_lev as defined in the formula
above. The calibration may then be performed in the µ-controller.
Defining the Programmed Word
The AS8118 allows for all on-chip programmable functions to be reprogrammed a second time. It is important to always use
the Bank ‘0‘ as the first programming option. This is necessary as once Bank ‘1‘ has been selected and this selection has
been permanently ‘Burned‘ into the AS8118 device, Bank ‘0‘ can no longer be selected.
When programming the AS8118, the Bank that is NOT selected should have all ‘0‘ values as the programmed values.
Confirmation of this is shown in the example below, where Bank ‘0‘ has been selected for programming. All the programme
bits of Bank ‘1‘ have been programmed as ‘0‘.
Important: The value of Bit [0] must always be ‘1‘ when programming the AS8118, regardless of the memory bank being
programmed. The Bits [69:68] are not used and are thus ‘Don’t Care‘ bits. The programmed value may be ‘1‘ or ‘0‘.
An example of the word to be programmed to the AS8118 should look as follows:
Bit Number
Bit Value
Description
[69:68]
00
Not used bits
[67:66]
00
Bank 1: Gain
[65:64]
00
Bank 1: Anticreep threshold
[63:62]
00
Bank 1: F_mon
[61:60]
00
Bank 1: F_cal
[59:57]
000
Bank 1: F_led
[56:35]
0x000000
[34:33]
00
Bank 0: Gain = 4 (CT mode)
[32:31]
01
Bank 0: Anticreep threshold = 7.43mA
[30:29]
00
Bank 0: F_mon: 100 imp/kWh
[28:27]
10
Bank 0: F_cal: Fmon x 32
[26:24]
101
Bank 0: F_led: 3200 imp/kWh
[23:2]
0x06A6D4
[1]
0
Select Bank 0
[0]
1
Select programmed values
Bank 1: Pulse_lev
Bank 0: Pulse_lev: 435924
After selecting all PROM parameters as required a complete 70-bit word (including two overhead bits) is formed, which must
be written to the PROM.
Revision 1.8, 15-Feb-05
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Data Sheet AS8118
Testwrite
Testwrite means that the word to be programmed is simply written to an on-chip shift register so that the resulting behavior of
the AS8118 device may be examined. Once the PROM word is confirmed correct, it may be burned into the device. i.e.
Irreversibly written to the AS8118.
Until the data has been burned into the device, in other words, if only a Testwrite procedure has been performed, the data
will be lost when the supply is removed from the AS8118 device.
Due to the respective on-chip processing it is required to testwrite the inverse of the word to be programmed. Continuing with
the above example the word defined in the example should be as follows:
69
1
68
1
50
1
67
1
…
…
18
1
17
0
16
1
66
1
65
1
64
1
63
1
62
1
61
1
60
1
59
1
58
1
57
1
56
1
55
1
54
1
53
1
52
1
51
1
34
1
33
1
32
1
31
0
30
1
29
1
28
0
27
1
26
0
25
1
24
0
23
1
22
1
21
1
20
0
19
0
15
0
14
1
13
1
12
0
11
0
10
1
9
0
8
0
7
1
6
0
5
1
4
0
3
1
2
1
1
1
0
0
The Testwrite procedure is carried out as described in the following timing diagram:
Startup
69
68
67
4
3
2
1
0
TM
High
Low
f1
High
DIRO
Low
t2
x
PROG
start
define
testwrite testwrite
mode
(DIRO=0)
x
H
t3
L
Imax:
500µA
H
H
H
L
3V-3.5V
0V
Note: High and Low refers to VDD and VSS respectively.
On the first falling TM edge the mode (Testwrite) is defined. On the next rising TM edge the procedure is started. Afterwards
70 clocks have to be sent to DIRO. As can be seen the logic level on PROG prior to the positive DIRO edges defines the
state to be shifted into the internal register.
Important timing parameters are:
f1: Maximum frequency, must not exceed 50kHz
t2: Data setup time, minimum is 100ns
t3: Data storage time: the programmed bit is stored after approximately 20ns
Burn
The Burn procedure irreversibly writes data to the PROM. To do this, the 1s in the original word to be programmed must be
burned.
Revision 1.8, 15-Feb-05
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Data Sheet AS8118
Continuing with the above example, the defined word to be burned will be as follows:
69
0
68
0
50
0
67
0
…
…
18
0
17
1
16
0
66
0
65
0
64
0
63
0
62
0
61
0
60
0
59
0
58
0
57
0
56
0
55
0
54
0
53
0
52
0
51
0
34
0
33
0
32
0
31
1
30
0
29
0
28
1
27
0
26
1
25
0
24
1
23
0
22
0
21
0
20
1
19
1
15
1
14
0
13
0
12
1
11
1
10
0
9
1
8
1
7
0
6
1
5
0
4
1
3
0
2
0
1
0
0
1
The following timing diagram shows how the burn procedure is carried out:
Startup
69
67
68
4
2
3
1
0
TM
f1
t1
t3
t2
High
Low
High
DIRO
Low
Vburn
x
PROG
define
burn
mode
(DIRO=1)
x
L
H
L
L
L
H
0V
start
burn
Note: High and Low refers to VDD and VSS respectively.
The first falling and rising edges on TM define the burn mode and starts it (as can be seen DIRO must be set to logic ‘high’ at
the falling edge, but must be low at the rising edge). Then the first PROM cell is selected. After each rising clock edge on
DIRO the next PROM cell is selected going from MSB to LSB. While one of the PROM cells is selected a defined (low-active)
pulse on TM must be applied to “burn” the respective PROM cell, i.e. write a permanent logic-1 to it.
Important specifications are:
Tburn: Temperature during burn cycle: 25°C ± 10°C
Vburn: 7.50 ± 0.25V (at the AS8118 PROG pin)
f1: Maximum DIRO clock frequency is 100kHz
t1: The burn pulse must have a delay of at least 1µs after the previous positive DIRO clock edge
t2: After one burn pulse there must be a delay of at least 1µs before the next PROM cell is selected
t3: The burn pulse width is defined to be 1.0 ± 0.2µs. The rise and fall time of the burn pulses on TM must be less than 50ns.
After a burn cycle has been completed, a read cycle must be initiated so that the actual data is loaded. (After “burn” the data
in the internal register is inverted!)
Read
The conditions for ‘burn’ are specified very tightly. In order to be certain that the ‘burn’ process was successful this process
has to be verified. There are 2 modes of readout, a digital readout and analog readout.
Revision 1.8, 15-Feb-05
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Data Sheet AS8118
Digital readout uses the threshold of the comparator internal to the AS8118. Thus, the result, which can be observed on the
CAL pin, is the same as that used internally by the AS8118. Digital readout does NOT allow the quality of the ‘burn’ to be
evaluated.
Analog readout does allow for the verification of the analog value of the zener diodes. With analog readout, the quality of the
‘burn’ can be verified.
In order to verify the ‘burn’ process, an ‘analog readout’ of the zener diodes voltages has to be performed as the last step
after calibration. This can be done during the ‘read’ process, which may be started during calibration mode. The goal is to
verify that burned diodes show a voltage level of not more than 0.5V during the analog readout and the ‘unburned’ diodes a
voltage level of more than 2.4V.
Digital Readout
The AS8118 offers the customer the ability to read the PROM data. For example, it may be necessary to examine if a device
has been calibrated already and what value is correctly stored in the PROM. For the read mode the same two digital inputs
(TM and DIRO) are used as for ‘testwrite’ and ‘burn’. As can be seen in the following timing diagram the read mode is
selected by setting DIRO=1 while there is a rising edge on TM. (This assumes that one of the 3 modes has been completed
or the chip has just been powered up, i.e. the chip expects to enter a new mode.)
The following timing diagram shows the digital readout of the zener diodes:
69
68
67
66
TM
f1
2
1
0
end
read
High
Low
t2
High
DIRO
Low
High
PROG
t3
Low
High
CAL
Low
define
read
mode
(DIRO=1)
Note:
1. High and Low refers to VDD and VSS respectively.
2. In this case, the term ‘digital’ means that there is an on-chip comparator, which decides on the values of the bits, 0 or 1,
relative to a certain threshold; it neither guarantees the burned zener diodes voltage level to be below 0.5V (ZVB) nor a
value for unburned zener diodes of higher than 2.4V (ZVUB) as shown in the Operating Conditions.
After starting read mode with each rising edge on DIRO one of the PROM cells is selected. Its content is stored in a separate
internal flip-flop, the output of which can be watched on pin CAL (only during read!). With one additional rising edge on TM
the read mode is left and pin CAL shows the normal pulse output again.
Important: The bits displayed on CAL are the inverse of the PROM contents, i.e. they have to be inverted to match with the
previous PROM contents table.
Important timings are:
f1: Maximum read frequency, for reliable reading this should not be higher than 100kHz.
t2: Delay between the two rising edges: >100ns
t3: Depending on the loading on pin CAL the delay between rising edge on TM and change of data on CAL may vary. A
typical value is 50 ns.
Revision 1.8, 15-Feb-05
Page 21 of 30
Data Sheet AS8118
Analog Readout
The analog readout can be performed by disconnecting the PROG pin from the calibration board and starting a ‘read’
sequence. At specific points in time the voltage level on the PROG pin must be sampled. These time points are shown in the
following timing diagram.
69
67
68
66
2
1
TM
0
end
read
High
Low
High
DIRO
Low
5V
PROG
2.4V
0.5V
High
CAL
measure
zener diode
voltage:
Low
69
68
67
66
65
0
The numbers at the bottom of this timing diagram indicate the sample points of the bits in the PROM table, at which the zener
diode voltage level can be measured and compared against the limits for burned and unburned zener diodes.
In general this readout is most important, when a new calibration system is installed. Variations on the burn voltage or even
the length of the cable connected to the AS8118 PROG pin may have an influence on the quality of the burn process.
Revision 1.8, 15-Feb-05
Page 22 of 30
Data Sheet AS8118
Application Circuit
LOAD
VDD
VDD
C11
+
+
C12
C9
R5
C3
12
11
10
7
8
9
13
14
C4
18
C2
15
R6
16
R4
XTAL
C5
17
SHUNT
R3
C10
6
5
4
3
2
1
AS8118
LED
MON
R1A
C13
R1B
C7
R7
C6
VDD
D2
VAR
3
+
D1
C14
R2
C8
IC1
VI
VO
GND
2
1
C1
MOP
CAL
DIRO
PROG
GND
N
L
POWER IN
Note:
1. There must be proper ground connection between the calibration hardware and the meter under calibration during
‘Calibration Mode’. This ensures that the programming procedure is not effected by spurious signals. Such spurious
signals could originate from load switching during calibration.
2.
When using a low resistance shunt for current sensing, a small parasitic inductance introduced by the shunt can have
negative effects on the measurement accuracy. The filters on the current inputs designated by the components R5, C5
and R6, C4 provide a cancellation effect on the parasitic shunt inductance. The filters assume a typical inductance of
between 1nH and 2nH.
Revision 1.8, 15-Feb-05
Page 23 of 30
Data Sheet AS8118
Parts List
Designation
Value
Unit
Rshunt
300
µOhm
Precision Resistor, ±5%
R1A
820
kOhm
Resistor, 0.6W, ±10%
R1B
750
kOhm
Resistor, 0.6W, ±10%
R2
820
Ohm
SMD Resistor, ±1%
AS8118
Description
Single Phase Average Energy Metering IC
R3, R4, R5, R6
680
Ohm
SMD Resistor, ±1%
R7
470
Ohm
Resistor, 1W, ±5%
C1
68
nF
SMD Capacitor, ±5%
C2, C3, C4, C5
33
nF
SMD Capacitor, ±5%
C6
10
nF
Capacitor (Polypropylene), 1000VDC/250VAC, ±10%
C7
470
nF
Capacitor (Polypropylene), 1000VDC/250VAC, ±10%
C8
470
µF
Capacitor (Electrolytic), ±20%
C9, C10
100
nF
SMD Capacitor, ±5%
C11
10
µF
Capacitor (Electrolytic) , ±10%
C12
220
µF
Capacitor (Electrolytic) , ±20%
C13, C14
100
nF
SMD Capacitor, ±10%
IC1
XTAL
LM78L05 Voltage Regulator, ±5%
3.579545
MHz
Quartz Crystal or Ceramic Resonator, 20ppm/K
D1
BZV85-C15 Zener Diode, 1.3W, 15V, ±5%
D2
1N4007 Diode
VAR S20K275
Varistor, VRMS = 275V, VDC = 350V
Revision 1.8, 15-Feb-05
Page 24 of 30
Data Sheet AS8118
Electrical Characteristics
Absolute Maximum Ratings *
Parameter
Symbol
Min
Max
Unit
VDD
-0.3
7.0
V
Input Pin Voltage
Vin
-0.3
VDD + 0.3
V
Input Current on any Pin
Iin
-100
+100
mA
Tstrg
-65
+150
°C
H
5
85
%
1000
V
1)
°C
2)
DC Supply Voltage
Storage Temperature
Humidity Noncondensing
Electrostatic Discharge
Lead Temperature
1)
2)
Note
25°C
MIL STD883 method 3015.7 ‘Human Body Model‘ (R = 1.5kΩ; C = 100pF)
IEC61760-1, soldering conditions
* Stresses above those listed may cause permanent damage to the device. This is a stress rating only and
functional operation of the device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended
periods may affect device reliability (eq. hot carrier degradation).
Operating Conditions
Parameter
Symbol
Min
Typ
Max
Unit
Positive Analog Supply Voltage
AVDD
4.5
5.0
5.5
V
Negative Analog Supply Voltage
AVSS
Difference of Supply
A-D
-0.1
Positive Digital Supply Voltage
DVDD
4.5
Negative Digital Supply Voltage
DVSS
Supply Current
Isupp
Ambient Temperature
Tamb
-40
Measured Frequency
fmeas
45
System Clock Frequency
fclk
3.56
Measurement Bandwidth
BW
PROM Zener Voltage Unburned
ZV UB
PROM Zener Voltage Burned
ZV B
Revision 1.8, 15-Feb-05
0
5.0
3.58
Referred to AVSS
Typical ±10%
V
0.1
V
AVDD – DVDD
AVSS – DVSS
5.5
V
Referred to DVSS
Typical ±10%
0
25
Note
V
4
mA
85
°C
65
Hz
3.60
MHz
870
Variations result in gain errors
which are calibrated out
Hz
2.4
0.5
V
Measured during analog
readout
V
Measured during analog
readout
Page 25 of 30
Data Sheet AS8118
DC Characteristics
Digital Input with Pull-down (TM)
Parameter
Vih
Min
Max
Note
0.7 * VDD
Vil
0.3 * VDD
Iih
30µA
160µA
Iil
NA
NA
1)
DI, cmos w/pull-down (1)
DI, cmos w/pull-down
Iih tested at VDD = 5.5V and Vin = 5.5V
Digital Input with Pull-up (DIRI)
Parameter
Vih
Min
Max
Note
0.7 * VDD
Vil
0.3 * VDD
Iih
NA
NA
Iil
30µA
160µA
2)
DI, cmos w/pull-up (2)
DI, cmos w/pull-up
Iil tested at VDD = 5.5V and Vin = 0V
Digital Input/Output with Pull-down (DIRO, CAL)
Parameter
Min
Max
Note
Input
Vih
0.7 * VDD
Vil
0.3 * VDD
Iih
30µA
160µA
Iil
NA
NA
(1)
DI, cmos w/pull-down
Output
Voh
4.0V
Vol
1)
Ioh = -4mA
0.4V
Iol =
4mA
Iih is tested at VDD = 5.5V and Vin = 5.5V
Digital Output (MON, MOP, LED)
Parameter
Min
Voh
4.0V
Vol
Revision 1.8, 15-Feb-05
Max
Note
Ioh = -10mA
0.4V
Iol =
10mA
Page 26 of 30
Data Sheet AS8118
Package Dimensions
PDIP-18
(ALL DIMENSIONS IN INCH)
0.900 (18 lead)
0.756 (16 lead)
SOIC-18
(ALL DIMENSIONS IN INCH)
.040
DIA.
.050
.035
.045
h x 45°
.013
.018
PARTING LINE
.045
.055
E
H
.034
.040
L
.018
.024
45°
DETAIL A
TOP VIEW
e
B
A
A1
A2
B
C
D
E
e
.097
.0050
.090
.014
.0091
H
h
L
.400
.010
.024
.406
.013
.032
.410
.016
.040
0°
SEE VARIATIONS
5°
8°
.085
.093
.100
SYMBOL
MIN
VARIATIONS
NOTE 3 (D)
NOM
MAX
NOTE 5
(N)
AA
AB
AC
AD
AE
.402
.451
.500
.602
.701
.407
.456
.505
.607
.706
.412
.461
.510
.612
.711
16
18
20
24
28
h x 45°
X
.292
C
A2
A
D
SIDE VIEW
MIN
N
SEE DETAIL A
A1
SEATING PLANE
END VIEW
COMMON DIMENSIONS
NOM
MAX
SYMBOL
.101
.104
.009
.0115
.092
.094
.016
.019
.010
.0125
SEE VARIATIONS
.296
.299
.050
NOTE
3
5
Ordering Information
Part Number
Package
AS8118D18
DIP-18
AS8118S18
SOIC-18
AS8118 Evaluation Kit
DIP-18
Revision 1.8, 15-Feb-05
Page 27 of 30
Data Sheet AS8118
Copyright
Copyright  1997-2004, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria - Europe.
Trademarks Registered . All rights reserved. The material herein may not be reproduced, adapted, merged, translated,
stored, or used without the prior written consent of the copyright owner.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its
Terms of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the
information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems
AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this
product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended
for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental
requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically
not recommended without additional processing by austriamicrosystems AG for each application.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to
personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or
consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical
data herein. NO obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG
rendering of technical or other services.
Revision 1.8, 15-Feb-05
Page 28 of 30
Data Sheet AS8118
Note:
Revision 1.8, 15-Feb-05
Page 29 of 30
Data Sheet AS8118
Contact
Headquarters
austriamicrosystems AG
A 8141 Schloss Premstaetten, Austria
Phone: +43 3136 500 0
Fax:
+43 3136 525 01
[email protected]
Sales Offices
austriamicrosystems Germany GmbH
Tegernseer Landstrasse 85
D 81539 München, Germany
Phone: +49 89 69 36 43 0
Fax : +49 89 69 36 43 66
austriamicrosystems AG
Klaavuntie 9 G 55
FI 00910 Helsinki, Finland
Phone: +358 9 72688 170
Fax:
+358 9 72688 171
austriamicrosystems France S.A.R.L.
124, Avenue de Paris
F 94300 Vincennes, France
Phone: +33 1 43 74 00 90
Fax : +33 1 43 74 20 98
austriamicrosystems AG
Bivägen 3B
S 19163 Sollentuna, Sweden
Phone: +46 8 6231 710
austriamicrosystems Switzerland AG
Rietstrasse 4
CH 8640 Rapperswil, Switzerland
Phone: +41 55 220 9008
Fax : +41 55 220 9001
austriamicrosystems AG
88, Barkham Ride,
Finchampstead, Wokingham,
Berkshire RG40 4ET, United Kingdom
Phone: +44 118 973 1797
Fax:
+44 118 973 5117
austriamicrosystems USA, Inc.
8601 Six Forks Road
Suite 400
Raleigh, NC 27615, USA
Phone: +1 919 676 5292
Fax : +1 509 696 2713
Revision 1.8, 15-Feb-05
austriamicrosystems AG
Suite 915, No. 1,
Suhua Road,
Suzhou Industrial Park,
PR China 215021
Phone: +86 512 6762 2590
(6762 2593)
Fax:
+86 512 6762 2594
austriamicrosystems AG
Suite 811, Tsimshatsui Centre,
East Wing, 66 Mody Road,
Tsim Sha Tsui East,
Kowloon, Hong Kong
Phone: +852 2268 6899
Fax:
+852 2268 6799
austriamicrosystems Japan, AG
th
AIOS Gotanda Annex 5 Fl.,
1-7-11,
Higashi-Gotanda,
Shinagawa-ku,
Tokyo 141-0022, Japan
Phone: +81 3 5792 4975
Fax : +81 3 5792 4976
austriamicrosystems AG
#805, Dong Kyung Bldg., 824-19,
Yeok Sam Dong,
Kang Nam Gu, Seoul
Korea 135-080
Phones: +82 2 557 8776
Fax:
+82 2 569 9823
austriamicrosystems AG
83, Clemenceau Avenue,
#02-01, UE Square,
Singapore 239920
Phone: +65 6 830 8305
Fax: +65 6 234 3120
austriamicrosystems AG
nd
2 Floor,
No. 31, Sec. 2
Nam-Chang Road,
Taipei, Taiwan
Phone: +886 2 2395 6600 227
Fax:
+886 2 2395 7330
Page 30 of 30