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The input of the MID400 consists of two back-to-back
LED diodes which will accept and convert alternating
currents into light energy. An integrated photo diode-
detector amplifier forms the output network. Optical cou-
pling between input and output provides 2500 V$&
RMS
voltage isolation. A very high current transfer ratio
(defined as the ratio of the DC output current and the DC
input current) is achieved through the use of high gain
amplifier. The detector amplifier circuitry operates from a
5V DC supply and drives an open collector transistor
output. The switching times are intentionally designed to
be slow in order to enable the MID400, when used as an
AC line monitor, to respond only to changes in input volt-
age exceeding many milliseconds. The short period of
time during zero-crossing which occurs once every half
cycle of the power line is completely ignored. To operate
the MID400, always add a resistor, RIN, in series with
theinput (as shown in ILJXUH) to limit the current to the
required value. The value of the resistor can be deter-
mined by the following equation:
Where,
VIN (RMS) is the input voltage.
VF is the forward voltage drop across the LED.
IIN (RMS) is the desired input current required to sustain a logic
“O” on the output.
Pin Description
Schematic Diagram
Glossary
VOLTAGES
VI1 (ONB506) On-State RMS Input Voltage
The RMS voltage at an input terminal for a
specified input current with output condi-
tions applied according to the product
specification will cause the output switch-
ing element to be sustained in the on-state
within one full cycle.
VI1 (OFFB506) Off-State RMS Input Voltage
VOL
VOH
VF
The RMS voltage at an input terminal for a
specified input current with output condi-
tions applied according to the product
specification will cause the output switch-
ing element to be sustained in the off-state
within one full cycle.
Low-Level Output Voltage
The voltage at an output terminal for a spe-
cific output current IOL, with input condi-
tions applied according to the product
specification will establish a low-level at
the output.
High-Level Output Voltage
The voltage at an output terminal for a spe-
cific output current IOH, with input condi-
tions applied according to the product
specification will establish a high-level at
the output.
LED Forward Voltage
The voltage developed across the LED
when input current IF is applied to the
anode of the LED.
CURRENTS
II1 (ONB506)On-State RMS Input Current
The RMS current flowing into an input with
output conditions applied according tothe
product specification will cause theoutput
switching element to be sustainedin the
on-state within one full cycle.
II1 (OFFB506)Off-state RMS Input Current
IOH
The RMS current flowing into an input with
output conditions applied according tothe
product specification will cause theoutput
switching element to be sustainedin the
off-state within one full cycle.
High-Level Output Current
The current flowing into an output with
input conditions applied according tothe
product specification will establish ahigh-
level at the output.
Pin
Number
Pin
Name Function
1, 3 VIN1, VIN2 Input terminals
2, 4 N/C No Connect
CC
V8 Supply voltage, output circuit.
7UXA Auxiliary terminal.
Programmable capacitor input
to adjust AC voltage sensing
level and time delay.
O
V6 Output terminal; open collector.
5 GND Circuit ground potential.
RIN
VIN –VF
IIN
=-----------------------
45
1
VIN1
N/C
N/C
VIN2
VCC
AUX.
GND
VO
2
3
8
7
6