Light modulation photo IC S4282-51, S6809, S6846, S6986, S7136/-10
■ Electrical and optical characteristics (Ta=25 °C, Vcc=5 V)
S4282-51, S6986 S6809, S6846, S7136 /-10
Output: built-in pull-up resistor * 2
Cathode: constant current drive
Output: open collector * 3
Cathode: open collector drive
Parameter Symbol Condition
Min. Typ. Max. Min. Typ. Max.
Unit
Supply voltage Vcc 4.5 - 16 4.5 - 16 V
Current
consumption Icc Vo, LED
terminals open - 4 11 - 4 11 mA
Low level
output volta
eVOL IOL=16 mA - 0.2 0.4 - 0.2 0.4 V
4.9 - - V
Output
High level
output
voltage
VOH 4.7 k
Ω
between
Vcc and Vo 4.9 - - V
Low level
output volta
eVcath Icath=40 mA - - 0.8 V
Low level
output current Icath Vcath=1.2 V 15 35 60 mA
Pulse cycle Tp 65 130 220 65 130 220 µs
Cathode
Pulse width Tw 4 8 13.7 4 8 13.7 µs
H→L
Threshold
light level
EHL λ=940 nm
No back
round li
ht -0.7 2 - 0.2 1.0 µW/mm2
0.45 0.65 0.95
Hysteresis - 0.45 0.65 0.95 0.65
(S6809)
0.8
(S6809)
0.95
(S6809)
-
Frequency
response f0.5 1.25 -0.5 1.25 -kHz
Allowable
background
light level
Ex
Signal light: 5
µ
W/mm
λp=940 nm
Background light:
A light source
5000 10000 - 2000 3000 - lx
Vcc
CATHODE
(LED)
GND
Vcc
Vout
GND
Cathode Output
10 k
*2: *3:
Vcc
CATHODE
(LED)
GND
Vcc
Vout
GND
Cathode Output
KPICC0009EA KPICC0010EA
CONSTANT
VOLTAGE
BUFFER
SIGNAL
PROCESSING
CIRCUIT
TIMING
GENERATOR
OSCILLATOR
LED
DRIVER
OUTPUT
CIRCUIT
GND
CATHODE
(LED)
Vout
Vcc
COMPARATOR
PREAMP
PD
Vref
TRUTH TABLE
INPUT OUTPUT LEVEL
LIGHT ON
LIGHT OFF
LOW
HIGH
■ Block diagram and internal functions (a) Oscillator and timing signal generator
The oscillator produces a reference oscillation output by charging and discharging the
built-in capacitor with constant current. The oscillation output is fed to the timing signal
generator, which then creates LED drive pulses and various timing pulses for digital
signal processing.
(b) LED driver circuit
This circuit drives an external LED using the LED drive pulses created by the timing
signal generator. The duty cycle is 1/16.
(c) Photodiode and preamplifier circuit
The photodiode is formed on the same monolithic chip. A photocurrent generated in the
photodiode is conver ted to a voltage by a preamplifier circuit. The preamplifier circuit
uses an AC amplifier to expand the dynamic range versus DC or low-frequency
background light, without impairing signal detection sensitivity.
(d) Capacitive coupling, buffer amplifier and reference voltage generator
Capacitive coupling removes low-frequency noise and also cancels the DC offset in
the preamplifier. The buffer amplifier boosts the signal up to the comparator level, and
the reference voltage generator produces a comparator level voltage.
(e) Comparator circuit
The comparator circuit has a hysteresis function to prevent chattering caused by
small fluctuations in the input light.
(f) Signal processing circuit
The signal processing circuit consists of a gate circuit and digital integrator circuit. The
gate circuit discriminates input pulses during synchronous detection, to prevent op-
erational errors caused by asynchronous background light. Background light which is
synchronized with the signal detection timing cannot be eliminated by the gate circuit,
but is canceled out by the digital integrator circuit at the latter stage.
(g) Output circuit
This circuit serves as an output buffer for the signal processing circuit and outputs the
signal to an external circuit.
KPICC0002EA