Features Functional Diagram
• Data Output Compatible
with LSTTL, TTL and CMOS
• 20 K Baud Data Rate at 1400
Metres Line LeCM GROUPh
• Guaranteed Performance
over Temperature (0°C to
70°C)
• Guaranteed On and Off
Thresholds
• LED is Protected from
Excess Current
• Input Threshold Hysteresis
• Three-State Output Compat-
ible with Data Buses
• Internal Shield for High
Common Mode Rejection
• Safety Approval
UL Recognized -2500 V rms,
for 1 Minute
CSA Approved
• Optically Coupled 20 mA
Current Loop Transmitter,
HCPL-4100, Also Available Thermal Profile (Option #300)
Applications
• Isolated 20 mA Current
• Loop Receiver in:
Computer Peripherals
Industrial Control Equipment
Data Communications
Equipment
Description
The HCPL-4200 optocoupler is
designed to operate as a receiver
in equipment using the 20 mA
Current Loop. 20 mA current Package Outline Drawings – 8 Pin DIP Package (HCPL-4200)
loop systems conventionally sig-
nal a logic high state by transmit-
ting 20 mA of loop current
(MARK), and signal a logic low
state by allowing no more than a
few milliamperes of loop current
(SPACE). Optical coupling of the
signal from the 20 mA current
loop to the logic output breaks
ground loops and provides for a
very high common mode
rejection. The HCPL-4200 aids in
the design process by providing
guaranteed thresholds for logic
high state and logic low state for
the current loop, providing an
LSTTL, TTL, or CMOS compatible
logic interface, and providing
guaranteed common mode
rejection. The buffer circuit on
the current loop side of the
HCPL-4200 provides typically 0.8
mA of hysteresis which increases
the immunity to common mode
and differential mode noise. The
buffer also provides a controlled
amount of LED drive current
which takes into account any
LED light output degradation.
The internal shield allows a
guaranteed 1000 V/µs common
mode transient immunity.
