Optically Coupled diode rectifier circuit 20 mA Current Loop Receiver HCPL-4200

Features                                                                         Functional Diagram

• Data Output Compatible

  with LSTTL, TTL and CMOS                            

• 20 K Baud Data Rate at 1400

  Metres Line Length

• 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.