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PC817

Manufacturer: Sharp, Everlight Electronics, Lite-On, onsemi

Figures from the datasheet: Sharp Corporation D2-A03101EN, September 30, 2003

Sharp PC817 (PC817X series) 4-pin phototransistor output optocoupler in DIP-4 and SMD-4; 5000 Vrms isolation, 80 V collector-emitter breakdown, and 50% to 600% CTR current transfer ratio.

PackagesDIP-4, SMD-4

Supply voltage3 – 35 V

Temperature range-25 – 85 °C

Official Datasheet (PDF)

Technical Overview

The PC817 (PC817X series) is an industry-standard 4-pin general-purpose photocoupler (optocoupler) manufactured by Sharp Corporation (datasheet D2-A03101EN). The device optically couples a gallium arsenide (GaAs) infrared emitting diode (IRED) on the input side with a high-voltage NPN silicon phototransistor on the output side, providing 5000 Vrms galvanic isolation between low-voltage logic domains and high-voltage industrial circuits. The modern PC817X series features an 80 V collector-emitter breakdown rating (V_CEO) and a maximum continuous collector current of 50 mA, making it ideal for noise isolation in switching power supplies (SMPS), microcontroller input isolation from noisy 24 V PLC field lines, and driving external relay or solenoid transistors without ground loops. Current transfer ratio (CTR) is classified into four standard grading ranks: Rank A (80% to 160%), Rank B (130% to 260%), Rank C (200% to 400%), and Rank D (300% to 600%) measured at IF = 5 mA and V_CE = 5 V. Standard packages include 4-pin plastic dual in-line (DIP-4) through-hole and gull-wing surface mount (SMD-4) with 2.54 mm pin pitch.

Package Pinout & Alternate Functions

Interactive package pinout and pin mapping for DIP-4.

Package illustration, not a dimensioned mechanical drawing.

4 / 4 pins

Pin name	Type	5V Tolerant	Alternate functions / details
A	passive	—	Anode of the input GaAs infrared emitting diode (IRED); connect to positive control signal via series current-limiting resistor
K	passive	—	Cathode of the input GaAs infrared emitting diode (IRED); sink to ground or logic driver to activate input current
E	passive	—	Emitter terminal of output NPN phototransistor; connect to isolated ground in common-emitter configuration or load in emitter-follower
C	passive	—	Collector terminal of output NPN phototransistor; pull up to isolated DC supply rail with external resistor (withstands up to 80V VCEO)

Key Specifications

Parametric attributes

Parameter	Min	Typical	Max	Unit	Test condition
Isolation Voltage(V_iso)	5000	5000	—	Vrms	AC 1 min, 40-60% RH
Collector-Emitter Breakdown Voltage(V_CEO)	80	80	—	V	IC = 0.1 mA, IF = 0
Emitter-Collector Breakdown Voltage(V_ECO)	6	6	—	V	IE = 10 µA, IF = 0
Continuous Forward Current(I_F)	—	20	50	mA	—
Forward Voltage(V_F)	—	1.2	1.4	V	IF = 20 mA
Reverse Current(I_R)	—	—	10	µA	VR = 4 V
Terminal Capacitance(C_t)	—	30	250	pF	V = 0, f = 1 kHz
Collector Dark Current(I_CEO)	—	—	100	nA	VCE = 50 V, IF = 0
Current Transfer Ratio(CTR)	50	100	600	%	IF = 5 mA, VCE = 5 V
Collector-Emitter Saturation Voltage(V_CE(sat))	—	0.1	0.2	V	IF = 20 mA, IC = 1 mA
Isolation Resistance(R_ISO)	5e10	1e11	—	Ω	DC 500 V, 40-60% RH
Floating Capacitance(C_f)	—	0.6	1	pF	V = 0, f = 1 MHz
Cut-Off Frequency(f_c)	—	80	—	kHz	VCE = 5 V, IC = 2 mA, RL = 100 Ω, -3 dB
Rise Time(t_r)	—	4	18	µs	VCE = 2 V, IC = 2 mA, RL = 100 Ω
Fall Time(t_f)	—	3	18	µs	VCE = 2 V, IC = 2 mA, RL = 100 Ω

Absolute Maximum Ratings

Max supply voltage (VDD/VCC)	80 V
Max input voltage	6 V
Max output / pin current	50 mA
Junction temperature	-30 – 100 °C
Storage temperature	-55 – 125 °C
Thermal resistance θJA (DIP-4)	350 °C/W
Thermal resistance θJA (SMD-4)	350 °C/W

Hardware Engineering Gotchas

Real-world hardware caveats, PCB layout constraints and silicon errata to know before manufacturing.

Warning

CTR Degradation Over Operating Lifetime and Elevated Temperature

The Current Transfer Ratio (CTR) of GaAs-based infrared LEDs naturally degrades over operational lifetime (typically dropping 10% to 30% after several thousand hours at elevated temperatures) and exhibits a negative temperature coefficient at high junction temperatures.

Mitigation

Design input drive circuits with a 2x to 3x safety overdrive margin (e.g. driving IF = 5 to 10 mA for a required IC = 2 mA) so switching performance and saturation are preserved over the product lifecycle.

Warning

Slow Switching Speed and Turn-Off Delay with High Load Resistors

The PC817 is a general-purpose phototransistor coupler with typical switching times of 3 to 18 µs; using a high pull-up resistor (RL >= 10 kΩ) charges parasitic Miller capacitance slowly, extending fall/turn-off times to over 50 µs and limiting digital baud rates to below 10 kHz.

Mitigation

For digital communication above 10 kHz or PWM switching, lower the collector pull-up resistor (1 kΩ to 2.2 kΩ) with higher LED drive current, or use high-speed logic optocouplers such as the 6N137.

Critical

Input Reverse Voltage Limit of 6 V Destroys IRED on Reverse Polarity

The internal GaAs infrared emitter diode has an absolute maximum reverse voltage rating VR of only 6 V; reverse polarity spikes on input control lines or AC ringing quickly cause reverse junction breakdown and destroy the internal LED.

Mitigation

Place an antiparallel protection diode (such as a 1N4148) directly across pins 1 and 2 to clamp negative transient excursions, or use a series blocking diode in dirty industrial 24 V input circuits.

Note

CTR Bin Dispersion Across Part Suffixes (A, B, C, D)

PC817 parts are sorted into wide CTR ranks: A (80% to 160%), B (130% to 260%), C (200% to 400%), and D (300% to 600%). Procuring unbinned or differently ranked variants can cause marginal saturation or timing variations across production batches.

Mitigation

Specify the exact rank suffix (such as PC817B or PC817C) in the design Bill of Materials and verify circuit calculations using the minimum specified CTR bound of that rank.

Cross-Reference & Equivalents

Part number (MPN)	Manufacturer	Compatibility	Electrical differences / BOM considerations
EL817	Everlight Electronics	pin to pin drop in	Direct 4-pin pin-to-pin compatible optocoupler with 5000 Vrms isolation and 80 V VCEO rating across comparable CTR bins A, B, C, D.
LTV-817	Lite-On	pin to pin drop in	Direct 4-pin pin-to-pin compatible optocoupler; check VCEO rating (35 V on standard LTV-817, 80 V on LTV-817S/M series) against system operating voltage.
FOD817	onsemi	pin to pin drop in	Direct 4-pin pin-to-pin compatible optocoupler with 5000 Vrms isolation rating and 70 V VCEO breakdown.
K1010	Cosmo Electronics	pin to pin drop in	Direct 4-pin pin-to-pin compatible optocoupler with 5000 Vrms isolation and 80 V VCEO breakdown.
4N35	Vishay	functional requires bom change	6-pin DIP package with base pin (pin 6); lower CTR (typically 100% at 10 mA) and 3550 Vrms isolation rating; requires PCB footprint layout change.

Reference Circuits

PC817 Optocoupler Galvanically Isolated Logic Interface

Topology: Unidirectional digital logic isolator providing 5000 Vrms galvanic isolation between field input and microcontroller logic, with 390 Ω input resistor, 1N4148 antiparallel clamp diode, and 4.7 kΩ pull-up to +5 V isolated rail.

Inspect schematic Open in Web CAD Editor

Official Documentation & Cited Datasheets

Primary semiconductor vendor datasheets, errata, and application notes.

DATASHEETSharp Corporation

Sharp PC817X Series DIP 4pin General Purpose Photocoupler Datasheet

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Technical Overview

Package Pinout & Alternate Functions

Key Specifications

Parametric attributes

Absolute Maximum Ratings

Hardware Engineering Gotchas

Cross-Reference & Equivalents

Reference Circuits

PC817 Optocoupler Galvanically Isolated Logic Interface

Official Documentation & Cited Datasheets

Sharp PC817X Series DIP 4pin General Purpose Photocoupler Datasheet

Help keep this page accurate

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