Product Overview
A Kodenshi Isolator With Its Feet Already Bent For Your Board
Condition
New old stock, unused, from an original factory tube. The photos show the tube these come out of: a clear rail with a green end plug, amber tape closing the other end, and a printed DEVICE / BIN end label with PC-17K1 written in the DEVICE field. Each body is marked PC-17K1 over 9345, alongside a small K logo and a dot at one corner. The 9345 reads as 1993 week 45 on the usual year-week convention, which is an interpretation rather than a decode against a published Kodenshi marking key. One detail matters more than any of that: the leads on these units are formed flat and outward for surface mounting, not left straight for a through-hole socket. The pieces in the photos are representative of the stock. The parts have not been electrically tested here.
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Product Overview
The Kodenshi PC-17K1 is a single-channel photocoupler: a gallium arsenide infrared emitting diode optically coupled to, and electrically isolated from, a silicon NPN phototransistor inside one 4-pin package. Current through the input LED produces collector current on the output side with no electrical connection between the two, which is how a low-voltage logic section talks to a noisy or differently referenced circuit without sharing a ground. The published ratings are 35 V collector-emitter (that figure is both the guaranteed minimum breakdown and the maximum you may apply), 50 mA collector current, 50 mA LED forward current with 5 V reverse, 200 mW total dissipation and an operating range of -30 to +100 degC. Current transfer ratio is specified from 50 percent minimum to 600 percent maximum at IF = 5 mA and VCE = 5 V, with nothing on the part narrowing that window to a bin or grade. Isolation is AC 5000 Vrms with a minimum 7.0 mm creepage and clearance, and the device is UL Recognized under file E107486. Rise and fall times run about 4 microseconds each, so treat this as a general-purpose isolator rather than a fast one. The package is the 4-pin DIP outline with the leads formed for surface mount; the topside marking is the bare PC-17K1, and whether Kodenshi gave that lead form its own suffix is not confirmed - verify against the datasheet before use. Sold each, from a shelf count of 10.
Key Features
- Single-channel photocoupler: GaAs infrared LED to silicon NPN phototransistor, 4 pins
- Rated 35 V collector-emitter, 50 mA collector current, 150 mW collector dissipation
- Current transfer ratio 50 to 600 percent at IF = 5 mA, VCE = 5 V
- AC 5000 Vrms isolation, minimum 7.0 mm creepage and clearance
- LED side: 50 mA forward current, 5 V reverse, 1.15 V typical drop at 10 mA
- 0.15 V typical saturation voltage, 100 nA maximum dark current
- About 4 microseconds rise and fall - general purpose, not high speed
- 200 mW total dissipation, -30 to +100 degC operating
- UL Recognized, file E107486
- Leads formed for surface mounting, marked PC-17K1 with a 9345 code
Applications
- A repair tech tracing a dead feedback path in 1990s Japanese industrial gear, who needs the original isolator rather than a modern substitute with different CTR behavior
- A controls builder isolating a microcontroller input from a 24 V field signal, where the 5000 Vrms rating and 7.0 mm creepage do the safety work
- A hobbyist adding an optically isolated trigger to a bench instrument and reflowing parts onto a small board, where the formed leads are the convenience rather than the obstacle
- A restorer stocking a drawer against the next board that comes in with a cooked coupler and a 35 V rail behind it
Frequently Asked Questions
Are these through-hole DIP parts?
No. The outline is the 4-pin DIP body, but the leads on these units are formed flat and outward for surface mounting. Dropping one into a through-hole board means straightening the leads first. If you need straight pins as supplied, this is not the piece for you.
What does the 9345 on the body mean?
It reads as a 1993 week 45 date code on the standard year-week convention. That is an interpretation, not a decode against a published Kodenshi key, so treat it as an age indicator rather than a specification. The PC-17K1 above it is the part number, confirmed both on the bodies and on the tube's end label.
What current transfer ratio will I get?
The datasheet window for the PC-17K1 is 50 percent minimum to 600 percent maximum at IF = 5 mA and VCE = 5 V. Nothing on the body or the tube label narrows that to a bin, so design for the full range unless you sort the pieces yourself.
Is a pinout included?
Not from us. Take the pin assignment from Kodenshi's published PC-17K1 datasheet before you lay out the footprint.
Why buy a few of these here instead of a bagged lot somewhere else?
Because you can take the exact count you need. Ten pieces are on the shelf, sold one at a time, so a single replacement for one board costs you one piece and a prototype run costs you the handful it actually takes - no forced minimum of 25 or 100 of an optocoupler you will never finish. They are NOS out of an original factory tube, the marking is photographed, and you can see the lead form before you commit. Shipping is $8 flat rate, free once your order passes $28, and orders leave our Idaho warehouse the same or next business day.
Marked PC-17K1 over 9345, still in the factory tube, legs already formed flat for a reflow board. However long they have been sitting there, it has not changed what they do: keep two circuits politely unaware of each other while passing the message along. Your board, your isolation barrier, your turn.
