Product Overview
SN74LS112AN 74LS TTL Dual J-K Negative-Edge-Triggered Flip-Flop with Preset and Clear, DIP-16 Through-Hole
Condition
Unused NOS sourced from an electronics parts distributor that was winding down operations. Units show minor scuffs and scratches consistent with storage; appear unused. Pin legs have mild tarnish due to age — should clean easily with a citric acid and water solution before soldering. Evaluation: Visual inspection only. Function testing not performed.
Ships same business day from Idaho. Packed carefully.
Product Overview
Dual J-K negative-edge-triggered flip-flop IC from Texas Instruments. Part number SN74LS112AN. Member of the 74LS (Low-power Schottky) TTL logic family. Each of the two independent flip-flop cells triggers on the falling edge of the clock signal, making it suitable for timing-critical digital circuits where positive-edge devices would introduce race conditions. Includes individual Preset and Clear inputs per cell. 16-pin plastic DIP package for through-hole PCB mounting. Requires a 5V supply.
Key Features
- Logic family: 74LS — Low-power Schottky TTL
- Function: Dual J-K negative-edge-triggered flip-flop
- Package: DIP-16 (16-pin through-hole, PDIP)
- Supply voltage: 4.75V to 5.25V (5V nominal)
- Maximum clock frequency: 30 MHz typical
- Independent Preset and Clear inputs per flip-flop cell
- Trigger: Falling (negative) clock edge only
Applications
- Vintage arcade PCB repair — Pac-Man, Galaga, and similar logic boards
- Retro computer restoration — Apple II, Commodore, and other 1970s-1980s motherboards
- Frequency divider and clock divider circuits
- State-machine logic in legacy industrial control systems
- General 74LS TTL logic board repair and replacement
Frequently Asked Questions
Is this compatible with 3.3V systems?
No. The SN74LS112AN is a 5V TTL device. It is not directly compatible with 3.3V CMOS systems. Level shifting is required if interfacing with 3.3V logic.
How does this differ from the 74HC112 or 74S112?
All three are pin-compatible, but they are electrically different. The 74LS variant uses Low-power Schottky TTL technology and runs at 5V. The 74HC112 is CMOS and operates at 2V-6V with different current characteristics. The 74S112 is High-speed Schottky with higher power consumption. Verify your circuit's logic family before substituting.
What is the difference between this and the SN74LS112AD?
The SN74LS112AN is a through-hole DIP-16 package. The SN74LS112AD is the surface-mount SOIC version. Same electrical function — different package footprint.
The pin legs have tarnish — will they solder properly?
Mild oxidation on NOS legs is common with age. Cleaning with a citric acid and water solution before soldering is recommended and should restore solderability.
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