Product Overview
High-Threshold Logic 15V Divide-by-10 Counter – Industrial HTL Series
Condition
Unused, New Old Stock (NOS) in original packaging. 14-pin PDIP with gold-plated leads as shown. Date code marked 807. Visual inspection completed with no issues noted.
Ships same business day. Reliable parts at honest prices since 1999. Real humans.
Product Overview
Motorola MC838P is a monolithic silicon decade counter from the MC800-series High-Threshold Logic (HTL) family. Designed for divide-by-ten counting applications, it operates on a nominal 15V supply and was engineered for electrically noisy industrial environments where standard 5V logic would miscount. The MC838P uses HTL architecture with a high switching threshold, providing substantial noise immunity at the expense of switching speed.
This 14-pin DIP version features gold-plated leads, a reliability choice common in late 1960s and 1970s industrial components. Unlike common 7490 or CMOS 4017 counters, this device is not pin-compatible and is intended strictly for 15V HTL systems.
Key Features
- Divide-by-10 (decade) counting function
- HTL – High-Threshold Logic family
- Nominal 15V operating supply
- High noise immunity with ~7.5V logic threshold
- Typical propagation delay: 100ns to 200ns
- Maximum clock frequency approximately 1MHz to 3MHz
- Power dissipation typically 150mW to 200mW
- 14-pin PDIP package
- Gold-plated leads for oxidation resistance and long-term solderability
- Date code 807
Applications
- 1970s industrial control systems
- Legacy CNC machinery timing stages
- Heavy-duty industrial timers and counters
- Steel mill and high-interference factory equipment
- Early laboratory instrumentation
- Restoration of HTL-based control boards
- Period-correct industrial electronics projects
Frequently Asked Questions
Can this replace a 7490 or CMOS 4017 counter?
No. This is a 15V High-Threshold Logic device and is not pin-compatible with 5V TTL or CMOS counters. Applying 15V to standard logic will cause damage. Match the original HTL design exactly.
What supply voltage does it require?
This device is designed for approximately 15V operation as part of the HTL family.
Why are the leads gold plated?
Gold plating resists oxidation and maintains reliable socket and solder connections over long storage periods, especially in industrial environments.
Is this suitable for modern microcontroller projects?
It is generally not practical for modern 5V or 3.3V systems due to voltage and logic-level differences. It is best suited for restoration or maintenance of original HTL-based equipment.
What does the 807 date code indicate?
Motorola date coding from this era indicates the 7th week of a year ending in 8, commonly interpreted as 1968 or 1978 depending on production context.
Built for factories where electrical noise was part of the job, not a bug. If you are keeping a 15V HTL system alive, this gold-lead Motorola counter is ready to take its place back on the board.
