Texas Instruments JM38510/36001B2A

Overview

JM38510/36001B2A from Texas Instruments is a military-grade TTL priority encoder that converts eight active-low data inputs (0–7) into three-bit active-low binary (octal) outputs (A0, A1, A2), with enable input (EI) and group signal (GS) / enable output (EO) for cascading. It operates over −55°C to +125°C, delivers 15 ns typical propagation delay, consumes 12 mA max supply current at VCC = 5 V, and is housed in a hermetically sealed 20-pin LCCC package. It is used in fault-tolerant avionics control panels requiring priority-based input encoding under extreme thermal stress.

For engineers reviewing the JM38510/36001B2A datasheet, JM38510/36001B2A pinout, JM38510/36001B2A application, or JM38510/36001B2A equivalent, key selection criteria include its −55°C to +125°C operating range, active-low input/output logic polarity, GS/EO cascading capability, 15 ns propagation delay (tPHL/tPLH), and compatibility with legacy 54LS-series TTL interface levels and loading.

Technical Context

The JM38510/36001B2A implements a priority-encoding logic function where only the highest-order asserted (low) input determines the output code - e.g., if inputs 3 and 5 are low, only input 5 (higher index) is encoded. Its internal architecture uses buffered TTL gates with normalized 1× 54/74LS load drive capability per input and totem-pole outputs capable of sinking 4 mA or sourcing −400 µA.

Cascading is supported via EI (active-low enable input) and EO (active-low enable output) for octal expansion, and GS (active-low group signal) indicates whether any input is asserted. All inputs and outputs are active-low, and unused inputs must be tied to VCC or GND to prevent floating states and ensure deterministic operation.

Key Specifications

Pinout & Package

Package: 20-pin Leadless Ceramic Chip Carrier (LCCC), FK package, 8.89 mm × 8.89 mm, 1.27 mm pitch, hermetically sealed, RoHS-exempt (SNPB finish), MSL N/A.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar priority encoder applications.

Compared with SNJ54LS148FK and JM38510/36001BEA, JM38510/36001B2A offers the highest assurance level for deployed systems via Class B qualification, hermetic LCCC packaging for moisture resistance, and guaranteed 20-year shelf life compliance - making it the sole choice for production flight hardware requiring zero field failures.

Availability

JM38510/36001B2A is available at Aetrix Electronics and suitable for avionics control units, missile guidance subsystems, secure comms chassis, and nuclear C2 interfaces requiring stable component supply across extended product lifecycles and extreme environmental conditions.

Supply support for JM38510/36001B2A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a U.S.-based semiconductor manufacturer with over 50 years of leadership in analog, embedded processing, and military-grade logic ICs, serving aerospace, defense, and industrial markets.

The JM38510/36001B2A belongs to TI's MIL-PRF-38535 qualified logic portfolio, designed specifically for high-reliability, radiation-tolerant, and thermally robust applications in mission-critical electronic systems.

FAQ

What is the operating temperature range of the JM38510/36001B2A?

The JM38510/36001B2A is rated for −55°C to +125°C continuous operation, fully qualified per MIL-PRF-38535 Class B screening requirements including temperature cycling, steady-state life test, and hermeticity verification - ensuring reliable performance in jet engine bays, missile canisters, and space-qualified payloads.

Does the JM38510/36001B2A support cascading with other priority encoders?

Yes, the JM38510/36001B2A supports hardware cascading via dedicated EI (enable input), EO (enable output), and GS (group signal) pins. When multiple JM38510/36001B2A devices are stacked, EO of a lower-priority unit drives EI of the next higher-priority unit, while GS asserts only when any input across the chain is active - enabling deterministic 16+ line encoding without external glue logic.

What is the logic polarity of inputs and outputs on the JM38510/36001B2A?

All inputs (0–7, EI) and outputs (A0, A1, A2, GS, EO) on the JM38510/36001B2A are active-low. A logic low on input 5, for example, encodes as binary 101 on A2–A0 (also low), and GS goes low when any input is asserted. This polarity matches legacy switch-to-ground and open-collector sensor interfaces common in military systems.

Is the JM38510/36001B2A pin-compatible with commercial SN74LS148 variants?

No - the JM38510/36001B2A uses a 20-pin LCCC (FK) package with 12 NC pins, whereas commercial SN74LS148 variants use 16-pin PDIP (N), SOIC (D), or SOP (NS) packages with full I/O allocation. Pin mapping, thermal design, and soldering profiles differ fundamentally; direct PCB replacement is not possible without layout revision.

What are the absolute maximum ratings for VCC and input voltage on the JM38510/36001B2A?

The absolute maximum VCC rating for the JM38510/36001B2A is 7 V, and the absolute maximum input voltage (VI) is 7 V - exceeding the recommended 4.5 V to 5.5 V operating range. Exceeding these limits risks permanent damage; operation above 5.5 V or below 4.5 V is not guaranteed and may cause timing violations or increased ICC.