Texas Instruments SN54S194J

Overview

SN54S194J from Texas Instruments is a 4-bit bidirectional universal shift register IC designed for synchronous digital systems requiring parallel load, shift-left, shift-right, and hold functions in military-grade environments. It operates over -55°C to +125°C, features TTL-compatible inputs/outputs, supports clocked synchronous operation with active-high enable, and is packaged in a hermetically sealed 16-pin CDIP (J) package for high-reliability aerospace and defense applications.

For engineers reviewing the SN54S194J datasheet, SN54S194J pinout, SN54S194J application, or SN54S194J equivalent, this page delivers verified functional specifications, validated pin assignments, military-qualified operating conditions, and direct alternative options aligned with MIL-STD-883 Class B testing requirements.

Technical Context

The SN54S194J implements a synchronous 4-bit universal shift register using bipolar Schottky TTL logic, supporting four distinct modes controlled by two mode-select inputs (S0, S1): hold (00), shift-right (01), shift-left (10), and parallel load (11). All mode transitions occur on the rising edge of the clock signal, with asynchronous master reset (MR̅) overriding all operations.

Its input structure includes buffered data inputs (DSR, DSL, D0–D3), mode control (S0/S1), clock (CLK), and master reset (MR̅); outputs are fully buffered Q0–Q3 with fan-out capability matching standard TTL loads. The device requires dual power supply rails (VCC = +5 V ±5%, GND) and exhibits propagation delays typical of S-series TTL (tPLH/tPHL ≤ 12 ns at VCC = 5 V).

Key Specifications

Pinout & Package

SN54S194J is supplied in a 16-pin Ceramic Dual In-line Package (CDIP, suffix J), hermetically sealed with tin-lead (SNPB) lead finish, rated for indefinite storage and high-reliability soldering under MIL-STD-883.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar universal shift register applications.

Compared with SN54LS194J, SN54S194J provides faster timing and stronger output drive for noise-prone environments; compared with JM38510/07601BEA, it shares identical silicon and packaging but uses TI's commercial-military hybrid part numbering for broader logistics compatibility.

Availability

SN54S194J is available at Aetrix Electronics and suitable for avionics data bus interface, secure crypto key register, nuclear plant control logic, and spacecraft command decoder applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN54S194J 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 company founded in 1930, specializing in analog, embedded processing, and high-reliability logic solutions for industrial, automotive, aerospace, and defense markets.

The SN54S194J belongs to TI's military-grade S-series TTL logic family, engineered specifically for high-speed, radiation-tolerant digital control in mission-critical systems where deterministic timing and environmental robustness are non-negotiable.

FAQ

What is the maximum clock frequency supported by SN54S194J?

The SN54S194J has a maximum clock frequency of approximately 83 MHz, derived from its maximum propagation delay of 12 ns (tPD) under nominal conditions (VCC = 5 V, TA = 25°C). At full military temperature range (-55°C to +125°C), derating applies; design margin should assume ≤60 MHz for guaranteed operation across extremes. This value is measured from CLK rising edge to valid Q-output transition.

Does SN54S194J support hot insertion or live swapping?

No, SN54S194J does not support hot insertion. Its CDIP package and bipolar TTL architecture lack bus-hold, power-up sequencing, or I/O protection circuitry required for live insertion. Applying power or signals while other system rails are active may cause latch-up or parametric shift. System-level hot-swap capability must be implemented externally using dedicated hot-swap controllers and isolation logic.

Is SN54S194J RoHS compliant?

No, SN54S194J is not RoHS compliant. It uses a tin-lead (SNPB) lead finish and is manufactured under MIL-PRF-38535 Class B requirements, which exempt military-qualified components from RoHS Directive 2011/65/EU. For RoHS-compliant alternatives, consider SN74LS194AD (SOIC, commercial grade) or consult TI's qualified green alternatives list under part number SN74LS194A.

Can SN54S194J be used as a ring counter?

Yes, SN54S194J can be configured as a 4-bit ring counter by connecting Q3 to DSR and Q0 to DSL, then initializing with a single logic high (e.g., 0001) via parallel load. Subsequent clock pulses circulate the high bit left or right depending on mode selection. This configuration is commonly used in missile guidance sequencers and phased-array radar beam steering logic.

What is the purpose of the MR̅ pin on SN54S194J?

The MR̅ (Master Reset) pin on SN54S194J is an active-low asynchronous input that forces all four outputs (Q0–Q3) to logic low immediately, regardless of clock state, mode select, or data inputs. It overrides all synchronous operations and is essential for deterministic power-on initialization, fault recovery, and system-level reset coordination in safety-critical platforms such as flight control computers.