Texas Instruments CD54AC109F3A

Overview

CD54AC109F3A from Texas Instruments is a dual J-K positive-edge-triggered flip-flop with independent asynchronous clear (CLR) and preset (PRE) inputs, operating across 1.5 V to 5.5 V supply range, delivering ±24 mA output drive, 114 MHz max clock frequency at 5 V, and qualified for -55°C to +125°C military-grade operation in CDIP packaging. It serves as a synchronous state-storage element in timing-critical digital control circuits.

For engineers reviewing the CD54AC109F3A datasheet, CD54AC109F3A pinout, CD54AC109F3A application, or CD54AC109F3A equivalent, key selection considerations include its dual-channel J-K architecture, active-low asynchronous controls, guaranteed propagation delay down to 2.6 ns (tPLH/tPHL), and MIL-qualified temperature performance - critical for aerospace, defense, and high-reliability industrial logic design.

Technical Context

The CD54AC109F3A implements two independent CMOS J-K flip-flops sharing no internal coupling; each channel features separate J, K, CLK, PRE, and CLR inputs with true and complement Q outputs. Its positive-edge-triggered clock response is voltage-level–based-not edge-rate–dependent-ensuring robust timing across varying slew rates.

Asynchronous PRE and CLR override all synchronous inputs, forcing Q to high or low regardless of clock or data states. When both are high, the device operates in standard J-K mode: toggle (J=K=1), set (J=1,K=0), reset (J=0,K=1), or hold (J=K=0), with setup time as low as 4.8 ns at 5 V and full functionality maintained over -55°C to +125°C.

Key Specifications

Pinout & Package

CD54AC109F3A uses a 16-pin Ceramic Dual In-line Package (CDIP, J package) with 19.56 mm × 6.92 mm body size, hermetically sealed for high-reliability environments. Pin 1 is located at the left end of the top row when viewed from the top with notch or dot orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual J-K flip-flop applications.

Compared with CD54AC109F3A, CD74AC109M96 trades hermetic sealing for RoHS compliance and SMT manufacturability, while SN54AC109J offers identical performance in a functionally equivalent legacy form - making CD54AC109F3A the preferred choice when hermeticity and long-term military logistics support are mandatory.

Availability

CD54AC109F3A is available at Aetrix Electronics and suitable for avionics timing control, secure communication synchronization, missile guidance logic, and spacecraft onboard computer applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD54AC109F3A 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 global semiconductor leader specializing in analog, embedded processing, and logic solutions with over 50 years of high-reliability component development.

CD54AC109F3A belongs to TI's military-grade AC logic family, engineered specifically for aerospace, defense, and industrial systems demanding guaranteed operation across extreme temperatures and harsh electromagnetic environments.

FAQ

What is the maximum clock frequency supported by CD54AC109F3A?

The CD54AC109F3A supports up to 114 MHz maximum clock frequency when operated at VCC = 5 V ± 0.5 V and TA = -40°C to +85°C. At the full military temperature range (-55°C to +125°C), the guaranteed maximum is 100 MHz. These values are measured under CL = 50 pF load and reflect worst-case timing across process, voltage, and temperature corners - ensuring robust timing closure in high-speed digital control designs using CD54AC109F3A.

Does CD54AC109F3A support 3.3 V operation?

Yes, CD54AC109F3A fully supports 3.3 V operation with guaranteed performance: at VCC = 3.3 V ± 0.3 V, it delivers up to 81 MHz clock frequency, 3.7 ns minimum propagation delay (tPLH/tPHL), and maintains ±24 mA output drive. Input thresholds scale proportionally (VIH = 2.1 V, VIL = 0.9 V), providing 1.2 V noise margin - making CD54AC109F3A interoperable with 3.3 V microcontrollers and FPGAs without level translation.

What is the function of the active-low K input in CD54AC109F3A?

The K input in CD54AC109F3A is active-low, meaning logical '0' enables reset behavior and logical '1' disables it. When J = 1 and K = 0, the flip-flop sets Q = 1 on the next clock edge; when J = 0 and K = 0, Q remains unchanged. This inversion simplifies direct connection to open-collector or pull-down control signals and aligns with legacy TTL J-K conventions - a deliberate design feature confirmed in the CD54AC109F3A function table and logic diagram.

How does CD54AC109F3A handle simultaneous PRE and CLR assertion?

When both PRE and CLR are driven low simultaneously in CD54AC109F3A, the output enters an unpredictable and unstable condition - explicitly documented in the function table as "unpredictable and unstable" with note (1). TI advises avoiding this state in hardware design; if required, external logic must ensure mutual exclusion between PRE and CLR signals. This behavior is inherent to the internal gate structure and cannot be overridden by timing or voltage adjustments - a critical constraint for fault-tolerant system architects using CD54AC109F3A.

Is CD54AC109F3A pin-compatible with CD74AC109E?

Yes, CD54AC109F3A is pin-compatible with CD74AC109E: both use 16-pin DIP footprints (CDIP vs PDIP), share identical pin numbering, signal assignments, and electrical interface definitions. However, CD54AC109F3A uses ceramic hermetic packaging with SNPB lead finish and -55°C to +125°C qualification, whereas CD74AC109E uses plastic PDIP with RoHS-compliant NiPdAu finish and -55°C to +125°C rating - making them mechanically interchangeable but not identical in reliability class or soldering profile.