Texas Instruments CY74FCT2245TQCT

Overview

CY74FCT2245TQCT from Texas Instruments is an 8-bit noninverting bidirectional transceiver with 3-state outputs, designed for bus interface applications. It features 25-Ω output series resistors to suppress transmission-line reflections, Ioff support for partial-power-down operation, and TTL-compatible input/output logic levels. It operates across –40°C to 85°C and delivers 12 mA sink / 15 mA source drive at 5 V.

For engineers reviewing the CY74FCT2245TQCT datasheet, CY74FCT2245TQCT pinout, CY74FCT2245TQCT application, or CY74FCT2245TQCT equivalent, key selection considerations include propagation delay (max 7 ns), 3-state control timing (tPZH/tPHZ ≤ 9.5 ns), Ioff leakage (< ±1 µA at VCC = 0 V), and SSOP-20 package compatibility with board-level noise mitigation requirements.

Technical Context

The CY74FCT2245TQCT implements edge-rate control circuitry to reduce switching noise and integrates on-die 25-Ω series termination at each output to minimize signal reflections on PCB traces. Its dual-control logic uses active-high T/R to select A→B (transmit) or B→A (receive) data flow and active-high OE to enable/disable both ports simultaneously into high-impedance state.

Ioff functionality disables output drivers when VCC = 0 V, preventing backflow current during partial power-down - a critical feature for hot-swap and mixed-voltage system designs. The device maintains full TTL input threshold compatibility (VIL = 0.8 V, VIH = 2.0 V) and drives standard TTL loads with guaranteed VOH ≥ 2.4 V and VOL ≤ 0.55 V at 12 mA sink.

Key Specifications

Pinout & Package

SSOP-20 (DBQ) package: 7.4 mm × 5.3 mm body, 0.65 mm lead pitch, 1.2 mm max height, moisture sensitivity level 2 (260°C reflow).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional bus transceiver applications.

Compared with SN74FCT245ATQCT and 74LVC245APW, the CY74FCT2245TQCT uniquely combines 5-V TTL compatibility, integrated 25-Ω termination, and Ioff - making it the sole option among these three for noise-sensitive, hot-swap-capable 5-V bus bridging without external components.

Availability

CY74FCT2245TQCT is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and test equipment requiring stable component supply with long-term lifecycle assurance.

Supply support for CY74FCT2245TQCT 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, scalability, and industrial-grade qualification.

The CY74FCT2245TQCT belongs to TI's FCT logic family, engineered specifically for noise-immune, high-drive 5-V bus interface applications in harsh electromagnetic environments.

FAQ

What is the maximum propagation delay of the CY74FCT2245TQCT at 5 V?

The CY74FCT2245TQCT has a maximum propagation delay of 7 ns under recommended operating conditions (VCC = 4.75–5.25 V, TA = –40°C to +85°C). This value applies to both tPLH and tPHL transitions and is measured with CL = 50 pF load, ensuring predictable timing for synchronous bus designs operating up to 140 MHz equivalent clock rates. The CY74FCT2245TQCT meets this spec across its full industrial temperature range.

Does the CY74FCT2245TQCT support partial-power-down operation?

Yes, the CY74FCT2245TQCT supports partial-power-down operation via its Ioff circuitry. When VCC = 0 V and any input or output is driven to 4.5 V, the Ioff leakage is limited to ±1 µA - preventing damaging backflow current. This feature is explicitly validated in the datasheet and enables safe use in hot-swap and mixed-power-domain systems where the CY74FCT2245TQCT may be unpowered while adjacent circuitry remains active.

What package type and dimensions does the CY74FCT2245TQCT use?

The CY74FCT2245TQCT uses a 20-pin SSOP (Shrink Small Outline Package) with JEDEC MO-153 registration, designated DBQ. Its dimensions are 7.4 mm × 5.3 mm body size, 0.65 mm lead pitch, and 1.2 mm maximum height. The package carries moisture sensitivity level 2 (MSL-2) and is rated for peak reflow at 260°C - fully compatible with standard surface-mount assembly processes.

How does the CY74FCT2245TQCT differ from the CY74FCT245TQCT?

The CY74FCT2245TQCT integrates 25-Ω output series resistors to suppress transmission-line reflections, whereas the CY74FCT245TQCT lacks this feature. Both share identical pinout, function table, and Ioff support, but the CY74FCT2245TQCT replaces the CY74FCT245TQCT in existing designs where board-level termination is impractical. The CY74FCT2245TQCT also has slightly higher propagation delay (7 ns vs. 4.6 ns) due to internal resistance.

Is the CY74FCT2245TQCT compatible with standard TTL logic levels?

Yes, the CY74FCT2245TQCT is fully compatible with standard TTL input and output logic levels. Its VIH threshold is guaranteed ≥ 2.0 V and VIL ≤ 0.8 V, matching TTL specifications. Output VOH is ≥ 2.4 V at –15 mA and VOL is ≤ 0.55 V at 12 mA - meeting or exceeding TTL voltage swing and drive requirements. This allows direct interconnection with legacy 74LS, 74ALS, and other 5-V TTL families without level-shifting circuitry.