Texas Instruments CD74HC245M

Overview

CD74HC245M from Texas Instruments is a high-speed CMOS octal bus transceiver with three-state non-inverting outputs, designed for bidirectional asynchronous data transfer between buses. It operates from 2 V to 6 V, delivers 9 ns typical propagation delay at 5 V/15 pF, supports -55°C to +125°C temperature range, and drives up to 15 LSTTL loads - used in industrial backplane interfaces and legacy bus isolation circuits.

For engineers reviewing the CD74HC245M datasheet, CD74HC245M pinout, CD74HC245M application, or CD74HC245M equivalent, key selection criteria include supply voltage flexibility (2–6 V), guaranteed three-state leakage (<±10 µA), wide temperature operation, and SOIC-20 package compatibility with standard PCB assembly processes.

Technical Context

The CD74HC245M implements a dual-bus bidirectional interface controlled by DIR (direction) and OE (output enable) pins, enabling data flow either A→B or B→A under logic-level control. Its HC-family CMOS architecture ensures rail-to-rail output swing, high noise immunity (30% of VCC), and low static current (≤160 µA at 6 V).

It features buffered inputs and three-state outputs with fast transition times (10–15 ns at 6 V), balanced propagation delays (tpd ≤28 ns at 4.5 V), and defined timing behavior across full military temperature range - supporting deterministic bus arbitration in mixed-voltage systems.

Key Specifications

Pinout & Package

CD74HC245M uses a 20-pin SOIC (DW) package with 12.80 mm × 7.50 mm body size, 1.27 mm lead pitch, and maximum height of 2.65 mm - compatible with IPC-7351 SOIC-20 land patterns and standard reflow profiles (MSL Level-1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC245N and CD74HCT245M96, CD74HC245M uniquely combines SOIC-20 surface-mount readiness, 2–6 V operation, and full military temperature range - making it optimal for volume-manufactured industrial and aerospace systems requiring long-term supply stability and reflow compatibility.

Availability

CD74HC245M is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive diagnostic interfaces, and avionics data concentrators requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD74HC245M 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 and embedded processing solutions, with over 90 years of innovation in precision analog, power management, and logic ICs.

The CD74HC245M belongs to TI's legacy HC logic family - engineered for robust, low-power, wide-voltage bidirectional bus interfacing in mission-critical industrial, aerospace, and automotive systems.

FAQ

What is the maximum clock frequency supported by CD74HC245M in a bus application?

The CD74HC245M does not operate on a clock; it is a combinational transceiver. Its usable data rate depends on propagation delay (≤28 ns at 4.5 V) and bus loading. With 50 pF load, it supports clean 20–25 MHz toggle rates - verified by tpd and tt specifications in the TI datasheet SCHS119B.

Can CD74HC245M interface directly between 3.3 V and 5 V logic domains?

Yes. CD74HC245M operates from 2 V to 6 V and accepts input voltages from 0 to VCC. At VCC = 5 V, it reliably interprets 3.3 V as VIH (≥3.15 V min), and its outputs swing rail-to-rail - enabling direct 3.3 V → 5 V translation without external components, as confirmed in Section 5.4 of the CD74HC245M datasheet.

Is CD74HC245M pin-compatible with CD74HCT245M96?

Yes - CD74HC245M and CD74HCT245M96 share identical SOIC-20 (DW) package, pin count, pinout, and mechanical footprint. However, they differ electrically: CD74HC245M supports 2–6 V operation with CMOS inputs, while CD74HCT245M96 is limited to 4.5–5.5 V with TTL-compatible inputs.

What is the recommended bypass capacitor for CD74HC245M?

Texas Instruments specifies a 0.1 µF ceramic capacitor placed as close as possible to the VCC pin of CD74HC245M, per Section 8 of the datasheet. For improved high-frequency noise suppression, pairing it with a 1 µF capacitor in parallel is acceptable - both must be low-ESR types with short traces to minimize inductance.

Does CD74HC245M require pull-up or pull-down resistors on unused pins?

Yes. Per Section 9.1 of the CD74HC245M datasheet, all unused inputs (including DIR and OE if not actively driven) must be terminated to VCC or GND to prevent floating states. Leaving them unconnected risks undefined operation, increased ICC, and potential latch-up - especially under temperature extremes.