Texas Instruments SN74AHCT245PWRE4

Overview

SN74AHCT245PWRE4 from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data bus communication between A and B ports. It operates from 4.5 V to 5.5 V, accepts TTL-compatible inputs (VIH = 2 V, VIL = 0.8 V), delivers ±8 mA output drive, and supports –40°C to 125°C industrial temperature range. It is used in level-shifting interfaces between 3.3 V logic and 5 V buses.

For engineers reviewing the SN74AHCT245PWRE4 datasheet, SN74AHCT245PWRE4 pinout, SN74AHCT245PWRE4 application, or SN74AHCT245PWRE4 equivalent, this page provides verified functional modes, switching timing under 15 pF/50 pF loads, thermal resistance values for TSSOP-20, latch-up immunity (>250 mA), and real-world design guidance for bus isolation and direction control.

Technical Context

The SN74AHCT245PWRE4 implements dual-directional 8-bit data flow controlled by DIR (direction) and OE (output enable) pins. Its CMOS design with TTL-compatible input thresholds enables reliable 3.3 V-to-5 V voltage translation without external level shifters. The device features slow edge rates to suppress output ringing on light loads.

Functional modes are strictly defined by OE and DIR logic: when OE = L, data flows A→B (DIR = H) or B→A (DIR = L); when OE = H, all outputs enter high-impedance state regardless of DIR. Input leakage remains ≤±1 µA across temperature, and power dissipation capacitance is 13 pF at 1 MHz.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.50 mm × 4.40 mm body, 0.65 mm lead pitch, surface-mount, RoHS-compliant NIPDAU finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AHCT245PWRE4, SN74LVC245APWR offers superior speed and drive in low-voltage domains but fails 5 V compatibility, while 74ACT245SCX matches voltage and pinout yet sacrifices industrial temperature range and static power efficiency.

Availability

SN74AHCT245PWRE4 is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, test equipment, and embedded microcontroller expansion requiring stable component supply and long-term manufacturability.

Supply support for SN74AHCT245PWRE4 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 connectivity technologies, with decades of experience in logic interface solutions.

The SN74AHCT family delivers TTL-compatible CMOS transceivers optimized for robust 5 V bus interfacing, voltage translation, and industrial-grade reliability - specifically engineered for mixed-signal system integration where signal integrity and wide temperature operation are critical.

FAQ

What is the maximum recommended load capacitance for SN74AHCT245PWRE4?

The SN74AHCT245PWRE4 is characterized for CL = 15 pF and CL = 50 pF loads. At 15 pF, propagation delay is 1–10 ns; at 50 pF, it increases to 1–11 ns. Exceeding 50 pF may degrade timing margins and increase output ringing - keep trace lengths short and avoid daisy-chaining more than three downstream loads per bus segment to maintain SN74AHCT245PWRE4 performance.

Can SN74AHCT245PWRE4 operate with a 3.3 V supply?

No. SN74AHCT245PWRE4 requires VCC between 4.5 V and 5.5 V per its Recommended Operating Conditions. Applying 3.3 V will result in undefined logic levels, excessive ICC, and potential failure to meet VIH/VIL thresholds. For 3.3 V systems, consider SN74LVC245A instead - but note it is not 5 V tolerant and cannot replace SN74AHCT245PWRE4 in mixed-voltage designs.

How should the OE pin be handled during power-up?

To ensure high-impedance state at power-on, tie OE to VCC through a pullup resistor (10 kΩ typical). This prevents bus contention while VCC ramps. Do not leave OE floating - undefined logic levels could activate the transceiver prematurely. The SN74AHCT245PWRE4 datasheet specifies that OE must be actively driven or pulled to avoid metastability, especially during brown-out conditions affecting SN74AHCT245PWRE4 functionality.

Is SN74AHCT245PWRE4 pin-compatible with other TSSOP-20 transceivers?

SN74AHCT245PWRE4 shares the same TSSOP-20 footprint and pinout as SN74AHCT245PWR, SN74AHCT245PWRG4, and SN74AHCT245PWR.A. All variants use identical DIR/OE/A/B pin assignments and electrical behavior. However, differences exist in packaging markings, RoHS compliance status, and MSL rating - verify reel labeling and moisture sensitivity before reflow for SN74AHCT245PWRE4 deployment.

Does SN74AHCT245PWRE4 support hot-swapping?

SN74AHCT245PWRE4 is not hot-swap rated. While its latch-up immunity exceeds 250 mA and inputs tolerate VI up to 5.5 V, the device lacks built-in current limiting or slew-rate control for live insertion. To implement safe hot-swap, add series current-limiting resistors (e.g., 100 Ω) on A/B lines and ensure OE is held high until VCC stabilizes - always validate system-level behavior before deploying SN74AHCT245PWRE4 in hot-plug scenarios.