Texas Instruments SN74AHCT245DGSR

Overview

SN74AHCT245DGSR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between 8-bit buses in 5 V systems. It operates from 4.5 V to 5.5 V, accepts TTL-compatible inputs (VIH = 2 V, VIL = 0.8 V), supports ±8 mA output drive, and features direction control (DIR) and output enable (OE) pins for flexible bus isolation and flow management - used in microcontroller peripheral expansion and legacy bus bridging.

For engineers reviewing the SN74AHCT245DGSR datasheet, SN74AHCT245DGSR pinout, SN74AHCT245DGSR application, or SN74AHCT245DGSR equivalent, key selection criteria include its VSSOP-20 (DGS) package footprint (5.10 mm × 3.00 mm), 3.3 V-to-5 V level translation capability, 10 ns typical propagation delay (CL = 15 pF), latch-up immunity (>250 mA), and ESD robustness (±2000 V HBM).

Technical Context

The SN74AHCT245DGSR implements dual 8-bit bidirectional I/O ports controlled by DIR and OE signals: DIR selects data flow direction (A→B or B→A), while OE places all outputs in high-impedance state for bus isolation. Its CMOS design with TTL-compatible input thresholds enables interoperability with both 3.3 V logic drivers and 5 V bus loads.

It delivers low-noise operation via controlled edge rates, minimizing overshoot/undershoot on light loads. Input overvoltage tolerance up to 5.5 V allows safe interfacing with higher-voltage sources regardless of VCC, and internal current limits (±25 mA per output, ±75 mA total) prevent damage during transient contention.

Key Specifications

Pinout & Package

VSSOP-20 (DGS) package: 5.10 mm × 3.00 mm body, 0.5 mm lead pitch, exposed thermal pad, RoHS-compliant NIPDAU finish, MSL Level-1 (260 °C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245A and 74ACT245, the SN74AHCT245DGSR uniquely balances 3.3 V–5 V interoperability, low static current, and industrial temperature support in a space-constrained VSSOP package - making it optimal for mixed-voltage embedded gateways where reliability and footprint matter more than raw speed.

Availability

SN74AHCT245DGSR is available at Aetrix Electronics and suitable for industrial automation, test equipment, and embedded gateway designs requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for SN74AHCT245DGSR 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 high-reliability logic and interface solutions.

The SN74AHCT245DGSR belongs to TI's AHCT logic family, engineered for robust 5 V bus interfacing in industrial and automotive-adjacent applications where TTL compatibility, latch-up immunity, and wide temperature operation are essential.

FAQ

What is the maximum operating temperature for SN74AHCT245DGSR?

The SN74AHCT245DGSR is rated for continuous operation from –40 °C to +125 °C ambient temperature. This extended industrial range is validated per TI's qualification standards and supports use in motor control enclosures, outdoor base stations, and under-hood automotive auxiliary modules where thermal margins are critical. The VSSOP package's low thermal resistance (RθJA = 118.4 °C/W) helps maintain junction temperature within safe limits under typical load conditions.

Does SN74AHCT245DGSR support 3.3 V to 5 V level translation?

Yes, the SN74AHCT245DGSR supports unidirectional and bidirectional 3.3 V to 5 V level translation. Its TTL-compatible inputs accept VIH ≥ 2 V and VIL ≤ 0.8 V, allowing direct connection to 3.3 V logic outputs, while its 5 V supply enables driving 5 V bus loads. No external resistors or biasing are needed - the device handles voltage translation inherently via its input threshold design and 5 V output swing.

What is the function of the DIR and OE pins on SN74AHCT245DGSR?

The DIR (Direction) pin controls data flow direction: logic low enables B→A transfer, logic high enables A→B transfer. The OE (Output Enable) pin controls output state: logic high places all A and B port outputs in high-impedance mode, isolating both buses; logic low activates outputs per DIR setting. Together, they allow dynamic bus arbitration, hot-swap safety, and conflict-free multi-master communication without external logic.

Can SN74AHCT245DGSR be used with a 3.3 V supply?

No, the SN74AHCT245DGSR requires a minimum supply voltage of 4.5 V and is not specified for operation below that level. Its internal circuitry is optimized for 5 V operation, and attempting to run it at 3.3 V will result in undefined logic behavior, failure to meet VIH/VIL thresholds, and potential output contention. For 3.3 V systems, consider the SN74LVC245A instead - but note it lacks native 5 V bus compatibility.

What package type is SN74AHCT245DGSR supplied in?

The SN74AHCT245DGSR is supplied in a VSSOP-20 (DGS) package: 5.10 mm × 3.00 mm body size, 0.5 mm lead pitch, with an exposed thermal pad. It is RoHS-compliant, uses NIPDAU lead finish, and carries MSL Level-1 rating (unlimited floor life at ≤30 °C/60% RH), making it suitable for standard surface-mount assembly without moisture sensitivity concerns.