Texas Instruments SN74HC253DBR

Overview

SN74HC253DBR from Texas Instruments is a dual 4-line to 1-line data selector/multiplexer with 3-state outputs, designed for digital signal routing in bus-organized systems. It operates across 2 V–6 V, delivers ±6 mA output drive at 5 V, exhibits typical propagation delay of 9 ns, and supports parallel-to-serial conversion in industrial control and test equipment.

For engineers reviewing the SN74HC253DBR datasheet, SN74HC253DBR pinout, SN74HC253DBR application, or SN74HC253DBR equivalent, this page provides verified functional modes, switching characteristics at CL = 50 pF and 150 pF, 3-state enable timing (ten/tdis), and SSOP-16 package-specific thermal and layout guidance.

Technical Context

The SN74HC253DBR implements two independent 4:1 multiplexers sharing common select inputs (A, B) and individual 3-state output-enable (OE) controls. Each section decodes binary inputs to route one of four data inputs (C0–C3) to its Y output, with full CMOS logic levels and rail-to-rail output swing.

Its 3-state outputs support bidirectional bus interfacing: when OE is high, Y enters high-impedance state; when OE is low, Y drives logic-high or logic-low with ±6 mA capability at 5 V and <100 nA input leakage - enabling clean bus arbitration without external pull-ups or contention.

Key Specifications

Pinout & Package

SN74HC253DBR is housed in a 16-pin SSOP (Shrink Small Outline Package) with 0.65 mm lead pitch, 6.20 mm × 5.30 mm body size, and 2.00 mm max height - optimized for high-density PCB layouts while maintaining hand-solderability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual 4:1 multiplexer applications.

Compared with SN74LV253ADBR and 74AC253M, SN74HC253DBR offers the broadest supply flexibility (2–6 V), lowest quiescent current (80 μA), and proven 3-state bus-driving capability - making it the default choice for industrial control and general-purpose digital routing where reliability and compatibility outweigh marginal speed gains.

Availability

SN74HC253DBR is available at Aetrix Electronics and suitable for industrial automation, automated test equipment, and embedded data acquisition systems requiring stable component supply and long-term manufacturability.

Supply support for SN74HC253DBR 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 90 years of innovation in industrial, automotive, and communications markets.

SN74HC253DBR belongs to TI's 74HC logic family - engineered for high noise immunity, low power consumption, and seamless interoperability across mixed-voltage digital systems.

FAQ

What is the maximum clock frequency supported by SN74HC253DBR in multiplexer mode?

SN74HC253DBR does not operate on a clock; it is a combinational logic device. Its maximum usable data rate depends on propagation delay and system timing margins. With tpd = 16 ns max at VCC = 6 V and CL = 50 pF, reliable operation up to 25 MHz is achievable in synchronous sampling applications - provided setup/hold times of downstream devices are met. The SN74HC253DBR itself imposes no clock limit.

Can SN74HC253DBR drive standard TTL loads directly?

Yes, SN74HC253DBR can drive up to 15 LSTTL loads directly at VCC = 5 V, delivering ±6 mA output current. Its VOH ≥ 3.98 V and VOL ≤ 0.26 V under 6 mA load meet LSTTL input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V). For standard TTL (not LSTTL), verify loading does not exceed ±25 mA absolute max output rating - SN74HC253DBR remains within safe limits for typical TTL fanout.

How should unused inputs be handled on SN74HC253DBR?

All unused inputs on SN74HC253DBR - including select lines A/B, data inputs C0–C3 for either section, and OE_A/OE_B - must be tied to a valid logic level (VCC or GND) to prevent floating states. Leaving inputs unconnected causes undefined output behavior, increased ICC, and potential oscillation. TI recommends tying unused data inputs to GND and unused OE pins to VCC to force corresponding outputs into high-Z state.

Is SN74HC253DBR compatible with 3.3 V microcontrollers?

Yes, SN74HC253DBR operates reliably from 2 V to 6 V, making it fully compatible with 3.3 V microcontrollers. At VCC = 3.3 V, VIH = 2.31 V and VIL = 0.99 V - comfortably within typical 3.3 V MCU output specs (VOH ≥ 2.4 V, VOL ≤ 0.4 V). Its 3-state outputs also interface cleanly with 3.3 V buses, and SN74HC253DBR maintains 9 ns typical tpd even at 3.3 V.

What thermal considerations apply to SN74HC253DBR in continuous operation?

SN74HC253DBR in SSOP-16 has RθJA = 82°C/W. At 80 μA ICC and worst-case 6 V supply, power dissipation is <0.5 mW - generating negligible self-heating. However, under heavy capacitive loading (e.g., CL = 150 pF) and high toggle rates, dynamic power dominates. With Cpd = 45 pF per section and f = 10 MHz, power rises to ~3 mW - still well below thermal limits. Maintain ≥1 mm clearance around the SN74HC253DBR for airflow in enclosed enclosures.