Texas Instruments SN74CBT3253DBR

Overview

SN74CBT3253DBR from Texas Instruments is a dual 1-of-4 high-speed TTL-compatible FET multiplexer/demultiplexer in SSOP-16 package, featuring 5 Ω typical on-state resistance at 4.5 V, <0.25 ns propagation delay (VCC = 5 V), and ±1 μA max input leakage current. It routes bidirectional data between one common A port and four B ports per channel under S0/S1 address control, used in high-speed bus switching and signal routing applications.

For engineers reviewing the SN74CBT3253DBR datasheet, SN74CBT3253DBR pinout, SN74CBT3253DBR application, or SN74CBT3253DBR equivalent, key selection criteria include its 4–5.5 V supply range, 82°C/W thermal impedance in DB package, TTL-level compatible control inputs, and guaranteed operation from −40°C to 85°C.

Technical Context

The SN74CBT3253DBR implements two independent 1:4 bidirectional analog/digital switches using low-threshold FETs, enabling rail-to-rail signal pass-through with minimal distortion. Its control logic uses active-low OE pins (1OE, 2OE) and 2-bit binary select lines (S1, S0) to route signals between A and one of four B terminals per channel.

Each switch exhibits flat on-resistance over input voltage range, supports hot-swap capability due to no DC path when disabled, and maintains signal integrity with 4 pF off-capacitance and 3.5 pF control-input capacitance - critical for high-frequency bus isolation and clock/data multiplexing.

Key Specifications

Pinout & Package

SSOP-16 (DB) package, 5.3 mm × 6.2 mm body, 0.65 mm lead pitch, 1.75 mm max height, gull-wing leads, pin 1 index area marked.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual 1-of-4 analog switch applications.

Compared with SN74CBT3253DBR, SN74CBTD3253DBR adds bus-hold but raises quiescent current, while TS3A227EYZTR offers lower Ron at 3.3 V but cannot operate at 5 V - making SN74CBT3253DBR the sole choice for robust 5 V TTL-compatible high-speed bus switching.

Availability

SN74CBT3253DBR is available at Aetrix Electronics and suitable for industrial I/O modules, PCIe lane management systems, and embedded JTAG test infrastructure requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74CBT3253DBR 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, precision, and industrial-grade performance.

The SN74CBT3253DBR belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered specifically for high-speed, low-distortion signal routing in 5 V digital systems where minimal propagation delay and rail-to-rail analog capability are critical.

FAQ

What is the maximum continuous current rating for SN74CBT3253DBR?

The SN74CBT3253DBR supports a continuous channel current of 128 mA per switch path. This rating applies under recommended operating conditions (VCC = 4–5.5 V, TA = −40°C to 85°C) and assumes proper PCB thermal design. Exceeding this current may increase on-resistance, induce thermal stress, or degrade long-term reliability - always verify junction temperature using θJA = 82°C/W for the DB package.

Does SN74CBT3253DBR support bidirectional signal flow?

Yes, SN74CBT3253DBR supports fully bidirectional signal routing between A and B ports without direction control pins. Each switch operates symmetrically: signals pass from 1A ↔ 1Bx or 2A ↔ 2Bx regardless of source/sink configuration. This enables use in data buses, JTAG chains, and analog sensor multiplexing where signal polarity or flow direction varies dynamically.

Can SN74CBT3253DBR be used with 3.3 V control logic?

No - SN74CBT3253DBR requires TTL-compatible control inputs (VIH ≥ 2 V, VIL ≤ 0.8 V) and is specified only for 4–5.5 V VCC operation. While 3.3 V logic may meet VIL, it fails VIH margin at temperature extremes and risks unreliable switching. For 3.3 V systems, consider TI's SN74CB3Q3253 or Analog Devices' ADG1414 as functionally matched alternatives.

What is the significance of the "DB" package designation in SN74CBT3253DBR?

The "DB" in SN74CBT3253DBR denotes the SSOP (Shrink Small-Outline Package) variant with 16 pins, 0.65 mm lead pitch, and 5.3 mm × 6.2 mm body size. It differs from DBQ (shrink SSOP, 0.5 mm pitch) and D (standard SOIC). The DB package provides higher pin density than SOIC while maintaining compatibility with standard surface-mount assembly processes and offering 82°C/W thermal resistance.

How does SN74CBT3253DBR handle unused control inputs?

All unused control inputs (S0, S1, 1OE, 2OE) of SN74CBT3253DBR must be actively tied to VCC or GND - floating inputs risk undefined switching states, increased ICC, or oscillation. TI recommends pull-up to VCC for OE pins (to disable by default) and defined logic levels for S0/S1 to prevent partial channel activation. Refer to TI application report SCBA004 for implementation guidance.