Diodes Incorporated PI5C3257Q

Overview

PI5C3257Q from Diodes Incorporated is a quad 2:1 analog multiplexer/demultiplexer bus switch with three-state outputs, pinout- and function-compatible with 74F257/74ALS257/PI74FCT257T. It features 5Ω on-resistance, near-zero propagation delay (0.25 ns), ultra-low quiescent current (0.2 µA typical), and operates over –40°C to +85°C ambient. Used in high-speed data routing for notebook and portable computing interfaces.

For engineers reviewing the PI5C3257Q datasheet, PI5C3257Q pinout, PI5C3257Q application, or PI5C3257Q equivalent, key selection factors include its low R_ON, sub-nanosecond switching, TTL-compatible control logic, 3.3V/5V supply flexibility, and QSOP-16 packaging for space-constrained PCB layouts.

Technical Context

The PI5C3257Q implements four independent bidirectional 2:1 analog switches controlled by a shared select (S) and enable (E) input. Each switch connects one of two inputs (IA/IB, etc.) to its corresponding output (YA–YD) with no level-shifting or signal inversion.

Its architecture eliminates ground bounce and propagation delay through low-R_ON MOSFET-based transmission gates and direct bus coupling when enabled. Control inputs accept standard TTL voltage thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V), and outputs enter high-impedance state when E = HIGH.

Key Specifications

Pinout & Package

PI5C3257Q is packaged in a 16-pin QSOP (150-mil width), with 1.27 mm pitch, 3.9 mm × 9.9 mm body dimensions, and exposed pad not present. Pin 1 is marked by a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2:1 bus switch applications.

Compared with SN74CBT3257DR and 74LVC257PW, the PI5C3257Q delivers superior analog signal fidelity, lower power, and faster switching-making it optimal for mixed-signal routing where voltage-level transparency and nanosecond timing matter.

Availability

PI5C3257Q is available at Aetrix Electronics and suitable for notebook computing, industrial I/O expansion, USB 2.0 hub design, and PCIe re-timing applications requiring stable component supply and long-term lifecycle support.

Supply support for PI5C3257Q 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and integrated circuits, specializing in high-performance, energy-efficient solutions for consumer, computing, industrial, and automotive markets.

The PI5C3257 belongs to Diodes' Pericom® high-speed analog switch product line, engineered specifically for low-distortion, low-latency signal routing in portable and embedded computing platforms.

FAQ

Is PI5C3257Q compatible with 3.3 V-only systems?

Yes. The PI5C3257Q operates reliably from 3.0 V to 5.5 V supply, with TTL-compatible input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) ensuring robust logic recognition even with 3.3 V drivers. Its 5 Ω R_ON and 6 pF capacitance maintain signal integrity without level shifters.

Can PI5C3257Q handle bidirectional analog signals like audio or sensor outputs?

No. While bidirectional, the PI5C3257Q is optimized for digital bus switching-not precision analog. Its 5 Ω R_ON and 6 pF C_OFF suit high-speed digital signals (e.g., USB, PCIe sideband), but lack rail-to-rail swing, THD specs, or guaranteed analog linearity required for audio or sensor conditioning.

What is the thermal performance of the QSOP-16 package under continuous 120 mA load?

The PI5C3257Q's maximum power dissipation is 0.5 W. At 120 mA through a 5 Ω switch, power per channel is 72 mW. With four channels active, total dissipation remains well below 0.5 W, and the QSOP-16 package achieves ~120°C/W junction-to-ambient (θ_JA), keeping T_J within spec at +85°C ambient.

Does PI5C3257Q require external pull-up or pull-down resistors on control pins?

No. The E and S inputs have CMOS-compatible input structure with ±1 µA leakage (IIH/IIL), and specified VIH/VIL thresholds ensure clean logic interpretation without external biasing. Pull-ups are unnecessary unless system-level noise immunity mandates them per board-level EMC design rules.