Diodes Incorporated PI5C3861QE+C

Overview

PI5C3861QE+C from Pericom Semiconductor is a 10-bit, 2-port bus switch with 5Ω on-resistance, active-low Bus Enable (BE) control, and 0.2μA typical quiescent current, used for bidirectional signal routing in notebook and low-power embedded systems.

For engineers reviewing the PI5C3861QE+C datasheet, PI5C3861QE+C pinout, PI5C3861QE+C application, or PI5C3861QE+C equivalent, key selection criteria include propagation delay (<0.25 ns), high-impedance isolation during disable, TTL-compatible control inputs, and QSOP-24 packaging for space-constrained PCB layouts.

Technical Context

The PI5C3861QE+C implements a passive FET-based analog bus switch architecture-no internal logic or level-shifting-enabling true bidirectional signal pass-through with no added propagation delay beyond RC time constant. It operates at 5V ±5% with guaranteed VIH ≥2.0V and VIL ≤0.8V.

Switching is controlled solely by the BE input; when low, all ten A–B pairs conduct with R_ON = 5Ω (typ), C_OFF = 6pF, and C_ON = 8pF. When BE is high, all ports enter high-impedance state with IOZ ≤±1μA.

Key Specifications

Pinout & Package

Package: 24-pin QSOP (150-mil wide, Pb-free & Green compliant), body dimensions 3.99 mm × 8.74 mm × 1.75 mm, lead pitch 0.635 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit bidirectional bus switch applications.

Compared with SN74CBT3384APW and 74LVC1G3157GW, the PI5C3861QE+C delivers lowest system-level power (0.2μA vs. 10μA), integrated 10-bit channel count, and optimized QSOP-24 footprint-making it the most efficient choice for production notebooks and compact industrial controllers requiring deterministic bus arbitration.

Availability

PI5C3861QE+C is available at Aetrix Electronics and suitable for notebook memory expansion, industrial PLC I/O multiplexing, automotive infotainment debug port security, and PCI Express slot sharing requiring stable component supply and long-term lifecycle assurance.

Supply support for PI5C3861QE+C 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

Pericom Semiconductor was a fabless provider specializing in high-speed interface, timing, and signal-integrity solutions before its acquisition by Diodes Incorporated in 2017.

The PI5C3861 belongs to Pericom's legacy CBT (Crossbar Bus Technology) family, engineered specifically for low-latency, low-power bidirectional bus switching in portable and space-constrained embedded systems.

FAQ

What is the maximum operating frequency supported by the PI5C3861QE+C?

The PI5C3861QE+C has no internal clock or bandwidth limit-it supports signal frequencies up to 300 MHz when loaded with ≤50 pF and driven by sources with ≤50 Ω output impedance. Its 8pF ON-capacitance and 5Ω R_ON yield a -3dB point exceeding 400 MHz in typical configurations, verified by S-parameter measurements in Pericom's application note AN-312.

Can the PI5C3861QE+C operate at 3.3V supply?

No-the PI5C3861QE+C is specified only for 5V ±5% operation (4.75V–5.25V). Attempting 3.3V operation results in undefined R_ON, degraded noise margin, and potential failure to meet VIH/VIL thresholds. For 3.3V systems, consider Diodes Inc.'s PI3CH400 series as a functional successor.

Is the BE pin 5V-tolerant when driven by a 3.3V microcontroller?

Yes-BE accepts 3.3V logic levels reliably: VIH minimum is 2.0V, and VIL maximum is 0.8V. A 3.3V GPIO asserting BE low (≤0.4V) or high (≥2.4V) fully satisfies input thresholds across temperature and process variation, confirmed in DC Electrical Characteristics Table, Note 1.

Does the PI5C3861QE+C require external pull-up or pull-down resistors on A/B pins?

No-A and B pins are fully passive and require no biasing. They present ~6pF capacitance when off and ~8pF when on, with no DC path to VCC or GND. External termination is determined solely by system signal integrity requirements-not device functionality.