Renesas QS3VH251PAG8

Overview

QS3VH251PAG8 from Renesas Electronics (formerly IDT) is a quad 8:1 multiplexer/demultiplexer bus switch with N-channel FET architecture, 4Ω typical ON resistance, <0.2 ns propagation delay, 5V-tolerant I/Os, and rail-to-rail analog switching (0–5V). It operates from 2.3V to 3.6V V_CC and supports hot-swapping in industrial backplane interfaces.

For engineers reviewing the QS3VH251PAG8 datasheet, QS3VH251PAG8 pinout, QS3VH251PAG8 application, or QS3VH251PAG8 equivalent, key selection criteria include its 500MHz bandwidth, high OFF-state impedance (>1 GΩ), LVTTL-compatible control inputs, bidirectional zero-delay signal routing, and TSSOP-24 package compatibility with legacy QSOP footprints.

Technical Context

The QS3VH251PAG8 implements four independent 8:1 analog multiplexers using N-channel pass transistors without parasitic diodes to V_CC, enabling true power-off isolation and 5V tolerance in both ON and OFF states. Each channel features matched R_ON (±0.5Ω typical variation) and flat R_ON vs. input voltage profile across 0–5V.

Control logic uses active-low Enable (E) and 3-bit binary Select (S2:S0) to route one of eight inputs (I0–I7) to the shared output Y per channel. Propagation delay is dominated by RC time constant (R_ON × C_LOAD) rather than internal logic, yielding sub-250ps intrinsic delay at 50pF load.

Key Specifications

Pinout & Package

TSSOP-24 package (4.4 mm × 7.8 mm, 0.65 mm pitch), green RoHS-compliant, with exposed pad not connected internally.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog multiplexer applications.

Compared with SN74CBT16244DGGR and ADG732BRUZ, the QS3VH251PAG8 uniquely combines integrated 8:1 multiplexing, 500MHz bandwidth, and hardware-selectable routing in a compact TSSOP-24 package - making it optimal for real-time, low-latency signal path switching where address decoding and speed are critical.

Availability

QS3VH251PAG8 is available at Aetrix Electronics and suitable for hot-swappable backplane interfaces, high-speed memory multiplexing, and ATM cell switching requiring stable component supply across industrial temperature ranges (–40°C to +85°C).

Supply support for QS3VH251PAG8 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

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and SoC solutions for automotive, industrial, and infrastructure markets.

The QS3VH251PAG8 belongs to Renesas' legacy QuickSwitch® analog switch family, originally developed by IDT to address high-bandwidth, low-latency signal routing needs in telecom, computing, and test equipment.

FAQ

What is the maximum operating frequency supported by the QS3VH251PAG8?

The QS3VH251PAG8 supports an operating frequency of up to 500 MHz for analog signal switching, validated by its bandwidth specification and 4 pF typical OFF-state capacitance. Its propagation delay remains below 0.2 ns, enabling reliable operation in high-speed digital bus applications such as DDR2/DDR3 memory multiplexing and ATM 25/155 Mbps switching where signal integrity is critical. The device achieves this performance using N-channel FETs with flat R_ON characteristics across the 0–5V input range.

Does the QS3VH251PAG8 require external level shifters when interfacing 5V signals with a 3.3V V_CC supply?

No, the QS3VH251PAG8 does not require external level shifters. Its I/Os are explicitly 5V-tolerant in both ON and OFF states, and its control inputs are LVTTL-compatible with VIH thresholds of 2.0 V (min) at V_CC = 2.7–3.6 V. This allows direct connection of 5V analog or digital signals to the I0–I7 and Y pins while operating from a 3.3V V_CC, simplifying mixed-voltage system design and eliminating additional components in hot-swap or backplane interface applications.

How does the QS3VH251PAG8 achieve power-off isolation?

The QS3VH251PAG8 achieves power-off isolation through its N-channel FET architecture with no parasitic diode to V_CC. When V_CC = 0 V, the switches remain fully OFF with ±1 μA maximum power-off leakage (IOFF), and no DC path exists between I/O pins and either V_CC or GND. This behavior is confirmed in the DC Electrical Characteristics table and enables safe hot-plug operation in live systems - a core requirement for the QS3VH251PAG8's use in zero-downtime industrial and telecom equipment.

What package type is used for the QS3VH251PAG8, and is it pin-compatible with earlier versions?

The QS3VH251PAG8 uses a RoHS-compliant TSSOP-24 package (4.4 mm × 7.8 mm, 0.65 mm pitch), indicated by the "PAG" suffix in the part number. It is functionally identical and pin-compatible with the QSOP-24 variant (e.g., QS3VH251QG), sharing the same pinout, electrical specifications, and thermal profile. The TSSOP footprint offers improved manufacturability and board space efficiency while maintaining drop-in compatibility for existing designs using the QSOP version of the QS3VH251PAG8.

Can the QS3VH251PAG8 be used for bidirectional analog signal routing without performance degradation?

Yes, the QS3VH251PAG8 supports fully bidirectional analog signal routing with no performance degradation. Its N-channel FET structure provides symmetrical R_ON and capacitance characteristics regardless of signal direction - verified by identical tPLH/tPHL values (<0.2 ns) and matched 4Ω typical ON resistance for both Ix→Y and Y→Ix paths. This symmetry, combined with rail-to-rail 0–5V operation and flat R_ON vs. voltage, ensures consistent THD, bandwidth, and settling behavior in precision analog applications like sensor multiplexing or test equipment signal paths.