Renesas QS3245SOG

Overview

QS3245SOG from Renesas Electronics is an 8-bit high-speed CMOS bus switch with TTL-compatible control inputs, 5Ω typical ON resistance, zero propagation delay, and industrial temperature range (–40°C to +85°C). It functions as a bidirectional signal path selector in data buses, enabling hot-swapping and voltage translation between 5V and 3.3V domains.

For engineers reviewing the QS3245SOG datasheet, QS3245SOG pinout, QS3245SOG application, or QS3245SOG equivalent, key selection criteria include guaranteed logic-level compatibility with 74FCT245/74F245, undershoot clamp diodes on all I/Os, and sub-0.25ns max propagation delay under 50pF load.

Technical Context

The QS3245SOG implements eight independent N-channel FET switches with no inherent body diode to V_CC, eliminating parasitic conduction paths during voltage translation. Its OE-controlled switching operates with zero ground bounce and supports bidirectional signal flow without direction pins.

It uses proprietary low-power CMOS process technology optimized for fast turn-on/turn-off (t_PZL ≤ 5.6 ns, t_PLZ ≤ 4.5 ns) and maintains stable performance across full industrial temperature range with V_CC = 5.0 V ±5%.

Key Specifications

Pinout & Package

QS3245SOG is packaged in a 20-pin Small Outline IC (SOIC) with green RoHS-compliant finish (SOG suffix). Pin layout matches industry-standard 74FCT245 footprint for drop-in replacement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus switching applications.

Compared with 74FCT245CTSO20 and SN74CBT3245APW, the QS3245SOG uniquely combines industrial temperature qualification, integrated undershoot protection, and lowest R_ON among pin-compatible alternatives-making it optimal for ruggedized hot-swap and mixed-voltage infrastructure.

Availability

QS3245SOG is available at Aetrix Electronics and suitable for hot-swappable backplanes, voltage translation bridges, and low-power system sleep mode implementations requiring stable component supply across extended temperature ranges.

Supply support for QS3245SOG 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 IoT applications.

The QS3245SOG belongs to Renesas' QuickSwitch® bus switch product line, engineered specifically for high-speed, low-noise, bidirectional signal routing in hot-pluggable and mixed-voltage systems.

FAQ

What is the maximum operating voltage for QS3245SOG?

The QS3245SOG supports DC supply voltage (V_TERM) from –0.5 V to +7 V relative to ground. This rating applies to both V_CC and all I/O terminals except V_CC, enabling robust handling of hot-swap transients and overvoltage conditions. The device is characterized for normal operation at V_CC = 5.0 V ±5%, and its undershoot clamp diodes protect inputs down to –3 V for short pulses.

Does QS3245SOG support bidirectional signal flow without direction control?

Yes, QS3245SOG provides fully bidirectional signal paths between A0–A7 and B0–B7 pins with no direction pin required. Each switch conducts equally in both directions when enabled by OE, making it ideal for data bus isolation and voltage translation where signal polarity or direction is undefined or variable. This eliminates timing complexity associated with directional transceivers.

Is QS3245SOG pin-compatible with standard 74-series transceivers?

Yes, QS3245SOG is explicitly pin-compatible with 74F245, 74FCT245, and 74FCT245T devices in SOIC-20 package. Its pinout matches the industry-standard 20-pin layout including V_CC, GND, OE, and dual-port I/O assignments-enabling drop-in replacement without PCB changes in existing designs using those transceivers.

What is the typical ON resistance of QS3245SOG and how does it affect signal integrity?

The QS3245SOG has a typical ON resistance of 5 Ω at V_IN = 0 V and V_CC = 5 V. This low R_ON minimizes voltage drop (<100 mV at 20 mA) and keeps RC time constants below 0.25 ns with 50 pF loads, preserving edge rates and reducing jitter in high-speed digital interfaces such as PCI, ISA, or custom parallel buses.

How does QS3245SOG handle undershoot transients during hot-plug events?

QS3245SOG integrates undershoot clamp diodes on all switch and control inputs (A0–A7, B0–B7, OE). These diodes conduct when input voltage falls below –0.5 V, limiting negative excursions to approximately –0.7 V and preventing latch-up or damage during connector arcing. This feature eliminates the need for external protection components in hot-swap applications.