Renesas QS3245QG8

Overview

QS3245QG8 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 data path isolator in hot-swap and voltage-translation applications between 5V and 3.3V domains.

For engineers reviewing the QS3245QG8 datasheet, QS3245QG8 pinout, QS3245QG8 application, or QS3245QG8 equivalent, key selection criteria include guaranteed sub-0.25ns max propagation delay, ±1μA input leakage, 5Ω R_ON, undershoot clamp diodes on all I/Os, and SOIC/QSOP package compatibility with 74FCT245.

Technical Context

The QS3245QG8 implements eight independent N-channel FET switches with no inherent body diode to V_CC, enabling true bidirectional signal flow without forward-bias risk. Its OE-controlled switching operates with zero ground bounce and supports hot-docking by maintaining Hi-Z outputs when disabled.

It uses proprietary low-power CMOS process technology optimized for capacitance reduction and isolation. All A/B I/O pins feature undershoot clamp diodes, and control inputs meet TTL voltage thresholds (V_IL ≤ 0.8V, V_IH ≥ 2.0V) while drawing ≤3μA quiescent supply current at V_CC = 5V.

Key Specifications

Pinout & Package

QS3245QG8 is packaged in a 20-pin QSOP (Quarter Size Outline Package), green RoHS-compliant, with 0.65mm lead pitch and JEDEC MO-137AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3245APW and 74FCT245CTSO, the QS3245QG8 uniquely delivers 5Ω R_ON, integrated undershoot protection, and zero-delay performance in a 5V industrial-grade package-making it optimal for hot-swap isolation and voltage-domain bridging where timing and robustness are critical.

Availability

QS3245QG8 is available at Aetrix Electronics and suitable for hot-swapping systems, voltage translation interfaces, and logic replacement applications requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for QS3245QG8 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 QS3245QG8 belongs to Renesas' QuickSwitch® bus switch product line, engineered specifically for high-speed, low-latency signal isolation and voltage-domain bridging in mission-critical industrial and infrastructure systems.

FAQ

What is the maximum operating voltage for QS3245QG8?

The QS3245QG8 supports a supply voltage (V_CC) range of 5.0V ±5%, with absolute maximum ratings allowing V_CC up to +7V. However, functional operation is specified only at 5.0V ±5%. Exceeding this range may cause reliability degradation or parametric shift, and is not recommended for production use. The QS3245QG8 is not rated for 3.3V-only operation.

Does QS3245QG8 support bidirectional signal flow?

Yes, the QS3245QG8 supports fully bidirectional signal flow through its eight independent A/B channel pairs. Each switch is implemented with an enhanced N-channel FET having no inherent diode to V_CC, eliminating forward-bias risk and enabling true AC-coupled or DC-coupled signal transmission in either direction without external biasing. This makes QS3245QG8 ideal for shared bus architectures.

Is QS3245QG8 pin-compatible with standard 74-series transceivers?

Yes, the QS3245QG8 is explicitly pin-compatible with 74F245, 74FCT245, and 74FCT245T devices in both SOIC and QSOP packages. Its 20-pin QSOP footprint matches the industry-standard 74FCT245 layout, enabling direct replacement without PCB modification. The OE pin aligns functionally and electrically with the 74'245 output enable, preserving existing control logic.

What is the purpose of the undershoot clamp diodes in QS3245QG8?

The undershoot clamp diodes on all A/B I/O and control pins protect the QS3245QG8 from negative transient voltages down to –3V for pulses ≤20ns. This feature prevents damage and latch-up during hot-swap events or ESD-induced transients. In systems where modules are inserted under power, these clamps ensure reliable operation without external protection components, directly enhancing system robustness.

Can QS3245QG8 be used for 5V-to-3.3V voltage translation?

Yes, the QS3245QG8 is widely used for passive 5V-to-3.3V voltage translation. Because it is a bidirectional switch with no internal level-shifting circuitry, it passes signals transparently across voltage domains when one side is driven at 5V and the other sees a 3.3V-tolerant receiver. Its 5Ω R_ON and low input capacitance preserve signal rise/fall times, making QS3245QG8 suitable for translating control and data lines in mixed-voltage systems.