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Renesas QS3244QG8
- Part No.:
- QS3244QG8
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
QS3244QG8.pdf
- Description:
- IC BUS SWITCH 4 X 1:1 20QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,056
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Product details
Overview
QS3244QG8 from Renesas Electronics is an 8-bit high-speed CMOS bus switch with TTL-compatible pinout, 5Ω ON resistance, zero propagation delay, and industrial temperature range (–40°C to +85°C). It functions as a bidirectional signal path controller for hot-swappable backplanes and voltage-level isolated data buses.
For engineers reviewing the QS3244QG8 datasheet, QS3244QG8 pinout, QS3244QG8 application, or QS3244QG8 equivalent, key selection criteria include guaranteed 5Ω RON at VCC = 5V, undershoot clamp diodes on all I/Os, dual independent enable control (1G/2G), and compatibility with 74FCT244/74F244 logic families in QSOP-20 packaging.
Technical Context
The QS3244QG8 implements eight independent N-channel FET switches with no inherent body diode to VCC, enabling true bidirectional DC coupling without forward-bias risk. Its zero-ground-bounce architecture eliminates switching noise during hot-insertion events.
Each switch channel features integrated undershoot clamp diodes on both A and Y terminals and control inputs, supporting robust I/O protection across –0.5V to +7V transient conditions. Dual enable signals (1G, 2G) provide granular 4-bit group control aligned with legacy 74'244 functional partitioning.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| RON (ON Resistance) | 5 Ω typical at VCC = 5V, VIN = 0V - enables sub-0.25 ns RC delay with 50 pF load |
| tPLH / tPHL | 0.25 ns max - no added propagation delay beyond system RC time constant |
| VIN Range | –0.5 V to +7 V - supports hot-swap transients and mixed-voltage domain interfacing |
| IOZ (Off-State Current) | ±1 μA max - ensures high-impedance isolation between disconnected buses |
| ICCQ (Quiescent Current) | 3 μA max - enables ultra-low static power in always-on isolation paths |
| Operating Temp | –40°C to +85°C - qualified for industrial-grade embedded and telecom infrastructure |
Pinout & Package
QS3244QG8 is packaged in RoHS-compliant, green QSOP-20 (Quarter Size Outline Package) with 0.65 mm pitch and standard JEDEC MO-137AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1G, 2G | Active-Low Enable Inputs | Independent control of two 4-bit switch groups; low enables bidirectional conduction |
| 1A1–1A4, 2A1–2A4 | Data Inputs/Outputs (Group 1 & 2) | Bidirectional I/O pins; no direction pin required - conduction path determined by enable state |
| 1Y1–1Y4, 2Y1–2Y4 | Data Inputs/Outputs (Group 1 & 2) | Paired with respective A pins; identical electrical behavior - fully symmetric signal path |
| VCC | Positive Supply | 5V ±5% only; powers internal clamp diodes and gate drive - not tolerant of 3.3V-only operation |
| GND | Ground Reference | Common return for all I/Os and internal circuitry; required for clamp diode functionality |
Key Features
| Feature | Design Value |
|---|---|
| Enhanced N-channel FET structure | No intrinsic body diode to VCC - prevents unintended current flow during voltage translation |
| Undershoot clamp diodes | On all A, Y, and G pins - protects against –3 V AC transients and –0.5 V DC faults |
| Zero ground bounce | Eliminates simultaneous switching noise - critical for signal integrity in dense backplane designs |
| Pin compatibility | Direct drop-in replacement for 74FCT244, 74F244, and 74ALS/AS/LS244 in same package |
| Capacitance reduction | 7 pF max per switch (OFF) - minimizes loading on driving sources and improves timing margins |
Applications
| Hot-Swappable Backplane Interface | Voltage-Level Isolated Data Bus |
|---|---|
Use Scenario: Inserting/removing line cards in telecom or server chassis without powering down the system. IC Role / Device Role / Timing Role: Bidirectional bus switch isolating card-side and backplane-side signal domains during insertion/removal. Use Value: Prevents bus contention and ground bounce via zero-delay switching and undershoot clamping - meets IEC 61000-4-2 Level 4 ESD immunity requirements. | Use Scenario: Interfacing 5V microcontroller peripherals with 3.3V FPGA I/O banks. IC Role / Device Role / Timing Role: Passive level translator enabling DC-coupled signal transfer without direction control or supply translation circuitry. Use Value: 5Ω RON and <0.25 ns delay preserve setup/hold timing across voltage domains - avoids need for active translators or level-shifting buffers. |
| Power-Gated Peripheral Subsystem | Logic Replacement in Legacy Systems |
Use Scenario: Dynamically disabling unused USB or PCIe endpoint interfaces to reduce system standby power. IC Role / Device Role / Timing Role: Low-leakage (±1 μA) isolation switch inserted between host controller and peripheral PHY. Use Value: ICCQ ≤ 3 μA and IOZ ≤ ±1 μA cut leakage paths without adding propagation delay - extends battery life in portable industrial controllers. | Use Scenario: Upgrading aging 74F244-based bus drivers in test equipment with higher-speed, lower-noise alternatives. IC Role / Device Role / Timing Role: Pin-identical drop-in replacement providing faster switching and improved EMI performance. Use Value: Maintains existing PCB layout while reducing ground bounce and improving signal fidelity - eliminates redesign cost and qualification cycle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3244DBR | Higher RON (7 Ω typ), no undershoot clamps, 3.3V-only supply | Limited to 3.3V systems; unsuitable for 5V↔3.3V translation or hot-swap | Select QS3244QG8 when mixed-voltage support, clamping, or industrial temp range is required |
| 74FCT244CTSO20 | Traditional TTL buffer with propagation delay (~5 ns), no zero-ground-bounce design | Provides logic-level amplification but adds delay and noise; no isolation capability | Choose QS3244QG8 where true bidirectional isolation, zero delay, and hot-swap safety are mandatory |
Compared with SN74CBT3244DBR and 74FCT244CTSO20, the QS3244QG8 uniquely delivers 5Ω RON, integrated undershoot protection, and zero ground bounce - making it the only option qualified for industrial hot-swap and mixed-voltage bus isolation without redesign.
Availability
QS3244QG8 is available at Aetrix Electronics and suitable for hot-swappable backplane interfaces, voltage-level isolated data buses, and power-gated peripheral subsystems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for QS3244QG8 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 QS3244QG8 belongs to Renesas' QuickSwitch® bus switch product line, engineered specifically for high-fidelity, zero-delay signal routing in hot-plug-capable systems and mixed-voltage digital interfaces.
FAQ
What is the maximum allowable input voltage for QS3244QG8?
The QS3244QG8 supports DC input voltages from –0.5 V to +7 V on all A, Y, and G pins, and –0.5 V to +7 V on VTERM(3) terminals. This rating enables robust handling of hot-swap transients and mixed-voltage domain interfacing without external protection circuitry. The VCC pin requires 5V ±5% only and must not be operated at 3.3V. Exceeding these limits risks permanent damage per absolute maximum ratings.
Does QS3244QG8 support true bidirectional signal flow?
Yes, the QS3244QG8 provides fully bidirectional signal conduction between each A–Y pair (e.g., 1A1 ↔ 1Y1) with no direction control pin required. Its enhanced N-channel FET architecture lacks an inherent body diode to VCC, eliminating forward-bias risk during reverse-current conditions. Signal integrity is preserved in both directions due to symmetrical 5Ω RON and matched capacitance (<7 pF OFF).
Is QS3244QG8 pin-compatible with standard 74-series logic devices?
Yes, the QS3244QG8 is explicitly pin-compatible with 74F244, 74FCT244, and 74FCT244T in QSOP-20, SOIC-20, and TSSOP-20 packages. Its pinout matches the 74'244 functional partitioning - including dual 4-bit groups controlled by 1G and 2G - enabling drop-in replacement without PCB modification or firmware changes.
What is the significance of "zero propagation delay" in QS3244QG8 specifications?
"Zero propagation delay" means the QS3244QG8 contributes no measurable logic delay beyond the inherent RC time constant of its 5Ω RON and load capacitance. With a 50 pF load, this time constant is ~0.25 ns - far smaller than typical driver rise/fall times. Thus, system-level timing is governed solely by upstream drivers and downstream loads, not the switch itself - a critical advantage for high-speed bus isolation.
Can QS3244QG8 be used for 5V to 3.3V voltage translation?
Yes, the QS3244QG8 is widely applied for 5V-to-3.3V voltage translation due to its passive, bidirectional FET architecture and wide input voltage tolerance (–0.5 V to +7 V). When a 5V signal drives an A pin with 3.3V VCC, the pass voltage VP is guaranteed 3.7–4.2 V - safely within 3.3V logic HIGH thresholds. No level-shifting circuitry or direction control is needed, preserving signal timing and reducing BOM count.
QS3244QG8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 20-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Bus Switch
- Circuit:
- 4 x 1:1
- Independent Circuits:
- 2
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QSOP
QS3244QG8 FAQ
1.How can I place an order for QS3244QG8 through Aetrix?
Please submit a Request for Quotation (RFQ) for QS3244QG8 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for QS3244QG8 reliable?
The price and inventory of QS3244QG8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for QS3244QG8 is usually 5 days.
3.What payment methods are accepted for QS3244QG8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for QS3244QG8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for QS3244QG8?
QS3244QG8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your QS3244QG8 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for QS3244QG8?
For technical support, including QS3244QG8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your QS3244QG8 requirements.
6.How does Aetrix verify that QS3244QG8 is sourced from the original manufacturer or authorized distributors?
All QS3244QG8 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that QS3244QG8 meets industry standards.
7.What is the process for return or replacement of QS3244QG8?
All QS3244QG8 units undergo pre-shipment inspection (PSI). If there is an issue with QS3244QG8, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The QS3244QG8 part is unused and in its original packaging.
Return procedure for QS3244QG8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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