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Renesas QS3257QG
- Part No.:
- QS3257QG
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
QS3257QG.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,618
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Product details
Overview
QS3257QG from Renesas Electronics is a high-speed CMOS quad 2:1 multiplexer/demultiplexer with LVTTL-compatible control inputs, 5Ω typical ON resistance, zero propagation delay, and operation over –40°C to +85°C. It serves as a pin-compatible replacement for 74F257/74FCT257 in logic-level signal routing for video/audio switching and bus funneling.
For engineers reviewing the QS3257QG datasheet, QS3257QG pinout, QS3257QG application, or QS3257QG equivalent, key selection considerations include bidirectional switch performance, undershoot clamp diodes on all I/O, TTL-compatible enable/select logic, and industrial-temperature-rated voltage translation (5V ↔ 3.3V).
Technical Context
The QS3257QG implements four independent bidirectional analog switches using enhanced N-channel FETs with no inherent body diode to VCC, enabling true rail-to-rail signal pass-through without forward conduction. Each channel features undervoltage clamping diodes on I/O and control pins, supporting hot-swap and hot-dock operation.
Switching is controlled by a single active-low Enable (E) and shared Select (S) input, allowing simultaneous 2:1 mux/demux selection across all four channels. Propagation delay is limited only by RC time constant of RON (5Ω) and load capacitance - not internal logic - yielding sub-0.25ns intrinsic delay at 50pF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| ON Resistance | 5Ω typical at VCC = 5V, 0V input - ensures minimal signal attenuation and distortion in analog/digital signal paths |
| Propagation Delay | <0.25ns max - adds negligible timing skew in high-speed data routing applications |
| Supply Voltage Range | –0.5V to +7V - supports 5V, 3.3V, and mixed-voltage system interfacing |
| Input Voltage Range | –0.5V to +7V on all I/O - enables robust undershoot/overshoot tolerance and level translation |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded and communications equipment |
| Control Compatibility | TTL-compatible E/S inputs - interfaces directly with legacy 74-series logic without level shifters |
| Off-State Leakage | ±1μA max - prevents signal coupling between inactive channels in high-impedance systems |
Pinout & Package
QS3257QG is packaged in a 16-pin QSOP (Quarter Size Outline Package), RoHS-compliant and green-processed, with 0.65mm lead pitch and standard JEDEC MO-137AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| I0A–I0D | Data Input 0 (Channel A–D) | First input pair per channel; connected to output when S = L and E = L |
| I1A–I1D | Data Input 1 (Channel A–D) | Second input pair per channel; connected to output when S = H and E = L |
| YA–YD | Data Output (Channel A–D) | Bidirectional node - passes signal from selected input or drives external load |
| S | Select Input | Shared 2:1 selector; L selects I0x, H selects I1x across all four channels |
| E | Enable Input | Active-low global enable; E = H forces all outputs to high-impedance state |
| VCC | Power Supply | Positive supply terminal (5V nominal); powers internal clamp diodes and control logic |
| GND | Ground Reference | Return path for all signals and internal circuitry; required for proper clamp diode operation |
Key Features
| Feature | Design Value |
|---|---|
| Zero-propagation-delay switching | RC-limited delay only - eliminates timing budget overhead in synchronous bus architectures |
| Undershoot clamp diodes | Integrated on all I/O and control pins - protects against negative transients during hot-plug events |
| Bidirectional 5Ω switches | Low RON with flat voltage dependence - preserves signal integrity for both analog and digital waveforms |
| Pin compatibility with 74F257/74FCT257 | Direct drop-in replacement - avoids PCB redesign when upgrading from legacy TTL/FT logic |
| Voltage translation capability | Supports 5V-to-3.3V and 3.3V-to-5V signal routing without external components |
Applications
| Video Signal Routing | Industrial Bus Funneling |
|---|---|
Use Scenario: Switching between dual HDMI source streams into a single display controller input. IC Role / Device Role / Timing Role: Quad 2:1 analog mux providing low-distortion, glitch-free video path selection with sub-nanosecond delay. Use Value: Maintains pixel clock integrity and eliminates visible artifacts during source switching due to 5Ω RON and absence of ground bounce. | Use Scenario: Consolidating four sensor interface buses (I²C/SPI) onto one microcontroller port under firmware control. IC Role / Device Role / Timing Role: Bidirectional bus switch enabling dynamic reconfiguration of peripheral connectivity without protocol layer changes. Use Value: Enables flexible hardware partitioning and reduces MCU GPIO count while preserving signal rise/fall times via low-capacitance switching. |
| Hot-Swappable Module Interface | Legacy Logic Upgrade Path |
Use Scenario: Enabling safe insertion/removal of daughter cards carrying 5V logic in a 3.3V backplane system. IC Role / Device Role / Timing Role: Level-translating, transient-protected signal bridge between mismatched voltage domains during live insertion. Use Value: Clamp diodes prevent latch-up; bidirectional RON allows handshake signaling in both directions without direction control logic. | Use Scenario: Replacing obsolete 74F257 multiplexers in aging test equipment with improved speed and reliability. IC Role / Device Role / Timing Role: Pin- and function-identical upgrade delivering zero added propagation delay and lower power consumption. Use Value: Eliminates need for board respin or firmware modification while improving system timing margin and thermal performance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2:1 analog switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74FCT257QSC | Higher RON (~15Ω), no undershoot clamps, no voltage translation support | Limited to same-voltage-domain TTL logic replacement; unsuitable for hot-swap or mixed-voltage use | Choose only if legacy 74FCT pinout compliance is mandatory and signal integrity requirements are relaxed |
| SN74CBT3257PWR | Similar RON (6Ω), but lacks integrated undershoot clamps and has narrower VI/O range (–0.5V to VCC + 0.5V) | Requires external protection diodes for hot-swap; less robust in noisy industrial environments | Preferable only where TI ecosystem integration or specific packaging (TSSOP) is required |
Compared with 74FCT257QSC and SN74CBT3257PWR, the QS3257QG uniquely combines sub-0.25ns delay, integrated undershoot protection, and full –0.5V to +7V I/O tolerance - making it the only option qualified for demanding hot-swap, voltage-translation, and high-fidelity analog signal routing.
Availability
QS3257QG is available at Aetrix Electronics and suitable for video switching, industrial bus funneling, hot-swappable module interfaces, and legacy logic upgrades requiring stable component supply and long-term industrial temperature support.
Supply support for QS3257QG 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, infrastructure, and IoT applications.
The QS3257QG belongs to Renesas' QuickSwitch® family of high-speed bus switches, engineered specifically for zero-delay, bidirectional signal routing in mixed-voltage, hot-plug-capable systems.
FAQ
What is the maximum allowable input voltage on QS3257QG I/O pins?
The QS3257QG supports DC input voltages from –0.5V to +7V on all switch and control pins, independent of VCC. This wide range enables robust undershoot/overshoot tolerance and seamless 5V-to-3.3V voltage translation without external components. The specification is guaranteed across the full industrial temperature range (–40°C to +85°C).
Does QS3257QG support hot-swap operation?
Yes, QS3257QG supports hot-swap operation due to integrated undershoot clamp diodes on all I/O and control inputs, combined with its ability to tolerate –0.5V on any pin. These features prevent latch-up and protect downstream circuitry during live insertion or removal of modules in powered-backplane systems.
Is QS3257QG pin-compatible with standard 74-series logic devices?
Yes, QS3257QG is explicitly designed as a pin- and function-compatible replacement for 74F257, 74FCT257, and 74ALS/AS/LS257 quad 2:1 multiplexers. Its 16-pin QSOP footprint matches industry-standard layouts, enabling direct drop-in upgrades without PCB modification.
What is the typical ON resistance of QS3257QG and how does it vary with signal voltage?
The QS3257QG has a typical ON resistance of 5Ω at VCC = 5V and VIN = 0V. At VIN = 2.4V, RON rises to 10Ω typical. This voltage-dependent behavior is inherent to MOSFET-based switches and is fully characterized in the datasheet - critical for predicting signal attenuation in analog applications.
Can QS3257QG be used for bidirectional signal routing in I²C or SPI buses?
Yes, QS3257QG supports bidirectional signal routing and is commonly used for I²C and SPI bus funneling. Its 5Ω RON, low capacitive loading (≤9pF), and TTL-compatible control inputs allow transparent integration without altering protocol timing or requiring direction-control logic.
QS3257QG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Multiplexer/Demultiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- 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:
- 16-QSOP
QS3257QG FAQ
1.How can I place an order for QS3257QG through Aetrix?
Please submit a Request for Quotation (RFQ) for QS3257QG 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 QS3257QG reliable?
The price and inventory of QS3257QG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for QS3257QG is usually 5 days.
3.What payment methods are accepted for QS3257QG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for QS3257QG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for QS3257QG?
QS3257QG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your QS3257QG 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 QS3257QG?
For technical support, including QS3257QG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your QS3257QG requirements.
6.How does Aetrix verify that QS3257QG is sourced from the original manufacturer or authorized distributors?
All QS3257QG 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 QS3257QG meets industry standards.
7.What is the process for return or replacement of QS3257QG?
All QS3257QG units undergo pre-shipment inspection (PSI). If there is an issue with QS3257QG, 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 QS3257QG part is unused and in its original packaging.
Return procedure for QS3257QG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
QS3257QG Tags
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P3S0200GMX
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TCA9546APWR
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