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Renesas QS3257QG8
- Part No.:
- QS3257QG8
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
QS3257QG8.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:215
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Product details
Overview
QS3257QG8 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 QS3257QG8 datasheet, QS3257QG8 pinout, QS3257QG8 application, or QS3257QG8 equivalent, key selection criteria include bidirectional switch performance, undershoot clamp diode protection, TTL-compatible enable/select logic, and industrial-temperature-rated 5V operation with ±1μA input leakage.
Technical Context
The QS3257QG8 implements four independent bidirectional analog switches controlled by a shared active-low Enable (E) and single Select (S) input, supporting mux/demux mode selection per channel. Each switch features enhanced N-channel FETs with no inherent body diode to VCC, enabling true rail-to-rail signal pass without forward conduction.
It operates at 5V ±5%, supports DC switch voltages from –0.5V to +7V on all I/O terminals (except VCC), and delivers sub-nanosecond turn-on/turn-off delays (tPZH/tPHZ ≤ 5.2 ns) under 50 pF load conditions - critical for hot-swap and voltage translation applications between 5V and 3.3V domains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| ON Resistance | 5 Ω typical at VCC = 5V, VIN = 0V - enables low-loss signal coupling with minimal RC delay |
| Propagation Delay | 0.25 ns max (tPLH/tPHL) - contributes negligible timing budget in high-speed data paths |
| Input Voltage Range | –0.5 V to +7 V on all I/O pins - supports voltage translation and undershoot tolerance |
| Supply Voltage | 5.0 V ±5% - compatible with standard TTL/LVTTL logic rails |
| Operating Temp | –40°C to +85°C - qualified for industrial-grade embedded and interface systems |
| Input Leakage | ±1 μA max - ensures low standby current and stable high-impedance states |
| Capacitance (Switch OFF) | 7 pF max - minimizes crosstalk and loading in high-frequency mux/demux paths |
Pinout & Package
QS3257QG8 is packaged in a 16-pin Quarter Size Outline Package (QSOP), green-compliant, with 0.65 mm lead pitch and JEDEC MO-137AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (S) | Select Input | Shared 2:1 channel selector; TTL-compatible, active-HIGH logic |
| 2 (I0A) | Data Input A0 | First input of Channel A; bidirectional when enabled |
| 3 (I1A) | Data Input A1 | Second input of Channel A; bidirectional when enabled |
| 4 (YA) | Data Output A | Common output of Channel A; connects to I0A or I1A based on S/E state |
| 5 (GND) | Ground | Reference return path for all signals and power |
| 6 (VCC) | Power Supply | +5V supply input; decoupling required near pin |
| 7 (E) | Enable Input | Active-LOW global enable; disables all channels when HIGH |
| 8 (I0B) | Data Input B0 | First input of Channel B; bidirectional when enabled |
| 9 (I1B) | Data Input B1 | Second input of Channel B; bidirectional when enabled |
| 10 (YB) | Data Output B | Common output of Channel B; connects to I0B or I1B based on S/E state |
| 11 (I0D) | Data Input D0 | First input of Channel D; bidirectional when enabled |
| 12 (I1D) | Data Input D1 | Second input of Channel D; bidirectional when enabled |
| 13 (YD) | Data Output D | Common output of Channel D; connects to I0D or I1D based on S/E state |
| 14 (I0C) | Data Input C0 | First input of Channel C; bidirectional when enabled |
| 15 (I1C) | Data Input C1 | Second input of Channel C; bidirectional when enabled |
| 16 (YC) | Data Output C | Common output of Channel C; connects to I0C or I1C based on S/E state |
Key Features
| Feature | Design Value |
|---|---|
| Zero propagation delay architecture | Eliminates added timing skew in high-speed data paths; delay dominated only by external RC load |
| Undershoot clamp diodes on all I/O | Protects against negative transients down to –3 V (20 ns pulse), enabling robust hot-swap operation |
| 5 Ω typical ON resistance | Reduces insertion loss and maintains signal integrity for analog and digital signals up to 100 MHz |
| TTL-compatible control inputs | Accepts standard 5V logic levels without level-shifting, simplifying integration with legacy controllers |
| Rail-to-rail bidirectional switching | Supports voltage translation between 5V and 3.3V domains without direction control or external bias |
Applications
| Video Signal Routing | Hot-Swappable Backplane Interface |
|---|---|
Use Scenario: Switching composite or RGB video sources between multiple displays or capture devices in industrial monitors. IC Role / Device Role / Timing Role: Quad 2:1 analog mux providing low-distortion, bidirectional signal path selection with <5Ω RON. Use Value: Preserves video bandwidth and DC coupling while eliminating ground bounce-induced artifacts during source switching. | Use Scenario: Enabling safe insertion/removal of daughter cards in modular test equipment with live backplane power. IC Role / Device Role / Timing Role: Isolates card-side buses from backplane during insertion using E-controlled Hi-Z outputs. Use Value: Clamp diodes and zero-delay switching prevent latch-up and transient damage during plug-in events. |
| 5V-to-3.3V Logic Translation | PCI/ISA Bus Funneling |
Use Scenario: Interfacing 5V microcontrollers with 3.3V peripherals in mixed-voltage embedded systems. IC Role / Device Role / Timing Role: Bidirectional level translator leveraging RON-based voltage division and rail-to-rail swing. Use Value: No external resistors or direction pins required; supports full-speed SPI/I²C signaling across voltage domains. | Use Scenario: Consolidating multiple ISA or PCI peripheral address/data lines onto a shared system bus in legacy industrial controllers. IC Role / Device Role / Timing Role: Low-capacitance (≤7 pF OFF), high-speed mux enabling time-multiplexed bus sharing. Use Value: Minimizes bus contention delay and signal degradation compared to gate-based solutions. |
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 |
|---|---|---|---|
| SN74CBT3257PW | 4.5Ω RON typ, same 16-pin TSSOP package, but no undershoot clamps on I/O | Lacks integrated transient protection; requires external TVS for hot-swap use | Preferred where board space is constrained and transient immunity is handled externally |
| 74FCT257CTSO | Logic-based mux (not analog switch); 3.5 ns tPD, higher power, unidirectional only | Cannot support bidirectional or voltage-translation use cases | Suitable only for pure digital logic replacement where analog pass-through is not needed |
Compared with SN74CBT3257PW and 74FCT257CTSO, the QS3257QG8 uniquely combines sub-ns delay, integrated undershoot clamps, and true bidirectional analog switching - making it the only option among the three that supports hot-swap-safe voltage translation without external components.
Availability
QS3257QG8 is available at Aetrix Electronics and suitable for video switching, hot-swappable interface design, and mixed-voltage logic translation requiring stable component supply across industrial temperature ranges.
Supply support for QS3257QG8 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 connectivity solutions for automotive, industrial, and IoT applications.
The QS3257QG8 belongs to Renesas' QuickSwitch® analog switch product line, engineered for ultra-low-delay, bidirectional signal routing in mixed-signal interface and hot-swap systems.
FAQ
What is the maximum allowable undershoot voltage on QS3257QG8 I/O pins?
The QS3257QG8 includes undershoot clamp diodes on all switch and control inputs rated for –3 V (pulse width ≤20 ns). This allows safe operation during hot-plug events where transient negative excursions may occur, provided the absolute maximum rating of –0.5 V DC is not exceeded continuously. The clamps protect internal circuitry without requiring external components.
Does QS3257QG8 support bidirectional signal flow in both mux and demux configurations?
Yes, QS3257QG8 supports fully bidirectional signal flow across all four channels. Each 2:1 switch operates identically in either direction - inputs I0x/I1x and output Yx are functionally interchangeable when enabled. This enables flexible use as a mux (I0x/I1x → Yx) or demux (Yx → I0x/I1x), critical for bus-sharing and voltage-translation applications.
What is the guaranteed ON resistance range for QS3257QG8 over temperature and voltage?
The QS3257QG8 guarantees ON resistance of 5 Ω to 7 Ω at VCC = minimum (4.75 V), VIN = 0 V, and ION = 30 mA. At VIN = 2.4 V, RON increases to 10–15 Ω. This variation is specified across the full industrial temperature range (–40°C to +85°C) and directly impacts insertion loss and signal fidelity in analog paths.
Can QS3257QG8 be used to translate between 5V and 3.3V logic without external components?
Yes, QS3257QG8 enables passive 5V-to-3.3V and 3.3V-to-5V logic translation without direction control or external resistors. Its rail-to-rail bidirectional switching, 5Ω RON, and –0.5 V to +7 V I/O voltage range allow clean signal pass-through across voltage domains - confirmed in the datasheet's "Voltage translation (5V to 3.3V)" application note.
Is QS3257QG8 pin-compatible with standard logic mux ICs like the 74F257?
Yes, QS3257QG8 is explicitly designed as a pin-compatible QuickSwitch replacement for 74F257, 74FCT257, and 74ALS/AS/LS257 quad 2:1 muxes. Pin functions, numbering, and physical layout match these legacy devices - allowing drop-in upgrades to achieve zero propagation delay, lower power, and improved hot-swap reliability without PCB redesign.
QS3257QG8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
QS3257QG8 FAQ
1.How can I place an order for QS3257QG8 through Aetrix?
Please submit a Request for Quotation (RFQ) for QS3257QG8 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 QS3257QG8 reliable?
The price and inventory of QS3257QG8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for QS3257QG8 is usually 5 days.
3.What payment methods are accepted for QS3257QG8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for QS3257QG8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for QS3257QG8?
QS3257QG8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your QS3257QG8 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 QS3257QG8?
For technical support, including QS3257QG8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your QS3257QG8 requirements.
6.How does Aetrix verify that QS3257QG8 is sourced from the original manufacturer or authorized distributors?
All QS3257QG8 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 QS3257QG8 meets industry standards.
7.What is the process for return or replacement of QS3257QG8?
All QS3257QG8 units undergo pre-shipment inspection (PSI). If there is an issue with QS3257QG8, 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 QS3257QG8 part is unused and in its original packaging.
Return procedure for QS3257QG8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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