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Renesas QS3126QG
- Part No.:
- QS3126QG
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
QS3126QG.pdf
- Description:
- IC BUS SWITCH 1 X 1:1 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,314
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Product details
Overview
QS3126QG from Renesas Electronics is a high-speed CMOS quadruple bus switch with individual active-high enables, designed for bidirectional signal isolation in 5V/3.3V mixed-voltage systems. It features 5 Ω typical ON resistance, zero propagation delay, undershoot clamp diodes on all control and switch inputs, and operates across –40°C to +85°C. It is used in hot-swap interfaces and clock gating circuits where ground bounce and timing skew must be eliminated.
For engineers reviewing the QS3126QG datasheet, QS3126QG pinout, QS3126QG application, or QS3126QG equivalent, key selection criteria include ON-resistance matching, enable-input voltage thresholds (VIH = 2 V, VIL = 0.8 V), industrial temperature support, QSOP-16 package compatibility, and absence of inherent body diode conduction to VCC.
Technical Context
The QS3126QG implements four independent N-channel FET switches with no intrinsic source-to-drain diode to VCC, enabling true bidirectional signal flow without forward-bias leakage. Each channel has a dedicated active-high OE input, and switching is governed by logic-level control without internal latching or buffering.
It delivers sub-nanosecond turn-on (tPZL ≤ 6.5 ns) and turn-off (tPLZ ≤ 5.5 ns) delays under 50 pF load, with dynamic supply current of only 0.25 mA/MHz. The device draws just 3 µA quiescent current and supports DC switch voltages from –0.5 V to +7 V, making it suitable for level translation between 5 V and 3.3 V domains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| ON Resistance (RON) | 5 Ω typical at VCC = 5 V, VIN = 0 V - ensures minimal voltage drop and RC delay in high-speed data paths |
| Propagation Delay | 0.25 ns max - contributes negligible timing skew in synchronous bus isolation |
| Input Voltage Thresholds | VIH = 2 V, VIL = 0.8 V - compatible with TTL and CMOS logic families without level shifters |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded and computing applications |
| Supply Voltage Range | VCC = 5 V ±5%, absolute max –0.5 V to +7 V - supports overvoltage transient tolerance |
| Capacitance (Switch OFF) | 5–7 pF per channel - reduces loading on upstream drivers and improves signal integrity |
| Quiescent Current (ICCQ) | 3 µA max - enables low-power standby in battery-backed or energy-sensitive systems |
Pinout & Package
QS3126QG is supplied in a 16-pin Quarter Size Outline Package (QSOP), package code PCG16, with 0.65 mm lead pitch and exposed pad not present. Pin 1 is marked by a notch or dot; pins are arranged in two rows with GND (Pin 8) and VCC (Pin 9) centrally located for noise suppression.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A–4A | Switch Input/Output | Bidirectional data terminals for Bus A side; no polarity constraint |
| 1Y–4Y | Switch Input/Output | Bidirectional data terminals for Bus Y side; electrically identical to A pins |
| 1OE–4OE | Digital Control Input | Active-high enable per channel; drives switch ON when HIGH (≥2 V) |
| GND (Pin 8) | Power Reference | System ground return for all internal circuitry and clamp diodes |
| VCC (Pin 9) | Power Supply | +5 V supply rail; powers internal logic and FET gate drive |
| NC (Pins 1,16) | No Connect | Unbonded die pads; must remain unconnected and unstubbed |
Key Features
| Feature | Design Value |
|---|---|
| Enhanced N-channel FET with no inherent diode to VCC | Eliminates unwanted forward conduction during undervoltage or hot-insertion events |
| Zero propagation delay architecture | ON-resistance and load capacitance dominate timing-no internal logic delay added |
| Undershoot clamp diodes on all inputs | Protects against –3 V AC transients and ESD-induced negative excursions |
| Pin-compatible with 74'126 function | Enables drop-in replacement in legacy designs using standard quad buffer footprints |
| Industrial temperature qualification | Validated operation from –40°C to +85°C without derating or thermal monitoring |
Applications
| Hot-Swappable Backplane Interface | 5V-to-3.3V Voltage Translation |
|---|---|
Use Scenario: Inserting/removing line cards in telecom or server backplanes while system remains powered. IC Role / Device Role / Timing Role: Bidirectional bus switch isolating control and status signals between hot-plug card and host controller. Use Value: Prevents ground bounce and signal contention during insertion; clamps undershoot transients induced by connector mating. | Use Scenario: Interfacing legacy 5 V microcontrollers with modern 3.3 V peripherals (e.g., I²C sensors, SPI flash). IC Role / Device Role / Timing Role: Passive level translator enabling DC-coupled bidirectional communication without direction control lines. Use Value: Maintains signal integrity across voltage domains with <5 Ω RON and <7 pF OFF capacitance-no added propagation delay. |
| Low-Power Clock Gating | Mass Storage Bus Isolation |
Use Scenario: Dynamically disabling clock distribution to inactive subsystems in portable or embedded SoC-based systems. IC Role / Device Role / Timing Role: High-speed switch enabling/disabling clock paths under firmware control via individual OE pins. Use Value: Reduces dynamic power by cutting clock tree loading; zero-delay switching avoids clock glitch generation. | Use Scenario: Isolating SATA or parallel ATA buses during drive initialization or failure recovery in RAID controllers. IC Role / Device Role / Timing Role: Signal isolation element placed between host controller and storage device to prevent fault propagation. Use Value: Limits capacitive loading on active bus segments; prevents back-drive damage during hot-swap or reset sequences. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3126PW | Higher RON (7 Ω typ), same QSOP-16 footprint, TI's CBT family uses different process with higher ICCD (0.5 mA/MHz) | Compatible for static isolation but less optimal for high-frequency clock gating due to higher dynamic current | Select if TI supply chain alignment or long-term availability is prioritized over minimal RON |
| 74LVC126APW | True tri-state buffer (not passive switch); requires direction control; 3.3 V only; no undershoot clamps | Not suitable for bidirectional translation or hot-swap-requires external direction logic and fails under –3 V transients | Use only in fixed-direction, single-supply 3.3 V systems where passive switching is unnecessary |
Compared with SN74CBT3126PW and 74LVC126APW, the QS3126QG uniquely combines zero-delay passive switching, VCC-independent bidirectionality, and –3 V transient protection-making it irreplaceable in mixed-voltage hot-swap and clock-gating designs where signal fidelity and robustness are non-negotiable.
Availability
QS3126QG is available at Aetrix Electronics and suitable for hot-swapping, voltage translation, and clock gating applications requiring stable component supply despite its obsolete status. Inventory is drawn from verified end-of-life allocations with full traceability and remaining shelf life assurance.
Supply support for QS3126QG 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, infrastructure, and IoT applications.
The QS3126QG belongs to Renesas' QuickSwitch® family of high-speed bus switches, engineered specifically for zero-delay, low-noise signal routing in mixed-voltage, hot-pluggable systems where ground bounce and propagation skew must be eliminated.
FAQ
Is QS3126QG still in production?
No, QS3126QG is officially obsolete per Renesas PLC230010 (EOL notice dated Jan 31, 2023). Last-time-buy expires July 31, 2024. Aetrix Electronics maintains limited inventory sourced from authorized channels with full traceability and certificate of conformance for legacy system support.
What is the maximum allowable undershoot voltage on QS3126QG inputs?
The QS3126QG includes integrated undershoot clamp diodes rated for –3 V AC pulses (≤20 ns duration) on all switch and control inputs. This protects against ESD and connector-induced negative transients without requiring external components-critical for hot-swap reliability in the QS3126QG design.
Can QS3126QG be used for 5V-to-3.3V bidirectional level translation?
Yes, QS3126QG supports true bidirectional 5V-to-3.3V level translation without direction control. Its passive FET structure, 5 Ω RON, and –0.5 V to +7 V DC switch voltage rating allow seamless signal passage across voltage domains-unlike buffered translators such as the 74LVC126APW, which require separate direction lines and fail below 3.3 V.
Does QS3126QG have a body diode that conducts to VCC?
No, QS3126QG uses an enhanced N-channel FET structure with no inherent source-to-drain diode to VCC. This eliminates unintended conduction during undervoltage conditions or hot-insertion events-a key differentiator from standard MOSFET switches and essential for reliable QS3126QG deployment in backplane and docking applications.
What is the thermal limit for continuous operation of QS3126QG?
QS3126QG is characterized for continuous operation from –40°C to +85°C ambient temperature. Its maximum power dissipation is 0.5 W at TA = 85°C. With only 3 µA quiescent current and low RON, thermal rise is negligible in typical QS3126QG applications-even at full channel utilization-eliminating need for heatsinking in standard PCB layouts.
QS3126QG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Bus Switch
- Circuit:
- 1 x 1:1
- Independent Circuits:
- 4
- 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
QS3126QG FAQ
1.How can I place an order for QS3126QG through Aetrix?
Please submit a Request for Quotation (RFQ) for QS3126QG 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 QS3126QG reliable?
The price and inventory of QS3126QG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for QS3126QG is usually 5 days.
3.What payment methods are accepted for QS3126QG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for QS3126QG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for QS3126QG?
QS3126QG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your QS3126QG 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 QS3126QG?
For technical support, including QS3126QG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your QS3126QG requirements.
6.How does Aetrix verify that QS3126QG is sourced from the original manufacturer or authorized distributors?
All QS3126QG 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 QS3126QG meets industry standards.
7.What is the process for return or replacement of QS3126QG?
All QS3126QG units undergo pre-shipment inspection (PSI). If there is an issue with QS3126QG, 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 QS3126QG part is unused and in its original packaging.
Return procedure for QS3126QG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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