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Renesas QS3861QG
- Part No.:
- QS3861QG
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 24-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
QS3861QG.pdf
- Description:
- IC BUS SWITCH 10 X 1:1 24QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:5,734
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Product details
Overview
QS3861QG from Renesas Electronics (formerly IDT) is a high-speed CMOS 10-bit bus switch with flow-through pinout, designed for bidirectional signal routing in TTL-compatible digital systems. It features 5 Ω ON resistance, zero propagation delay, undershoot clamp diodes on all I/O and control pins, and operates across –40°C to +85°C for industrial hot-swap and voltage translation applications.
For engineers reviewing the QS3861QG datasheet, QS3861QG pinout, QS3861QG application, or QS3861QG equivalent, key selection criteria include its 5 Ω bidirectional switch resistance, flow-through layout minimizing trace skew, industrial temperature rating, undervoltage clamping, and compatibility with 5V/3.3V mixed-voltage bus isolation.
Technical Context
The QS3861QG implements ten independent N-channel FET switches with no inherent body diode to VCC, enabling true bidirectional signal pass-through without forward-bias conduction. Its flow-through pinout (A0–A9 on one side, B0–B9 on the other, BE centrally located) eliminates signal layer crossover in PCB layout.
Switching is controlled solely by the Bus Enable (BE) input: logic LOW connects An↔Bn; logic HIGH places all channels in high-impedance state. No internal level shifting is performed - voltage translation relies on external bus voltage domains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| ON Resistance | 5 Ω typical at VCC = 5 V, enabling minimal RC delay and preserving signal integrity in high-speed buses |
| Propagation Delay | 0 ns intrinsic delay; system-level delay dominated only by external RLOAD/CLOAD time constant |
| Input Voltage Range | –0.5 V to +7 V on all pins, supporting robust undershoot clamping and mixed-supply interfacing |
| Operating Temperature | –40°C to +85°C, qualified for industrial-grade hot-plug and docking environments |
| Capacitance (OFF) | 5–7 pF per channel, reducing loading on inactive buses and improving isolation performance |
| Supply Current (Quiescent) | 0.2 μA typical, enabling ultra-low static power in always-on isolation paths |
Pinout & Package
QS3861QG is packaged in a 24-pin QSOP (Quarter Size Outline Package), green RoHS-compliant, with 0.635 mm pitch and standard JEDEC MO-137AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | GND | Signal and power reference ground plane connection |
| 2–11 | A0–A9 | Bus A side inputs/outputs; bidirectionally connected to B0–B9 when BE = L |
| 12 | VCC | Positive supply (4.5–5.5 V); powers internal clamp diodes and gate drive |
| 13–22 | B0–B9 | Bus B side inputs/outputs; mirror A0–A9 with flow-through alignment |
| 23 | BE | Active-LOW bus enable control; synchronous turn-on/off of all 10 channels |
| 24 | NC | No connect; internally unconnected, must be left floating or tied to GND |
Key Features
| Feature | Design Value |
|---|---|
| Enhanced N-channel FET | No parasitic source-body diode to VCC, preventing unintended current paths during voltage translation |
| Zero ground bounce | Eliminates simultaneous switching noise during multi-bit bus transitions |
| Undershoot clamp diodes | Protects all A/B/BE pins against –3 V transient spikes without external components |
| Flow-through pinout | Enables straight-layer PCB routing between A and B buses, reducing crosstalk and stub length |
Applications
| Hot-Swapping Systems | Voltage Translation |
|---|---|
Use Scenario: Insertion/removal of PCIe or CompactPCI cards while main system remains powered. IC Role / Device Role / Timing Role: Bidirectional bus switch isolating backplane from card-side logic during insertion sequence. Use Value: Prevents bus contention and supply rail droop via 5 Ω low-resistance path and fast turn-off (≤5.5 ns). | Use Scenario: Interfacing 5 V legacy microcontrollers to 3.3 V FPGA I/O banks. IC Role / Device Role / Timing Role: Passive voltage-domain translator without level-shifting circuitry or direction control. Use Value: Maintains signal timing integrity with zero added propagation delay and supports bidirectional data flow. |
| Power-Gated Subsystems | High-Speed Clock Gating |
Use Scenario: Disabling power to peripheral modules (e.g., USB PHY, ADC) during sleep mode. IC Role / Device Role / Timing Role: Signal isolation switch placed between active controller and idle peripheral clock/data lines. Use Value: Reduces dynamic and leakage current via high-impedance OFF-state (±1 μA IOZ) and <0.2 μA quiescent ICCQ. | Use Scenario: Enabling/disabling clock distribution to CPU cores or memory controllers. IC Role / Device Role / Timing Role: Low-skew, low-capacitance clock path switch activated by power management unit. Use Value: Delivers sub-nanosecond edge fidelity with 5–7 pF OFF capacitance and flow-through layout minimizing inter-pin skew. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3384APW | 10-bit, 5 Ω RON, but uses separate OE pins per 5-bit group; no undershoot clamps | Requires two control signals instead of one; less robust in noisy hot-swap environments | Preferred when per-group enable granularity is needed and clamping is handled externally |
| PI3CHD3245LEX | 10-bit, 6 Ω RON, integrated ESD protection (±8 kV HBM), same flow-through pinout | Higher ESD rating enables use in handheld docking stations without external TVS | Preferred where system-level ESD compliance exceeds ±4 kV and layout space allows alternate package |
Compared with SN74CBT3384APW and PI3CHD3245LEX, the QS3861QG uniquely combines single-BE control, built-in undershoot clamping, and industrial temperature qualification - making it optimal for cost-sensitive, high-reliability hot-swap isolation where minimal control logic and transient resilience are critical.
Availability
QS3861QG is available at Aetrix Electronics and suitable for hot-swapping systems, voltage translation interfaces, and power-gated subsystems requiring stable component supply across extended industrial temperature ranges.
Supply support for QS3861QG 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 QS3861QG belongs to Renesas' legacy QuickSwitch® bus switch product line, originally developed by IDT to address high-speed, low-latency digital signal isolation in mixed-voltage computing and communications platforms.
FAQ
What is the maximum allowable voltage on QS3861QG I/O pins?
The QS3861QG specifies an absolute maximum DC input voltage of –0.5 V to +7 V on all A, B, and BE pins. This range accommodates transient undershoot down to –3 V (per AC rating) and supports operation across 3.3 V, 5 V, and mixed-supply interfaces without external clamping. Exceeding these limits risks permanent damage.
Does QS3861QG support level shifting between 5V and 3.3V buses?
Yes, QS3861QG enables passive voltage translation: when A-side is driven by 5 V logic and B-side connects to a 3.3 V-tolerant receiver, the 5 Ω RON ensures signal pass-through without level conversion circuitry. However, the device itself does not regulate or shift voltages - compatibility depends on receiver input thresholds and bus termination.
What is the function of the NC pin on QS3861QG?
Pin 24 of the QS3861QG is marked NC (No Connect) and is internally unconnected. It must remain unpopulated or be tied to GND for mechanical stability; connecting it to VCC or driving it may cause undefined behavior. This pin has no electrical function in the QS3861QG die.
How does QS3861QG achieve zero propagation delay?
QS3861QG achieves zero intrinsic propagation delay because its FET switches introduce only RC delay - typically ~0.25 ns at 50 pF load - which is negligible compared to driver rise/fall times. The datasheet confirms no added delay beyond external circuit effects, making QS3861QG ideal for timing-critical clock and data paths.
Is QS3861QG pin-compatible with other QuickSwitch devices?
QS3861QG shares the same 24-pin QSOP flow-through pinout with QS3861PAG (TSSOP) and earlier IDT QS3861 variants, but is not pin-compatible with non-3861 family members like QS3257 or QS3253 due to differing channel count and control architecture. Always verify pin mapping against the specific variant's datasheet.
QS3861QG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 24-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Bus Switch
- Circuit:
- 10 x 1:1
- 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:
- 24-QSOP
QS3861QG FAQ
1.How can I place an order for QS3861QG through Aetrix?
Please submit a Request for Quotation (RFQ) for QS3861QG 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 QS3861QG reliable?
The price and inventory of QS3861QG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for QS3861QG is usually 5 days.
3.What payment methods are accepted for QS3861QG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for QS3861QG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for QS3861QG?
QS3861QG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your QS3861QG 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 QS3861QG?
For technical support, including QS3861QG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your QS3861QG requirements.
6.How does Aetrix verify that QS3861QG is sourced from the original manufacturer or authorized distributors?
All QS3861QG 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 QS3861QG meets industry standards.
7.What is the process for return or replacement of QS3861QG?
All QS3861QG units undergo pre-shipment inspection (PSI). If there is an issue with QS3861QG, 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 QS3861QG part is unused and in its original packaging.
Return procedure for QS3861QG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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