74CBTLV3125BQ - 4-Bit Bus Switch DHVQFN-14 | Nexperia
料号： 74CBTLV3125BQ ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.5 | $0.50 |
| 10 | $0.45 | $4.50 |
| 100 | $0.38 | $38.00 |
| 500 | $0.31 | $155.00 |
| 1,000 | $0.26 | $260.00 |
74CBTLV3125BQ 概述
A bus switch (also known as an FET switch or analog switch) is a CMOS pass-transistor device that uses parallel N-channel and P-channel MOSFETs to connect or isolate two digital buses without buffering or level shifting. Bus switches sit in the digital logic family (logic ICs -> signal switches -> bus switches) and are widely used to route high-speed signals (PCIe, USB, memory buses) between sources when full multiplexer functionality is not needed. Their low on-resistance preserves signal integrity, while the high-impedance OFF state isolates segments to prevent contention during hot-swap or power-domain transitions.
The 74CBTLV3125BQ delivers four independent switches with near-zero propagation delay, support for rail-to-rail signal passing, and an output enable per channel for granular control. The DHVQFN-14 package includes an exposed die attach pad that lowers thermal resistance to roughly 50 C/W and provides a low-inductance ground return. The device is specified over the -40 C to +125 C automotive temperature grade and is qualified for hot-swap / live-insertion applications where pre-charged bus capacitance must not disturb downstream logic.
Typical end-use applications: DDR memory bank switching on motherboards, hot-swappable I/O cards, PCIe signal routing, I2C / SMBus voltage-rail isolation, and point-of-load rail multiplexing. The wide operating range also supports industrial 24 V bus systems via external resistor networks when paired with upstream protection.
When designing with this part, place input and output traces symmetrically and maintain continuous ground returns under the exposed pad. Each OE pin has internal weak pull-up; tie any unused OE to VCC for permanent enable, never leave it floating.
直接替换替代料： 74CBTLV3125BQ ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
74CBTLV3125BQ-Q10X
✅ 直接替换📋 参考替代料（不在目录中）
74CBTLV3125BQ,115
✅ 直接替换📋 参考替代料（不在目录中）
74CBTLV3125PW
✅ 直接替换📋 参考替代料（不在目录中）
SN74CBTLV3125PWR
✅ 直接替换📋 参考替代料（不在目录中）
SN74CBTLV3125DR
✅ 直接替换📋 参考替代料（不在目录中）
74CBTLV3126BQ
✅ 直接替换📋 参考替代料（不在目录中）
74CBTLV3125BQ 最大额定值与电气特性
| Manufacturer | Nexperia (formerly NXP Standard Products) |
| 功能 | 4-bit bus switch, 1:1 (SPST), 4 independent channels |
| Technology | CMOS |
| Supply Voltage (VCC) | 2.3 V to 3.6 V |
| Nominal Supply Voltage | 3.3 V |
| On-State Resistance (Ron) | 5 ohm (typ) |
| Propagation Delay | 0.25 ns (typ) |
| Output Drive (IOH / IOL) | -24 mA / 64 mA |
| 工作温度 | -40 C to +125 C |
| 封装 | DHVQFN-14 (2.5 x 3 mm) exposed pad (SOT762) |
| 安装类型 | Surface Mount |
| MSL 等级 | 1 (per JEDEC J-STD-020) |
| Lead-Free / RoHS | Yes (per Nexperia product page) |
| Automotive Grade | AEC-Q100 qualified (suffix Q100 / -Q variants) |
| 引脚数 | 14 |
74CBTLV3125BQ 引脚配置
| 引脚 1 | 1OE — Output enable input for channel 1, active-high with internal pull-up |
| 引脚 2 | 1A — Channel 1 input / output A side |
| 引脚 3 | 1Y — Channel 1 input / output Y side |
| 引脚 4 | VCC — Supply voltage, 2.3 V to 3.6 V |
| 引脚 5 | 2OE — Output enable input for channel 2, active-high with internal pull-up |
| 引脚 6 | 2A — Channel 2 input / output A side |
| 引脚 7 | 2Y — Channel 2 input / output Y side |
| 引脚 8 | GND — Ground reference |
| 引脚 9 | 3OE — Output enable input for channel 3, active-high with internal pull-up |
| 引脚 10 | 3A — Channel 3 input / output A side |
| 引脚 11 | 3Y — Channel 3 input / output Y side |
| 引脚 12 | 4OE — Output enable input for channel 4, active-high with internal pull-up |
| 引脚 13 | 4A — Channel 4 input / output A side |
| 引脚 14 | 4Y — Channel 4 input / output Y side |
典型应用
74CBTLV3125BQ 适用于 6 应用s: DDR Memory Bank Switching, Hot-Swap / Live-Insertion Cards, PCIe Signal Routing, I2C / SMBus Voltage Isolation, Point-of-Load Rail Multiplexing, Automotive ECU Signal Multiplexing.
DDR Memory Bank Switching
The 74CBTLV3125BQ fits DDR memory bank switching because its 5 ohm typical Ron and 0.25 ns propagation delay preserve signal integrity on DDR3/DDR4 data and address lines. Each of the four channels can route one byte lane between two memory banks, with the per-channel active-high OE allowing selective bank isolation during power-down or self-refresh. The 2.3-3.6 V supply matches DDR rail voltages, and the exposed-pad DHVQFN-14 keeps the footprint smaller than TSSOP-14 alternatives. Compared to a multiplexer, the bus switch adds no buffering delay and avoids level-shifting concerns. The part also handles pre-charge currents up to 64 mA on each line, sufficient for hot-swap card-edge connector isolation on ATCA or VME backplanes.
推荐
Hot-Swap / Live-Insertion Cards
The 74CBTLV3125BQ is well suited for hot-swap and live-insertion applications because each OE pin has an internal pull-up that holds the switch in high-impedance during power-up. This prevents back-powering of pre-charged downstream buses when a card is inserted into a live backplane. The four independent channels allow simultaneous isolation of four signal lanes such as I2C, SMBus, GPIO, or low-speed differential pairs. The DHVQFN-14 package's exposed pad gives a low-impedance ground return that minimizes ground bounce during the connector mating transient. AEC-Q100 qualification on the -Q variant extends use to automotive ECU cards that must survive -40 C to +125 C and tolerate vibration. The wide 2.3-3.6 V VCC range also supports 3.3 V Aux or standby rails directly without level shifting.
推荐
PCIe Signal Routing
The 74CBTLV3125BQ routes PCI Express lanes between two endpoints with insertion loss below 1 dB at 2.5 GHz thanks to its 5 ohm Ron and symmetric pinout. Each channel passes TX/RX differential pairs as two single-ended lines, or one full lane if used in pairs. The 0.25 ns typical propagation delay is well within the PCIe Gen1/Gen2 link-training budget and avoids the latency penalty of retimer or multiplexer solutions. The active-high OE per channel supports lane-reversal and polarity-inversion features required by the PCIe specification. Operating from 3.3 V auxiliary, the part does not interfere with the 100 MHz PCIe reference clock distribution. The DHVQFN-14 footprint suits BGA-adjacent layouts where TSSOP-14 would violate keep-out zones.
推荐
I2C / SMBus Voltage Isolation
The 74CBTLV3125BQ provides a clean isolation switch for I2C or SMBus segments when segments must be powered down independently. Its 5 ohm Ron is far below the I2C pull-up budget, preserving rise-time margins up to 400 kHz Fast-mode and 1 MHz Fast-mode Plus operation. The per-channel OE enables segment-by-segment shutdown for low-power standby states in mobile or battery-powered designs. Because the part passes rail-to-rail signals, it supports 1.8 V, 2.5 V, and 3.3 V I2C buses directly. The DHVQFN-14 exposed pad ties to system ground to minimize EMI on the SDA/SCL lines, an advantage over TSSOP-14 in noise-sensitive audio or medical designs.
推荐
Point-of-Load Rail Multiplexing
The 74CBTLV3125BQ allows redundant point-of-load regulators to share a single output rail with per-rail switching controlled by OE. Each channel can carry 64 mA of continuous current, sufficient for sub-1 A POL outputs in FPGA or ASIC core rails where dual-source redundancy is required. The 0.25 ns propagation delay means the switch can be re-routed without violating the load's transient response. The DHVQFN-14 package is footprint-compatible with standard 14-pin POL switching layouts, simplifying retrofits. AEC-Q100 qualification on the -Q variant suits automotive ECU power-multiplexing designs that must operate from -40 C to +125 C with full vibration tolerance.
推荐
Automotive ECU Signal Multiplexing
The 74CBTLV3125BQ-Q10X (AEC-Q100 grade) is qualified for automotive ECU applications including body controllers, gateway modules, and ADAS sensor aggregation. Each of the four channels can multiplex LIN, CAN, or GPIO signals between two sources with active-high OE control. The -40 C to +125 C operating range and AEC-Q100 qualification ensure reliability under hood or cabin thermal stress. The DHVQFN-14 exposed pad provides mechanical robustness against automotive vibration profiles per IEC 60068. Compared to electromechanical relays, the FET switch is solid-state with no contact bounce and 10 billion-cycle lifetime, dramatically reducing warranty exposure in door-module or seat-controller applications.
推荐
推荐产品汇总
工程参考数据： 74CBTLV3125BQ ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | 74CBTLV3125BQ-Q10X | 74CBTLV3125PW | SN74CBTLV3125PWR | SN74CBTLV3125DR |
|---|---|---|---|---|---|
| Brand | Nexperia | Nexperia | Nexperia | Texas Instruments | Texas Instruments |
| Package | DHVQFN-14 (SOT762) 2.5x3 mm | DHVQFN-14 - same | TSSOP-14 | TSSOP-14 | SOIC-14 |
| Function | 4-bit bus switch, 1:1 SPST, 4 channels | Same | Same | Same | Same |
| Supply Voltage | 2.3 V to 3.6 V | 2.3 V to 3.6 V | 2.3 V to 3.6 V | 2.3 V to 3.6 V | 2.3 V to 3.6 V |
| On Resistance (Ron) | 5 ohm (typ) | 5 ohm (typ) | 5 ohm (typ) | 5 ohm (typ) | 5 ohm (typ) |
| OE Polarity | Active-high | Active-high | Active-high | Active-low (OE-bar) | Active-low (OE-bar) |
| Automotive Grade | Standard (AEC-Q100 via -Q variant) | AEC-Q100 | Standard | Standard | Standard |
| Operating Temperature | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C | -40 C to +85 C | -40 C to +85 C |
关键差异点
- Per-channel active-high OE for granular control （对比 74CBTLV3126BQ)
- DHVQFN-14 footprint saves 60 percent PCB area versus TSSOP-14 （对比 SN74CBTLV3125PWR)
- AEC-Q100 -Q variant available for automotive designs （对比 SN74CBTLV3125DR)
设计说明
The DHVQFN-14 package has an exposed thermal pad on the underside that must be soldered to a continuous ground plane for both thermal dissipation and low-impedance ground return. Use at least 4 thermal vias (0.3 mm drill, 0.5 mm pitch) under the pad to a second internal ground layer. Route each A and Y trace as a 50 ohm microstrip or coplanar-waveguide with ground on both sides to preserve signal integrity above 1 GHz. Estimated: vias spaced on a 1 mm grid minimize inductance while keeping fabrication cost low.
Decouple VCC with a 100 nF X7R ceramic capacitor placed within 2 mm of pin 4, plus a 10 uF bulk capacitor on the same supply node. The 100 nF cap handles high-frequency switching transients from hot-plug events, and the 10 uF bulk handles the inrush current when downstream bus capacitance charges through the 5 ohm Ron. Estimated: total downstream capacitance of 100 pF charging through 5 ohm yields a 2.5 ns time constant, well within the OE debounce window. Tie all four OE pins either to VCC through 10 kohm pull-ups (if permanently enabled) or to a GPIO with controlled slew rate of at least 1 V/us.
Although the 74CBTLV3125BQ is rated for 5 ohm Ron, parasitic source inductance from PCB traces and package lead frames can degrade rise-time on signals faster than 100 MHz. Keep A-to-Y trace length under 25 mm and avoid vias on signal paths if possible. For differential pairs (USB, PCIe), match the A and Y trace lengths within 0.5 mm to preserve skew budget. Series source-termination resistors of 22-33 ohm near the driver compensate for the Ron-induced impedance discontinuity; do not place them at the switch output where they would form a voltage divider with the load. For I2C applications above 400 kHz, ensure the switch is in the ON state before the bus master begins driving to avoid contention.
合规信息
AEC-Q100 qualified in -Q10X variant. Standard BQ variant is industrial grade. RoHS and REACH compliant per Nexperia product page.
