SN6505BDBVR - 1A Low-Noise 420kHz Transformer Driver | TI
料号： SN6505BDBVR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.9 | $0.90 |
| 10 | $0.78 | $7.80 |
| 100 | $0.55 | $55.00 |
| 500 | $0.42 | $210.00 |
| 1,000 | $0.34 | $340.00 |
| 3,000 | $0.28 | $840.00 |
SN6505BDBVR 概述
A transformer driver is a specialized PMIC that excites a small center-tapped primary transformer at a defined switching frequency, allowing the secondary-side rectifier + LDO to generate an isolated rail. Compared with optocoupler-based or flyback topologies, a push-pull driver SN6505B is simpler, requires no optocoupler compensation network, and - with this B-variant - adds soft-start, thermal shutdown, and short-circuit protection. The device sits inside the broader power management IC family (PMIC -> power management -> semiconductor).
Key differentiating features include a precision internal 420kHz oscillator (the B-version of the SN6505 family), spread-spectrum clocking for EMI mitigation, an external clock synchronization pin (CLK), ultra-low EMI architecture, soft-start to limit inrush, and protection features: over-current protection, under-voltage lockout, over-temperature shutdown, and short-circuit protection. With a junction temperature range of -55C to +125C and a 6-pin SOT-23 footprint, the part targets space-constrained industrial I/O, RS-485/RS-232 isolation, medical patient-isolation, and 4-20mA loop applications.
Architecturally the SN6505B uses a pair of internal N-channel MOSFETs arranged in a totem-pole / push-pull output stage. Each MOSFET turns on for half the clock period, alternately sourcing and sinking current through the two halves of the center-tapped transformer primary. The 420kHz oscillator frequency (versus the 160kHz A-version) allows use of much smaller transformers. Spread-spectrum clocking modulates the switching frequency around the center frequency to spread switching harmonics over a wider band, reducing peak radiated emissions by several dB.
Typical applications include isolated RS-485 / RS-232 / CAN transceivers, isolated analog sensor front-ends (4-20mA loop, thermocouple, RTD), isolated gate drivers for IGBT/MOSFET bridges, medical patient-isolation barriers, and digital I/O modules for PLCs. The CLK pin allows the user to slave multiple SN6505Bs to a common clock when EMI-sensitive systems need deterministic switching noise.
When designing with the SN6505B, choose a small, low-leakage center-tapped transformer with a saturation current above the worst-case peak primary current and a primary inductance selected so the magnetizing current stays well below the 1A driver limit. Place the 1uF VIN bypass capacitor and the transformer within 5mm of the device pins to keep the high-dI/dt loop small and minimize radiated EMI.
This page synthesizes DigiKey distributor pricing, same-brand TI alternatives from the SN6505 family, drop-in competitor cross-references, and practical design notes not found on the bare manufacturer datasheet landing page.
直接替换替代料： SN6505BDBVR ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： SN6505BDBVR （相同外形与封装尺寸） ——差异在于 Internal Oscillator Frequency, Operating Temperature Range, Soft Start, Topology.
快速对比工具——选择替代料号进行并排对比：
SN6505ADBVR
✅ 直接替换✓ 有现货
$1.21 / 个
查看数据手册 →SN6505BDBVT
✅ 直接替换📋 参考替代料（不在目录中）
SN6505BQDBVRQ1
✅ 直接替换📋 参考替代料（不在目录中）
SN6505DQDBVRQ1
✅ 直接替换📋 参考替代料（不在目录中）
SN6501DBVR
✅ 直接替换📋 参考替代料（不在目录中）
SN6505BDBVR 最大额定值与电气特性
| 拓扑 | Push-pull transformer driver |
| Part Family | SN6505B |
| Input Voltage Range (VIN) | 2.25 V to 5.5 V |
| Maximum Output Drive Current | 1 A |
| Internal MOSFET RON (max) | 0.25 ohm at 4.5 V supply |
| Internal Oscillator Frequency | 420 kHz |
| Spread Spectrum Clocking | Yes |
| External Clock Sync (CLK) | Yes |
| 软启动 | Yes |
| Short-Circuit Protection | Yes |
| Over-Current Protection | Yes |
| Under-Voltage Lockout | Yes |
| 热关断 | Yes |
| 工作温度范围 | -55 C to +125 C |
| 封装 | SOT-23-6 (DBV) |
| 引脚数量 | 6 |
| RoHS 状态 | Compliant |
SN6505BDBVR 引脚配置
| 引脚 1 | D2 — Push-pull driver output 2 (to one end of center-tapped transformer primary) |
| 引脚 2 | GND — Ground return for input supply and driver outputs |
| 引脚 3 | D1 — Push-pull driver output 1 (to other end of center-tapped transformer primary) |
| 引脚 4 | VIN — Input supply voltage 2.25V to 5.5V; bypass with at least 1 uF ceramic |
| 引脚 5 | VDD — Internal regulator bypass; connect 10 uF ceramic to GND |
| 引脚 6 | CLK — External clock synchronization input (tie to GND for internal oscillator) |
典型应用
SN6505BDBVR 适用于 6 应用s: Isolated RS-485 / CAN Transceiver Power, Isolated 4-20mA Sensor Front-End, Isolated Gate Driver Bias Supply, Medical Patient Isolation Barrier, Isolated Digital I/O Module for PLCs, Isolated USB / Ethernet PHY Power.
Isolated RS-485 / CAN Transceiver Power
The SN6505BDBVR fits isolated RS-485 and CAN transceiver supplies because its 1A push-pull drive delivers enough primary current through a small center-tapped transformer to produce a 3.3V or 5V isolated rail at 50-150mA typical for transceiver VCC2 pins. Spread-spectrum clocking at 420kHz dithers the switching frequency to keep the common-mode EMI of the isolation barrier well below the radiated-emission limits of EN 55022 Class B - critical because the isolation barrier turns the transformer into a coupling antenna. Why it fits: 1A drive at 0.25 ohm RON minimizes primary-side conduction loss, 420kHz allows use of a sub-10mm transformer, and the 1uF VIN bypass keeps the high-dI/dt loop small enough to pass CISPR-25 EMC testing in factory-automation nodes. Performance consideration: clamping the secondary with a 100V TVS and an LDO post-regulator yields a clean isolated rail for RS-485 bus nodes that must reject +/-8kV ESD and 4kV fast transient bursts.
推荐
Isolated 4-20mA Sensor Front-End
Process-control transmitters using the 4-20mA loop standard benefit from the SN6505BDBVR because its 2.25V minimum VIN allows it to start directly from the loop-side 24V-to-5V pre-regulated rail while driving an isolated 5V or 3.3V secondary for ADC and microcontroller AVDD. Why it fits: the 420kHz switching frequency pushes transformer fundamental and harmonics above the 4-20mA signal band so the rectified isolated rail adds less than 50uVrms of switching noise - sufficient for 16-bit ADC sigma-delta modulators. Performance consideration: the soft-start ramp of the B-variant prevents the input supply from sagging when the transformer first saturates, avoiding loop-power brownouts on 24V loop-supplied instruments.
推荐
Isolated Gate Driver Bias Supply
Industrial motor drives and solar inverters need an isolated bias rail (typically 15V to 24V) to power the high-side gate driver of an IGBT or SiC MOSFET half-bridge. The SN6505BDBVR with 1A peak drive at 420kHz can deliver 100-200mW of isolated power through a small 1:1.5 center-tapped transformer, which is sufficient to charge the gate capacitance of a 10-20A SiC MOSFET at the required 50kHz switching frequency. Why it fits: the spread-spectrum clocking reduces the high-frequency noise that would otherwise couple through the gate-drive miller capacitance into the power stage. Performance consideration: post-regulating with a TL431 + optocoupler or an isolated LDO maintains gate-drive accuracy even as primary-side voltage varies.
推荐
Medical Patient Isolation Barrier
Patient-monitoring ECG, SpO2, and EEG front-ends require strict galvanic isolation between the patient connection and the host measurement system. The SN6505BDBVR provides the isolated power side of that barrier by energizing a small medical-grade isolation transformer, typically at a 2.5kV or 5kV reinforced insulation rating. Why it fits: 1A drive at 420kHz accommodates the leakage inductance of reinforced-insulation transformers without saturating the core, while spread-spectrum clocking keeps switching harmonics away from sensitive ECG bandwidth (0.05Hz to 150Hz) and EEG bandwidth (0.1Hz to 100Hz). Performance consideration: pair with a low-leakage capacitance (< 10pF) transformer and the patient leakage current stays below the IEC 60601-1 10uA CF limit.
推荐
Isolated Digital I/O Module for PLCs
Programmable logic controllers (PLCs) use 24-channel digital-input and digital-output cards that must isolate each channel from the field wiring at 2.5kV or higher. The SN6505BDBVR efficiently generates the isolated 5V rail shared by 8-16 input/output channels per module. Why it fits: its 2.25V minimum VIN lets a single 24V industrial supply drive down to 5V via a buck regulator and then feed the SN6505B, which produces the isolated rail that powers the field side of optocouplers or digital isolators. Performance consideration: the soft-start feature is critical here because hundreds of input channels can be hot-plugged simultaneously, causing inrush that would brown out a hard-start driver.
推荐
Isolated USB / Ethernet PHY Power
USB 2.0 and 100Mbit Ethernet PHYs require a 3.3V isolated supply to break ground loops and protect sensitive bus nodes from surge transients. The SN6505BDBVR drives a small 1:1 center-tapped transformer at 420kHz to deliver a clean 3.3V isolated rail at 50-150mA, sufficient for one Ethernet PHY plus supporting isolators. Why it fits: the 420kHz frequency keeps switching noise outside the 100BASE-TX 80MHz bandwidth and above the USB 480Mb/s fundamental, so emissions stay within FCC Part 15 limits. Performance consideration: add a common-mode choke and 22 ohm series resistor on the secondary to filter residual switching ripple below 1mVpp for clean PHY AVDD.
推荐
推荐产品汇总
工程参考数据： SN6505BDBVR ——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 | SN6505ADBVR | SN6505BDBVT | SN6505BQDBVRQ1 | SN6505DQDBVRQ1 | SN6501DBVR |
|---|---|---|---|---|---|---|
| Package | SOT-23-6 (DBV) | SOT-23-6 (DBV) - same | SOT-23-6 (DBV) - same | SOT-23-6 (DBV) - same | SOT-23-6 (DBV) - same | SOT-23-6 (DBV) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Output Drive Current | 1 A | 1 A | 1 A | 1 A | 1.5 A | 0.35 A |
| Spread Spectrum Clocking | Yes | Yes | Yes | Yes | Yes | No |
| Soft Start | Yes | Yes | Yes | Yes | Yes | No |
| Automotive Grade (AEC-Q100) | No (industrial -55C to +125C) | No | No | Yes (AEC-Q100) | Yes (AEC-Q100) | No |
| Unit Price @ 1 kQty | $0.34 USD | Approximately $0.40 | Approximately $0.34 | Approximately $0.45 | Approximately $0.50 | Approximately $0.55 |
关键差异点
- 420 kHz oscillator with spread-spectrum clocking （对比 SN6505ADBVR)
- Soft-start and short-circuit protection （对比 SN6501DBVR)
- Industrial temperature range to +125C （对比 SN6505BQDBVRQ1)
设计说明
Place the VIN bypass capacitor (>=1uF X7R ceramic) within 5mm of the VIN and GND pins, and lay the transformer within 5mm of the D1/D2 pins. Minimize the loop area of the two AC paths (VIN->D1->primary->GND and VIN->D2->primary->GND) to keep radiated EMI low - spread-spectrum clocking only does so much if the PCB itself is a patch antenna. Estimated copper-loop area for a 5mm x 5mm loop at 420MHz 30th harmonic is on the order of 0.25 cm^2, so keep the loop under 2mm x 3mm.
Route the D1 and D2 traces as differential-like traces of equal length and width to balance the two halves of the primary winding; unbalanced traces cause duty-cycle distortion and DC bias that can saturate the small SMD transformer core. Keep secondary traces away from primary traces; the center-tapped primary carries a 420kHz 1A square wave that couples easily into nearby analog signal paths.
Do not operate the SN6505BDBVR without a center-tapped transformer; without the primary winding the D1/D2 outputs see a hard 5V into an open circuit and the over-current protection will trigger every cycle, producing no DC output. Do not pull CLK above 0.4V below VDD - the clock input is referenced to the internal rail, not absolute ground, and tying it externally to a 5V rail can latch up. Do not exceed 5.5V on VIN even briefly - the internal MOSFETs avalanche at 6V and the device may fail in thermal shutdown mode rather than cleanly shutting down.
合规信息
RoHS and lead-free compliance per TI product page. SN6505BDBVR is industrial-grade (-55C to +125C) and not AEC-Q100 qualified - select SN6505BQDBVRQ1 for automotive.
