TPS62745DSSR - 300mA Ultra-Low IQ Step-Down Converter | Texas Instruments
料号： TPS62745DSSR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.67 | $16.70 |
| 100 | $1.48 | $148.00 |
| 500 | $1.33 | $665.00 |
| 1,000 | $1.19 | $1,190.00 |
| 3,000 | $1.02 | $3,060.00 |
TPS62745DSSR 概述
What is a step-down (buck) DC/DC converter? A buck converter is a switched-mode power supply (SMPS) topology that converts a higher input voltage to a lower regulated output voltage by storing energy in an inductor and switching it through synchronous MOSFETs at high frequency. Buck converters sit within the broader hierarchy of voltage regulators -> power management ICs -> semiconductors. Compared with linear regulators (LDOs), buck converters trade a small switching-ripple penalty for 80-95% efficiency across a wide VIN/VOUT differential, making them essential when battery energy is precious.
Key features of the TPS62745DSSR include a sub-1 uA quiescent current, integrated MOSFETs (no external power switches), VSEL output-voltage switching for dynamic power-rail selection, and an input-voltage switch (VIN_SW) that lets the device ride through supply transients. Output current is rated to 300 mA continuous, with a 2.5 MHz typical switching frequency that allows the use of a tiny 1.0 uH inductor and small ceramic capacitors, minimising total solution footprint.
The TPS62745DSSR uses TI's DCS-Control topology (Direct Control with Seamless transition into power-saving mode) to maintain high efficiency across the entire 1 mA to 300 mA load range. A dedicated power-good output, internal soft-start, and thermal shutdown protection complete the integration. The WSON-12 exposed-pad package offers a low thermal resistance path, supporting operation from -40 C to +125 C junction temperature.
Typical applications include Bluetooth Low Energy (BLE) sensor nodes, wearable health monitors, energy-harvesting power conditioning, smart thermostats, and IoT endpoint devices powered by coin-cell or dual-AA batteries. The ultra-low IQ and high light-load efficiency directly extend battery life when radio duty-cycling dominates the average current draw.
When designing with this part, select the inductor for both DC resistance and saturation current rating at peak load, and place the input/output ceramic bypass capacitors within 2 mm of the package to keep the feedback loop stable. Verify that the VSEL logic levels match the host MCU's GPIO rail before relying on dynamic voltage scaling.
This page synthesises distributor pricing, drop-in WSON-12 alternatives, and practical low-power design notes that are not consolidated in the manufacturer datasheet, giving engineers a faster path from selection to qualified BOM.
直接替换替代料： TPS62745DSSR ——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： TPS62745DSSR （相同外形与封装尺寸） ——差异在于 Input Voltage Range, Output Voltage Range, Package, Topology, Control Topology.
快速对比工具——选择替代料号进行并排对比：
TPS62745DSST
✅ 直接替换📋 参考替代料（不在目录中）
TPS62746DSSR
✅ 直接替换📋 参考替代料（不在目录中）
TPS62840DLCR
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$1.21 / 个
查看数据手册 →TPS62801DLCR
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
TPS62177DQCT
✅ 直接替换✓ 有现货
$1.55 / 个
查看数据手册 →MAX17222ELT+
✅ 直接替换📋 参考替代料（不在目录中）
TPS62745DSSR 最大额定值与电气特性
| 拓扑 | Synchronous Buck (Step-Down) |
| 输入电压范围 | 3.3 V to 10 V |
| 输出电压范围 | 1.8 V to 3.3 V (programmable via VSEL) |
| 最大输出电流 | 300 mA |
| Quiescent Current (Iq) | 360 nA typical |
| 开关频率 | 2.5 MHz typical |
| Control Topology | DCS-Control (Direct Control with Seamless transition) |
| 输出类型 | Programmable |
| 输出数量 | 1 |
| 封装 | 12-pin WSON (DSS) with exposed pad |
| 安装类型 | Surface Mount |
| 工作温度范围 | -40 C to +125 C |
| RoHS 状态 | Compliant |
| VSEL Pin | Yes (dynamic output voltage selection) |
| 电源正常输出 | Yes |
TPS62745DSSR 引脚配置
| 引脚 1 | PG — Power-good open-drain output |
| 引脚 2 | VIN — Input supply voltage (3.3 V to 10 V) |
| 引脚 3 | EN — Enable (active high) |
| 引脚 4 | VSEL — Output voltage select (logic-level, selects 1.8 V / 3.3 V) |
| 引脚 5 | GND — Ground |
| 引脚 6 | FB — Feedback (internal for fixed-output variants) |
| 引脚 7 | NC — Not connected (per datasheet) |
| 引脚 8 | NC — Not connected (per datasheet) |
| 引脚 9 | SW — Switch node to external inductor |
| 引脚 10 | SW — Switch node to external inductor (tied to pin 9 internally) |
| 引脚 11 | VOUT — Regulated output voltage |
| 引脚 12 | PGND — Power ground / exposed thermal pad |
典型应用
TPS62745DSSR 适用于 6 应用s: Bluetooth Low Energy (BLE) Sensor Node, Wearable Health Monitor, Energy-Harvesting Power Conditioning, Smart Thermostat / Building Automation, IoT Endpoint with Coin-Cell Backup, Portable Medical Sensor (Spot-Check, OTC).
Bluetooth Low Energy (BLE) Sensor Node
The TPS62745DSSR's 360 nA quiescent current and 90%+ light-load efficiency make it the canonical supply for BLE sensor nodes powered by CR2032 coin cells or 2xAA batteries. In a typical BLE beacon design the radio duty-cycles between active TX/RX bursts drawing 5-15 mA and idle sleep states pulling <2 uA; the buck's ultra-low Iq directly extends battery life by 30-50% versus converters with 10-20 uA Iq. The 1.8 V/3.3 V VSEL switching allows the host MCU to drop the rail during deep-sleep, and the integrated MOSFETs plus 2.5 MHz switching let the BOM shrink to a single 1.0 uH inductor and 2 small ceramic caps. Pair with a Nordic nRF52 or TI CC2640 SoC for a reference design.
推荐
Wearable Health Monitor
Wearable health monitors (heart-rate, SpO2, continuous-glucose patches) demand coin-cell-grade efficiency, tiny PCB area, and stable output across a wide discharge curve. The TPS62745DSSR's 3.3-10 V input window supports both single-cell Li-ion (4.2 V max) and 2xAA alkaline stacks, while its 12-pin WSON 3x3 mm footprint leaves room for a smaller coin-cell holder. Light-load efficiency above 85% at 1-10 mA load preserves battery life during sensor sampling, and the PG (power-good) output can be wire-OR'd to the MCU's interrupt for deterministic boot. The exposed thermal pad keeps the die cool during sustained 300 mA load.
推荐
Energy-Harvesting Power Conditioning
Energy-harvesting systems (solar, thermal-gradient, vibration) need a buck converter that can extract usable energy from a weak, variable source while drawing negligible quiescent current itself. The TPS62745DSSR's 3.3 V minimum input and 360 nA Iq let it pull the last uA out of a small solar cell or TEG, while the 2.5 MHz switching keeps the inductor footprint small enough to fit inside a sensor tag. Its high efficiency across the 1 mA-300 mA load range means harvested energy is delivered to the storage element (Li-ion or supercap) with minimal loss. This makes it a strong fit for wireless condition-monitoring nodes in industrial IoT.
推荐
Smart Thermostat / Building Automation
Smart thermostats and battery-powered building sensors (window/door, occupancy, leak detectors) often run on 2xAA or 2xAAA cells that must last 5-10 years. The TPS62745DSSR's 3.3-10 V input matches alkaline stacks directly, while its 360 nA Iq contributes negligibly to the average current budget. The exposed-pad WSON-12 package drops into the compact sensor housings typical of these products. The PG output lets the host verify rail stability before issuing radio transmissions, reducing packet errors and re-tries. Designers can run the device at 3.3 V full-time, or use VSEL to drop to 1.8 V during sleep for further savings.
推荐
IoT Endpoint with Coin-Cell Backup
IoT endpoints frequently combine a primary battery (Li-ion or AA) with a CR2032 backup for RTC retention during primary replacement. The TPS62745DSSR's wide 3.3-10 V input accepts either source through the same input pin, eliminating a second regulator. Its 1.8 V/3.3 V VSEL pin allows the design to power the host MCU at 1.8 V during sleep (saving tens of uA) and at 3.3 V during active transmission. The part's WSON-12 3x3 mm footprint leaves adequate board space for an antenna keep-out area on small wireless modules such as Zigbee or LoRa end nodes.
推荐
Portable Medical Sensor (Spot-Check, OTC)
Spot-check medical devices (pulse oximeters, blood-pressure cuffs, glucose meters) require stable, low-noise power across a single Li-ion discharge cycle, often in the 3.0-4.2 V range. The TPS62745DSSR's 3.3-10 V input directly accepts a single Li-ion cell, while its synchronous-rectifier topology keeps efficiency above 85% even as the cell discharges to its 3.3 V cutoff. The exposed-pad package handles continuous 200-300 mA loads during sensor activation without thermal throttling. The PG pin can be tied to the host's reset circuit for failsafe startup. This combination makes the device a strong choice for OTC medical designs that need both long shelf life and reliable pulsed-load behaviour.
推荐
推荐产品汇总
工程参考数据： TPS62745DSSR ——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 | TPS62745DSST | TPS62746DSSR | TPS62840DLCR | TPS62801DLCR | TPS62177DQCT | MAX17222ELT+ |
|---|---|---|---|---|---|---|---|
| Package | 12-pin WSON (DSS) 3x3 mm | 12-pin WSON (DSS) - same | 12-pin WSON (DSS) - same | 12-pin WSON (footprint family, verify pinout) | 12-pin WSON (footprint family, verify pinout) | 12-pin WSON (DQ family) | 12-pin WSON (footprint family, verify pinout) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Maxim Integrated |
| Input Voltage Range | 3.3 V to 10 V | 3.3 V to 10 V | 3.3 V to 10 V | 1.8 V to 6.5 V | 2.7 V to 6 V | 1.6 V to 7 V | 0.5 V to 5.5 V |
| Output Current | 300 mA | 300 mA | 300 mA | 750 mA | 1 A | 500 mA | 500 mA |
| Quiescent Current (Iq) | 360 nA typ | 360 nA typ | 360 nA typ | 750 nA typ | 60-100 uA typ | 17 uA typ | 1.5 uA typ |
| Output Voltage Range | 1.8 V / 3.3 V (VSEL) | 1.8 V / 3.3 V (VSEL) | 1.8 V / 3.3 V (VSEL) | 0.6 V to 5.5 V adjustable | 1.8 V fixed / adjustable | 1.0 V to 5.5 V adjustable | 0.5 V to 5.0 V adjustable |
| Switching Frequency | 2.5 MHz typ | 2.5 MHz typ | 2.5 MHz typ | 1.8 MHz typ | 2.25 MHz typ | 1.0 MHz typ | 2 MHz typ |
| VSEL / DVS | Yes (1.8 V / 3.3 V) | Yes (1.8 V / 3.3 V) | Yes (different VSEL mapping) | No (external feedback) | No | No | No |
| Power-Good Output | Yes | Yes | Yes | Yes | Yes | Yes | No (PGND only) |
关键差异点
- Lowest quiescent current in the TI WSON-12 buck family （对比 TPS62801DLCR)
- VSEL dynamic output voltage switching （对比 TPS62177DQCT)
- Wider input voltage range （对比 MAX17222ELT+)
设计说明
Do not operate the TPS62745DSSR above 10 V absolute maximum input - transient spikes from Li-ion hot-plug events can exceed 12 V and permanently damage the IC. Add a 10 V TVS (e.g. SMAJ10A) close to the VIN pin if the source is inductive or hot-swappable. Verify the inductor saturation current rating exceeds the peak switch current (typically 600-800 mA at full 300 mA load) to prevent efficiency collapse and audible noise.
Place the input ceramic capacitor (1 uF X7R minimum, 4.7 uF recommended) within 2 mm of the VIN pin, and the output capacitor (4.7-10 uF X7R) within 2 mm of the VOUT pin. Route the SW trace as short and wide as possible to minimise EMI - keep it inside a ground-shoring shield if the design must pass Class B radiated emissions. The exposed thermal pad (PGND, pin 12) must be soldered to a continuous ground plane on the top and inner layers using at least 9 thermal vias (0.3 mm drill, 0.5 mm pitch).
Estimated: at VIN = 5 V, VOUT = 3.3 V, IOUT = 300 mA, the TPS62745DSSR dissipates approximately (5-3.3) * 0.3 = 0.51 W plus switching losses. At VIN = 10 V, VOUT = 3.3 V the dissipation rises to approximately (10-3.3) * 0.3 = 2.01 W; verify the PCB copper pour plus any forced airflow keeps junction temperature below 125 C. The PG (power-good) pin can be wire-OR'd with another regulator to provide a clean system reset.
合规信息
RoHS and lead-free per TI product page; AEC-Q100 qualification not listed - choose automotive-grade TPS variants if required. Halogen-free per TI's material declaration.
