Texas Instruments TPS62745DSSR

Overview

TPS62745DSSR from Texas Instruments is an ultra-low-quiescent-current synchronous step-down converter optimized for low-power wireless systems. It delivers up to 300 mA output current with 400 nA typical IQ, operates from 3.3 V to 10 V input (e.g., dual Li-ion or 4–6 alkaline cells), and provides 16 selectable output voltages from 1.8 V to 3.3 V via four VSEL pins - used in Bluetooth Low Energy sensor nodes requiring long battery life.

For engineers reviewing the TPS62745DSSR datasheet, TPS62745DSSR pinout, TPS62745DSSR application, or TPS62745DSSR equivalent, key selection criteria include its DCS-Control™ topology for RF-friendly transient response, integrated VIN_SW switch for ADC scaling, open-drain PG output, VOUT discharge function, and WSON-12 package compatibility with space-constrained energy-harvesting designs.

Technical Context

The TPS62745DSSR implements TI's DCS-Control™ architecture, combining hysteretic and voltage-mode control to achieve seamless PFM/PWM transition, <2.5% output voltage accuracy over load/line/temperature, and sub-10 mVpp ripple at light loads. Its internal 50 MΩ feedback divider eliminates external resistors, while the EN_VIN_SW-controlled MOSFET (85–160 Ω R_DS(ON)) enables precision input voltage scaling without continuous current draw.

Functional modes include soft-start with reduced 40–180 mA current limit, UVLO (3.1 V rise / 2.9 V fall), and automatic VOUT discharge upon shutdown. The device maintains >90% efficiency above 15 µA load and supports dynamic VSEL reconfiguration during operation for adaptive power management in multi-sensor IoT endpoints.

Key Specifications

Pinout & Package

TPS62745DSSR is housed in a 12-pin WSON package (3 mm × 2 mm) with exposed thermal pad connected to GND. Pin functions are validated per TI SLVSC68A datasheet Rev A (June 2015).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-IQ step-down converter applications.

Compared with TPS62745DSSR, TPS62746DSSR adds programmability at the cost of higher quiescent current and firmware dependency, while MAX17050G+T reduces complexity but sacrifices integration - making TPS62745DSSR optimal for RF-critical, fixed-output, space-constrained applications demanding lowest possible IQ with full feature set.

Availability

TPS62745DSSR is available at Aetrix Electronics and suitable for Bluetooth Low Energy sensor nodes, industrial smart meters, energy harvesting systems, and remote wireless actuators requiring stable component supply across multi-year production cycles.

Supply support for TPS62745DSSR 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-efficiency DC/DC conversion and low-power system design.

The TPS62745DSSR belongs to TI's ultra-low-IQ buck converter product line, engineered specifically for battery- and energy-harvesting-powered wireless endpoints where multi-year operational life and RF coexistence are mandatory design requirements.

FAQ

What is the minimum input voltage required for TPS62745DSSR to regulate output?

The TPS62745DSSR requires VIN ≥ VOUT + 0.7 V for regulation, with absolute minimum VIN of 3.3 V per datasheet. For example, at VOUT = 3.3 V, VIN must be ≥ 4.0 V. Below this, the device enters undervoltage lockout (UVLO) and disables switching. The UVLO threshold is 3.1 V (rising) and 2.9 V (falling), ensuring stable startup and shutdown behavior for TPS62745DSSR.

Can TPS62745DSSR operate with a 3.3 µH inductor instead of the recommended 4.7 µH?

Yes, TPS62745DSSR supports inductors from 2.8 µH to 6.2 µH per recommended operating conditions. A 3.3 µH inductor increases peak inductor current and output ripple but remains stable with proper COUT selection (e.g., 22 µF). TI's Table 4 confirms 3.3 µH + 22 µF as a validated LC combination - however, 4.7 µH is preferred for lowest ripple and best light-load efficiency in TPS62745DSSR designs.

How does the EN_VIN_SW pin function in TPS62745DSSR, and what happens if left unconnected?

The EN_VIN_SW pin controls an internal MOSFET that connects VIN to the VIN_SW output. When high, it enables the switch (R_DS(ON) = 85–160 Ω); when low or floating, the switch opens. Leaving EN_VIN_SW unconnected risks undefined state and potential leakage. Per TI guidelines, unused EN_VIN_SW must be tied to GND to ensure the switch remains off and avoid unintended current paths in TPS62745DSSR applications.

Does TPS62745DSSR support dynamic output voltage changes during operation?

Yes, TPS62745DSSR supports real-time VOUT reconfiguration via VSEL1–VSEL4 pins. Changing their logic states adjusts output in 100-mV steps (1.8–3.3 V) with controlled slew rate. This enables adaptive power scaling - e.g., lowering VOUT during MCU sleep and raising it before RF transmission. No restart or sequencing is needed; TPS62745DSSR regulates smoothly to the new target voltage.

What is the purpose of the exposed thermal pad on the TPS62745DSSR WSON package?

The exposed thermal pad on the TPS62745DSSR WSON package serves as the primary heat dissipation path, reducing junction-to-board thermal resistance to 25.7 °C/W. It must be soldered to a solid GND plane using thermal vias to maximize power handling and reliability. Proper pad connection ensures safe operation at 300 mA continuous load and maintains TJ ≤ 125°C ambient - critical for long-term stability in sealed TPS62745DSSR deployments.