Texas Instruments TPS2045D

Overview

TPS2045D from Texas Instruments is a current-limited, high-side N-channel MOSFET power-distribution switch in an 8-pin SOIC (D) package, featuring 135 mΩ on-resistance at 5 V, 250 mA continuous output current, and active-low enable logic. It provides short-circuit and thermal protection with open-drain overcurrent (OC) reporting, operating across 2.7–5.5 V input range for USB peripheral power management.

For engineers reviewing the TPS2045D datasheet, TPS2045D pinout, TPS2045D application, or TPS2045D equivalent, key selection criteria include its 0.44-A current-limit threshold, 2.5-ms typical rise time, undervoltage lockout (~2 V), and compatibility with hot-insertion systems requiring controlled inrush current and fault signaling.

Technical Context

The TPS2045D integrates an internal charge pump to drive the N-channel MOSFET gate above the source, enabling full enhancement down to 2.7 V input while maintaining low quiescent current (<10 µA in disable state). Its current-sense FET architecture avoids series resistive losses and enables precise constant-current limiting during overload.

Thermal protection activates at ~140°C junction temperature with ~20°C hysteresis, causing automatic cycling until fault removal. The OC output asserts low during overcurrent or overtemperature events and remains latched until condition clears - supporting host-level fault monitoring in USB hubs and portable peripherals.

Key Specifications

Pinout & Package

TPS2045D is housed in an 8-pin SOIC (D) package, surface-mount compatible with standard reflow profiles and tape-and-reel handling (R-suffix variant available). Pin 1 is GND; pins 2 and 3 are parallel IN inputs; pin 4 is active-low EN; pins 6–8 are paralleled OUT outputs; pin 5 is open-drain OC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power-distribution switch applications.

Compared with TPS2045D, TPS2041BD offers identical protection and performance with reversed enable polarity, while AP2171SG-13 trades OC reporting and thermal hysteresis for lower on-resistance and reduced cost - making it viable only in applications with external supervision.

Availability

TPS2045D is available at Aetrix Electronics and suitable for USB peripheral power management, hot-plug I/O modules, and portable device load switching requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TPS2045D 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 USB, power distribution, and industrial interface solutions.

The TPS2045D belongs to TI's current-limited power-distribution switch family, designed specifically for USB-compliant hot-plug applications requiring integrated current limiting, thermal protection, and fault reporting in compact SOIC packaging.

FAQ

What is the enable logic polarity of the TPS2045D?

The TPS2045D features active-low enable logic: the power switch turns ON when the EN pin voltage is below 0.4 V (typical) and turns OFF when EN rises above 2 V. This matches common microcontroller GPIO configurations where low-active signals simplify pull-down biasing and reduce standby current. The TPS2045D datasheet specifies VIH = 2 V min and VIL = 0.4 V max at 2.7–4.5 V input, ensuring reliable TTL/CMOS compatibility. Always verify EN voltage thresholds against your host controller's output levels.

Does the TPS2045D support 3.3-V input operation?

Yes, the TPS2045D operates across 2.7 V to 5.5 V input range, including 3.3-V rails. At 3.3 V and 25°C, its R_DS(on) is 105 mΩ max (vs. 135 mΩ at 5 V), resulting in lower conduction loss. The internal charge pump maintains sufficient gate drive even at minimum input, and undervoltage lockout remains functional. However, current-limit threshold drops slightly (~0.41 A at 3.3 V), and rise time increases to ~3 ms - both confirmed in the SLVS182 datasheet Figures 14 and 23. System validation at 3.3 V is recommended.

How does the OC pin behave during a short circuit?

During a short circuit, the TPS2045D's OC pin pulls low within microseconds and remains asserted (low) until the fault is removed. It is an open-drain output requiring an external pull-up resistor (typically 4.7–10 kΩ to V_CC) to generate a valid logic signal for host interrupt or status polling. The OC pin also activates during thermal shutdown and stays low throughout the thermal cycling period. Note that heavy capacitive loads may cause momentary false OC assertion due to inrush; adding a 500-µs RC filter (e.g., 10 kΩ + 50 nF) to the OC line mitigates this, as documented in Figure 30 of the TPS2045D datasheet.

Can multiple TPS2045D devices share a single OC signal line?

Yes - the OC pin is open-drain, so multiple TPS2045D units can wire-OR their OC outputs to a single microcontroller interrupt pin using one shared pull-up resistor. This enables consolidated fault monitoring across several power domains (e.g., USB ports or I/O banks). Ensure total sink current does not exceed 10 mA per OC pin under worst-case simultaneous faults, and confirm logic-low voltage remains below 0.5 V at the MCU input. No level-shifting is needed if all devices operate from the same V_CC domain as the pull-up.

What thermal considerations apply to the TPS2045D in SOIC package?

The TPS2045D in SOIC-8 has θ_JA = 172°C/W. At 250 mA and 5 V input, power dissipation is ~8.4 mW (135 mΩ × 0.25²), yielding ~1.4°C rise above ambient - well within limits. However, at 0.44 A short-circuit clamp, dissipation reaches ~29 mW, raising junction temperature by ~5°C. Under sustained overload, thermal shutdown triggers at ~140°C junction, with ~20°C hysteresis. PCB copper area and airflow significantly impact real-world performance; TI recommends ≥1 in² of 2-oz copper connected to GND pins for optimal thermal relief in the TPS2045D layout guidelines.