Texas Instruments TPS62561DDCT

Overview

TPS62561DDCT from Texas Instruments is a synchronous step-down DC-DC converter optimized for battery-powered portable applications. It delivers up to 600 mA output current from 2.5 V–5.5 V input sources (e.g., single Li-ion or AA/AAA cells), features fixed 2.25-MHz PWM operation (no PFM mode), ±2.5% output voltage accuracy in PWM mode, and 15-μA quiescent current in light-load PFM-disabled operation - used in low-power DSP supplies and point-of-load regulation.

For engineers reviewing the TPS62561DDCT datasheet, TPS62561DDCT pinout, TPS62561DDCT application, or TPS62561DDCT equivalent, key selection considerations include its SOT-5 package footprint, absence of MODE pin (fixed PWM only), adjustable output via FB resistor divider, 100% duty-cycle dropout capability, and thermal performance with R_θJA = 226.9°C/W.

Technical Context

The TPS62561 operates exclusively in fixed-frequency PWM mode - unlike TPS62560/62, it lacks a MODE pin and cannot enter power-save (PFM) mode. Its voltage-mode control with input-voltage feed-forward enables fast line/load regulation using small ceramic capacitors.

It integrates high-side (252–492 mΩ) and low-side (194–391 mΩ) MOSFETs, supports soft-start (250 μs ramp-up), undervoltage lockout (1.85 V falling threshold), and thermal shutdown (140°C). Output voltage is set externally via FB pin with 0.6 V reference; no internal resistor divider is present.

Key Specifications

Pinout & Package

TPS62561DDCT uses a 5-pin TSOT-23 (SOT-5) package measuring 2.90 mm × 1.60 mm × 1.0 mm, with exposed pad not connected internally and not required for thermal conduction per datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS62561DDCT, TPS62560DRV offers PFM flexibility but requires MODE pin routing and larger layout area, while TPS62290DSGR provides higher current and better thermal metrics but shifts reference voltage - making TPS62561DDCT optimal for cost-sensitive, EMI-constrained SOT-5 designs requiring strict PWM-only operation.

Availability

TPS62561DDCT is available at Aetrix Electronics and suitable for portable media players, low-power DSP supplies, and point-of-load (POL) applications requiring stable component supply, long-term manufacturability, and consistent parametric performance across production batches.

Supply support for TPS62561DDCT 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 company headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and power management solutions for industrial, automotive, and consumer markets.

The TPS6256x family was developed specifically for space-constrained, battery-powered portable electronics - emphasizing high efficiency at light loads, small solution size, and robust operation across wide input voltage ranges.

FAQ

What is the function of the MODE pin on the TPS62561DDCT?

The TPS62561DDCT does not have a MODE pin. Unlike the TPS62560DRV and TPS62562, the TPS62561DDCT is designed for fixed-frequency PWM operation only and omits the MODE terminal entirely. This eliminates PFM mode transitions, ensuring constant switching frequency for deterministic EMI filtering - a key distinction confirmed in the device comparison table and pin configuration section of the SLVS815D datasheet.

Can the TPS62561DDCT be used to generate a 1.2-V output?

Yes, the TPS62561DDCT can generate a 1.2-V output using an external resistor divider on the FB pin. With a 0.6-V internal reference voltage, setting R1/R2 = 1.0 yields V_OUT = 0.6 × (1 + 1) = 1.2 V. The datasheet specifies an output voltage range of 0.85 V to VIN, and recommends R2 = 180 kΩ or 360 kΩ to minimize divider current while maintaining noise immunity - confirming 1.2 V is a supported and validated configuration for the TPS62561DDCT.

What is the maximum recommended output capacitance for the TPS62561DDCT?

The TPS62561DDCT supports output capacitance up to 22 μF, as specified in Section 9.2.2.2 of the SLVS815D datasheet. While the typical application uses 10 μF, values up to 22 μF improve load transient response and reduce output ripple - particularly beneficial in DSP or FPGA core supply applications. Exceeding 22 μF is not prohibited but may affect stability margins; TI's WEBENCH design tool validates 22 μF as the upper limit for stable operation with standard 2.2-μH inductors.

Does the TPS62561DDCT support 100% duty-cycle operation, and what is its practical benefit?

Yes, the TPS62561DDCT supports 100% duty-cycle operation, enabling regulation when V_IN approaches V_OUT. This feature maximizes usable battery energy - for example, sustaining a 3.3-V output down to ~3.4 V input - extending runtime in single-cell Li-ion applications by up to 18 minutes. The datasheet explicitly states this capability in Section 8.4.2.1 and provides the V_IN(min) equation based on R_DS(on), inductor DCR, and load current - a confirmed design feature of the TPS62561DDCT.

How does the thermal performance of the TPS62561DDCT compare to the TPS62560DRV?

The TPS62561DDCT (SOT-5) has R_θJA = 226.9°C/W, significantly higher than the TPS62560DRV (SON-6) at 67.8°C/W. This means the TPS62561DDCT heats up ~3.3× faster under identical conditions. For 600-mA loads at 85°C ambient, the TPS62561DDCT junction temperature may exceed 125°C without adequate copper pour, whereas the DRV variant remains within safe limits. This thermal difference is documented in Table 7.4 and directly impacts layout requirements - confirming a real, quantified trade-off between package size and thermal capability in the TPS62561DDCT.