Texas Instruments TPS54494RSAR

Overview

TPS54494RSAR from Texas Instruments is a dual-channel synchronous step-down DC/DC converter with integrated 90 mΩ high-side and 60 mΩ low-side N-channel MOSFETs per channel, delivering 4 A on Channel 1 and 2 A on Channel 2. It operates from 4.5 V to 18 V input, supports output voltages from 0.76 V to 7 V, and uses D-CAP2™ adaptive on-time control for fast transient response in digital TV, STB, and gaming console power supplies.

For engineers reviewing the TPS54494RSAR datasheet, TPS54494RSAR pinout, TPS54494RSAR application, or TPS54494RSAR equivalent, key selection considerations include its HTSSOP-16 (RSA) package with PowerPAD™ thermal pad, non-sinking pre-biased soft start, cycle-by-cycle over-current protection, and Eco-mode™ operation enabling >90% efficiency at light loads across –40°C to 85°C ambient.

Technical Context

The TPS54494RSAR implements D-CAP2™ control combining adaptive on-time PWM with internal compensation-eliminating external loop components while supporting ceramic and polymer output capacitors. Its two independent channels share no critical analog resources, enabling asymmetric configurations (e.g., 3.3 V/4 A + 1.5 V/2 A).

Each channel features thermally compensated rDS(on)-based current sensing, fixed 1 ms soft-start, and independent power-good (PG1/PG2) outputs with ±16% voltage window and 1.5 ms enable delay. Switching frequency is pseudo-fixed at 700 kHz, varying <±5% over input voltage and load due to adaptive on-time calculation (TON ∝ VOx/VINx).

Key Specifications

Pinout & Package

TPS54494RSAR is housed in a 4 mm × 4 mm, 16-pin HTSSOP (RSA) package with exposed thermal pad (PowerPAD™) soldered to PCB ground for enhanced thermal dissipation (θJB = 9.9°C/W). Pin numbering follows standard top-view orientation with Pin 1 at bottom-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel synchronous buck converter applications.

Compared with TPS54494RSAR, TPS544B20RJER offers higher per-channel current and wider input range but adds external compensation and removes Eco-mode efficiency optimization, while MP8845GQ-Z reduces feature set and precision to achieve lower BOM cost and smaller footprint-making TPS54494RSAR optimal for applications demanding fast transient response, pre-biased startup, and dual-rail power-good monitoring.

Availability

TPS54494RSAR is available at Aetrix Electronics and suitable for digital TV power supplies, networking home terminals, and gaming console mainboards requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for TPS54494RSAR 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.

The TPS54494RSAR belongs to TI's D-CAP2™ synchronous buck converter product line, designed specifically for space-constrained, high-transient consumer and computing applications where minimal external components and robust pre-biased startup are essential.

FAQ

What is the maximum allowable input voltage for the TPS54494RSAR?

The absolute maximum input voltage rating for VIN1 and VIN2 pins of the TPS54494RSAR is 20 V. However, the recommended operating range is 4.5 V to 18 V. Exceeding 18 V may trigger UVLO or cause reliability degradation; operation above 20 V risks permanent damage. The device includes internal clamping and thermal shutdown to mitigate transient overvoltage events, but sustained operation beyond 18 V is not advised.

Does the TPS54494RSAR support independent enable control for each channel?

Yes, the TPS54494RSAR provides fully independent enable inputs: EN1 (Pin 7) controls Channel 1 and EN2 (Pin 14) controls Channel 2. Each has a 2.0 V logic-high threshold and internal 450 kΩ pull-down resistor, allowing flexible power sequencing-such as powering up the 3.3 V rail before the 1.5 V rail in an SoC system. Both channels can also be tied together for simultaneous enable if needed.

How does the TPS54494RSAR handle pre-biased output conditions during startup?

The TPS54494RSAR implements non-sinking pre-biased soft start: when the output voltage is already present (e.g., from another supply), the controller delays activation of the low-side FET until the internal soft-start DAC voltage exceeds the feedback voltage. It then incrementally increases low-side gate pulse width cycle-by-cycle, preventing reverse current flow and ensuring monotonic ramp-up. This behavior is intrinsic to the TPS54494RSAR and requires no external circuitry.

What thermal performance can be expected from the TPS54494RSAR in a typical 2-layer PCB layout?

In a standard 2-layer PCB with 1 oz copper, 200 mm² thermal pad area, and no additional copper pours, the TPS54494RSAR achieves θJB = 9.9°C/W. At 4 A/2 A full load with 12 V input, junction temperature rise is approximately 45°C above ambient-well within the 150°C max rating. Performance improves significantly with internal layer copper pours and thermal vias under the PowerPAD™, enabling continuous operation at full rated current in 60°C ambient.

Can the TPS54494RSAR operate with ceramic output capacitors only, and what is the minimum recommended value?

Yes, the TPS54494RSAR is explicitly optimized for ceramic output capacitors, supported by D-CAP2™ control stability with ultra-low ESR types. The recommended total output capacitance is 20 µF to 68 µF per channel; for example, two parallel 22 µF X5R 0805 capacitors (44 µF total) are commonly used. Ceramic-only designs eliminate electrolytic bulk caps, reduce board area, and improve reliability-no tantalum or aluminum polymer is required for stable operation.