Texas Instruments TPS543B22RYSR

Overview

TPS543B22RYSR from Texas Instruments is a 20A synchronous step-down DC/DC converter with integrated 6.5mΩ high-side and 2mΩ low-side MOSFETs, fixed-frequency advanced current mode (ACM) control, 4V–18V input range, 0.5V–7V output range, and true differential remote sense amplifier - deployed in wireless infrastructure power rails requiring tight regulation and fast transient response.

For engineers reviewing the TPS543B22RYSR datasheet, TPS543B22RYSR pinout, TPS543B22RYSR application, or TPS543B22RYSR equivalent, key selection considerations include selectable switching frequencies (500kHz–2.2MHz), monotonic start-up into prebiased outputs, ±0.5% reference accuracy over –40°C to +150°C, and pin compatibility with TPS543A22/TPS543A26 for design reuse.

Technical Context

The TPS543B22RYSR implements an internally compensated advanced current mode (ACM) control architecture that emulates inductor current using three programmable PWM ramp options - enabling stable operation with low-ESR MLCC output capacitors without external compensation. It operates exclusively in forced continuous conduction mode (FCCM) across its full load and temperature range.

Its 17-pin WQFN-FCRLF (RYS) package integrates dual N-channel MOSFETs, a 4.5V internal LDO (VDRV), differential remote sensing (FB/GOSNS), and five resistor-selectable switching frequencies - all coordinated via dedicated pins (SYNC/FSEL, MSEL) with precise UVLO thresholds (VIN rising: 3.95V, EN rising: 1.25V) and thermal shutdown at 170°C.

Key Specifications

Pinout & Package

TPS543B22RYSR is housed in a thermally enhanced 2.5mm × 4.5mm, 17-pin WQFN-FCRLF (RYS) package with 0.5mm pitch and exposed thermal pad - optimized for high-current density PCB layouts and compatible with standard QFN reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS543B22RYSR, TPS543A22RYSR offers reduced current capacity but lower cost, while TPS543B25TRYSR delivers identical functionality with superior thermal metrics - making the latter ideal for space-constrained industrial or medical systems demanding long-term reliability at elevated temperatures.

Availability

TPS543B22RYSR is available at Aetrix Electronics and suitable for wireless infrastructure, optical networking, and test equipment applications requiring stable component supply, long-lifecycle assurance, and consistent parametric performance across production batches.

Supply support for TPS543B22RYSR 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 over 50 years of innovation in high-efficiency DC/DC conversion.

The TPS543B22RYSR belongs to TI's SWIFT™ synchronous buck converter family, designed specifically for high-current, high-density POL applications in communications, computing, and industrial systems where thermal performance and design simplicity are critical.

FAQ

What is the maximum recommended output current for TPS543B22RYSR under continuous operation?

The TPS543B22RYSR is rated for 20A continuous output current with proper PCB thermal design - including ≥2 oz copper on top/bottom layers, thermal vias under the exposed pad, and adequate airflow. At 12V input and 1.2V output, it sustains 20A with junction temperature ≤150°C in typical JEDEC high-K board conditions. Derating applies above 60°C ambient unless enhanced cooling is implemented.

Does TPS543B22RYSR support synchronization to an external clock, and what are the timing constraints?

Yes, TPS543B22RYSR supports external clock synchronization via the SYNC/FSEL pin. The external clock must be a square wave with 20–80% duty cycle and frequency within ±20% of the internally programmed switching frequency. If applied after startup, synchronization locks within four consecutive cycles; if applied before startup, no RFSEL resistor is required. Loss of sync causes automatic fallback to the internal oscillator.

How does the differential remote sense (FB + GOSNS) function in TPS543B22RYSR, and what is its common-mode range?

The TPS543B22RYSR uses true differential remote sensing: FB measures the positive side of the output divider, while GOSNS returns the load ground reference - rejecting voltage drops across PCB traces. Its common-mode input range is ±100 mV relative to AGND, allowing accurate regulation even with up to 200 mV total IR error between the IC and load. This ensures ±0.5% output accuracy at the point of load.

Can TPS543B22RYSR be used in prebiased start-up scenarios, and how is monotonicity ensured?

Yes, TPS543B22RYSR guarantees monotonic start-up into prebiased outputs - meaning it will not force reverse current into an already energized rail. This is achieved through controlled gate drive sequencing and valley-current limiting during soft-start. When the output voltage exceeds the FB threshold before soft-start completion, the controller enters a high-impedance state until regulation is established, preventing negative current flow.

What are the thermal resistance values for TPS543B22RYSR in the RYS package, and how do they impact layout design?

For the 17-pin RYS package, TPS543B22RYSR has RθJA = 33.9°C/W (JEDEC standard), RθJB = 5.5°C/W, and RθJC(bot) = 5.9°C/W. These values indicate strong board conduction capability - requiring ≥8 thermal vias (0.3mm diameter, filled) under the exposed pad connected to inner-layer ground planes. Minimizing RθJB via copper area and via count is essential to sustain 20A operation at 85°C ambient without exceeding 150°C junction temperature.