Texas Instruments TPS2231PWPR

Overview

TPS2231PWPR from Texas Instruments is a single-slot ExpressCard™ power interface switch IC that distributes and regulates 3.3 V, 1.5 V, and AUX power rails to ExpressCard|34/|54 sockets with integrated current limiting, thermal protection, and undervoltage lockout. It supports notebook computers and desktop systems requiring compliant hot-plug power sequencing for PCI Express and USB-based ExpressCards.

For engineers reviewing the TPS2231PWPR datasheet, TPS2231PWPR pinout, TPS2231PWPR application, or TPS2231PWPR equivalent, key selection considerations include its 24-pin PowerPAD™ HTSSOP package, dual-rail current limits (1.3 A @ 3.3VOUT, 650 mA @ 1.5VOUT), 45 mΩ typical R_DS(on) at 25°C, –40°C to 85°C operating range, and ExpressCard™ compliance including PERST timing and RCLKEN coordination.

Technical Context

The TPS2231PWPR implements three independent MOSFET power switches - one each for 3.3VIN→3.3VOUT, 1.5VIN→1.5VOUT, and AUXIN→AUXOUT - each with dedicated overcurrent sensing, thermal shutdown (trip at 155–165°C), and UVLO (2.6–2.9 V for 3.3VIN/AUXIN, 1.0–1.25 V for 1.5VIN). Its control logic interprets CPPE/CPUSB, SHDN, STBY, and SYSRST to manage six discrete power states: OFF, Shutdown, No Card, Standby, and Card Inserted.

It features open-drain status outputs (PERST, OC, RCLKEN) with precise timing: PERST de-assertion delay of 4–10 ms after all rails stabilize and RCLKEN release, 100–250 µs minimum PERST pulse width, and 500 ns SYSRST-to-PERST assertion delay. All outputs include discharge FETs activated during card removal or shutdown to safely sink residual charge.

Key Specifications

Pinout & Package

TPS2231PWPR is housed in a thermally enhanced 24-pin PowerPAD™ HTSSOP (PWP) package with exposed thermal pad soldered to PCB ground plane for optimal junction-to-board thermal resistance (33.19 mW/°C derating above 25°C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ExpressCard power interface applications.

Compared with TPS2231PW and TPS2236DAP, the TPS2231PWPR offers the optimal balance of thermal performance, ExpressCard™ compliance, and single-slot integration - its PowerPAD™ package enables 4.5× higher power dissipation than the TSSOP variant, while avoiding the unnecessary complexity and cost of dual-channel functionality.

Availability

TPS2231PWPR is available at Aetrix Electronics and suitable for notebook computers, desktop computers, personal digital assistants (PDAs), and digital cameras requiring stable component supply, ExpressCard™-compliant power sequencing, and industrial-grade thermal reliability.

Supply support for TPS2231PWPR 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 connectivity technologies, with decades of expertise in power management and interface ICs.

The TPS2231PWPR belongs to TI's ExpressCard™ power interface switch product line, engineered specifically to meet the stringent sequencing, protection, and timing requirements defined in the ExpressCard™ standard for mobile and desktop host systems.

FAQ

What is the primary function of the TPS2231PWPR in an ExpressCard system?

The TPS2231PWPR serves as the dedicated power interface switch for single-slot ExpressCard|34 and ExpressCard|54 hosts. It manages the distribution, sequencing, and protection of three critical power rails - 3.3 V, 1.5 V, and AUX - while generating compliant PERST and RCLKEN signals. Its integrated current limiting, thermal shutdown, and UVLO ensure safe hot-plug operation and prevent damage from overloads or brownouts. The TPS2231PWPR is essential for achieving ExpressCard™ certification in host platforms.

How does the TPS2231PWPR handle card insertion and removal events?

The TPS2231PWPR detects card presence via CPPE and CPUSB inputs, which are internally pulled up to AUXIN. When either signal is grounded by the inserted card, the device transitions from No Card mode to Card Inserted mode, enabling all three power rails with controlled rise times. During removal, it activates discharge FETs on 3.3VOUT, 1.5VOUT, and AUXOUT to rapidly sink residual charge - preventing floating voltages and ESD risks. This behavior is fully automatic and requires no firmware intervention, ensuring robust hot-plug reliability for the TPS2231PWPR.

What are the key timing parameters governing PERST and RCLKEN behavior in the TPS2231PWPR?

The TPS2231PWPR enforces strict ExpressCard™-aligned timing: PERST remains asserted (low) until all three output rails stabilize within tolerance, then de-asserts (goes high) after a 4–10 ms delay. RCLKEN releases (goes high) immediately upon rail stabilization, initiating the PERST timer. If RCLKEN is held low externally (e.g., by host CPU), PERST de-assertion is delayed indefinitely - enabling host-controlled power sequencing. The TPS2231PWPR also guarantees ≤500 ns SYSRST-to-PERST assertion delay for warm resets, ensuring deterministic system-level reset behavior.

Can the TPS2231PWPR be used in systems without PCI Express or USB ExpressCards?

Yes - the TPS2231PWPR functions as a general-purpose triple-rail hot-swap power switch even outside ExpressCard™ applications. Its 3.3 V, 1.5 V, and AUX outputs can power any peripheral requiring coordinated, protected, and sequenced voltage delivery. However, features like PERST generation, RCLKEN timing, and CPPE/CPUSB logic are optimized for ExpressCard™ use; in non-ExpressCard systems, those pins may be left unconnected or repurposed as generic GPIOs. The core power switching, current limiting, and thermal protection remain fully functional for the TPS2231PWPR.

What thermal design considerations apply to the TPS2231PWPR's PowerPAD™ HTSSOP package?

The TPS2231PWPR's 24-pin PowerPAD™ HTSSOP (PWP) package requires soldering the exposed thermal pad to a large PCB copper area tied to ground for effective heat dissipation. With proper thermal pad layout, its power dissipation rating reaches 3153 mW at 25°C, derating linearly at 33.19 mW/°C above ambient. Without the thermal pad soldered, ratings drop significantly. Thermal performance directly impacts maximum continuous current capability - especially critical at elevated ambient temperatures or under sustained 1.3 A 3.3VOUT loads. Designers must follow TI's layout guidelines to ensure the TPS2231PWPR operates reliably within its 120°C junction limit.