Texas Instruments LM21215MHX/NOPB

Overview

LM21215MHX/NOPB from Texas Instruments is a monolithic voltage-mode synchronous buck regulator delivering up to 15 A continuous output current with 0.6 V to VIN adjustable output, integrated 7-mΩ high-side and 4.3-mΩ low-side FETs, 500-kHz fixed switching frequency, and operation across 2.95 V–5.5 V input for FPGA core power and point-of-load regulation.

For engineers reviewing the LM21215MHX/NOPB datasheet, LM21215MHX/NOPB pinout, LM21215MHX/NOPB application, or LM21215MHX/NOPB equivalent, key selection criteria include programmable current limit via ILIM resistor, prebias start-up capability, output voltage tracking via SS/TRK, precision enable with hysteresis, and thermal protection with 165°C shutdown threshold.

Technical Context

The LM21215MHX/NOPB implements voltage-mode control with trailing-edge PWM modulation, enabling stable loop compensation across diverse output capacitance types and supporting wide bandwidth error amplifier (95 dB open-loop gain, 11 MHz GBW). Its internal 0.6 V reference exhibits ±1% accuracy over temperature and line.

Functional integration includes resistor-programmable OCP (ICLR = 3.8–23.5 A), dual-stage overvoltage/undervoltage protection on FB (105–120% / 82–97% VFB thresholds), and open-drain PGOOD with 15 µs deglitch timing. The device supports multi-rail sequencing via SS/TRK pin and operates in diode emulation mode below critical conduction boundary to improve light-load efficiency.

Key Specifications

Pinout & Package

LM21215MHX/NOPB is housed in a thermally enhanced 20-pin HTSSOP package (6.50 mm × 4.40 mm) with exposed pad electrically and thermally connected to PGND, requiring PCB ground plane connection for optimal thermal dissipation (θ_JA = 24°C/W on 4-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS543C20RTVR and MP2315GJ-Z, LM21215MHX/NOPB offers optimized 2.95–5.5 V operation, integrated tracking and prebias functionality, and proven thermal performance in HTSSOP-making it the preferred choice for 3.3/5-V FPGA and ASIC core supplies requiring robust sequencing and reliability.

Availability

LM21215MHX/NOPB is available at Aetrix Electronics and suitable for high-performance FPGA core supplies, ASIC point-of-load regulation, and industrial CPU power subsystems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LM21215MHX/NOPB 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 specializing in analog, embedded processing, and power management technologies, with leadership in high-reliability power conversion ICs for industrial and communications infrastructure.

LM21215MHX/NOPB belongs to TI's high-current synchronous buck regulator product line, designed specifically for low-voltage, high-efficiency point-of-load applications in FPGA, ASIC, and microprocessor power domains.

FAQ

What is the maximum continuous output current supported by the LM21215MHX/NOPB?

The LM21215MHX/NOPB supports up to 15 A of continuous output current under recommended operating conditions (T_J ≤ 125°C, proper PCB thermal design). This rating assumes use of the exposed pad soldered to a 4-layer board with ≥12 thermal vias, input voltage between 2.95 V and 5.5 V, and ambient temperature ≤ 85°C. Derating applies at higher temperatures or with reduced copper area.

Does the LM21215MHX/NOPB support start-up into a prebiased output?

Yes, the LM21215MHX/NOPB supports start-up into a prebiased output. When VOUT is initially held above the target regulation voltage (e.g., by another supply), the device prevents reverse current flow by disabling the low-side FET until the internal soft-start voltage exceeds the feedback voltage. This behavior is confirmed in Figure 6-16 of the datasheet and eliminates need for external reverse-blocking circuitry.

How is the current limit threshold set on the LM21215MHX/NOPB?

The current limit threshold on the LM21215MHX/NOPB is set via an external resistor (R_ILIM) connected between Pin 1 (ILIM) and AGND. Typical values range from 10 kΩ (ICLR ≈ 20 A) to 130 kΩ (ICLR ≈ 3.8 A). The relationship is monotonic and documented in Figures 6-12 through 6-15; R_ILIM = 16.5 kΩ yields ICLR = 20 A nominal at 25°C.

What package type and thermal characteristics does the LM21215MHX/NOPB use?

The LM21215MHX/NOPB uses a 20-pin HTSSOP package (PWP) with 6.50 mm × 4.40 mm body and exposed thermal pad. Thermal resistance is θ_JA = 24°C/W on a 2-inch × 2-inch, 4-layer PCB with twelve 8-mil vias under the exposed pad. The pad must be soldered to the PCB ground plane to achieve rated performance and prevent thermal shutdown under full load.

Can the LM21215MHX/NOPB be used in applications requiring output voltage tracking?

Yes, the LM21215MHX/NOPB supports output voltage tracking via its SS/TRK pin (Pin 2). When an external voltage ramp is applied to this pin, the output follows that ramp with ±10 mV accuracy (V_SS − V_FB). This enables coordinated power-up sequencing with other rails in multi-supply systems such as DDR memory interfaces or FPGA I/O banks without external controllers.