LMZM33603RLRR - 3A 36V Step-Down DC/DC Power Module | Texas Instruments
MPN: LMZM33603RLRR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.96 | $8.96 |
| 10 | $8.42 | $84.20 |
| 100 | $7.65 | $765.00 |
| 500 | $6.83 | $3,415.00 |
| 1,000 | $6.07 | $6,070.00 |
LMZM33603RLRR Overview
A power module is a fully-encapsulated subsystem that integrates the active switches (MOSFETs or IGBTs), magnetic energy-storage elements (typically a shielded inductor), and the passive compensation network of a switching regulator into a single, characterized, factory-tuned package. As a member of the broader category of point-of-load (PoL) converters inside the DC/DC converter family, power modules sit within the power management IC hierarchy and effectively eliminate the loop-compensation, magnetics-selection, and EMI-filter design steps that a discrete buck regulator would otherwise require. Engineers specify them when deterministic performance, fast time-to-market, and a small PCB footprint matter more than absolute lowest BOM cost.
Key features of the LMZM33603RLRR include a Power-Good output for sequencing, internal compensation, all I/O accessible from the perimeter for easy probing, pin compatibility with the 2 A LMZM33602, adjustable soft-start, and the ability to meet EN55011 Class B radiated EMI with a simple filter network. The wide 4 V to 36 V input range makes the device suitable for industrial 24 V buses, battery-powered, and distributed 12 V systems alike. Up to 18 V output at 3 A allows direct generation of system, FPGA, or industrial-rail voltages from a higher-voltage source without an intermediate regulator.
The architecture uses a current-mode control topology with an internal MOSFET pair, an integrated shielded power inductor, and factory-tuned feedback compensation. The exposed top-side pad provides a low thermal resistance path, while the perimeter-only pinout simplifies PCB routing and enables a single-layer layout if desired. Compared with a discrete buck, the integrated magnetics reduce EMI hotspot area and remove the sensitivity to external inductor tolerance that often requires rework during design validation.
Typical applications include industrial 24 V distributed bus POL converters, factory-automation PLC and sensor-supply rails, battery-powered 12 V/24 V input portable equipment, telecommunications equipment requiring high-efficiency dense power, test and measurement systems needing low-noise regulated rails, and FPGA/DSP core or I/O rail generation. The QFN package and 4 mm profile are particularly attractive for space-constrained boards.
When designing with this device, pay close attention to input bulk-capacitor sizing (a minimum 22 µF X7R ceramic is recommended at the VIN pins) and to PCB layout beneath the module - the integrated inductor's magnetic field benefits from a small keep-out region and from stitching the inner-layer ground pour around the perimeter. The PG pin can be used for multi-rail sequencing, while the SS/TR pin sets soft-start time and supports tracking with another rail.
Drop-in alternatives for LMZM33603RLRR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LMZM33602RLLR
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LMZM33603RLRR
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View Datasheet →LMZM33604RLLR
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LMZM33603RLRRG1
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LMZM33603RLRR Maximum Ratings & Electrical Characteristics
| Topology | Step-Down (Buck) DC/DC Power Module |
| Input Voltage Range | 4 V to 36 V |
| Output Voltage Range | 1 V to 18 V (1 V to 13.5 V at 3 A) |
| Maximum Output Current | 3 A |
| Peak Efficiency | Up to 95% |
| Switching Frequency Range | 200 kHz to 1.2 MHz (adjustable, sync to external clock) |
| Typical Switching Frequency | 400 kHz |
| Operating Temperature Range | -40 °C to +105 °C |
| Package | 18-pin QFN (RLR), 9 mm × 7 mm × 4 mm |
| Mounting Type | Surface Mount |
| MSL Level | 3 |
| RoHS Status | Compliant |
| Power Good Output | Yes (open-drain) |
| Soft Start / Tracking | Adjustable via external capacitor |
| EMI Compliance | Meets EN55011 Class B (with simple filter) |
| Integrated Inductor | Yes (shielded) |
| Internal Compensation | Yes (factory-tuned) |
| Pin Compatibility | Pin-compatible with 2 A LMZM33602 |
LMZM33603RLRR Pin Configuration
| Pin 1 | VIN — Input supply voltage (4 V to 36 V) |
| Pin 2 | VIN — Input supply voltage (4 V to 36 V) |
| Pin 3 | PGND — Power ground |
| Pin 4 | PGND — Power ground |
| Pin 5 | SW — Switch node - internal MOSFET output to internal inductor |
| Pin 6 | SW — Switch node - internal MOSFET output to internal inductor |
| Pin 7 | VOUT — Regulated output voltage |
| Pin 8 | VOUT — Regulated output voltage |
| Pin 9 | FB — Feedback voltage input (connect to VOUT via resistor divider) |
| Pin 10 | COMP — Compensation node (internal compensation, leave open in typical use) |
| Pin 11 | AGND — Analog ground |
| Pin 12 | RT — Timing resistor - sets switching frequency 200 kHz to 1.2 MHz |
| Pin 13 | SYNC — Sync input - tie low for RT mode, drive with external clock to synchronize |
| Pin 14 | PGOOD — Power-good open-drain output (high when VOUT is in regulation) |
| Pin 15 | SS/TR — Soft-start / tracking - external capacitor sets soft-start time |
| Pin 16 | EN — Enable input (active high, with internal pull-up) |
| Pin 17 | PGND — Power ground (exposed thermal pad) |
| Pin 18 | PGND — Power ground (exposed thermal pad) |
Typical Applications
LMZM33603RLRR is suitable for 6 applications: Industrial 24 V Distributed Bus POL Converter, Factory Automation PLC and Sensor-Supply Rails, Battery-Powered 12 V/24 V Portable Equipment, Telecom and Networking Equipment Power, Test and Measurement Instrumentation, FPGA/DSP Core and I/O Rail Generation.
Industrial 24 V Distributed Bus POL Converter
The LMZM33603RLRR is purpose-built for 24 V industrial distributed-bus point-of-load (POL) conversion. Its 4 V to 36 V input window tolerates 24 V nominal plus the load-dump and surge transients typical of factory backplanes, while the 3 A continuous output drives downstream MCUs, sensors, and analog rails. The integrated shielded inductor and factory compensation mean a 2-layer PCB can deliver a clean 5 V or 3.3 V rail with as few as four external components, and the EN55011 Class B EMI compliance is achieved with a small input filter - critical for factory-automation certification timelines.
Recommended
Factory Automation PLC and Sensor-Supply Rails
PLC I/O modules and 24 V industrial sensors require dense, regulated 5 V/3.3 V or ±15 V rails that fit in narrow DIN-rail form factors. The LMZM33603RLRR's 9 × 7 × 4 mm QFN footprint allows multiple modules to be placed side-by-side without crowding, while the 3 A output easily handles digital I/O banks plus analog-front-end subsystems. The integrated magnetics and exposed thermal pad support convection-cooled operation in sealed enclosures - no external heatsink required for typical PLC loads under 2 A continuous.
Recommended
Battery-Powered 12 V/24 V Portable Equipment
Portable industrial and medical equipment powered by 12 V or 24 V battery stacks benefits from the LMZM33603RLRR's high efficiency (up to 95%) and wide input window that accepts battery voltage directly without a pre-regulator. The synchronous topology extends battery run-time by reducing conduction losses versus a diode-rectified buck, and the adjustable 200 kHz to 1.2 MHz switching frequency lets designers optimize the output-ripple versus efficiency trade-off. PGOOD and SS/TR enable sequenced startup that protects downstream battery-management circuitry from inrush currents.
Recommended
Telecom and Networking Equipment Power
Telecom base-station and networking equipment commonly operate from -48 V nominal supplies that step down to 12 V intermediate buses, which the LMZM33603RLRR can accept directly within its 4 V to 36 V input range when the upstream bus is locally regulated. The 3 A output is well matched to FPGA SoCs, PHY transceivers, and clock-distribution ICs that require low-noise, high-current rails. Adjustable switching frequency combined with the SYNC pin allows synchronization to a system clock, avoiding beat frequencies that could interfere with sensitive RF or SERDES links.
Recommended
Test and Measurement Instrumentation
Bench-top and ATE test-and-measurement systems demand clean, stable power rails to drive precision ADCs, DACs, and analog signal-conditioning paths. The LMZM33603RLRR's synchronous buck topology and integrated inductor deliver low-ripple output well-suited for 16-bit and 24-bit acquisition systems, while the Power-Good output supports deterministic rail-sequencing during instrument calibration. The wide input range lets the module accept 5 V, 12 V, or 24 V bench supplies without reconfiguration, simplifying multi-rail test-system design.
Recommended
FPGA/DSP Core and I/O Rail Generation
Modern FPGA and DSP SoCs require multiple low-voltage, high-current rails (0.85 V core, 1.2 V/1.8 V auxiliary, 3.3 V I/O) generated from a 5 V or 12 V intermediate bus. The LMZM33603RLRR's 18 V maximum output covers the higher-voltage I/O rails directly, while its 3 A continuous current can be paralleled with a second module or split with downstream LDOs to feed sub-rails. The adjustable switching frequency and synchronization pin minimize interference with SERDES links that are notoriously sensitive to switching-noise spurs in the 100 kHz to 1 MHz band.
Recommended
Recommended Products Summary
Engineering reference data for LMZM33603RLRR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LMZM33602RLLR | LMZM33604RLLR | LMZM33603RLRRG1 |
|---|---|---|---|---|
| Package | 18-pin QFN (RLR) 9x7x4 mm | 18-pin QFN (RLR) 9x7x4 mm - same | 18-pin QFN (RLR) 9x7x4 mm - same | 18-pin QFN (RLR) 9x7x4 mm - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Topology | Synchronous Buck Module | Synchronous Buck Module | Synchronous Buck Module | Synchronous Buck Module |
| Input Voltage Range | 4 V to 36 V | 4 V to 36 V | 4 V to 36 V | 4 V to 36 V |
| Maximum Output Current | 3 A | 2 A (-33%) | 4 A (+33%) | 3 A (identical) |
| Output Voltage Range | 1 V to 18 V | 1 V to 18 V | 1 V to 18 V | 1 V to 18 V |
| Switching Frequency | 200 kHz to 1.2 MHz | 200 kHz to 1.2 MHz | 200 kHz to 1.2 MHz | 200 kHz to 1.2 MHz |
| Peak Efficiency | 95% | 95% | 95% | 95% |
| Integrated Inductor | Yes (shielded) | Yes (shielded) | Yes (shielded) | Yes (shielded) |
| Pin Compatibility | Base 3 A variant | Pin-compatible (2 A) | Pin-compatible (4 A) | Pin-compatible (same part) |
Key Differentiators
- Fully integrated inductor and compensation (vs TPS54360 (discrete buck IC))
- Pin-compatible 2 A / 3 A / 4 A family (vs LMZM33602 (2 A) and LMZM33604 (4 A))
- Wide 4 V to 36 V input with 18 V output (vs Discrete buck regulators typically limited to 28 V or 36 V input)
Design Notes
Estimated: At VIN = 24 V, VOUT = 5 V, and 2.5 A load, the LMZM33603RLRR dissipates roughly (24 - 5) × 2.5 = 47.5 W in an ideal linear-loss model; switching losses and synchronous-FET RDSon typically bring this to 1.5 W to 2 W of heat. The QFN RLR package should be soldered to a ground copper pour of at least 1 square inch on the top and bottom layers for convection-cooled operation. Without that copper area, junction temperature will rise rapidly above the +125 °C limit at sustained loads above 2 A.
Place the input bulk capacitor (22 µF X7R 50 V minimum) within 5 mm of the VIN pins, and use wide copper pours on VIN and PGND. Stitch the inner ground plane around the module perimeter to provide a low-impedance return path for the synchronous FET. The exposed thermal pad must be soldered to the PCB - skipped solder coverage will more than double the effective θJA and may cause thermal shutdown at half the rated current.
Route the FB trace away from the SW node to minimize noise injection into the feedback loop. Keep the RT resistor close to the RT pin to avoid parasitic capacitance that shifts the programmed switching frequency. If using external SYNC, route the SYNC trace over a continuous ground plane and keep it well away from the SW node to prevent false triggering. For EN55011 Class B EMI, add a small LC filter on VIN (typically 1 µF X7R + 1 µH chip ferrite) within 10 mm of the module.
Common pitfalls: (1) Skipping the SS/TR capacitor results in output-voltage overshoot at startup that may damage downstream loads; (2) Driving SYNC with a noisy clock source can cause frequency jitter and EMI spikes; (3) Exceeding the 18 V maximum output voltage - even transient - may damage the internal MOSFETs; (4) Forgetting to connect the AGND pin - leaving it floating shifts the FB reference and the output will regulate at the wrong voltage. Always refer to TI's application schematic in the datasheet when in doubt.
Compliance Information
RoHS compliant per TI product page. Standard grade - not AEC-Q100 qualified; for automotive applications, look at the LMZM33603-Q1 family. Halogen-free per TI packaging materials disclosure.
