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Texas Instruments LM43603PWP
- Part No.:
- LM43603PWP
- Manufacturer:
- Texas Instruments
- Package:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM43603PWP.pdf
- Description:
- IC REG BUCK ADJ 3A 16HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,248
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Product details
Overview
LM43603PWP from Texas Instruments is a 3.5-V to 36-V, 3-A synchronous step-down DC-DC converter in HTSSOP-16 (5.1 mm × 6.6 mm) package. It delivers up to 3 A output current with 27-µA quiescent current in regulation, 500 kHz default switching frequency, and meets EN55022 Class B radiated EMI limits. It serves as a primary voltage regulator in industrial power supplies and automotive sub-AM band systems.
For engineers reviewing the LM43603PWP datasheet, LM43603PWP pinout, LM43603PWP application, or LM43603PWP equivalent, key selection criteria include input voltage range (3.5–36 V), output current capability (3 A), thermal performance (RθJA = 38.9°C/W), EMI compliance (EN55022 Class B), and integrated features including power-good flag, soft-start, and frequency synchronization.
Technical Context
The LM43603PWP employs peak current mode control for stable loop compensation and cycle-by-cycle current limiting. Its internal synchronous rectification eliminates external diodes, while programmable switching frequency (200 kHz–2.2 MHz) and external clock synchronization enable EMI optimization across system-level timing constraints.
It integrates an internal LDO for VCC biasing and supports optional BIAS pin connection to VOUT (3.3–28 V) or external rail to improve light-load efficiency. Protection includes hiccup-mode short-circuit response, thermal shutdown at 160°C, and precision enable with 200-mV hysteresis for reliable system UVLO sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5 V to 36 V - supports wide-input industrial and automotive rails without pre-regulation |
| Output Current | 3 A continuous - sufficient for high-efficiency point-of-load conversion in FPGA or microcontroller power domains |
| Quiescent Current | 27 µA in regulation - enables battery-backed or always-on subsystems with minimal standby drain |
| Switching Frequency | 200 kHz to 2.2 MHz (500 kHz default) - allows layout-optimized inductor selection and EMI spread-spectrum tuning |
| Feedback Reference | 1.011 V ±1.2% over –40°C to +125°C - ensures accurate output regulation across temperature extremes |
| Thermal Shutdown | 160°C shutdown / 150°C recovery - provides robust overtemperature protection with hysteresis to prevent oscillation |
| EMI Compliance | Meets EN55022 Class B radiated emissions - validated on LM43603PWPEVM evaluation board per standard test setup |
Pinout & Package
LM43603PWP is housed in a 16-pin HTSSOP (PWP) package measuring 5.1 mm × 6.6 mm × 1.2 mm, with exposed thermal pad connected internally to AGND. The package supports standard reflow and offers low RθJB = 19.9°C/W for PCB heat sinking via the thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1,2) | Power switch node | Connects to both internal MOSFETs and external inductor; requires low-inductance routing to minimize switching losses |
| CBOOT (3) | Bootstrap capacitor terminal | Supplies gate drive for high-side FET; requires 470-nF ceramic capacitor tied to SW |
| VCC (4) | Internal LDO output | Bypassed to AGND with capacitor; no external load permitted - powers internal circuitry only |
| BIAS (5) | Optional LDO input | Tie to VOUT (3.3–28 V) or external 3.3/5 V rail to reduce power loss; bypass with 1–10 µF capacitor |
| SYNC (6) | External clock input | Enables synchronization to system clock; requires proper high-speed termination to avoid ringing |
| RT (7) | Frequency programming | Resistor to AGND sets switching frequency; open circuit defaults to 500 kHz |
| PGOOD (8) | Open-drain power-good flag | Asserts when VOUT is within ±10% of target; requires 10–100 kΩ pull-up to ≤12 V logic rail |
| FB (9) | Feedback sense input | Monitors resistor divider midpoint; 1.011 V reference enables precise output voltage setting |
| AGND (10) | Analog ground reference | Ground return for internal references and logic; must be connected to system ground with low-impedance path |
| SS/TRK (11) | Soft-start and tracking control | Internal 4.1-ms soft-start when floating; connect capacitor to extend ramp time or external ramp for voltage tracking |
| EN (12) | Enable input | Logic-compatible enable with precision UVLO thresholds (2.2 V ON / 2.0 V OFF); hysteresis prevents chatter |
| VIN (13,14) | Main input supply | Connects to input capacitors and high-side FET; shortest possible path to PGND and CIN required |
| PGND (15,16) | Power ground | Internal connection to low-side FET source; tie directly to PCB ground plane and CIN/COUT grounds |
| PAD | Thermal pad | Exposed die attach pad connected to AGND; must be soldered to large copper area for thermal dissipation |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode, reducing conduction loss and board area in 3-A buck designs |
| Stable with diverse output capacitors | Supports ceramic, polymer, tantalum, and aluminum electrolytic capacitors without stability compromise |
| Power-good flag with deglitching | 220-µs rise/fall deglitch ensures clean system reset signaling under transient load conditions |
| Soft-start into pre-biased loads | Prevents reverse current flow during startup when output is already charged - critical for hot-swap applications |
| Discontinuous conduction mode (DCM) | Automatically engages at light loads to maintain >85% efficiency down to 1 mA output current |
Applications
| Industrial Power Supplies | Telecommunications Systems |
|---|---|
Use Scenario: Distributed 24-V or 36-V DC bus powering PLC I/O modules, sensors, and actuators in factory automation. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator delivering tightly regulated 3.3 V or 5 V to microcontrollers and communication interfaces. Use Value: 27-µA quiescent current extends uptime in battery-buffered backup operation; EN pin enables remote power sequencing. | Use Scenario: Intermediate bus conversion in base station power shelves feeding RF amplifiers and digital signal processors. IC Role / Device Role / Timing Role: Point-of-load regulator converting 48-V intermediate bus to 12-V or 5-V rails with fast transient response. Use Value: 3-A capability and 500-kHz switching support compact magnetics; EN hysteresis ensures clean power-up across temperature. |
| Sub-AM Band Automotive | High Efficiency Point-Of-Load Regulation |
Use Scenario: Powering infotainment head units, ADAS camera modules, and body control modules from 12-V battery with cold-crank tolerance. IC Role / Device Role / Timing Role: Wide-input buck converter maintaining regulation down to 3.5 V input during cranking events. Use Value: 36-V absolute max rating and hiccup-mode short-circuit protection meet automotive reliability requirements; RT pin enables EMI tuning. | Use Scenario: Supplying core voltage to FPGA, ASIC, or DSP in embedded computing platforms requiring tight output accuracy and low noise. IC Role / Device Role / Timing Role: Precision-adjustable buck regulator using FB pin feedback and internal 1.011-V reference for ±1% output tolerance. Use Value: Internal compensation reduces external component count; PGOOD flag enables safe processor boot sequence coordination. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM43602PWP | 2-A output current rating; identical pinout and feature set except reduced current limit and thermal derating | Suitable where 2-A maximum load suffices; lower RDS-ON at 2 A improves light-load efficiency but cannot sustain 3-A continuous | Select LM43602PWP if system peak load remains ≤2 A and thermal margin is constrained |
| LM43603DSU | VSON-16 package (4.1 mm × 5.1 mm); same electrical specs but different thermal pad layout and soldering profile | Preferred for space-constrained layouts; requires requalification of thermal performance due to lower RθJA (31.3°C/W) and different PCB land pattern | Choose LM43603DSU when board area is critical and thermal management uses enhanced copper pour or forced air |
Compared with LM43602PWP and LM43603DSU, the LM43603PWP uniquely balances 3-A capability, HTSSOP thermal robustness (RθJB = 19.9°C/W), and drop-in compatibility with existing LM4360x PWP footprints - making it optimal for industrial and automotive designs requiring full 3-A delivery without layout revision.
Availability
LM43603PWP is available at Aetrix Electronics and suitable for industrial power supplies, telecommunications systems, and sub-AM band automotive applications requiring stable component supply, long-term lifecycle support, and verified EN55022 Class B EMI compliance.
Supply support for LM43603PWP 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 automotive and industrial qualification expertise.
The LM43603 product line delivers high-efficiency, wide-input synchronous buck converters optimized for rugged environments - designed specifically for industrial automation, telecom infrastructure, and automotive subsystems demanding reliability, EMI control, and thermal resilience.
FAQ
What is the absolute maximum input voltage rating for the LM43603PWP?
The LM43603PWP has an absolute maximum VIN-to-PGND rating of 42 V, as specified in Section 6.1 of the datasheet. This rating applies for transient conditions up to 10 ns; continuous operation must remain within the recommended 3.5–36 V range. Exceeding 42 V risks permanent damage, even briefly. The LM43603PWP's 36-V operating maximum makes it suitable for 24-V industrial and 12-V automotive systems with cold-crank or load-dump margins.
Does the LM43603PWP support soft-start into a pre-biased output?
Yes, the LM43603PWP supports soft-start into a pre-biased output, preventing reverse current flow during startup when the output capacitor is already charged. This behavior is enabled by internal circuitry that monitors the SS/TRK pin voltage and controls high-side FET turn-on accordingly. The feature is confirmed in the "Features" section and functional description of the LM43603PWP datasheet, and is critical for hot-swap and redundant power applications where output voltage may be present before input is applied.
How does the BIAS pin improve efficiency in the LM43603PWP?
The BIAS pin on the LM43603PWP allows connection to VOUT (when 3.3 V ≤ VOUT ≤ 28 V) or an external 3.3 V/5 V rail, enabling the internal LDO to draw bias current from a higher-efficiency source instead of VIN. This reduces power loss in the LDO, especially at light loads and high VIN-to-VOUT ratios. When unused, BIAS must be tied to ground - floating is prohibited. The LM43603PWP datasheet specifies typical BIAS current savings of ~125 µA versus VIN-only operation under defined test conditions.
What is the purpose of the AGND and PGND separation in the LM43603PWP?
The LM43603PWP separates AGND (analog ground) and PGND (power ground) to isolate sensitive reference and control circuitry from high-current switching noise. AGND serves as the reference for FB, EN, and internal regulators; PGND connects to the low-side MOSFET source and high-current return paths. Proper PCB layout requires connecting AGND and PGND at a single point near the device, typically via the thermal pad, to prevent ground bounce while maintaining noise immunity. This separation is essential for achieving the LM43603PWP's specified 1.011 V ±1.2% feedback accuracy.
Can the LM43603PWP be synchronized to an external clock, and what are the interface requirements?
Yes, the LM43603PWP supports external clock synchronization via the SYNC pin (Pin 6). The input accepts TTL- or CMOS-level clocks with thresholds of 0.4 V (low) and 2 V (high), minimum pulse width of 80 ns, and duty cycle between 10% and 90%. To prevent ringing and false triggering, TI recommends proper high-speed termination - typically a series resistor near the SYNC source and controlled-impedance routing. Synchronization allows the LM43603PWP to align switching edges with other converters in multi-rail systems, reducing beat frequencies and easing EMI filtering.
LM43603PWP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.5V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 1V
- Voltage - Output (Max):
- 28V
- Current - Output:
- 3A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-HTSSOP
LM43603PWP FAQ
1.How can I place an order for LM43603PWP through Aetrix?
Please submit a Request for Quotation (RFQ) for LM43603PWP on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM43603PWP reliable?
The price and inventory of LM43603PWP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM43603PWP is usually 5 days.
3.What payment methods are accepted for LM43603PWP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM43603PWP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM43603PWP?
LM43603PWP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM43603PWP order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM43603PWP?
For technical support, including LM43603PWP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM43603PWP requirements.
6.How does Aetrix verify that LM43603PWP is sourced from the original manufacturer or authorized distributors?
All LM43603PWP products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM43603PWP meets industry standards.
7.What is the process for return or replacement of LM43603PWP?
All LM43603PWP units undergo pre-shipment inspection (PSI). If there is an issue with LM43603PWP, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM43603PWP part is unused and in its original packaging.
Return procedure for LM43603PWP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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