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Texas Instruments LM43603PWPT
- Part No.:
- LM43603PWPT
- Manufacturer:
- Texas Instruments
- Package:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM43603PWPT.pdf
- Description:
- IC REG BUCK ADJ 3A 16HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,204
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Product details
Overview
LM43603PWPT from Texas Instruments is a 3.5-V to 36-V, 3-A synchronous step-down DC-DC converter in HTSSOP-16 (PWP) package. It delivers high efficiency across load range via DCM/PEM light-load modes, features internal compensation, 27-µA quiescent current in regulation, and meets EN55022 Class B radiated EMI limits - used in industrial power supplies and telecom systems requiring compact wide-input regulation.
For engineers reviewing the LM43603PWPT datasheet, LM43603PWPT pinout, LM43603PWPT application, or LM43603PWPT equivalent, key selection criteria include input voltage range (3.5–36 V), output current capability (3 A), adjustable switching frequency (200 kHz–2.2 MHz), precision enable threshold (2.2 V typical), and thermal shutdown at 160°C.
Technical Context
The LM43603PWPT employs peak current mode control for stable loop compensation and cycle-by-cycle current limiting. Its integrated synchronous rectification eliminates external diode losses, while internal soft-start (4.1 ms default) and output voltage tracking support controlled power-up sequencing.
EMI performance is enhanced by spread-spectrum-like behavior in PFM mode and optimized pin layout for low-noise SW node routing. The device supports external frequency synchronization and uses a single RT resistor to set switching frequency - with 10% accuracy over temperature and line.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5 V to 36 V - supports 12 V, 24 V, and 36 V industrial rails with 42 V absolute max rating. |
| Output Current | 3 A continuous - sufficient for FPGA core, DSP, or multi-rail point-of-load applications. |
| Quiescent Current | 27 µA in regulation - enables battery-backed or always-on systems with minimal standby loss. |
| Switching Frequency | 200 kHz to 2.2 MHz adjustable - allows optimization of size (higher fSW → smaller L/C) vs. efficiency (lower fSW → lower switching loss). |
| Feedback Reference | 1.011 V ±1.2% - enables precise output regulation down to 1 V with standard resistor dividers. |
| Thermal Shutdown | 160°C trip / 150°C recovery - provides robust protection during overload or poor heatsinking conditions. |
| Power-Good Flag | Open-drain PGOOD with 77–113% FB threshold hysteresis - ensures reliable system power sequencing and fault detection. |
Pinout & Package
LM43603PWPT 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 for PCB-level heat dissipation. Pin 1 is SW (switch node), and pins 15–16 are PGND - critical for minimizing high-current loop inductance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1,2) | Switch node | Connects to inductor; carries full switching current and high dv/dt - requires short, low-inductance trace to minimize EMI. |
| CBOOT (3) | Bootstrap capacitor connection | Supplies gate drive for high-side FET; requires 470-nF ceramic capacitor between CBOOT and SW. |
| VCC (4) | Internal bias supply output | Bypassed to AGND; powers internal circuitry - no external loading permitted. |
| BIAS (5) | Optional LDO input | Improves efficiency when tied to VOUT (3.3–28 V) or external 3.3/5 V rail; 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 fSW; open-circuit defaults to 500 kHz with ±10% tolerance. |
| PGOOD (8) | Power-good flag | Open-drain output indicating valid VOUT; requires 10–100 kΩ pullup to logic rail ≤12 V. |
| FB (9) | Feedback sense | Monitors output via resistor divider; 1.011 V reference enables accurate regulation from 1 V to 28 V. |
| AGND (10) | Analog ground | Reference for internal references and logic; must be connected to system ground with low-impedance path. |
| SS/TRK (11) | Soft-start / tracking control | Controls startup slew rate; connect capacitor to extend soft-start time or external ramp for voltage tracking. |
| EN (12) | Enable input | Logic-level control with precision UVLO (2.2 V typical); hysteresis prevents chatter near threshold. |
| VIN (13,14) | Main input supply | Connects to input capacitors; dual pins reduce IR drop and improve high-frequency decoupling. |
| PGND (15,16) | Power ground | Low-side FET source connection; must tie directly to AGND, CIN ground, and thermal pad for optimal thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode, reducing conduction loss and board area - improves full-load efficiency by ~3–5% vs. asynchronous designs. |
| Stable with diverse output capacitors | Compatible with ceramic, polymer, tantalum, and aluminum electrolytic capacitors - simplifies BOM and enables cost-optimized output filtering. |
| Internal soft-start + extendable timing | Fixed 4.1 ms internal soft-start; adding external capacitor scales ramp time linearly - prevents inrush current in sensitive loads. |
| Output voltage tracking | SS/TRK pin accepts external voltage ramp to coordinate startup with other rails - essential for multi-rail processors and FPGAs. |
| EMI-compliant design | Meets EN55022 Class B radiated emissions without added filters - reduces system-level EMI mitigation cost and complexity. |
Applications
| Industrial PLC Power | Telecom Remote Radio Unit |
|---|---|
Use Scenario: Powers FPGA, ADCs, and communication interfaces in programmable logic controllers operating from 24 V DC bus. IC Role / Device Role / Timing Role: Primary buck regulator delivering 3.3 V/3 A with tight load transient response and low ripple. Use Value: 27-µA quiescent current extends backup battery life; EN pin UVLO enables clean brownout recovery. | Use Scenario: Supplies 5 V to RF front-end ICs and baseband processors in 4G/5G remote radio heads with strict thermal constraints. IC Role / Device Role / Timing Role: High-efficiency point-of-load converter with thermal shutdown (160°C) and PGOOD sequencing. Use Value: Internal compensation and stable ceramic-capacitor operation reduce design cycle time and bill-of-materials count. |
| Automotive Sub-AM Band Systems | General Purpose Wide VIN Regulation |
Use Scenario: Provides 12 V intermediate rail for infotainment subsystems in vehicles with 12 V/24 V battery architectures. IC Role / Device Role / Timing Role: Wide-input buck converter supporting cold-crank (3.5 V) and load-dump (36 V) transients. Use Value: 42 V absolute max input withstands automotive transients; BIAS pin improves efficiency when tied to 12 V output. | Use Scenario: Delivers regulated 3.3 V or 5 V from unregulated 12–36 V sources in test equipment, medical devices, and IoT gateways. IC Role / Device Role / Timing Role: Flexible, easy-to-design synchronous buck with adjustable frequency and external sync capability. Use Value: RT pin programmability and SYNC input allow system-level clock alignment - critical for noise-sensitive analog circuits. |
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 |
|---|---|---|---|
| LM43602PWPT | 2-A output current, identical pinout and feature set - shares same HTSSOP-16 footprint and register compatibility. | Suitable where 2 A suffices; lower current limit reduces thermal stress but limits peak load headroom. | Select LM43602PWPT for cost-sensitive or thermally constrained designs needing <2 A sustained output. |
| LM46002QWRNXTQ1 | Automotive-grade (AEC-Q100), 2-A output, VSON-16 package - includes enhanced ESD and extended temperature range (–40°C to +150°C). | Required for automotive under-hood applications; lacks HTSSOP package and some industrial EMI optimizations. | Choose LM46002QWRNXTQ1 only for automotive safety-critical systems requiring qualification and higher junction temperature rating. |
Compared with LM43602PWPT and LM46002QWRNXTQ1, the LM43603PWPT uniquely balances 3-A capability, industrial EMI compliance, and HTSSOP thermal performance - making it optimal for non-automotive wide-VIN applications demanding full 3-A delivery with minimal external components.
Availability
LM43603PWPT is available at Aetrix Electronics and suitable for industrial PLC power, telecom remote radio units, and automotive sub-AM band systems requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM43603PWPT 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 technologies - with decades of expertise in high-reliability DC-DC conversion.
The LM43603PWPT belongs to TI's LM436xx family of wide-input synchronous buck converters, designed specifically for industrial, telecom, and automotive subsystems needing compact, efficient, and EMI-compliant power solutions.
FAQ
What is the maximum input voltage rating for the LM43603PWPT?
The LM43603PWPT has an absolute maximum input voltage rating of 42 V across VIN to PGND, with recommended operating range from 3.5 V to 36 V. This allows safe operation during automotive load-dump events and industrial 36 V rail surges while maintaining regulation down to cold-crank 3.5 V. Exceeding 42 V risks permanent damage per the Absolute Maximum Ratings table in the official datasheet.
Does the LM43603PWPT require external compensation components?
No, the LM43603PWPT features internal compensation - eliminating the need for external Type-II or Type-III compensation networks. This simplifies design, reduces BOM count, and improves consistency across production units. All loop stability is ensured across the full input/output range and load conditions specified in the datasheet, provided layout guidelines (especially PGND and AGND separation) are followed.
How does the BIAS pin improve efficiency in the LM43603PWPT?
The BIAS pin on the LM43603PWPT allows the internal LDO to draw bias current from VOUT (when 3.3 V ≤ VOUT ≤ 28 V) instead of VIN, reducing power dissipation in the high-side FET driver. When tied to VOUT, it lowers total quiescent current and improves light-load efficiency by up to 2–3 percentage points - especially beneficial in battery-powered or energy-sensitive applications where the LM43603PWPT operates at partial load.
Can the LM43603PWPT synchronize to an external clock signal?
Yes, the LM43603PWPT supports external clock synchronization via the SYNC pin. It accepts TTL- or CMOS-compatible clock signals with thresholds of 0.4 V (low) and 2 V (high), duty cycle range of 10–90%, and minimum pulse width of 80 ns. Synchronization enables noise reduction in systems with multiple switching regulators and facilitates EMI spectral shaping - a capability confirmed in Section 6.7 of the LM43603PWPT datasheet.
What thermal performance can be expected from the LM43603PWPT in HTSSOP package?
In the HTSSOP-16 (PWP) package, the LM43603PWPT achieves a junction-to-board thermal resistance (RθJB) of 19.9°C/W on a 4-layer JEDEC board. With proper PCB copper area under the thermal pad and vias to inner ground planes, it sustains 3 A continuous output at ambient temperatures up to 85°C without derating - validated by thermal imaging in TI's LM43603PWPEVM evaluation reports.
LM43603PWPT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
LM43603PWPT FAQ
1.How can I place an order for LM43603PWPT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM43603PWPT 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 LM43603PWPT reliable?
The price and inventory of LM43603PWPT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM43603PWPT is usually 5 days.
3.What payment methods are accepted for LM43603PWPT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM43603PWPT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM43603PWPT?
LM43603PWPT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM43603PWPT 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 LM43603PWPT?
For technical support, including LM43603PWPT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM43603PWPT requirements.
6.How does Aetrix verify that LM43603PWPT is sourced from the original manufacturer or authorized distributors?
All LM43603PWPT 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 LM43603PWPT meets industry standards.
7.What is the process for return or replacement of LM43603PWPT?
All LM43603PWPT units undergo pre-shipment inspection (PSI). If there is an issue with LM43603PWPT, 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 LM43603PWPT part is unused and in its original packaging.
Return procedure for LM43603PWPT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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