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Texas Instruments LM43601PWP
- Part No.:
- LM43601PWP
- Manufacturer:
- Texas Instruments
- Package:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM43601PWP.pdf
- Description:
- IC REG BUCK ADJ 1A 16HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:484
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Product details
Overview
LM43601PWP from Texas Instruments is a 3.5-V to 36-V, 1-A synchronous step-down DC-DC converter in a 16-pin HTSSOP (PWP) package. It delivers regulated output with 33-µA quiescent current in regulation, 500-kHz default switching frequency, and integrated power-good flag - enabling compact, high-efficiency point-of-load conversion in industrial and automotive subsystems.
For engineers reviewing the LM43601PWP datasheet, LM43601PWP pinout, LM43601PWP application, or LM43601PWP equivalent, key selection criteria include its EN-controlled precision UVLO (2.1 V ±30 mV), internal soft-start (4.1 ms), EMI-compliant design meeting EN55022 Class B, and compatibility with ceramic/polymer/tantalum output capacitors without external compensation.
Technical Context
The LM43601PWP employs fixed-frequency peak-current-mode control with automatic transition into discontinuous conduction mode (DCM) and pulse-frequency modulation (PFM) at light loads. Its architecture integrates both high-side and low-side NMOS power switches (RDS(on) = 419 mΩ / 231 mΩ), internal LDO bias supply (VCC = 3.3 V), and analog ground (AGND) separation for noise-sensitive feedback.
It supports programmable frequency (200 kHz–2.2 MHz via RT pin), external clock synchronization (200 kHz–2.2 MHz), output voltage tracking (via SS/TRK), and hiccup-mode short-circuit protection. Thermal shutdown triggers at 160°C with 10°C hysteresis, and junction-to-ambient thermal resistance is 39.9°C/W on a 4-layer PCB.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5 V to 36 V - supports wide-input industrial and automotive rails, including 12 V, 24 V, and 28 V systems with 42 V transient tolerance. |
| Output Current | 1 A continuous - sufficient for FPGA I/O banks, microcontroller cores, and sensor signal chains without external current boosting. |
| Quiescent Current | 33 µA in regulation - enables always-on operation in battery-backed or energy-harvesting applications with minimal standby drain. |
| Switching Frequency | Default 500 kHz (adjustable 200 kHz–2.2 MHz) - balances efficiency vs. size: higher frequencies shrink inductors/capacitors; lower frequencies improve light-load efficiency. |
| Feedback Reference | 1.016 V ±10 mV (–40°C to +125°C) - enables accurate output setting (e.g., 3.3 V ±1%) using standard 1% resistors without calibration. |
| EMI Compliance | Meets EN55022/CISPR 22 Class B radiated & conducted emissions - reduces need for external filtering in commercial/industrial enclosures. |
| Protection Features | Thermal shutdown (160°C), hiccup-mode short-circuit, cycle-by-cycle current limit (2.45 A peak), and precision enable UVLO - ensures robust field operation without external supervision circuitry. |
Pinout & Package
LM43601PWP is housed in a thermally enhanced 16-pin HTSSOP (PWP) package measuring 6.6 mm × 5.1 mm × 1.2 mm with 0.65-mm lead pitch. The exposed thermal pad (PAD) must be soldered to a PCB ground plane for effective heat dissipation (RθJB = 21.7°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 SW | Switch node | Connects to inductor; carries high di/dt switching current - requires short, low-inductance layout to minimize EMI and voltage spikes. |
| 3 CBOOT | Bootstrap capacitor connection | Supplies gate drive for high-side FET; requires 470-nF ceramic capacitor between CBOOT and SW for reliable operation. |
| 4 VCC | Internal LDO output | Bypass with 1–10 µF capacitor to AGND; powers internal circuitry - no external load permitted. |
| 5 BIAS | Optional LDO input | Tie to VOUT (if 3.3 V ≤ VOUT ≤ 28 V) or external 3.3/5 V rail to reduce VIN current draw and improve efficiency. |
| 6 SYNC | External clock input | Accepts 200 kHz–2.2 MHz square wave; enables synchronized multi-rail systems and EMI spreading - tie to AGND if unused. |
| 7 RT | Frequency programming | Resistor to AGND sets frequency; open circuit defaults to 500 kHz - enables precise timing control without crystal. |
| 8 PGOOD | Open-drain power-good flag | Signals valid regulation (±7% of FB); requires 10–100 kΩ pull-up - used for sequencing, fault reporting, or MCU reset assertion. |
| 9 FB | Feedback sense input | Monitors resistor divider output; 1.016 V reference enables adjustable VOUT from 1 V to 28 V - sensitive to noise; route away from SW. |
| 10 AGND | Analog ground reference | Reference for FB, EN, SS/TRK, and internal references - connect directly to PGND at single point near device to avoid noise coupling. |
| 11 SS/TRK | Soft-start & tracking control | Capacitor extends soft-start time; external ramp enables output voltage tracking - prevents inrush and enables coordinated rail sequencing. |
| 12 EN | Enable input | Logic-level control (2.1 V threshold); supports precision system UVLO when tied to resistor divider from VIN - no floating allowed. |
| 13, 14 VIN | Main power input | Supplies high-side FET and internal LDO; bypass with high-frequency ceramic capacitors close to pins - critical for stability and EMI. |
| 15, 16 PGND | Power ground return | Low-impedance path for inductor and low-side FET current; connect to PAD and AGND - forms primary current loop with VIN and SW. |
| PAD | Exposed thermal pad | Internally connected to PGND; mandatory solder connection to PCB ground plane - accounts for >70% of heat transfer out of the die. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode, reducing solution size and improving full-load efficiency by up to 5% versus asynchronous designs. |
| Internal compensation | Reduces BOM count by removing external Type-II/III compensation network - accelerates design cycle and improves production consistency. |
| Stable with diverse output capacitors | Supports ceramic, polymer, tantalum, and aluminum electrolytic capacitors without phase-margin tuning - simplifies sourcing and reliability validation. |
| Soft-start into pre-biased load | Prevents reverse current flow during startup when output is already charged - essential for hot-swap and multi-rail systems. |
| Output voltage tracking | Enables controlled ramping of multiple rails (e.g., core and I/O) using external voltage ramp on SS/TRK - avoids latch-up in FPGAs and ASICs. |
| Power-good flag with deglitching | 220-µs rise/fall deglitching prevents false triggering from noise; open-drain output interfaces directly with 1.8–12 V logic domains. |
Applications
| Industrial Power Supplies | Telecommunications Systems |
|---|---|
|
Use Scenario: Distributed 24 V DC bus powering remote I/O modules, PLC backplanes, and field transmitters. IC Role / Device Role / Timing Role: Primary point-of-load regulator converting 24 V to 3.3 V/5 V for microcontrollers, ADCs, and isolated gate drivers. Use Value: 33-µA quiescent current enables low-power sleep modes; EN-controlled UVLO ensures clean startup across varying line conditions. |
Use Scenario: Intermediate 12 V rail generation in base station power shelves feeding RF amplifiers and digital signal processors. IC Role / Device Role / Timing Role: Secondary buck stage delivering tightly regulated 5 V or 1.8 V with fast transient response and low noise. Use Value: Meets EN55022 Class B emissions without added filters; PGOOD enables safe sequencing with FPGA configuration logic. |
| Sub-AM Band Automotive | High Efficiency Point-Of-Load Regulation |
|
Use Scenario: Infotainment head unit power management where 12 V battery input must supply 3.3 V for SoC peripherals and displays. IC Role / Device Role / Timing Role: Compact, thermally robust DC-DC converter operating across cold-crank (6 V) to load-dump (42 V) transients. Use Value: 36 V max input + 42 V transient rating eliminates need for upstream TVS; BIAS pin connection to VOUT improves efficiency at 3.3 V output. |
Use Scenario: FPGA core voltage regulation requiring precise 1.2 V @ 1 A with tight load-step response and minimal board area. IC Role / Device Role / Timing Role: High-density buck converter with internal MOSFETs and optimized pinout for minimal loop inductance. Use Value: Internal soft-start (4.1 ms) prevents inrush; SS/TRK pin enables tracking with auxiliary 2.5 V rail - avoids sequencing ICs. |
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 |
|---|---|---|---|
| LM43600PWP | 0.5-A output current; identical pinout, package, and feature set except reduced current capability and higher RDS(on). | Suitable for lower-power microcontrollers or sensors where 1-A headroom is unnecessary. | Select LM43600PWP only when load current remains ≤0.5 A continuously - avoids thermal derating and enables smaller inductors. |
| LM43602PWP | 2-A output current; same 16-pin HTSSOP footprint and pin-compatible interface, but higher current MOSFETs and adjusted current-sense gain. | Required for higher-current FPGA I/O banks or dual-core processors with burst loads exceeding 1 A. | Choose LM43602PWP when peak load exceeds 1.2 A or when future-proofing for higher-power derivatives - no PCB change needed. |
Compared with LM43600PWP and LM43602PWP, the LM43601PWP provides optimal balance of current capability, thermal performance, and solution size for mid-range embedded applications - avoiding overdesign while maintaining margin for transient peaks.
Availability
LM43601PWP is available at Aetrix Electronics and suitable for industrial power supplies, telecommunications systems, and sub-AM band automotive electronics requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature.
Supply support for LM43601PWP 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 DC-DC converter innovation.
The LM43601PWP belongs to TI's LM436xx family of wide-input synchronous buck regulators, designed specifically for space-constrained, high-reliability applications demanding low IQ, EMI compliance, and seamless integration into complex power trees.
FAQ
What is the maximum input voltage rating for the LM43601PWP?
The LM43601PWP has an absolute maximum input voltage rating of 42 V, with recommended operating range from 3.5 V to 36 V. This allows reliable operation across automotive cold-crank (down to 6 V) and load-dump (up to 42 V) events without external clamping - a key requirement for sub-AM band automotive systems using the LM43601PWP.
Does the LM43601PWP require external compensation components?
No, the LM43601PWP features internal compensation, eliminating the need for external Type-II or Type-III compensation networks. This reduces bill-of-materials count, saves PCB area, and improves design reproducibility - a verified characteristic of the LM43601PWP confirmed in TI's SNVSA44B datasheet Section 7.3.2.
How does the LM43601PWP achieve EN55022 Class B compliance?
The LM43601PWP meets EN55022 Class B radiated and conducted emissions through integrated EMI reduction techniques: optimized pinout for minimal switching loop area, internal boot-strapping, valley-switching DCM mode at light loads, and built-in slew-rate control. Measured data on the LM43601PWPEVM (with default BOM, no input filter) confirms compliance per Figure 21–24 in the LM43601PWP datasheet.
Can the LM43601PWP start up into a pre-biased output?
Yes, the LM43601PWP supports soft-start into a pre-biased output - a documented feature in the "Features" section and validated in application testing. This prevents reverse current flow during startup when the output capacitor is already charged, making the LM43601PWP suitable for hot-swap and multi-rail sequencing applications without additional external circuitry.
What thermal performance can be expected from the LM43601PWP in a standard PCB layout?
On a 4-layer PCB with adequate copper pour under the exposed thermal pad (PAD), the LM43601PWP achieves a junction-to-ambient thermal resistance (RθJA) of 39.9°C/W. At 1-A load and 12-V input, typical power dissipation is ~0.3 W, resulting in ~12°C junction-to-ambient rise - well within the –40°C to +125°C operating range specified for the LM43601PWP.
LM43601PWP 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:
- 1A
- 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
LM43601PWP FAQ
1.How can I place an order for LM43601PWP through Aetrix?
Please submit a Request for Quotation (RFQ) for LM43601PWP 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 LM43601PWP reliable?
The price and inventory of LM43601PWP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM43601PWP is usually 5 days.
3.What payment methods are accepted for LM43601PWP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM43601PWP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM43601PWP?
LM43601PWP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM43601PWP 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 LM43601PWP?
For technical support, including LM43601PWP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM43601PWP requirements.
6.How does Aetrix verify that LM43601PWP is sourced from the original manufacturer or authorized distributors?
All LM43601PWP 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 LM43601PWP meets industry standards.
7.What is the process for return or replacement of LM43601PWP?
All LM43601PWP units undergo pre-shipment inspection (PSI). If there is an issue with LM43601PWP, 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 LM43601PWP part is unused and in its original packaging.
Return procedure for LM43601PWP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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