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Texas Instruments LM43601PWPT
- Part No.:
- LM43601PWPT
- Manufacturer:
- Texas Instruments
- Package:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM43601PWPT.pdf
- Description:
- IC REG BUCK ADJ 1A 16HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:768
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Product details
Overview
LM43601PWPT from Texas Instruments is a 3.5-V to 36-V, 1-A synchronous step-down DC-DC converter in HTSSOP-16 (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 LM43601PWPT datasheet, LM43601PWPT pinout, LM43601PWPT application, or LM43601PWPT equivalent, key selection criteria include its EN55022 Class B EMI compliance, precision enable threshold (2.1 V typ), internal soft-start (4.1 ms), and support for external frequency synchronization across 200 kHz–2.2 MHz.
Technical Context
The LM43601PWPT employs peak-current-mode control with discontinuous conduction mode (DCM) and pulse-frequency modulation (PFM) at light loads to maintain high efficiency across 0–1 A output range. Its internal compensation eliminates loop-stability tuning, while programmable RT resistor and SYNC input allow flexible frequency control and system-level clock alignment.
It integrates both high-side (419 mΩ RDS(on)) and low-side (231 mΩ RDS(on)) NMOS FETs, supports pre-biased soft-start, and features hiccup-mode short-circuit protection with 2.45-A peak current limit. Thermal shutdown triggers at 160°C with 10°C hysteresis, and VCC UVLO ensures reliable startup above 3.14 V.
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 low-power monitoring applications. |
| Switching Frequency | 200 kHz to 2.2 MHz (500 kHz default) - allows optimization for size (high-freq) or efficiency (low-freq), with external sync capability. |
| Feedback Reference | 1.016 V ±12 mV (–40°C to 125°C) - enables precise output voltage setting (e.g., 3.3 V ±1%) using standard resistor dividers. |
| EMI Compliance | Meets EN55022/CISPR 22 Class B - reduces need for external filtering in commercial-grade equipment. |
| Thermal Resistance | RθJA = 39.9°C/W (4-layer PCB) - supports 1-A operation up to +125°C junction temperature with minimal heatsinking. |
Pinout & Package
LM43601PWPT is housed in a 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 ground plane for optimal thermal performance and electrical stability.
| 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 terminal | Supplies gate drive for high-side FET; requires 470-nF ceramic capacitor tied to SW for reliable bootstrapping. |
| 4 VCC | Internal LDO output | Bypass with 1–10 µF capacitor to AGND; powers internal circuitry - never load externally or short to ground. |
| 5 BIAS | 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 if used. |
| 6 SYNC | External clock input | Accepts 200 kHz–2.2 MHz square wave; requires proper high-speed termination to prevent ringing - tie to AGND if unused. |
| 7 RT | Frequency programming | Resistor to AGND sets frequency; open circuit yields 500 kHz default - accuracy ±10% with 1% resistors. |
| 8 PGOOD | Open-drain power-good flag | Asserts high when VOUT is within ±7% of target; requires 10–100 kΩ pull-up to ≤12 V logic rail. |
| 9 FB | Feedback sense input | Monitors resistor divider midpoint; 1.016 V reference enables accurate output regulation - avoid floating or shorting. |
| 10 AGND | Analog ground reference | Ground for internal references and error amplifier - connect directly to system ground with low-impedance path. |
| 11 SS/TRK | Soft-start / tracking control | Internal 4.1-ms ramp when open; extend via capacitor or use for output voltage tracking with external ramp source. |
| 12 EN | Enable input | Logic-high (>2.1 V) enables regulator; precision UVLO allows system-level brownout control - do not float. |
| 13, 14 VIN | Main input supply | Connects to input capacitors and high-side FET; place high-frequency CIN as close as possible to these pins and PGND. |
| 15, 16 PGND | Power ground | Low-side FET return path; tie to AGND, PAD, and all input/output capacitor grounds - critical for EMI and thermal performance. |
| PAD | Exposed thermal pad | Internally connected to AGND; must be soldered to large PCB ground plane for heat dissipation and noise reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode, reducing conduction loss and board area - enables >90% efficiency at 1-A load. |
| Stable with diverse output capacitors | Works reliably with ceramic, polymer, tantalum, or aluminum electrolytic capacitors - simplifies BOM and design reuse. |
| Pre-biased soft-start | Allows safe startup into powered output rails (e.g., hot-swap or backplane systems) without reverse current flow. |
| Output voltage tracking | SS/TRK pin accepts external ramp to coordinate power sequencing with other regulators - essential for multi-rail SoCs. |
| Hiccup-mode short-circuit protection | Enters current-limited retry mode on overload - prevents thermal runaway and enables automatic recovery after fault clears. |
| WEBENCH® Power Designer support | Enables full schematic generation, BOM export, and performance simulation directly from TI's online tool - accelerates prototyping. |
Applications
| Industrial PLC I/O Module | Automotive Sub-AM Band Infotainment |
|---|---|
Use Scenario: Powering isolated analog input channels and digital isolators in modular PLC backplanes with 24 V DC input. IC Role / Device Role / Timing Role: Primary 3.3 V/1 A point-of-load regulator delivering stable, low-noise supply to ADC drivers and SPI interface ICs. Use Value: 33-µA quiescent current extends standby runtime; EN55022 Class B compliance avoids costly EMI filters in cabinet-mounted designs. |
Use Scenario: Supplying 5 V to AM/FM radio tuner modules and display controllers in vehicles where 12 V battery input varies from 9 V to 16 V. IC Role / Device Role / Timing Role: Wide-VIN buck converter providing regulated 5 V rail with precision enable for ignition-synchronized power-up. Use Value: 3.5–36 V input range accommodates cold-crank (6.5 V) and load-dump (36 V) transients; hiccup protection handles antenna short faults. |
| Telecom Remote Radio Unit | General-Purpose Wide-VIN Embedded System |
Use Scenario: Generating 3.3 V for FPGA configuration and RF front-end bias in outdoor small-cell base stations with -40°C to +85°C ambient. IC Role / Device Role / Timing Role: High-efficiency synchronous buck supplying FPGA core and SerDes I/O with thermal shutdown at 160°C. Use Value: RθJA = 39.9°C/W enables 1-A operation without heatsink; PGOOD flag synchronizes FPGA configuration sequence. |
Use Scenario: Powering ARM Cortex-M7 MCU, Ethernet PHY, and CAN transceiver in industrial gateway with unregulated 12–24 V input. IC Role / Device Role / Timing Role: Single-chip 1-A buck converter replacing discrete controller + external MOSFETs to reduce footprint and bill-of-materials. Use Value: Internal compensation and pin-to-pin compatibility with LM43600/LM43602 simplify scalability across 0.5–3 A load requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM43600PWPT | 0.5-A output rating; identical pinout, package, and feature set except lower current capability and higher RDS(on). | Suitable for lower-power peripherals (e.g., sensors, UART interfaces) where 1-A headroom is unnecessary. | Select when load current remains ≤500 mA and thermal margin is constrained - same layout, no redesign needed. |
| LM43602PWPT | 2-A output rating; same 16-pin HTSSOP package, pin-compatible, but higher RDS(on) and slightly higher IQ (36 µA). | Required for higher-current rails (e.g., DDR memory termination, dual-core processors) with shared PCB footprint. | Choose for future-proofing or load growth beyond 1 A - drop-in upgrade with verified thermal derating curves. |
Compared with LM43600PWPT and LM43602PWPT, the LM43601PWPT provides optimal balance of 1-A capability, 33-µA quiescent current, and thermal performance in the same compact HTSSOP-16 package - making it ideal for mid-range embedded power nodes where efficiency, size, and reliability are jointly critical.
Availability
LM43601PWPT is available at Aetrix Electronics and suitable for industrial PLCs, automotive infotainment systems, and telecom remote radio units requiring stable component supply, long-term lifecycle support, and EN55022-compliant power conversion.
Supply support for LM43601PWPT 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 over 90 years of innovation in high-reliability electronics.
The LM43601PWPT belongs to TI's LM436xx family of wide-input synchronous buck converters, designed specifically for robust, space-constrained industrial and automotive power supplies demanding high efficiency, low IQ, and EMI compliance.
FAQ
What is the minimum input voltage required for the LM43601PWPT to start switching?
The LM43601PWPT requires a minimum input voltage of 3.8 V to initiate startup and enter regulation. Below this threshold, the device remains in shutdown mode even if the EN pin is asserted. This specification ensures reliable turn-on across temperature and process variations, and is validated per the absolute maximum ratings table in the official datasheet. The LM43601PWPT will not switch or regulate below 3.8 V VIN.
Does the LM43601PWPT support output voltage tracking during power-up sequencing?
Yes, the LM43601PWPT supports output voltage tracking via the SS/TRK pin. When an external voltage ramp is applied to this pin, the output voltage follows the ramp with high fidelity, enabling coordinated power sequencing with other regulators in multi-rail systems. This function is explicitly documented in Section 7.3.10 of the LM43601 datasheet and verified in typical application circuits using the LM43601PWPEVM evaluation module.
Can the LM43601PWPT operate without an external RT resistor?
Yes, the LM43601PWPT operates at its default switching frequency of 500 kHz when the RT pin is left floating. This behavior is specified in the Electrical Characteristics table (FOSC_DEFAULT = 445–570 kHz) and confirmed in functional block diagrams. No external resistor is required for basic operation, though adding an RT resistor enables precise frequency adjustment between 200 kHz and 2.2 MHz.
What is the purpose of the BIAS pin on the LM43601PWPT, and how should it be configured?
The BIAS pin on the LM43601PWPT provides an optional input to the internal LDO, improving efficiency when tied to VOUT (for 3.3–28 V outputs) or an external 3.3 V/5 V rail. When unused, it must be tied to AGND - floating is prohibited. Configuration directly affects quiescent current: using BIAS reduces IQ-SW from 33 µA (VIN-powered) to ~140 µA (BIAS-powered), as measured under typical conditions in the datasheet's Electrical Characteristics section.
How does the LM43601PWPT handle short-circuit conditions on its output?
The LM43601PWPT responds to output short-circuits with hiccup-mode protection: it limits peak inductor current to 2.45 A (typ), shuts down for 5.5 ms, then retries. This cycle repeats until the fault clears, preventing thermal damage and enabling automatic recovery. The behavior is defined in the Current Limit and Hiccup section (NOC = 32 cycles, TOC = 5.5 ms) and validated in thermal stress testing per JEDEC JESD22-A104.
LM43601PWPT 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:
- 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
LM43601PWPT FAQ
1.How can I place an order for LM43601PWPT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM43601PWPT 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 LM43601PWPT reliable?
The price and inventory of LM43601PWPT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM43601PWPT is usually 5 days.
3.What payment methods are accepted for LM43601PWPT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM43601PWPT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM43601PWPT?
LM43601PWPT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM43601PWPT 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 LM43601PWPT?
For technical support, including LM43601PWPT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM43601PWPT requirements.
6.How does Aetrix verify that LM43601PWPT is sourced from the original manufacturer or authorized distributors?
All LM43601PWPT 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 LM43601PWPT meets industry standards.
7.What is the process for return or replacement of LM43601PWPT?
All LM43601PWPT units undergo pre-shipment inspection (PSI). If there is an issue with LM43601PWPT, 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 LM43601PWPT part is unused and in its original packaging.
Return procedure for LM43601PWPT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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