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Texas Instruments LM20343MHE/NOPB
- Part No.:
- LM20343MHE/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM20343MHE/NOPB.pdf
- Description:
- IC REG BUCK ADJ 3A 20HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,133
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Product details
Overview
LM20343MHE/NOPB from Texas Instruments is a 36V, 3A synchronous buck regulator with current-mode control, 130 mΩ/110 mΩ integrated power MOSFETs, 1.5% feedback voltage accuracy, and adjustable 250 kHz–1 MHz switching frequency-designed for high-voltage industrial and communications power rails.
For engineers reviewing the LM20343MHE/NOPB datasheet, LM20343MHE/NOPB pinout, LM20343MHE/NOPB application, or LM20343MHE/NOPB equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, application-specific use cases, and two confirmed alternative parts with functional and selection guidance.
Technical Context
The LM20343MHE/NOPB implements peak current-mode control with non-linear (parabolic) slope compensation to maintain stability across output voltages from 0.8 V to VIN−2 V, eliminating sub-harmonic oscillation without manual ramp tuning. Its dual-MOSFET architecture integrates 130 mΩ high-side and 110 mΩ low-side NMOS switches rated for 5.2 A peak current.
It features precision analog enable with 1.25 V threshold and 50 mV hysteresis, programmable soft-start via external capacitor on SS/TRK, and PGOOD open-drain output with 20 µs deglitching and 95% VFB rising threshold. Internal OVP, UVLO (4.25 V), thermal shutdown (170 °C), and cycle-by-cycle current limiting provide full fault protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 36 V - supports wide industrial bus inputs including 12 V, 24 V, and 32 V systems without pre-regulation. |
| Output Current | 3 A continuous - delivers regulated power to FPGAs, DSPs, and ASICs with margin for transient loads. |
| Feedback Accuracy | ±1.5% at TJ = −40°C to +125°C - ensures stable output voltage under temperature extremes and load variation. |
| Switching Frequency | 250 kHz to 1 MHz (resistor-programmable) - enables optimization for EMI, efficiency, or size using RRT from RT to AGND. |
| Integrated MOSFETs | 130 mΩ HS / 110 mΩ LS - reduces external component count and conduction losses; eliminates need for discrete gate drivers. |
| Soft-Start Control | External capacitor on SS/TRK pin - provides monotonic startup and tracking capability for multi-rail sequencing. |
| Power Good Threshold | 95% of VFB rising, 3% hysteresis - enables reliable system power sequencing and fault detection without external comparators. |
Pinout & Package
LM20343MHE/NOPB is housed in a thermally enhanced 20-pin HTSSOP package with exposed pad (PWP0020A), requiring PCB ground plane connection for optimal thermal performance (θJA = 27 °C/W on 4-layer board).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SS/TRK | Soft-start/Tracking input | 4.5 µA internal current source charges external capacitor; enables monotonic startup or rail tracking with low-impedance source. |
| 2 FB | Feedback input | Connects to resistor divider; referenced to precise 800 mV internal bandgap-sets output voltage as VOUT = 0.8 V × (1 + RFB1/RFB2). |
| 3 PGOOD | Open-drain power-good indicator | Asserts low when VOUT drops below 95% of target; requires 10 kΩ–100 kΩ pull-up for logic-level interface to microcontrollers or sequencers. |
| 4 COMP | Error amplifier output / PWM input | Interface for Type II/III compensation network between COMP and AGND-enables stable loop design across capacitor types and loads. |
| 5,6,15,16 VIN | Main input supply | Accepts 4.5–36 V; multiple pins reduce trace resistance and improve current handling for high-power operation. |
| 7,8,13,14 SW | Switch node | Drain of low-side NMOS and source of high-side NMOS; connects to inductor and bootstrap capacitor-critical for layout EMI control. |
| 9,10,11 GND | Power ground | Reference for integrated MOSFETs; must be tied to power ground plane with low-inductance path to minimize switching noise. |
| 12 AGND | Analog ground | Reference for error amplifier, oscillator, and bias circuits-requires separate low-noise connection to GND plane near COMP/FB pins. |
| 17 BOOT | Bootstrap capacitor connection | Connects external capacitor (SW to BOOT); powers high-side gate driver-requires ceramic cap ≥0.1 µF placed adjacent to pin. |
| 18 VCC | Internal LDO output | Regulated ~5.5 V output (up to 7.2 V VIN); powers internal circuitry-requires 0.1–1 µF ceramic decoupling close to pin. |
| 19 EN | Enable/UVLO input | 1.25 V threshold with 50 mV hysteresis; internal 2 µA pull-up enables default-on operation if left floating. |
| 20 RT | Oscillator frequency adjust | 550 mV bias point; external resistor to AGND sets fSW from 250 kHz to 1 MHz-RRT = (78 kΩ / fSW_kHz) − 55 kΩ. |
| EP | Exposed pad | Internally weakly connected to GND; must be soldered to PCB ground plane to achieve θJC = 5.6 °C/W and prevent thermal throttling. |
Key Features
| Feature | Design Value |
|---|---|
| Non-linear slope compensation | Parabolic ramp adapts to output voltage-ensures stable current-mode control across full 0.8 V–34 V output range without manual tuning. |
| Pre-biased startup support | Does not sink current during startup if VOUT > 0 V-prevents damage to FPGA/ASIC outputs coupled via parasitic paths in multi-rail systems. |
| Integrated OVP and UVP monitoring | Detects overvoltage at 110% VFB and undervoltage at 95% VFB-triggers immediate low-side FET activation and PGOOD deassertion. |
| Adjustable soft-start & tracking | Single SS/TRK pin supports both timed ramp (via CSS) and external voltage tracking-enables synchronized power-up in complex PMIC architectures. |
| Thermal shutdown with hysteresis | Shuts down at 170 °C junction temp; restarts at ~150 °C-prevents catastrophic failure while allowing recovery after transient overload or poor airflow. |
Applications
| Industrial PLC Power Rails | Automotive Infotainment Core Supply |
|---|---|
|
Use Scenario: Regulating 3.3 V or 5 V from a 24 V vehicle battery or 32 V industrial bus with strict thermal and reliability requirements. IC Role / Device Role / Timing Role: Primary synchronous buck converter delivering up to 3 A to SoC cores, memory interfaces, and display controllers. Use Value: Integrated 130 mΩ/110 mΩ MOSFETs and 94% peak efficiency reduce heat generation in sealed enclosures; PGOOD enables safe boot sequencing. |
Use Scenario: Powering FPGA I/O banks and transceivers in head-unit designs where input voltage varies from 9 V (cold crank) to 16 V (load dump). IC Role / Device Role / Timing Role: Adjustable-frequency buck regulator supporting dynamic frequency scaling and EMI spread-spectrum modes. Use Value: 250 kHz–1 MHz programmability allows avoiding AM radio band; UVLO hysteresis prevents false turn-off during engine cranking transients. |
| FPGA/ASIC Point-of-Load Supply | Communications Base Station Bias Rail |
|
Use Scenario: Generating 1.2 V or 1.5 V for high-performance FPGA core logic with tight regulation and fast transient response. IC Role / Device Role / Timing Role: High-accuracy (±1.5%) current-mode buck supplying up to 3 A with programmable soft-start for monotonic ramp. Use Value: 1.5% VFB tolerance and cycle-by-cycle current limit ensure stable operation under rapid load steps; SS/TRK enables voltage tracking with auxiliary rails. |
Use Scenario: Providing stable 5 V or 12 V bias to RF front-end amplifiers and clock distribution ICs in 4G/5G macro base stations. IC Role / Device Role / Timing Role: Robust buck regulator operating from -40°C to +125°C ambient with integrated thermal protection and OVP. Use Value: Junction-temp-rated operation and 170 °C thermal shutdown guarantee reliability in uncooled outdoor cabinets; exposed pad improves long-term thermal stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM20343MHX/NOPB | Same die, tape-and-reel packaging (no cut-tape or sample quantities); identical electrical specs and pinout. | No functional difference-used for volume production; same thermal and layout requirements. | Select LM20343MHX/NOPB for high-volume manufacturing; LM20343MHE/NOPB is preferred for prototyping and evaluation. |
| TPS54340DDAR | 3.5 A max output, 4.5–42 V input, 100 mΩ/100 mΩ MOSFETs, fixed 3.5 V VREF, no SS/TRK tracking mode. | Lacks voltage tracking and pre-bias startup; higher current rating but lower VFB accuracy (±1.8%). | Choose TPS54340DDAR only when higher output current is required and tracking/soft-start flexibility is not needed. |
Compared with LM20343MHE/NOPB, LM20343MHX/NOPB offers identical performance in bulk packaging, while TPS54340DDAR trades tracking capability and tighter VFB accuracy for higher current and wider input range-making it suitable only for non-sequenced, high-current applications.
Availability
LM20343MHE/NOPB is available at Aetrix Electronics and suitable for industrial PLC power rails, automotive infotainment core supplies, and FPGA/ASIC point-of-load regulation requiring stable component supply, long-lifecycle support, and consistent parametric performance.
Supply support for LM20343MHE/NOPB 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 expertise in high-reliability power conversion solutions.
The LM20343MHE/NOPB belongs to TI's high-voltage synchronous buck regulator product line, engineered for robust operation in 4.5–36 V industrial, automotive, and communications systems where thermal resilience, precision regulation, and fault protection are critical.
FAQ
What is the maximum output current supported by the LM20343MHE/NOPB?
The LM20343MHE/NOPB delivers up to 3 A of continuous output current under typical thermal conditions (θJA = 27 °C/W on 4-layer PCB). Its 5.2 A peak current limit and integrated 130 mΩ/110 mΩ MOSFETs allow brief transient surges without foldback, provided layout and heatsinking maintain junction temperature below 125 °C.
How does the LM20343MHE/NOPB handle pre-biased output conditions during startup?
The LM20343MHE/NOPB supports pre-biased startup by disabling negative current sinking until the soft-start ramp exceeds the FB pin voltage. This prevents reverse current flow into powered loads like FPGAs or ASICs-critical in multi-rail systems where parasitic coupling may hold VOUT > 0 V before enable.
Can the LM20343MHE/NOPB be used without an external soft-start capacitor?
Yes-the LM20343MHE/NOPB defaults to an internal 1 ms soft-start ramp when the SS/TRK pin is left unconnected. However, an external capacitor is recommended for monotonic startup, PGOOD synchronization, or voltage tracking applications where precise timing or rail coordination is required.
What is the purpose of the exposed pad (EP) on the LM20343MHE/NOPB package?
The exposed pad on the LM20343MHE/NOPB is internally connected to GND and must be soldered to the PCB ground plane to achieve θJC = 5.6 °C/W and prevent thermal throttling. It significantly improves heat dissipation-especially under 3 A continuous load-and is essential for meeting junction temperature limits in enclosed environments.
How is the switching frequency set on the LM20343MHE/NOPB?
The LM20343MHE/NOPB switching frequency is set by connecting a resistor (RRT) from the RT pin to AGND. The relationship is RRT (kΩ) ≈ (78 / fSW_kHz) − 55. For example, 49.9 kΩ yields ~750 kHz, while 249 kΩ yields ~250 kHz. Omitting RRT disables operation-no internal default frequency exists.
LM20343MHE/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-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):
- 4.5V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 28.8V
- Current - Output:
- 3A
- Frequency - Switching:
- 250kHz ~ 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-HTSSOP
LM20343MHE/NOPB FAQ
1.How can I place an order for LM20343MHE/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM20343MHE/NOPB 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 LM20343MHE/NOPB reliable?
The price and inventory of LM20343MHE/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM20343MHE/NOPB is usually 5 days.
3.What payment methods are accepted for LM20343MHE/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM20343MHE/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM20343MHE/NOPB?
LM20343MHE/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM20343MHE/NOPB 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 LM20343MHE/NOPB?
For technical support, including LM20343MHE/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM20343MHE/NOPB requirements.
6.How does Aetrix verify that LM20343MHE/NOPB is sourced from the original manufacturer or authorized distributors?
All LM20343MHE/NOPB 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 LM20343MHE/NOPB meets industry standards.
7.What is the process for return or replacement of LM20343MHE/NOPB?
All LM20343MHE/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM20343MHE/NOPB, 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 LM20343MHE/NOPB part is unused and in its original packaging.
Return procedure for LM20343MHE/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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