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Texas Instruments LM3103MHX/NOPB
- Part No.:
- LM3103MHX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3103MHX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 750MA 16HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,342
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Product details
Overview
LM3103MHX/NOPB from Texas Instruments is a synchronous step-down DC-DC voltage regulator IC delivering 0.75 A output current with input voltage range 4.5 V to 42 V, 0.6 V ±2% internal reference, and integrated dual N-channel MOSFETs in HTSSOP-16 package - used in industrial control power rails and automotive body electronics.
For engineers reviewing the LM3103MHX/NOPB datasheet, LM3103MHX/NOPB pinout, LM3103MHX/NOPB application, or LM3103MHX/NOPB equivalent, key selection considerations include its constant-on-time (COT) control architecture, no-loop-compensation design, ceramic-capacitor compatibility, programmable switching frequency up to 1 MHz, and valley-current-limit protection at 0.9 A.
Technical Context
The LM3103MHX/NOPB implements a Constant-On-Time (COT) regulation scheme using an internal 0.6 V reference and comparator-driven on-timer, eliminating need for external loop compensation. Its operating frequency remains nearly constant across line variations due to inverse VIN–ton relationship, programmable via RON resistor.
It integrates dual N-channel MOSFETs (RDS(on) = 0.37 Ω main, 0.22 Ω synchronous), supports DCM/CCM operation, and includes zero-coil-current detection for light-load efficiency. Protection features include thermal shutdown (165°C), output over-voltage protection (0.68 V FB threshold), and VCC UVLO (3.7 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 42 V - enables direct conversion from 2–4 cell Li-ion batteries or 12/24 VDC industrial/automotive supplies. |
| Output Current | 0.75 A continuous - sufficient for point-of-load regulation of microcontrollers, sensors, and interface ICs. |
| Reference Voltage | 0.6 V ±2% - sets minimum adjustable output voltage and defines feedback accuracy for stable regulation. |
| Switching Frequency | Up to 1 MHz - allows compact magnetics and high transient response; externally programmable via RON resistor. |
| Main MOSFET RDS(on) | 0.37 Ω (typ) - reduces conduction loss at full load, supporting >90% efficiency at mid-load conditions. |
| Current Limit Threshold | 0.9 A valley detection - provides overcurrent protection without requiring sense resistors or external circuitry. |
| Thermal Shutdown | 165°C with 20°C hysteresis - prevents permanent damage during overload or poor heatsinking; auto-recovery at 145°C. |
Pinout & Package
LM3103MHX/NOPB is housed in a thermally enhanced HTSSOP-16 package (5.00 mm × 4.40 mm) with exposed thermal pad (DAP/EP) for PCB-level heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 1,2) | Main input supply | Accepts 4.5–42 V; powers startup regulator (VCC) and gate drivers; requires local CIN/CIN3 decoupling. |
| SW (Pins 3,4) | Switch node | Connects to inductor; carries high di/dt switching waveform; ties internally to source of main MOSFET and drain of sync MOSFET. |
| BST (Pin 5) | Bootstrap capacitor connection | Requires 33 nF ceramic cap to SW; supplies floating gate drive voltage for main N-MOSFET during on-time. |
| AGND (Pin 6) | Analog ground reference | Ground return for internal bias, FB, SS, EN, RON; must be star-connected to PGND near device. |
| SS (Pin 7) | Soft-start control | 70 µA internal current source charges external CSS; controls output ramp rate and prevents inrush current. |
| NC (Pin 8) | No connection | Internally unconnected; must remain floating - not tied to GND or any other net. |
| GND (Pins 9,10) | Digital ground reference | Must be connected to AGND externally; not internally bonded - ensures clean signal reference separation. |
| FB (Pin 11) | Feedback input | Monitors output via resistor divider; regulated at 0.6 V; bias current <1 nA enables high-impedance dividers. |
| EN (Pin 12) | Enable input | Active-high; internal 1 µA pull-up; enables device when >1.6 V; pulls SS low during disable. |
| RON (Pin 13) | On-time programming | Resistor from VIN to RON sets main MOSFET on-time and thus switching frequency (up to 1 MHz). |
| VCC (Pin 14) | Startup regulator output | 6.0 V ±0.2 V, 33 mA current-limited; powers internal circuitry; requires ≥1 µF ceramic bypass to AGND. |
| PGND (Pins 15,16) | Power ground return | Source connection for synchronous MOSFET; high-current path; must connect to solid ground plane under EP. |
| DAP/EP | Exposed thermal pad | Internally connected to PGND; mandatory solder connection to PCB ground plane for thermal performance (RθJA = 35°C/W). |
Key Features
| Feature | Design Value |
|---|---|
| Constant-On-Time (COT) Control | Enables ultra-fast transient response and eliminates need for external compensation components - simplifies layout and reduces BOM count. |
| Ceramic-Capacitor Stability | Operates stably with low-ESR ceramic output capacitors (≥10 µF), avoiding reliance on capacitor ESR for loop stability. |
| Integrated Dual N-Channel MOSFETs | Reduces external component count by integrating main (0.37 Ω) and synchronous (0.22 Ω) switches - minimizes solution size and conduction losses. |
| Programmable Soft-Start | 70 µA internal current source charges external CSS capacitor - prevents output overshoot and inrush current during power-up. |
| Valley Current Limit Protection | Detects re-circulating inductor current during off-time at 0.9 A threshold - provides robust short-circuit and overload protection without sense resistors. |
| Pre-bias Startup | Allows safe start-up into pre-charged output rail - avoids reverse current flow and potential damage to downstream loads. |
Applications
| Industrial PLC Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Regulating 24 VDC vehicle battery down to 3.3 V for microcontroller, CAN transceiver, and sensor interfaces in door modules or lighting controllers. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, efficient, and protected 3.3 V rail with fast load transient response to handle burst-mode communication. Use Value: Enables single-stage conversion from wide-input automotive supply while maintaining <±2% output regulation and surviving cold-crank (4.5 V) and load-dump (42 V) events. |
Use Scenario: Generating 5 V from 12 VAC/DC systems in factory automation I/O modules where space and thermal constraints limit heatsink use. IC Role / Device Role / Timing Role: Compact, self-contained step-down regulator delivering 0.75 A with minimal external components and no compensation network. Use Value: Reduces board area by 40% vs discrete controller + MOSFET solutions and achieves >88% efficiency at 0.5 A load with ceramic output caps. |
| Point-of-Load for Embedded CPU | Storage System Power Management |
|
Use Scenario: Providing 1.2 V or 1.8 V core voltage to low-power ARM Cortex-M processors in edge IoT gateways powered from 12 V or 24 V backplanes. IC Role / Device Role / Timing Role: Adjustable-output buck regulator with precision 0.6 V reference and programmable soft-start - ensures clean, sequenced power-up. Use Value: Supports output as low as 0.6 V with ±2% accuracy; DCM mode maintains >82% efficiency at 10 mA load for always-on monitoring functions. |
Use Scenario: Powering SATA SSD controllers and flash memory interfaces in NAS enclosures where 12 V or 24 V DC input must be converted to 3.3 V/5 V rails. IC Role / Device Role / Timing Role: High-reliability buck regulator with thermal shutdown, OVP, and current limiting - critical for unattended storage operation. Use Value: Thermal protection (165°C trip) and overvoltage lockout (0.68 V FB threshold) prevent data corruption during thermal runaway or feedback fault conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3102MHX/NOPB | Same family, 1.5-A rated output; higher RDS(on) (0.28 Ω main, 0.18 Ω sync); identical pinout and control architecture. | Supports higher current loads but draws more quiescent current (1.25 mA vs 1.0 mA); requires larger inductor and output cap. | Select when >0.75 A output current is required and board space allows larger magnetics. |
| TPS5430DDAR | 3-A current rating; fixed 500-kHz frequency; external compensation required; different pinout (SOIC-8); no integrated sync FET. | Needs external high-side MOSFET and compensation network; less compact solution but offers higher peak current capability. | Choose for designs needing >0.75 A with proven SOIC layout practices and existing compensation expertise. |
Compared with LM3102MHX/NOPB, the LM3103MHX/NOPB delivers lower quiescent current and smaller solution size for 0.75-A loads; versus TPS5430DDAR, it offers integrated MOSFETs and COT control for simpler, faster-response designs - making LM3103MHX/NOPB optimal for space-constrained industrial and automotive point-of-load applications.
Availability
LM3103MHX/NOPB is available at Aetrix Electronics and suitable for industrial control, automotive telematics, and embedded system power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM3103MHX/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 designing analog ICs, embedded processors, and power management solutions for industrial, automotive, and communications markets.
The LM3103MHX/NOPB belongs to TI's high-voltage synchronous buck regulator product line, engineered for reliable, compact DC-DC conversion in harsh environments - especially where wide input range (4.5–42 V), low ESR capacitor compatibility, and fast transient response are critical.
FAQ
What is the maximum input voltage supported by the LM3103MHX/NOPB?
The LM3103MHX/NOPB supports a maximum input voltage of 42 V, with absolute maximum rating at 43.5 V. This allows direct integration into 24 VDC industrial systems and automotive applications subject to load-dump transients. Operation above 42 V risks permanent damage, and the device includes VCC undervoltage lockout (UVLO) that disables operation below ~4.0 V to ensure safe startup.
Does the LM3103MHX/NOPB require external compensation components?
No, the LM3103MHX/NOPB uses a Constant-On-Time (COT) control architecture that eliminates the need for external compensation components. Its stability is inherently independent of output capacitor ESR, enabling robust operation with ceramic and other low-ESR capacitors. This simplifies design, reduces BOM count, and improves transient response without tuning loop dynamics.
How is the switching frequency set on the LM3103MHX/NOPB?
The switching frequency of the LM3103MHX/NOPB is programmed externally via a resistor (RON) connected between VIN and Pin 13. The on-time varies inversely with VIN, yielding nearly constant frequency across input voltage changes. With RON = 33 kΩ and VIN = 18 V, typical fSW is ~1 MHz; minimum on-time (100 ns) limits maximum achievable frequency based on VIN and RON selection.
Can the LM3103MHX/NOPB operate with a pre-biased output?
Yes, the LM3103MHX/NOPB supports pre-bias startup - meaning it can safely begin regulation when the output voltage is already present (e.g., from another supply or hold-up capacitor). During startup, the synchronous MOSFET remains off until the FB voltage falls below 0.6 V, preventing reverse current flow and ensuring controlled ramp-up even into a pre-charged rail.
What thermal management provisions does the LM3103MHX/NOPB include?
The LM3103MHX/NOPB integrates thermal shutdown at 165°C (with 20°C hysteresis) and is packaged in an HTSSOP-16 with exposed thermal pad (DAP/EP). For reliable operation, the DAP must be soldered to a PCB ground plane; this achieves RθJA = 35°C/W. Layout best practices include minimizing thermal resistance from DAP to copper area and separating AGND/PGND traces to avoid noise coupling.
LM3103MHX/NOPB 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):
- 4.5V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 7V
- Current - Output:
- 750mA
- Frequency - Switching:
- Up to 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-HTSSOP
LM3103MHX/NOPB FAQ
1.How can I place an order for LM3103MHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3103MHX/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 LM3103MHX/NOPB reliable?
The price and inventory of LM3103MHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3103MHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3103MHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3103MHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3103MHX/NOPB?
LM3103MHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3103MHX/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 LM3103MHX/NOPB?
For technical support, including LM3103MHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3103MHX/NOPB requirements.
6.How does Aetrix verify that LM3103MHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3103MHX/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 LM3103MHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3103MHX/NOPB?
All LM3103MHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3103MHX/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 LM3103MHX/NOPB part is unused and in its original packaging.
Return procedure for LM3103MHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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