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Texas Instruments LM20125MH/NOPB
- Part No.:
- LM20125MH/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM20125MH/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A 16HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,690
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Product details
Overview
LM20125MH/NOPB from Texas Instruments is a 5A, 500 kHz synchronous buck regulator in HTSSOP-16 with exposed pad, featuring peak current mode control, 0.8V adjustable output, and integrated 32 mΩ/36 mΩ high-side/low-side FETs. It delivers high efficiency (97%) from 2.95V–5.5V input for FPGA, DSP, and ASIC core power rails.
For engineers reviewing the LM20125MH/NOPB datasheet, LM20125MH/NOPB pinout, LM20125MH/NOPB application, or LM20125MH/NOPB equivalent, key selection considerations include pre-bias startup capability, SS/TRK voltage tracking, PGOOD open-drain signaling, internal 2.7V VCC regulator, and nonlinear slope compensation for stable operation across 0.8V–3.3V outputs.
Technical Context
The LM20125MH/NOPB employs peak current mode control with nonlinear (parabolic) slope compensation-dynamically adjusted per output voltage-to prevent subharmonic oscillation above 50% duty cycle and ensure stability with any output capacitor type. Its transconductance error amplifier (gm = 510 µmho) interfaces with external RC1/CC1 compensation to set crossover frequency and optimize transient response.
Internal protection includes cycle-by-cycle current limiting (7.4A typ), thermal shutdown at 160°C (10°C hysteresis), overvoltage protection (108% of VFB), and precision enable with 1.18V turn-on threshold and 66 mV hysteresis. The device supports monotonic startup into pre-biased outputs and voltage tracking via the SS/TRK pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5A continuous-supports high-current digital loads like FPGAs without external MOSFETs. |
| Input Voltage Range | 2.95V to 5.5V-directly compatible with 3.3V and 5V system buses. |
| Switching Frequency | 500 kHz (440–560 kHz range)-enables compact 1.5 µH inductors and balances EMI vs. efficiency. |
| Feedback Reference | 0.8V ±1.5%-sets output as low as 0.8V using resistor divider; enables precise core voltage regulation. |
| High-Side RDS(on) | 36 mΩ (typ) at 3.5A-minimizes conduction loss and thermal stress in high-current paths. |
| Soft-Start Control | External capacitor on SS/TRK pin-configures monotonic ramp time; default 1 ms internal ramp if unconnected. |
| Power Good Output | Open-drain PGOOD with 94% VFB rising threshold and 16 µs deglitch-provides reliable rail sequencing signal. |
Pinout & Package
LM20125MH/NOPB uses a 16-pin HTSSOP package (PWP0016A) with exposed thermal pad (EP) soldered to PCB ground for enhanced heat dissipation. Package dimensions: 5.0 mm × 4.4 mm × 1.2 mm, pitch 0.65 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SS/TRK | Soft-start/Tracking control | 5 µA internal current source charges external capacitor; overrides FB reference when driven below 800 mV for rail tracking. |
| 2 FB | Feedback input | Connects to resistor divider; regulates output by comparing against internal 0.8V reference. |
| 3 PGOOD | Power good indicator | Open-drain output asserted high when VOUT within ±6% of target; requires 10–100 kΩ pull-up. |
| 4 COMP | Compensation node | Connects external RC network to stabilize control loop; interfaces with transconductance error amplifier. |
| 5,16 NC | No connect | Must be tied to AGND for proper operation-no internal connection. |
| 6,7 PVIN | Main power input | High-current input pins for internal FETs; require local low-ESR ceramic capacitor placement. |
| 8,9 SW | Switch node | Drives external inductor; transitions between PVIN and PGND; requires careful layout to minimize ringing. |
| 10,11 PGND | Power ground | Return path for high-current switch loops; separate from AGND to reduce noise coupling. |
| 12 EN | Enable input | Precision analog threshold (1.18V typ); 66 mV hysteresis enables clean power sequencing with resistor divider. |
| 13 VCC | Internal 2.7V regulator output | Bypass with 1 µF ceramic capacitor; powers internal circuitry independent of PVIN. |
| 14 AVIN | Analog supply input | Filtered input (via RC) for bias generation; must connect to PVIN through low-pass filter to suppress noise. |
| 15 AGND | Analog ground | Quiet reference for error amplifier and bias circuits; separate from PGND to preserve PSRR. |
| EP | Exposed thermal pad | Weakly connected to GND internally; must be soldered to PCB ground plane for thermal performance (θJA = 38°C/W). |
Key Features
| Feature | Design Value |
|---|---|
| Nonlinear slope compensation | Parabolic ramp adapts to output voltage-ensures stability across full 0.8V–3.3V range without redesigning compensation. |
| Pre-bias startup | Starts up into pre-charged outputs without sinking current-prevents damage to downstream logic during multi-rail power sequencing. |
| Voltage tracking (SS/TRK) | Tracks external voltage rail via resistive divider-enables coordinated ramp-up with higher-voltage supplies in complex systems. |
| Diode emulation mode | Disables low-side FET at zero inductor current-eliminates reverse conduction losses and improves light-load efficiency below 100 mA. |
| Integrated protection suite | Combines OVP (108% VFB), thermal shutdown (160°C), UVLO (2.7V), and cycle-by-cycle current limit-reduces need for external fault management. |
Applications
| FPGA Core Power | DSP I/O Supply |
|---|---|
|
Use Scenario: Powering Xilinx or Intel FPGA core rails requiring tightly regulated 0.85V–1.2V at up to 5A with strict monotonic startup. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering core voltage; manages soft-start ramp and PGOOD signaling for configuration sequence. Use Value: Pre-bias startup prevents current injection into partially powered FPGA banks; SS/TRK pin enables tracking with auxiliary 2.5V I/O rail. |
Use Scenario: Generating clean 1.8V or 2.5V I/O supply for TI C6000 or Analog Devices SHARC DSPs with fast load transients. IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator; uses peak current mode control to maintain regulation during 2A step changes. Use Value: 97% efficiency at 500 kHz reduces thermal load on dense DSP carrier boards; PGOOD enables synchronized reset assertion. |
| ASIC Memory Interface | Optical Transceiver Bias |
|
Use Scenario: Supplying DDR3/DDR4 termination voltage (VTT) or memory controller core voltage in networking ASICs. IC Role / Device Role / Timing Role: Secondary buck regulator in multi-rail architecture; tracks main 1.2V core rail via SS/TRK pin. Use Value: Adjustable 0.8V reference allows precise VDDQ matching; integrated current limit protects against shorted DIMM stubs. |
Use Scenario: Providing stable 3.3V bias for SFP+ or QSFP optical module lasers and TIAs in telecom infrastructure. IC Role / Device Role / Timing Role: Low-noise, high-PG reliability regulator; leverages AVIN/AGND separation to minimize switching noise on analog bias lines. Use Value: 32 mΩ/36 mΩ FETs reduce dropout under 3.3V input; thermal shutdown prevents laser drift during airflow failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54560QPWPRQ1 | 60V input, 5A, 100–2500 kHz adjustable frequency; larger solution size; no pre-bias startup. | Designed for automotive 12V/24V systems-not optimized for 3.3V/5V bus step-down. | Select when wide VIN range and AEC-Q100 qualification are required over pre-bias or tracking capability. |
| LM2678SX-5.0/NOPB | 5A, 5V fixed output, 260 kHz, TO-220-5 package; no adjustable VOUT, no SS/TRK, no PGOOD. | Legacy non-synchronous design; higher dropout and lower efficiency than LM20125MH/NOPB. | Choose only for cost-sensitive, fixed-output applications where footprint and advanced features are secondary. |
Compared with TPS54560QPWPRQ1 and LM2678SX-5.0/NOPB, the LM20125MH/NOPB uniquely combines 5A capability at 500 kHz with pre-bias startup, voltage tracking, and a thermally enhanced HTSSOP package-making it optimal for space-constrained, multi-rail digital power systems where sequencing and efficiency are critical.
Availability
LM20125MH/NOPB is available at Aetrix Electronics and suitable for FPGA core power, DSP I/O supply, ASIC memory interface, and optical transceiver bias applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM20125MH/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 LM20125MH/NOPB belongs to TI's PowerWise® synchronous buck regulator family, engineered for high-efficiency, low-voltage point-of-load conversion in FPGA, DSP, and ASIC power architectures.
FAQ
What is the maximum continuous output current supported by the LM20125MH/NOPB?
The LM20125MH/NOPB supports 5A of continuous output current under typical thermal conditions (θJA = 38°C/W, TA = 25°C). Its integrated 32 mΩ/36 mΩ high-side/low-side FETs and exposed thermal pad enable this rating without external MOSFETs. At elevated ambient temperatures or with reduced airflow, derating per the thermal equations in the datasheet is required to maintain junction temperature below 125°C.
Does the LM20125MH/NOPB support startup into a pre-biased output voltage?
Yes, the LM20125MH/NOPB supports pre-bias startup: when the output is already charged at power-on, it will not sink current until the soft-start ramp exceeds the FB pin voltage. This behavior prevents reverse current flow through parasitic paths in FPGAs or ASICs, protecting downstream logic. The SS/TRK pin remains inactive during pre-bias conditions unless externally driven.
How is output voltage adjusted on the LM20125MH/NOPB?
The LM20125MH/NOPB uses an external resistor divider (RFB1/RFB2) connected to the FB pin to set output voltage, referenced to its internal 0.8V precision bandgap. For example, a 10.2 kΩ RFB2 and 8.87 kΩ RFB1 yields 1.2V output. The device supports outputs from 0.8V to 3.3V; RFB2 should be selected between 4.99 kΩ and 49.9 kΩ for optimal noise immunity and bias current error.
What protection features are integrated into the LM20125MH/NOPB?
The LM20125MH/NOPB integrates overvoltage protection (OVP at 108% of VFB), thermal shutdown (160°C with 10°C hysteresis), undervoltage lockout (UVLO at 2.7V), cycle-by-cycle current limiting (7.4A typical), and PGOOD fault detection. These functions operate autonomously without external components, enhancing system reliability in mission-critical digital power applications.
Can the LM20125MH/NOPB be used to track another voltage rail?
Yes, the SS/TRK pin enables voltage tracking: when driven by an external voltage source (e.g., via resistor divider from a 2.5V rail), the LM20125MH/NOPB output follows that reference during startup. Tracking accuracy is ±15 mV relative to VFB, supporting coordinated power sequencing in multi-rail systems such as those powering FPGAs with separate core and I/O supplies.
LM20125MH/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- PowerWise®
- 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):
- 2.95V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 4.68V
- Current - Output:
- 5A
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-HTSSOP
LM20125MH/NOPB FAQ
1.How can I place an order for LM20125MH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM20125MH/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 LM20125MH/NOPB reliable?
The price and inventory of LM20125MH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM20125MH/NOPB is usually 5 days.
3.What payment methods are accepted for LM20125MH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM20125MH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM20125MH/NOPB?
LM20125MH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM20125MH/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 LM20125MH/NOPB?
For technical support, including LM20125MH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM20125MH/NOPB requirements.
6.How does Aetrix verify that LM20125MH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM20125MH/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 LM20125MH/NOPB meets industry standards.
7.What is the process for return or replacement of LM20125MH/NOPB?
All LM20125MH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM20125MH/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 LM20125MH/NOPB part is unused and in its original packaging.
Return procedure for LM20125MH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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