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Texas Instruments LM34922MY/NOPB
- Part No.:
- LM34922MY/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 10-PowerTFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM34922MY/NOPB.pdf
- Description:
- IC REG BUCK ADJ 2A 10HVSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:674
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Product details
Overview
LM34922MY/NOPB from Texas Instruments is a 28V, 2A constant on-time synchronous buck switching regulator with integrated N-channel MOSFET switch, adjustable current limit, and precision 2.51V feedback reference. It operates from 6V to 28V input, delivers adjustable output voltage down to 2.51V, and features power good (PGD) indication and thermal shutdown - used in industrial power supplies and automotive auxiliary rails.
For engineers reviewing the LM34922MY/NOPB datasheet, LM34922MY/NOPB pinout, LM34922MY/NOPB application, or LM34922MY/NOPB equivalent, key selection considerations include its 10-pin HVSSOP-PowerPAD package, valley-current-limit-based overload protection, COT topology enabling ceramic-capacitor stability without loop compensation, and 90ns minimum off-time for high-frequency operation up to 1MHz.
Technical Context
The LM34922MY/NOPB implements constant on-time (COT) control using an internal comparator comparing FB voltage against a 2.51V reference, triggering a one-shot on-timer whose duration is inversely proportional to VIN and set by RT resistor value. This architecture eliminates need for external compensation while delivering ultra-fast transient response.
Current limiting operates via valley-current sensing at CS/CSG pins with –130mV threshold, enabling smooth transition into constant-current mode; on-time reduces ~40% during current limit to suppress peak inductor current. Thermal shutdown activates at 155°C with 20°C hysteresis, and PGD asserts high when FB reaches ≥95% of 2.51V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 28V operating; supports 30V absolute max - enables direct use in 12V/24V industrial and automotive systems without pre-regulation. |
| Output Current | 2A continuous load capability - sufficient for powering FPGAs, DSPs, and multi-rail subsystems from single high-voltage rail. |
| Feedback Reference | 2.51V ±2% - sets precise output regulation point; allows VOUT = 2.51V × (1 + RFB1/RFB2) with external resistor divider. |
| Switching Frequency | Adjustable up to 1MHz via RT resistor - permits optimization of size vs. efficiency; remains stable across line/load variations due to COT architecture. |
| Current Limit Threshold | –130mV at CS pin - defines valley current limit; enables scalable overcurrent protection using RS sense resistor value. |
| Power Good Output | PGD logic output active-high when FB ≥95% of 2.51V - provides system-level power sequencing and fault monitoring without external comparators. |
| Thermal Shutdown | 155°C activation with 20°C hysteresis - protects device under sustained overload or poor heatsinking; resumes operation only after junction cools to ~135°C. |
Pinout & Package
LM34922MY/NOPB is housed in a thermally enhanced 10-pin HVSSOP-PowerPAD (DGQ) package with exposed thermal pad on bottom, requiring connection to PCB ground plane for optimal thermal performance and EMI reduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply voltage | Accepts 6V–28V DC; requires low-ESR capacitor placed adjacent to VIN/SGND for stable operation and noise suppression. |
| RT | On-time control | Resistor from VIN to RT sets switching frequency; inverse relationship with VIN ensures near-constant fSW across input range. |
| PGD | Power good indicator | Open-drain output requiring external pull-up ≤7V; signals valid regulation when FB ≥2.385V (95% of 2.51V). |
| SS | Soft-start timing | Internal 10µA current source charges external CSS capacitor; ramp time determines controlled VOUT rise to avoid inrush current. |
| SGND | Signal ground reference | Reference for internal circuitry except current-sense path; must be separated from power ground to minimize noise coupling. |
| FB | Feedback input | Connects to resistor divider; regulated at 2.51V; determines final output voltage via VOUT = 2.51V × (1 + RFB1/RFB2). |
| CSG | Current sense ground | Ground return for current-sense amplifier; must connect directly to RS ground side and SGND with short trace. |
| CS | Current sense input | Senses voltage drop across external RS; threshold of –130mV triggers valley-current limit and on-time reduction. |
| SW | Switching node | Connects to inductor, diode cathode, and BST capacitor; carries high dv/dt; requires minimized loop area for EMI control. |
| BST | Bootstrap supply | 0.1µF capacitor between BST and SW powers high-side gate driver; recharged during off-time via internal 5V regulator. |
Key Features
| Feature | Design Value |
|---|---|
| Constant On-Time (COT) Control | Eliminates need for external compensation network; maintains stable operation with ceramic output capacitors and fast load-step response. |
| Adjustable Valley Current Limit | Enables precise overload protection scaling via RS value; avoids foldback behavior and ensures smooth CV-to-CC transition. |
| Integrated 2A N-Channel Buck Switch | Reduces BOM count and layout complexity; RDS(ON) ≤0.6Ω minimizes conduction loss at full load. |
| Power Good (PGD) Output | Provides system-level status flag for power sequencing, fault detection, and microcontroller reset coordination without external circuitry. |
| Thermal Shutdown with Hysteresis | Prevents thermal runaway under sustained overload; 20°C hysteresis avoids oscillation near trip point during marginal cooling conditions. |
Applications
| Industrial PLC Power Rails | Automotive Body Control Modules |
|---|---|
Use Scenario: Providing isolated 3.3V/5V bias rails for I/O modules and communication interfaces in programmable logic controllers. IC Role / Device Role / Timing Role: Primary step-down regulator converting 24V DC bus to stable low-voltage rails; manages startup sequencing via SS pin and monitors health via PGD. Use Value: Enables compact, high-efficiency design with minimal external components; COT topology ensures immunity to load transients common in relay-driven outputs. | Use Scenario: Generating 5V supply for microcontrollers, CAN transceivers, and sensor interfaces in body electronics such as door modules and lighting controllers. IC Role / Device Role / Timing Role: High-input-voltage buck converter supporting wide automotive battery range (9V–28V); uses PGD for safe MCU boot validation. Use Value: Operates reliably across cold-crank (6V) to load-dump (30V transient) conditions; thermal shutdown protects against enclosure overheating in sealed modules. |
| Point-of-Load Converters for FPGA I/O Banks | Industrial Motor Drive Auxiliary Supplies |
Use Scenario: Delivering tightly regulated 1.8V or 2.5V to FPGA I/O banks requiring low-noise, fast-transient response. IC Role / Device Role / Timing Role: Secondary regulator downstream of main DC/DC; leverages COT control for sub-100ns load-step recovery and minimal output capacitance. Use Value: Achieves <15mVp-p output ripple with small ceramic caps; adjustable soft-start prevents I/O bank latch-up during configuration. | Use Scenario: Supplying gate driver and logic power for 3-phase inverter stages in variable-frequency drives and servo amplifiers. IC Role / Device Role / Timing Role: Robust auxiliary supply tolerant of high EMI and voltage spikes; uses current limit to protect against shorted gate drive paths. Use Value: Integrated current sense and valley-limiting prevent destructive shoot-through events; exposed PowerPAD aids thermal management in enclosed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5116MH/NOPB | Wide-input (6–100V), current-mode controller without integrated switch; requires external high-side MOSFET. | Used where higher input voltage (>28V) or higher output current (>2A) is required; lacks integrated switch and PGD output. | Select when input exceeds 28V or when discrete MOSFET selection is needed for thermal/power optimization. |
| TPS54202DDCR | Lower input range (4.5–28V), integrated 2A switch, but uses voltage-mode control with external compensation; no valley-current limit. | Targeted at cost-sensitive consumer applications; lacks PGD and has slower transient response than COT architecture. | Choose for simpler designs where 4.5V start-up is critical and PGD/status signaling is not required. |
Compared with LM5116MH/NOPB, LM34922MY/NOPB offers lower BOM count and faster transient response but limits max input to 28V; versus TPS54202DDCR, it provides superior overload handling and system monitoring via PGD, at the cost of slightly higher minimum input voltage.
Availability
LM34922MY/NOPB is available at Aetrix Electronics and suitable for industrial PLC power rails, automotive body control modules, FPGA point-of-load conversion, and motor drive auxiliary supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM34922MY/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 LM34922MY/NOPB belongs to TI's Constant On-Time (COT) buck regulator product line, engineered for high-efficiency, low-component-count DC/DC conversion in space-constrained industrial and automotive applications where fast transient response and robust overload protection are essential.
FAQ
What is the minimum recommended input voltage for reliable startup of the LM34922MY/NOPB?
The LM34922MY/NOPB features an under-voltage lockout (UVLO) with a rising threshold of 4.6V to 5.3V. Reliable startup occurs once VIN exceeds the upper UVLO threshold (~5.3V typical), and the device remains operational down to 6.0V per its specified operating range. Below 4.6V, the IC disables the buck switch and pulls SS low to prevent unstable regulation.
How does the LM34922MY/NOPB implement current limiting, and what is the role of the CS and CSG pins?
The LM34922MY/NOPB uses valley-current limiting sensed differentially across the external current-sense resistor RS. The CS pin connects to the resistor's high side and the freewheeling diode anode; CSG connects to the resistor's low side and signal ground. When the voltage at CS falls below –130mV relative to CSG, the current limit comparator triggers, reducing on-time by ~40% to limit peak inductor current.
Can the LM34922MY/NOPB operate with ceramic output capacitors, and why is this possible?
Yes, the LM34922MY/NOPB is fully compatible with ceramic output capacitors due to its constant on-time (COT) control architecture, which requires no external loop compensation. The internal emulated ripple mode (ERM) generates necessary ripple for regulation from the CS pin waveform, eliminating stability dependence on capacitor ESR - enabling smaller, lower-ESR ceramic caps and reduced output ripple.
What is the function of the BST and SW pins, and how should the bootstrap capacitor be selected for the LM34922MY/NOPB?
The BST pin supplies the floating gate drive voltage for the internal N-channel buck switch. A 0.1µF ceramic capacitor must be placed between BST and SW to store charge during the off-time, replenished via an internal 5V regulator and diode. This capacitor must have low ESR and be placed close to the pins; insufficient capacitance causes gate drive undervoltage and switch failure.
Does the LM34922MY/NOPB support power sequencing, and how is the PGD pin used in system-level design?
Yes, the LM34922MY/NOPB supports power sequencing via its open-drain PGD output, which goes high when FB reaches ≥95% of the 2.51V reference (i.e., VOUT ≥2.385V). System designers connect PGD to microcontroller reset inputs or enable pins of downstream regulators to ensure proper startup order and detect output faults without additional supervision circuitry.
LM34922MY/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-PowerTFSOP, 10-MSOP (0.118", 3.00mm 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):
- 6V
- Voltage - Input (Max):
- 28V
- Voltage - Output (Min/Fixed):
- 2.51V
- Voltage - Output (Max):
- 28V
- Current - Output:
- 2A
- Frequency - Switching:
- Adj to 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-HVSSOP
LM34922MY/NOPB FAQ
1.How can I place an order for LM34922MY/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM34922MY/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 LM34922MY/NOPB reliable?
The price and inventory of LM34922MY/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM34922MY/NOPB is usually 5 days.
3.What payment methods are accepted for LM34922MY/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM34922MY/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM34922MY/NOPB?
LM34922MY/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM34922MY/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 LM34922MY/NOPB?
For technical support, including LM34922MY/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM34922MY/NOPB requirements.
6.How does Aetrix verify that LM34922MY/NOPB is sourced from the original manufacturer or authorized distributors?
All LM34922MY/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 LM34922MY/NOPB meets industry standards.
7.What is the process for return or replacement of LM34922MY/NOPB?
All LM34922MY/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM34922MY/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 LM34922MY/NOPB part is unused and in its original packaging.
Return procedure for LM34922MY/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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