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Texas Instruments LM34923MMX/NOPB
- Part No.:
- LM34923MMX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM34923MMX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 600MA 10VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,794
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Product details
Overview
LM34923MMX/NOPB from Texas Instruments is a high-voltage, constant on-time synchronous buck switching regulator with integrated 80-V N-channel MOSFET switch, 6 V to 75 V input range, adjustable 2.5 V to 60 V output, and 600 mA load capability - used in telecom bias supplies and +42 V automotive post-regulation.
For engineers reviewing the LM34923MMX/NOPB datasheet, LM34923MMX/NOPB pinout, LM34923MMX/NOPB application, or LM34923MMX/NOPB equivalent, key selection criteria include its no-loop-compensation architecture, programmable UV detection with status flag, ultra-fast transient response, and thermal shutdown with 165 °C trip point.
Technical Context
The LM34923MMX/NOPB implements a constant on-time control scheme where on-time is inversely proportional to VIN, enabling stable switching frequency across line and load variations without external compensation. Its internal 2.5 V reference (±2.5%) and FB comparator regulate output by comparing feedback voltage against this threshold.
Current limiting uses intelligent forced off-time inversely proportional to VOUT, minimizing foldback during overload while ensuring short-circuit protection. The integrated pre-charge switch enables reliable bootstrap capacitor charging during light-load or startup conditions, preventing gate-drive UVLO faults.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 75 V - supports wide industrial, telecom, and automotive bus voltages including +42 V systems. |
| Output Current | 600 mA - sufficient for bias rails in isolated DC/DC controllers and auxiliary power domains. |
| Switching Frequency | Constant with line/load - enabled by VIN-inversely-proportional on-time; typical 200–900 kHz depending on RT and VIN. |
| Feedback Reference | 2.5 V ±2.5% - sets precise output regulation point via external resistor divider (VOUT = 2.5 × (RFB1 + RFB2)/RFB1). |
| Integrated Switch | 80 V, N-channel MOSFET - eliminates external high-voltage switch; RDS(on) = 0.56 Ω (typ) at 200 mA. |
| Startup Regulator | VCC = 7.5 V regulated - powers internal gate driver and logic; current-limited to ≈30 mA; UVLO at 4.0–4.8 V. |
| Thermal Shutdown | 165 °C with 20 °C hysteresis - protects against sustained overtemperature; resumes operation at ≈145 °C. |
Pinout & Package
LM34923MMX/NOPB is housed in a thermally enhanced 10-pin VSSOP package (DGK suffix), with 0.5 mm pitch and exposed thermal pad for improved power dissipation in high-input-voltage applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SW | Switching Node | Power switching node connected to inductor, freewheeling diode/synchronous FET, and BST capacitor. |
| 2 BST | Bootstrap Supply | Charged from VCC via internal diode when SW is low; requires ≥0.01 µF ceramic cap to SW for gate drive. |
| 3 N/C | No Connect | Not internally bonded; must remain unconnected per datasheet. |
| 4 RTN | Signal Ground | Common return path for all analog and power circuits; separate from high-current power ground paths. |
| 5 UV | UV Threshold Input | Resistor-divider input for programmable under-voltage detection; internal 2.5 V threshold with hysteresis. |
| 6 UVO | UV Status Output | Open-drain flag indicating UV condition, VCC UVLO, or shutdown activation; requires external pull-up. |
| 7 FB | Feedback Input | Inverting input of regulation comparator; referenced to 2.5 V internal reference; senses output via resistor divider. |
| 8 RT/SD | On-Time Set / Shutdown | Resistor-to-VIN sets on-time; grounding disables regulator; minimum on-time ≥200 ns at max VIN. |
| 9 VCC | Bias Supply Output | Internally regulated 7.5 V supply for gate driver and logic; requires 1 µF ceramic decoupling to RTN. |
| 10 VIN | Main Power Input | Primary input rail; supports 6–75 V continuous operation with 80 V transient rating. |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Constant on-time architecture eliminates need for external compensation network - reduces BOM count and design iteration time. |
| Ultra-fast transient response | On-demand switching triggered by FB falling below 2.5 V enables immediate correction of load steps - critical for digital IC bias rails. |
| Programmable input UV detector | Adjustable threshold via external resistor divider on UV pin, with open-drain UVO flag for system-level fault signaling. |
| Pre-charge switch for bootstrap | 150 ns active pre-charge pulse ensures reliable BST capacitor recharge during long off-times - prevents gate-drive dropout at light loads. |
| Intelligent current limit | Off-time inversely proportional to VOUT reduces foldback severity during partial overloads - improves recovery time and startup reliability. |
Applications
| Telecom Bias Supply | Automotive Post-Regulator |
|---|---|
|
Use Scenario: Generating stable 5 V or 12 V bias for optical transceivers and line-card controllers in 48 V telecom systems. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator delivering clean, regulated auxiliary power from -48 V or +48 V backplane. Use Value: Wide 6–75 V input accommodates rectified AC line surges and battery transients; no compensation simplifies layout in dense line cards. |
Use Scenario: Regulating 12 V or 5 V from a 42 V automotive main bus for infotainment and ADAS domain controllers. IC Role / Device Role / Timing Role: High-reliability secondary regulator providing ECU core voltage with thermal and UV fault reporting. Use Value: 165 °C thermal shutdown and programmable UV detection meet ASIL-B functional safety requirements for vehicle subsystems. |
| Industrial HV DC-DC Bias | Server Auxiliary Power |
|
Use Scenario: Providing isolated gate drive or sensor bias from 24–72 V industrial DC buses in motor drives and PLCs. IC Role / Device Role / Timing Role: Compact, self-contained buck converter powering isolated gate drivers and analog front-ends. Use Value: Integrated 80 V switch and startup regulator eliminate external HV components; VSSOP-10 footprint saves board space. |
Use Scenario: Delivering standby or management rail (e.g., 3.3 V) from server 12 V intermediate bus to BMC and PMBus controllers. IC Role / Device Role / Timing Role: Efficient, low-noise auxiliary regulator supporting always-on functions with fast wake-up response. Use Value: Ultra-fast transient response maintains regulation during sudden CPU power state transitions; UVO flag enables system-level power sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QDDARQ1 | Wider 3–100 V input; integrated 1.5 A switch; requires external compensation; AEC-Q100 qualified. | Targeted at automotive main power rails (not just bias); higher current, higher integration, but larger solution size. | Choose LM5164QDDARQ1 for AEC-Q100 compliance and >600 mA loads; LM34923MMX/NOPB remains optimal for cost-sensitive, compact bias supplies. |
| TPS54260DGQR | 6–60 V input; 2.6 A output; adjustable frequency; requires external compensation; no integrated UV flag or pre-charge switch. | Designed for higher-power industrial converters; lacks UVO status flag and intelligent current limit off-time scaling. | Choose TPS54260DGQR when higher output current and adjustable frequency are needed; LM34923MMX/NOPB offers simpler design for ≤600 mA bias rails. |
Compared with LM5164QDDARQ1 and TPS54260DGQR, the LM34923MMX/NOPB delivers superior design simplicity for low-to-mid current bias applications due to its no-compensation architecture, integrated UV status flag, and pre-charge-assisted bootstrap - reducing component count and validation effort without sacrificing robustness.
Availability
LM34923MMX/NOPB is available at Aetrix Electronics and suitable for telecom bias supplies, automotive post-regulators, industrial HV DC-DC converters, and server auxiliary power rails requiring stable component supply and long-term manufacturability.
Supply support for LM34923MMX/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 technologies, with decades of expertise in high-reliability power conversion ICs.
The LM34923MMX/NOPB belongs to TI's high-voltage buck regulator product line, designed specifically for efficient, compact, and easy-to-implement bias power solutions in telecom, automotive, and industrial systems operating above 40 V.
FAQ
What is the maximum input voltage rating for the LM34923MMX/NOPB?
The LM34923MMX/NOPB has an absolute maximum input voltage rating of 80 V, with continuous operation specified from 6 V to 75 V. This allows safe use in 48 V telecom systems with surge margins and +42 V automotive applications with battery transients. Exceeding 75 V continuously may trigger thermal or current-limit protection.
Does the LM34923MMX/NOPB require external loop compensation components?
No, the LM34923MMX/NOPB does not require external loop compensation components. Its constant on-time control architecture - where on-time is inversely proportional to VIN - provides inherent stability and ultra-fast transient response without feedback compensation networks, simplifying design and reducing bill-of-materials cost.
How is the output voltage set on the LM34923MMX/NOPB?
The output voltage of the LM34923MMX/NOPB is set using an external resistor divider connected to the FB pin. With a precise internal 2.5 V reference, VOUT = 2.5 × (RFB1 + RFB2) / RFB1. For example, RFB1 = 1.00 kΩ and RFB2 = 3.01 kΩ yields a nominal 10 V output. The FB pin draws only 1 nA, minimizing divider current error.
What is the purpose of the UVO pin on the LM34923MMX/NOPB?
The UVO pin on the LM34923MMX/NOPB is an open-drain status flag that goes low when the UV pin voltage falls below 2.5 V, or when VCC drops below its UVLO threshold (4.0–4.8 V), or when the device is shut down via the RT/SD pin. It enables system-level fault monitoring and power sequencing without additional logic circuitry.
Can the LM34923MMX/NOPB operate with no load?
Yes, the LM34923MMX/NOPB can operate with no load. Its pre-charge switch activates for ~150 ns during minimum off-time to maintain BST capacitor charge, preventing gate-drive dropout. In discontinuous conduction mode (DCM) at light loads, frequency drops naturally while maintaining regulation - verified in TI's typical performance curves up to zero load.
LM34923MMX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-TFSOP, 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):
- 75V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 75V
- Current - Output:
- 600mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-VSSOP
LM34923MMX/NOPB FAQ
1.How can I place an order for LM34923MMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM34923MMX/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 LM34923MMX/NOPB reliable?
The price and inventory of LM34923MMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM34923MMX/NOPB is usually 5 days.
3.What payment methods are accepted for LM34923MMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM34923MMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM34923MMX/NOPB?
LM34923MMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM34923MMX/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 LM34923MMX/NOPB?
For technical support, including LM34923MMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM34923MMX/NOPB requirements.
6.How does Aetrix verify that LM34923MMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM34923MMX/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 LM34923MMX/NOPB meets industry standards.
7.What is the process for return or replacement of LM34923MMX/NOPB?
All LM34923MMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM34923MMX/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 LM34923MMX/NOPB part is unused and in its original packaging.
Return procedure for LM34923MMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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