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Analog Devices Inc. LT3999MPMSE#TRPBF
- Part No.:
- LT3999MPMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3999MPMSE#TRPBF.pdf
- Description:
- IC REG PUSH-PULL ADJ 1A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,335
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Product details
Overview
LT3999MPMSE#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic high-voltage push-pull DC/DC transformer driver IC designed for isolated power generation in safety-critical and low-noise systems. It integrates dual 1A current-limited switches, programmable 50kHz–1MHz switching frequency, duty cycle control for line regulation, and precision UVLO/OVLO thresholds. It delivers stable isolated supplies in medical instrumentation and distributed power architectures.
For engineers reviewing the LT3999MPMSE#TRPBF datasheet, LT3999MPMSE#TRPBF pinout, LT3999MPMSE#TRPBF application, or LT3999MPMSE#TRPBF equivalent, key selection criteria include its –55°C to 150°C extended temperature grade, 10-lead MSOP package with exposed GND pad, dual-switch cross-conduction prevention, <1µA shutdown current, and programmable soft-start via ILIM/SS pin.
Technical Context
The LT3999MPMSE#TRPBF implements a synchronous push-pull topology with out-of-phase switching of SWA and SWB, enabling efficient center-tapped transformer drive. Its oscillator supports internal RT-programmed operation up to 1MHz or external synchronization-critical for EMI-sensitive data acquisition and RS485 interfaces.
Duty cycle is actively controlled via OVLO/DC and RDC pins to compensate input voltage variation, while independent UVLO and OVLO thresholds (1.25V ±100mV) provide precise input rail monitoring. The ILIM/SS pin simultaneously configures cycle-by-cycle current limit and soft-start timing through resistor-capacitor networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Limit | 1.0A typical (internal default); programmable down to 0.5A via ILIM/SS resistor |
| Switching Frequency | 50kHz–1MHz; set by RT resistor or synchronized externally up to 1MHz | Input Voltage Range | 2.7V–36V; with programmable UVLO (1.25V threshold) and OVLO (1.25V threshold) |
| Duty Cycle Control | 20%–48% range; adjustable via RDC and OVLO/DC voltage for line regulation |
| Shutdown Current | <1µA; enables ultra-low-power standby in safety-isolated systems |
| Operating Temp Range | –55°C to +150°C junction; 100% tested MP-grade for aerospace/military use |
| Package | 10-lead MSOP (MSE) with exposed GND pad; θJA = 40°C/W, θJC = 10°C/W |
Pinout & Package
LT3999MPMSE#TRPBF uses the 10-lead MSOP (MSE) package with exposed GND pad (Pin 11), requiring soldering to PCB ground plane for thermal and electrical performance. Pin 1 is SWA; Pin 10 is SWB; Pin 11 is GND (exposed pad).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SWA (Pin 1) | Power switch A collector | Drives outer terminal of center-tapped transformer primary; handles 1A peak current |
| RBIAS (Pin 2) | Bias current reference | Sets internal switch bias via 49.9kΩ-to-GND resistor; stabilizes switching characteristics |
| VIN (Pin 3) | Main supply input | Accepts 2.7V–36V; requires ≥4.7µF low-ESR ceramic capacitor for transient current handling |
| UVLO (Pin 4) | Undervoltage lockout input | Disables switching below 1.25V threshold; enables low-current shutdown mode when pulled low |
| OVLO/DC (Pin 5) | Overvoltage lockout / duty cycle control | Configurable as OVLO disable input or duty cycle reference node; 1.25V threshold with 125mV hysteresis |
| RDC (Pin 6) | Duty cycle programming | Resistor-to-GND sets duty cycle; floating or tied to OVLO/DC disables control and defaults to ~50% |
| RT (Pin 7) | Oscillator timing | Resistor-to-GND programs switching frequency from 50kHz to 1MHz per datasheet table |
| SYNC (Pin 8) | External clock input | Accepts >2V square wave; synchronizes internal oscillator for harmonic placement control |
| ILIM/SS (Pin 9) | Current limit / soft-start | Resistor sets current limit; capacitor sets soft-start ramp time; open defaults to 1A internal limit |
| GND (Pin 11) | Ground reference | Exposed pad; must be soldered to PCB ground plane for thermal dissipation and noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise push-pull topology | Minimizes common-mode EMI; enables sub-100mVP-P output ripple with optional LC filter |
| Cross-conduction prevention | 70ns non-overlap time between SWA/SWB ensures zero shoot-through current |
| Programmable soft-start | Capacitor on ILIM/SS pin ramps peak switch current over user-defined time, limiting inrush |
| ∆VIN compensation | Duty cycle adjustment via OVLO/DC and RDC maintains stable VOUT across wide input ranges |
| High-temp reliability | MP-grade qualification (–55°C to +150°C) with 100% testing supports mission-critical applications |
Applications
| Medical Isolated Power Supplies | Noise-Immune Data Acquisition |
|---|---|
Use Scenario: Providing galvanically isolated ±12V rails for patient-connected analog front-ends in ECG/EEG systems. IC Role / Device Role / Timing Role: LT3999MPMSE#TRPBF drives center-tapped transformer to generate dual regulated outputs with low conducted EMI. Use Value: <1µA shutdown current extends battery life; 150°C rating ensures reliability under sterilization conditions. | Use Scenario: Powering isolated RS485 transceivers and ADC reference circuits in industrial PLCs. IC Role / Device Role / Timing Role: LT3999MPMSE#TRPBF supplies clean 5V/12V isolated rails with synchronized switching to avoid spectral interference with data signals. Use Value: Frequency synchronization capability places harmonics outside communication bands; duty cycle control maintains regulation during brownouts. |
| Distributed Power Architectures | Positive-to-Negative Conversion |
Use Scenario: Generating local 12V isolated supplies from a 24V backplane in telecom shelf systems. IC Role / Device Role / Timing Role: LT3999MPMSE#TRPBF operates as primary-side driver in compact push-pull converter with Coilcraft PA6384 transformer. Use Value: 1MHz max switching frequency enables small magnetics; exposed pad improves thermal management in dense layouts. | Use Scenario: Creating –12V rail from +12V input for op-amp biasing in precision signal conditioning. IC Role / Device Role / Timing Role: LT3999MPMSE#TRPBF drives center-tapped transformer with inverted secondary winding to produce negative output. Use Value: Dual 1A switches support high peak loads; programmable current limit prevents transformer saturation during startup. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolated push-pull driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3439EMSE#TRPBF | Lower VIN max (17.5V vs 36V); fixed 1A current limit; no duty cycle control | Optimized for ultralow noise (<100mVP-P) but lacks line regulation capability | Select when absolute noise floor matters more than input voltage range or regulation |
| LT1533CS#TRPBF | SO-16 package; 2.7V–23V input; no sync input; higher quiescent current (12mA vs 4.3mA) | Legacy part with slew-rate control for EMI reduction, not duty cycle compensation | Select only for drop-in replacement in existing SO-16 designs where footprint compatibility is mandatory |
Compared with LT3439EMSE#TRPBF and LT1533CS#TRPBF, the LT3999MPMSE#TRPBF uniquely combines extended temperature operation, programmable duty cycle for line regulation, and 1MHz synchronization-making it optimal for new designs requiring robustness across wide input and environmental ranges.
Availability
LT3999MPMSE#TRPBF is available at Aetrix Electronics and suitable for medical instrumentation, industrial data acquisition, and distributed power systems requiring stable component supply across extreme temperature environments.
Supply support for LT3999MPMSE#TRPBF 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
Analog Devices acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for all Linear parts including the LT3999 family.
The LT3999 product line was designed specifically for high-reliability isolated DC/DC conversion in safety-critical applications such as medical devices, avionics, and industrial control-emphasizing low EMI, wide input range, and extended temperature operation.
FAQ
What is the maximum operating junction temperature for LT3999MPMSE#TRPBF?
The LT3999MPMSE#TRPBF is 100% tested and guaranteed over a junction temperature range of –55°C to +150°C. This MP-grade qualification exceeds commercial and industrial grades, making LT3999MPMSE#TRPBF suitable for aerospace, downhole, and military applications where thermal stress is extreme. Derating applies above 125°C to ensure long-term reliability.
How does duty cycle control work on LT3999MPMSE#TRPBF?
LT3999MPMSE#TRPBF implements duty cycle control using the OVLO/DC and RDC pins: OVLO/DC is biased from VIN via resistor divider to create a voltage proportional to input, while RDC sets the reference. The internal circuit adjusts duty cycle (20%–48%) to maintain constant output despite VIN variation-enabling pseudo-regulation before post-LDO stages. Leaving RDC floating disables this function.
Can LT3999MPMSE#TRPBF synchronize to an external clock?
Yes, LT3999MPMSE#TRPBF supports external synchronization via the SYNC pin. It accepts a >2V square wave up to 1MHz; the internal oscillator must be set 10–50% lower than the sync frequency. Synchronization allows precise placement of switching harmonics-critical for compliance in EMI-sensitive applications like RS485 or data acquisition systems.
What is the purpose of the exposed pad on LT3999MPMSE#TRPBF?
The exposed pad (Pin 11) on LT3999MPMSE#TRPBF is electrically and thermally connected to GND. It must be soldered directly to the PCB ground plane using multiple thermal vias to achieve θJA = 40°C/W and ensure safe operation at full load. Failure to connect the pad degrades thermal performance and may cause premature thermal shutdown or reliability issues.
Does LT3999MPMSE#TRPBF support programmable current limiting?
Yes, LT3999MPMSE#TRPBF supports programmable current limiting via the ILIM/SS pin. A resistor (e.g., 43.2kΩ) sets the cycle-by-cycle current limit to 0.5A; open-circuit defaults to 1.0A internal limit. This feature protects external transformers and MOSFETs during fault conditions and enables controlled soft-start by combining the resistor with a capacitor.
LT3999MPMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Push-Pull
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- -
- Voltage - Output (Max):
- -
- Current - Output:
- 1A
- Frequency - Switching:
- 50kHz ~ 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT3999MPMSE#TRPBF FAQ
1.How can I place an order for LT3999MPMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3999MPMSE#TRPBF 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 LT3999MPMSE#TRPBF reliable?
The price and inventory of LT3999MPMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3999MPMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3999MPMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3999MPMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3999MPMSE#TRPBF?
LT3999MPMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3999MPMSE#TRPBF 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 LT3999MPMSE#TRPBF?
For technical support, including LT3999MPMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3999MPMSE#TRPBF requirements.
6.How does Aetrix verify that LT3999MPMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3999MPMSE#TRPBF 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 LT3999MPMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3999MPMSE#TRPBF?
All LT3999MPMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3999MPMSE#TRPBF, 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 LT3999MPMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3999MPMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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