My Inquiry
My Account
Analog Devices Inc. LT3999MPMSE#PBF
- Part No.:
- LT3999MPMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3999MPMSE#PBF.pdf
- Description:
- IC REG PUSH-PULL ADJ 1A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,657
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3999MPMSE#PBF from Analog Devices (formerly Linear Technology) is a monolithic, high-voltage, high-frequency push-pull DC/DC transformer driver IC designed for isolated power generation in compact, low-noise applications. It integrates dual 1A current-limited switches operating out-of-phase, supports programmable switching frequency up to 1MHz, features duty cycle control for line regulation, and delivers stable isolated output in aerospace-grade temperature range (–55°C to 150°C). It is used in medical isolation supplies and precision data acquisition front-ends requiring ultralow noise.
For engineers reviewing the LT3999MPMSE#PBF datasheet, LT3999MPMSE#PBF pinout, LT3999MPMSE#PBF application, or LT3999MPMSE#PBF equivalent, key selection criteria include its –55°C to 150°C guaranteed junction temperature rating, dual 1A switch capability with <350mV saturation voltage, programmable soft-start via ILIM/SS pin, and precise input UVLO/OVLO thresholds with hysteresis - all critical for ruggedized isolated DC/DC designs.
Technical Context
The LT3999MPMSE#PBF implements a synchronous push-pull topology with non-overlap timing (70ns) to prevent cross-conduction between SWA and SWB. Its oscillator supports internal RT-programmed operation (50kHz–1MHz) or external synchronization up to 1MHz, enabling harmonic placement control in EMI-sensitive systems.
Duty cycle is actively adjusted via OVLO/DC and RDC pins to compensate for input voltage variation, providing pseudo-regulation before post-LDO stages. Protection includes precision undervoltage lockout (1.25V ±100mV threshold), overvoltage lockout (1.25V ±125mV), and thermal shutdown - all fully specified across the –55°C to 150°C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Junction Temp | –55°C to 150°C - 100% tested and guaranteed for aerospace/military extended-range applications |
| Switch Current Limit | 1.0A to 1.7A (typical 1.4A) - sets maximum primary-side transformer current per switch |
| Switch Saturation Voltage | 350mV at 1A - determines conduction loss and thermal rise in push-pull primary winding |
| Switching Frequency Range | 50kHz to 1MHz - selectable via RT resistor; higher frequencies reduce transformer size but increase switching loss |
| UVLO Threshold | 1.25V ±100mV - enables precise input undervoltage detection with 125mV hysteresis for reliable startup |
| Shutdown Current | <1µA - ensures negligible battery drain in always-on isolated sensor nodes |
| Duty Cycle Control | 20% to 48% (programmable) - adjusts output voltage vs. input variation without feedback loop |
Pinout & Package
LT3999MPMSE#PBF is housed in a 10-lead MSOP package (MSE) with exposed pad (Pin 11 = GND), measuring 3.00mm × 3.00mm × 0.86mm. The exposed pad must be soldered to PCB ground plane for thermal and electrical integrity (θJA = 40°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SWA (Pin 1) | Power switch A collector | Drives outer terminal of center-tapped transformer primary; carries full 1A pulsed current |
| RBIAS (Pin 2) | Bias current setting | 49.9kΩ to GND sets optimal base drive for both switches; affects efficiency and thermal performance |
| VIN (Pin 3) | Main supply input | Accepts 2.7V–36V; requires ≥4.7µF low-ESR ceramic capacitor close to pin for transient current handling |
| UVLO (Pin 4) | Undervoltage lockout input | 1.25V threshold with 125mV hysteresis; disables switching below valid input voltage |
| OVLO/DC (Pin 5) | Overvoltage lockout / duty cycle control | 1.25V threshold with hysteresis; when used for duty cycle, enables VIN compensation |
| RDC (Pin 6) | Duty cycle programming | Resistor to GND sets duty cycle (20–48%); floating = ~50% fixed duty cycle |
| RT (Pin 7) | Oscillator frequency setting | Resistor value (e.g., 28kΩ = 500kHz) programs switching frequency; defines transformer size trade-off |
| SYNC (Pin 8) | External clock synchronization | Accepts square wave ≥2V; synchronizes harmonics for EMI compliance in noisy environments |
| ILIM/SS (Pin 9) | Current limit / soft-start | Resistor sets current limit (0.5A typ. w/43.2kΩ); capacitor enables controlled inrush current ramp |
| SWB (Pin 10) | Power switch B collector | Complementary switch to SWA; operates 180° out-of-phase for push-pull transformer drive |
| GND (Pin 11) | Ground / exposed pad | Thermal and electrical reference; must be soldered to solid PCB ground plane with multiple vias |
Key Features
| Feature | Design Value |
|---|---|
| Programmable soft-start | Capacitor on ILIM/SS pin ramps peak switch current over user-defined time (tSS = CSS × 80ms), limiting inrush into transformer primary |
| Cross-conduction prevention | 70ns non-overlap timing between SWA and SWB ensures zero shoot-through current during switching transitions |
| Low-noise push-pull topology | No transformer reset winding or snubber required; inherent symmetry reduces common-mode EMI vs. flyback |
| Input voltage lockouts | Independent, precision UVLO (1.25V) and OVLO (1.25V) with hysteresis enable robust brown-in/brown-out protection |
| Frequency synchronization | SYNC pin accepts external clock up to 1MHz, allowing deterministic harmonic placement for CISPR/EN55032 compliance |
Applications
| Medical Isolation Power | Industrial Data Acquisition |
|---|---|
Use Scenario: Powering isolated analog front-ends in patient-connected ECG or EEG monitors where leakage current and noise must meet IEC 60601-1. IC Role / Device Role / Timing Role: Push-pull transformer driver generating clean ±12V isolated rails for op-amps and ADC drivers. Use Value: 350mV switch VCE(SAT) and programmable soft-start minimize input ripple and transformer stress, ensuring long-term reliability under continuous operation. |
Use Scenario: Supplying isolated RS485 transceivers and precision ADC references in factory automation PLC modules. IC Role / Device Role / Timing Role: High-frequency (500kHz–1MHz) isolated DC/DC driver enabling compact layout and reduced magnetic interference near signal traces. Use Value: Synchronization capability aligns switching harmonics away from critical 1MHz CAN FD or 2.4GHz wireless bands, simplifying EMC filtering. |
| Aerospace Remote Sensors | Test & Measurement Equipment |
Use Scenario: Providing isolated bias for radiation-hardened sensors in satellite subsystems operating across extreme ambient temperatures. IC Role / Device Role / Timing Role: Ruggedized transformer driver delivering stable 5V/12V isolated outputs with guaranteed operation from –55°C to 150°C. Use Value: MP-grade qualification and 100% high-temp testing ensure no derating required - eliminates need for thermal margin calculations in LEO missions. |
Use Scenario: Generating low-noise isolated supplies for high-resolution digital multimeters and oscilloscope front-ends where supply-induced offset drift degrades accuracy. IC Role / Device Role / Timing Role: Low-noise push-pull driver feeding post-regulation LDOs to achieve sub-100µVPP output ripple. Use Value: Duty cycle control compensates for input rail sag during high-current test pulses, maintaining stable LDO headroom and minimizing measurement error. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar push-pull transformer driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3439EMSE#PBF | Lower input voltage range (2.7V–17.5V); slew-rate controlled switches; SO-16 package | Optimized for <100mVPP noise in sensitive analog circuits; lacks duty cycle control and extended temp grade | Select LT3439EMSE#PBF only if ultra-low noise dominates over wide VIN range and extended temperature operation. |
| LT3999HMSE#PBF | Same architecture and pinout; rated for –40°C to 150°C (not –55°C); lower cost, non-MP screening | Suitable for industrial automotive under-hood applications but not space-grade or military cold-start requirements | Choose LT3999HMSE#PBF for cost-sensitive high-temp designs where –55°C startup is not required. |
Compared with LT3439EMSE#PBF, LT3999MPMSE#PBF offers wider input range and true extended-temperature qualification, while LT3999HMSE#PBF provides identical functionality at lower cost but without cold-start assurance - making LT3999MPMSE#PBF the sole choice for mission-critical aerospace or defense deployments.
Availability
LT3999MPMSE#PBF is available at Aetrix Electronics and suitable for medical isolation power, aerospace remote sensing, industrial data acquisition, and test equipment requiring stable component supply with guaranteed extended-temperature performance and traceable sourcing.
Supply support for LT3999MPMSE#PBF 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, datasheets, and application engineering for legacy Linear parts including the LT3999 family.
The LT3999 product line was designed specifically for high-reliability isolated DC/DC conversion in noise-sensitive, wide-temperature, and safety-critical applications - emphasizing low EMI, precise protection thresholds, and rugged packaging.
FAQ
What is the guaranteed operating temperature range for LT3999MPMSE#PBF?
The LT3999MPMSE#PBF is 100% tested and guaranteed over the full junction temperature range of –55°C to 150°C. This MP (military plastic) grade exceeds commercial and industrial specifications, making it suitable for aerospace, downhole, and defense applications where cold-start reliability and high-temperature endurance are mandatory. Unlike standard grades, LT3999MPMSE#PBF undergoes extended burn-in and parametric validation at temperature extremes.
How does duty cycle control work on LT3999MPMSE#PBF?
LT3999MPMSE#PBF implements duty cycle control using the OVLO/DC and RDC pins: OVLO/DC is biased from VIN via a resistor divider, and RDC connects to ground with a resistor. The resulting duty cycle (20–48%) adjusts dynamically with input voltage to stabilize output voltage before post-regulation. This pseudo-regulation reduces power dissipation in downstream LDOs. Leaving RDC floating disables this function and defaults to ~50% duty cycle.
Can LT3999MPMSE#PBF synchronize to an external clock?
Yes, LT3999MPMSE#PBF supports external synchronization via the SYNC pin (Pin 8). It accepts a square wave ≥2V and ≤1MHz, with internal oscillator set 10–50% below sync frequency. The rising edge triggers oscillator discharge, enabling precise harmonic alignment for EMI compliance. When unused, SYNC must be tied to GND - floating is not allowed.
What is the purpose of the RBIAS pin on LT3999MPMSE#PBF?
The RBIAS pin (Pin 2) sets the base drive current for both internal power switches (SWA/SWB). A 49.9kΩ resistor to GND establishes optimal bias for efficient switching and minimal VCE(SAT). Deviating from this value alters switch turn-on speed and conduction losses - undersizing risks incomplete saturation; oversizing increases quiescent current and thermal load without benefit.
Does LT3999MPMSE#PBF require an external transformer? If so, what type?
Yes, LT3999MPMSE#PBF requires an external center-tapped transformer to generate isolated output. Recommended parts include Coilcraft PA6384 (12V→12V, 10W) and Cooper Bussmann CTX02-19061 (24V→24V, 20W). The transformer must support the selected switching frequency (50kHz–1MHz), handle peak primary current ≥1A, and provide adequate inter-winding isolation (≥2.5kV RMS) for medical or industrial safety standards.
LT3999MPMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LT3999MPMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3999MPMSE#PBF 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#PBF reliable?
The price and inventory of LT3999MPMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3999MPMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3999MPMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3999MPMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3999MPMSE#PBF?
LT3999MPMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3999MPMSE#PBF 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#PBF?
For technical support, including LT3999MPMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3999MPMSE#PBF requirements.
6.How does Aetrix verify that LT3999MPMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3999MPMSE#PBF 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#PBF meets industry standards.
7.What is the process for return or replacement of LT3999MPMSE#PBF?
All LT3999MPMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3999MPMSE#PBF, 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#PBF part is unused and in its original packaging.
Return procedure for LT3999MPMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3999MPMSE#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
