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Analog Devices Inc. LTC3126MPFE#TRPBF
- Part No.:
- LTC3126MPFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3126MPFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 2.5A 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,510
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Product details
Overview
LTC3126MPFE#TRPBF from Analog Devices (formerly Linear Technology) is a 42V, 2.5A synchronous step-down regulator with no-loss PowerPath™ supporting seamless dual-input power source selection. It operates across 2.4V–42V input, delivers up to 2.5A continuous output current, features 2µA Burst Mode® quiescent current, and supports pin-selectable ideal diode-OR or priority input modes - enabling robust automotive battery backup and supercapacitor hold-up applications.
For engineers reviewing the LTC3126MPFE#TRPBF datasheet, LTC3126MPFE#TRPBF pinout, LTC3126MPFE#TRPBF application, or LTC3126MPFE#TRPBF equivalent, key selection criteria include its –55°C to 150°C extended temperature rating, programmable UVLO thresholds via VSET1/VSET2, 200kHz–2.2MHz adjustable switching frequency, and dual Kelvin-sense inputs for precise input validation in high-reliability power systems.
Technical Context
The LTC3126MPFE#TRPBF implements current-mode control with 60ns minimum on-time and integrates two independent input comparators with user-programmable undervoltage lockout (UVLO) thresholds set by external resistor dividers from VREF. Its internal PowerPath™ architecture enables automatic, sub-50µs switchover between VIN1 (priority) and VIN2 (backup), eliminating hold-up capacitors while maintaining uninterrupted output regulation.
It supports both fixed-frequency PWM and Burst Mode® operation, with synchronization capability via the PWM/SYNC pin. The device uses separate high-side (200mΩ) and low-side (70mΩ) MOSFETs, includes dedicated BST1/COM1 and BST2/COM2 charge pump rails, and provides open-drain status indicators (VALID1, VALID2, PRIORITY, PGOOD) for full system-level power monitoring.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.4V to 42V - supports wide-range sources including automotive batteries (9V–24V), supercapacitors, and multicell Li-ion stacks. |
| Output Current | Up to 2.5A continuous - sufficient for powering FPGA I/O banks, industrial microcontrollers, or RF transceivers without external current boosting. |
| Quiescent Current | 2µA in Burst Mode® - enables >1-year battery life in always-on backup systems using primary alkaline or lithium-thionyl chloride cells. |
| Switching Frequency | 200kHz to 2.2MHz, programmable via RT resistor - allows optimization of efficiency vs. size trade-offs using 2.2µH to 10µH inductors. |
| Operating Temperature | –55°C to +150°C - fully tested and guaranteed over this range, suitable for under-hood automotive, downhole oil/gas, and military-grade embedded systems. |
| PowerPath™ Switchover | Automatic, <50µs transition - eliminates output rail disturbance during input source failure, removing need for large hold-up capacitance. |
| Feedback Accuracy | ±1% over temperature - ensures stable 0.818V to VIN output regulation with minimal drift across harsh environments. |
Pinout & Package
Package: 28-lead plastic TSSOP (4.4mm width), thermally enhanced with exposed PGND pad (Pin 29). Designed for high-power density and reliable thermal dissipation in space-constrained industrial and automotive PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1 / VIN2 | Kelvin sense inputs | Low-impedance sensing paths for priority and secondary inputs; must be connected directly to PVIN1/PVIN2 respectively to avoid UVLO errors. |
| PVIN1 / PVIN2 | Main power inputs | High-current input terminals requiring ≥4.7µF ceramic bypass caps; support 42V transient protection in automotive applications. |
| VALID1 / VALID2 | Open-drain status outputs | Indicate real-time validity of each input above programmed UVLO threshold; enable host MCU to monitor source health without ADC polling. |
| PRIORITY | Open-drain mode indicator | Asserts low only when operating from VIN1 in priority mode - provides unambiguous system-level visibility into active power path. |
| DIODE | Mode select logic input | High = ideal diode-OR (auto-select highest valid input); Low = priority mode (VIN1 first, fallback to VIN2 only on failure). |
| VSET1 / VSET2 | UVLO programming inputs | Accept 0–1V reference voltage from VREF to set custom UVLO thresholds from 0–20V per input, overriding fixed 2.34V internal threshold. |
| PGOOD | Open-drain output monitor | Signals ±8.7% to ±9.8% output deviation or disable state - used for sequencing, fault latching, or watchdog reset generation. |
| BST1 / COM1 / BST2 / COM2 | Charge pump terminals | Support gate drive for internal high-side MOSFETs; require 0.1µF/5V ceramic caps placed adjacent to IC for stable bootstrap operation. |
Key Features
| Feature | Design Value |
|---|---|
| No-loss PowerPath™ architecture | Eliminates series diode losses and associated heat generation during dual-source operation, preserving >95% peak efficiency even at light loads. |
| Pin-selectable input prioritization | Enables deterministic power sourcing behavior via single DIODE pin - critical for fail-safe systems where VIN1 (e.g., main battery) must always be preferred unless invalid. |
| Programmable UVLO with hysteresis | VSET1/VSET2 allow independent, temperature-stable UVLO thresholds per input with 11% hysteresis - prevents oscillation during marginal input conditions. |
| 200kHz–2.2MHz frequency programming | RT resistor sets exact switching frequency, enabling EMI compliance tuning and optimal inductor selection for size/cost/efficiency balance. |
| –55°C to +150°C guaranteed operation | Extended temperature grade validated per MIL-STD-883 methods - supports deployment in engine compartments, avionics bays, and industrial motor drives without derating. |
| Integrated VREF output | 1.000V ±1% precision reference powers external resistor dividers for VSET1/VSET2 and serves as general-purpose analog reference for system sensors or DACs. |
Applications
| Automotive Battery Backup Systems | Industrial Supercapacitor Hold-Up |
|---|---|
Use Scenario: Maintaining 3.3V/2.5A power to ADAS domain controllers during cold-crank (5V–10V) or stop-start events where main 12V battery dips below 6V. IC Role / Device Role / Timing Role: Dual-input buck controller with priority mode ensures uninterrupted supply from backup LiFePO₄ cell when main battery fails, with <50µs switchover. Use Value: Eliminates need for 10,000µF+ electrolytic hold-up capacitors, reducing board area by >65% and improving long-term reliability in vibration-prone environments. | Use Scenario: Providing regulated 5V/2A output during AC mains failure in programmable logic controllers (PLCs), using 10F/2.7V supercapacitor stack as energy reservoir. IC Role / Device Role / Timing Role: Synchronous buck with no-loss PowerPath™ draws from supercapacitor only when DC bus drops below 18V, minimizing self-discharge during normal operation. Use Value: Achieves >92% efficiency at 1A load with 2.2µH inductor, extending supercapacitor runtime by 3.2× versus discrete diode-OR solutions. |
| Uninterruptible Power Supplies (UPS) | Ruggedized Portable Test Equipment |
Use Scenario: Seamless transition between wall adapter (24V) and sealed lead-acid battery (12V) in medical-grade UPS powering Ethernet switches during grid outage. IC Role / Device Role / Timing Role: Ideal diode-OR mode automatically selects higher-voltage source; PGOOD and VALID signals feed system supervisor MCU for predictive maintenance alerts. Use Value: Reduces standby power to 2µA, enabling >30-day battery-only operation; open-drain indicators simplify isolation from safety-critical control logic. | Use Scenario: Power management in handheld oscilloscopes and spectrum analyzers operating from either USB-C PD (5–20V) or internal Li-ion pack (3.0–4.2V). IC Role / Device Role / Timing Role: Wide 2.4V–42V input range accommodates variable USB-C PD voltages; programmable UVLO prevents brownout during battery depletion. Use Value: Single-chip solution replaces discrete OR-ing FETs + LDO + supervisor, cutting BOM count by 7 components and PCB footprint by 42 mm². |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-input buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3122IUFD#TRPBF | 28-pin QFN, –40°C to 125°C rating, identical electrical specs but lower temperature grade and smaller thermal resistance (θJA = 34°C/W vs. 30°C/W). | Suitable for commercial/industrial ambient environments; not qualified for extended temperature or under-hood use. | Select when cost sensitivity outweighs extended temperature requirement and PCB layout permits QFN thermal pad routing. |
| MAX20406AATJ+ | 32-pin TQFN, 36V max input, 3A output, integrated FETs, but lacks dual-Kelvin inputs and programmable UVLO - uses fixed 3.2V/2.7V thresholds. | Requires external UVLO supervision circuitry for flexible input validation; no native PowerPath™ switchover timing guarantee. | Choose for higher output current needs where dual-input flexibility is secondary to integration density and cost. |
Compared with LTC3126MPFE#TRPBF, the LTC3122IUFD#TRPBF offers identical functionality at lower cost but sacrifices guaranteed operation below –40°C and above 125°C, while the MAX20406AATJ+ trades programmable input control for higher current and smaller package - making LTC3126MPFE#TRPBF uniquely suited for mission-critical dual-source systems demanding extended temperature resilience and deterministic switchover.
Availability
LTC3126MPFE#TRPBF is available at Aetrix Electronics and suitable for automotive battery backup, industrial supercapacitor hold-up, and ruggedized portable test equipment requiring stable component supply across extreme temperature ranges and long product lifecycles.
Supply support for LTC3126MPFE#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 its legacy of high-performance power management ICs with rigorous qualification standards and long-term product availability commitments.
The LTC3126MPFE#TRPBF belongs to Linear's PowerPath™ family of dual-input synchronous buck regulators, engineered specifically for seamless, high-efficiency power source redundancy in automotive, industrial, and aerospace systems where reliability under thermal stress is non-negotiable.
FAQ
What is the guaranteed operating temperature range for the LTC3126MPFE#TRPBF?
The LTC3126MPFE#TRPBF is fully tested and guaranteed over –55°C to +150°C junction temperature. This extended range is validated per MIL-STD-883 methods and supports deployment in under-hood automotive, downhole instrumentation, and military-grade embedded systems where standard industrial-grade parts would fail.
How does the LTC3126MPFE#TRPBF achieve seamless switchover between two input sources?
The LTC3126MPFE#TRPBF uses an internal no-loss PowerPath™ architecture with independent input comparators and fast analog control loops. When configured in priority mode (DIODE = low), it transitions from VIN1 to VIN2 in under 50µs upon VIN1 dropping below its programmed UVLO threshold - all without output droop or need for hold-up capacitance.
Can the LTC3126MPFE#TRPBF operate with only one input source connected?
Yes. The LTC3126MPFE#TRPBF functions correctly with only VIN1/PVIN1 or only VIN2/PVIN2 connected. In ideal diode-OR mode, it will regulate from the single valid source; in priority mode, it operates from VIN1 if present and valid, otherwise remains disabled. Unused input pins must be left floating or tied to ground through appropriate RC filtering to prevent noise coupling.
What is the purpose of the VSET1 and VSET2 pins on the LTC3126MPFE#TRPBF?
The VSET1 and VSET2 pins on the LTC3126MPFE#TRPBF allow precise programming of the UVLO thresholds for VIN1 and VIN2 inputs using resistor dividers referenced to the internal 1.000V VREF. Each accepts 0–1V to set corresponding UVLO thresholds from 0–20V, enabling adaptive input validation for varying battery chemistries or degraded supply conditions.
Does the LTC3126MPFE#TRPBF support external clock synchronization?
Yes. The LTC3126MPFE#TRPBF supports external clock synchronization via the PWM/SYNC pin. Applying a 200kHz–2.2MHz square wave synchronizes the internal oscillator, forcing fixed-frequency PWM operation and eliminating beat frequencies in multi-rail systems - essential for EMI-sensitive applications like medical imaging or radar subsystems.
LTC3126MPFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- 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):
- 2.4V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.818V
- Voltage - Output (Max):
- 42V
- Current - Output:
- 2.5A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LTC3126MPFE#TRPBF FAQ
1.How can I place an order for LTC3126MPFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3126MPFE#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 LTC3126MPFE#TRPBF reliable?
The price and inventory of LTC3126MPFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3126MPFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3126MPFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3126MPFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3126MPFE#TRPBF?
LTC3126MPFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3126MPFE#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 LTC3126MPFE#TRPBF?
For technical support, including LTC3126MPFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3126MPFE#TRPBF requirements.
6.How does Aetrix verify that LTC3126MPFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3126MPFE#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 LTC3126MPFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3126MPFE#TRPBF?
All LTC3126MPFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3126MPFE#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 LTC3126MPFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3126MPFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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