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Analog Devices Inc. LTC3126EFE#TRPBF
- Part No.:
- LTC3126EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3126EFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 2.5A 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,498
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Product details
Overview
LTC3126EFE#TRPBF from Analog Devices (formerly Linear Technology) is a 42V, 2.5A synchronous step-down regulator with integrated no-loss PowerPath™ for seamless dual-input power source management. It supports pin-selectable ideal diode-OR or priority input mode, programmable UVLO thresholds (2.34V–20V), and operates from 2.4V to 42V input while delivering 0.818V to VIN output. Used in automotive battery backup systems where transient robustness and automatic switchover are critical.
For engineers reviewing the LTC3126EFE#TRPBF datasheet, LTC3126EFE#TRPBF pinout, LTC3126EFE#TRPBF application, or LTC3126EFE#TRPBF equivalent, key selection criteria include dual-input UVLO programmability, 2µA Burst Mode quiescent current, 200kHz–2.2MHz frequency setting via RT resistor, 60ns minimum on-time, and thermal performance in the 28-lead TSSOP package with exposed PGND pad.
Technical Context
The LTC3126EFE#TRPBF implements current-mode control with independent input validation comparators, internal VREF (1.000V ±1.8mV), and dual charge-pump gate drivers (BST1/COM1, BST2/COM2) enabling high-side MOSFET drive. Its PowerPath architecture eliminates hold-up capacitors by enabling sub-50µs automatic switchover between VIN1 (priority) and VIN2 (backup) without output rail disturbance.
It features three operating modes controlled by the DIODE pin: priority mode (VIN1 preferred), ideal diode-OR mode (higher valid input selected), and shutdown (ENA low). The PRIORITY, VALID1, VALID2, and PGOOD open-drain indicators provide real-time system-level power status feedback with 70Ω pull-down strength and 5.5V absolute max rating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.4V to 42V - supports automotive transients (42V), supercapacitor discharge, and multicell battery stacks without external protection. |
| Output Current | 2.5A continuous - sufficient for powering FPGA I/O banks, microcontroller cores, or industrial sensors directly. |
| Burst Mode IQ | 2µA - enables >10-year battery life in always-on backup systems with low-duty-cycle wakeups. |
| Switching Frequency | 200kHz to 2.2MHz - set by RT resistor (e.g., 33.2kΩ = 1MHz); allows optimization of size vs. efficiency in space-constrained designs. |
| Feedback Voltage | 818mV ±12mV - precise reference enables accurate output regulation across temperature (±0.5% line/load regulation). |
| UVLO Threshold Range | 2.34V to 20V - programmed per input via VSET1/VSET2 resistive dividers from 1.000V VREF, enabling custom brownout behavior. |
| Min On-Time | 46ns - supports high VIN-to-VOUT ratios (e.g., 24V→3.3V at 2MHz) without pulse skipping or instability. |
Pinout & Package
Package: 28-lead plastic TSSOP (4.4mm width), thermally enhanced with exposed PGND pad (Pin 29) requiring PCB soldering for thermal and electrical integrity. θJA = 30°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1 / VIN2 | Kelvin sense inputs | Low-impedance sensing paths for UVLO validation; must be connected to respective PVIN pins with short traces to avoid false undervoltage trips. |
| PVIN1 / PVIN2 | Main power inputs | High-current paths requiring ≥4.7µF ceramic bypass caps; Schottky diodes needed if inductive shorts possible. |
| DIODE | Mode select logic input | High = ideal diode-OR; Low = priority mode; determines whether switchover is voltage-based or hierarchy-based. |
| VALID1 / VALID2 | Open-drain status outputs | Assert low when corresponding input exceeds its programmed UVLO threshold; used for system-level power sequencing. |
| PRIORITY | Open-drain indicator | Asserts low only when buck is actively sourcing from VIN1 in priority mode - enables fault isolation in dual-rail systems. |
| PGOOD | Open-drain output monitor | Signals regulation error (>±8.7% deviation) or disable state; drives host MCU reset or LED alert with 70Ω pull-down. |
| VSET1 / VSET2 | UVLO programming inputs | Accept 0–1V to set 0–20V UVLO thresholds; referenced to internal 1.000V VREF for ratio accuracy. |
| RT | Frequency programming node | Connects to ground via resistor to set fSW; internal current source enables precise frequency control independent of supply variation. |
Key Features
| Feature | Design Value |
|---|---|
| No-loss PowerPath™ | Eliminates hold-up capacitors and associated ESR/size penalties by enabling <50µs switchover with zero output droop during input transitions. |
| Programmable dual-input UVLO | VSET1/VSET2 pins allow independent, resistor-programmed undervoltage lockout thresholds (2.34V–20V) per input, supporting asymmetric backup policies. |
| 2.5A integrated synchronous switches | 200mΩ high-side + 70mΩ low-side MOSFETs deliver >95% efficiency at 1A (12V→5V), reducing external component count and thermal footprint. |
| 2µA Burst Mode quiescent current | Extends runtime in energy-harvesting or battery-backed applications where load is idle >99% of time, with minimal ripple penalty. |
| 28-lead TSSOP with exposed PGND | Thermally optimized package (θJA = 30°C/W) enables 2.5A operation without heatsink in industrial ambient (≤85°C). |
Applications
| Automotive Battery Backup Supply | Industrial Uninterruptible Power Module |
|---|---|
Use Scenario: Maintaining 3.3V/2.5A power to CAN transceivers and microcontrollers during engine cranking (4.2V–24V battery sag) or alternator failure. IC Role / Device Role / Timing Role: Dual-input buck controller managing seamless transition from main 12V bus to isolated 24V backup rail with <50µs switchover. Use Value: Prevents system reset during 100ms–500ms brownouts; eliminates need for 10,000µF hold-up capacitors and associated board area/cost. | Use Scenario: Providing regulated 5V/2.5A to PLC I/O modules during AC mains loss, using supercapacitor bank as secondary source. IC Role / Device Role / Timing Role: Synchronous buck with no-loss PowerPath acting as primary regulator and automatic backup selector. Use Value: Enables >30-second ride-through without battery chemistry limitations; 2µA quiescent current extends supercapacitor hold-up time by 4× vs. discrete solutions. |
| Portable Test Equipment Power | Redundant Telecom Power Interface |
Use Scenario: Powering handheld oscilloscope front-end ADCs and FPGAs from either USB-C PD (5–20V) or internal Li-ion (3.0–4.2V) with zero output glitch. IC Role / Device Role / Timing Role: Dual-input step-down regulator configured in ideal diode-OR mode to select highest valid input automatically. Use Value: Eliminates manual power source selection; maintains 3.3V/2.5A output stability during hot-swap of power adapters or battery swaps. | Use Scenario: Delivering 1.8V/2.5A to telecom baseband processors from either primary -48V DC feed (via intermediate 12V) or secondary 24V battery bank. IC Role / Device Role / Timing Role: Priority-mode buck converter ensuring primary feed is used unless voltage drops below programmable 42V UVLO. Use Value: Guarantees failover only on actual fault-not noise or ripple-reducing false triggers in noisy telecom environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-input buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3122EFE#TRPBF | Lower 36V max input, 1.5A output, no programmable UVLO - fixed 2.5V threshold. | Suitable only for ≤36V, ≤1.5A applications without custom brownout requirements. | Select when cost sensitivity outweighs programmability and current headroom needs. |
| MAX20406AATG+T | 42V input, 3A output, but lacks dual-input validation logic and PowerPath; requires external OR-ing FETs. | Needs external ideal diode controllers and UVLO comparators to replicate LTC3126 functionality. | Choose only if higher 3A current is mandatory and board space permits added discretes. |
Compared with LTC3126EFE#TRPBF, LTC3122EFE#TRPBF sacrifices UVLO flexibility and current capability for lower cost, while MAX20406AATG+T delivers higher current but increases BOM count and design complexity to achieve dual-input autonomy.
Availability
LTC3126EFE#TRPBF is available at Aetrix Electronics and suitable for automotive battery backup, industrial uninterruptible power modules, and portable test equipment requiring stable component supply across extended temperature ranges (–40°C to 125°C).
Supply support for LTC3126EFE#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 ICs including the LTC3126 series.
The LTC3126 belongs to Linear's high-voltage PowerPath™ regulator family, designed specifically for mission-critical dual-input power systems where seamless, autonomous switchover and ultra-low quiescent current are non-negotiable.
FAQ
What is the maximum input voltage rating for LTC3126EFE#TRPBF?
The LTC3126EFE#TRPBF has an absolute maximum input voltage rating of 42V on PVIN1, PVIN2, VIN1, and VIN2 pins. This rating enables direct connection to automotive 24V systems with 42V load-dump transients without external clamping. Operation above 42V risks permanent damage per Absolute Maximum Ratings.
How does the LTC3126EFE#TRPBF handle switchover between two input sources?
The LTC3126EFE#TRPBF performs automatic switchover in <50µs using its internal no-loss PowerPath™ architecture. In priority mode (DIODE = low), it sources from VIN1 until voltage falls below its VSET1-programmed UVLO; then it transitions to VIN2 without output droop. In ideal diode-OR mode (DIODE = high), it selects the higher valid input dynamically.
Can LTC3126EFE#TRPBF operate with only one input source connected?
Yes, LTC3126EFE#TRPBF operates normally with only VIN1 or only VIN2 connected. If the connected input exceeds its UVLO threshold, the buck converter regulates normally. If both inputs are below UVLO, the part disables the output and asserts PGOOD low. No external components are required for single-input use.
What is the purpose of the EXTVCC pin on LTC3126EFE#TRPBF?
The EXTVCC pin on LTC3126EFE#TRPBF bootstraps the internal VCC LDO. When driven ≥3.15V (e.g., from VOUT), it powers the control circuitry more efficiently than VIN-derived VCC-reducing quiescent current and improving light-load efficiency. If left open, VCC is powered from VIN1/VIN2, increasing no-load current by ~3µA.
Does LTC3126EFE#TRPBF require external MOSFETs for the PowerPath function?
No, LTC3126EFE#TRPBF integrates all necessary power switches and control logic for the no-loss PowerPath™ function. It contains dual synchronous rectifiers, gate drivers, and input validation comparators-no external MOSFETs, diodes, or controllers are needed to implement seamless dual-input switchover.
LTC3126EFE#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:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LTC3126EFE#TRPBF FAQ
1.How can I place an order for LTC3126EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3126EFE#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 LTC3126EFE#TRPBF reliable?
The price and inventory of LTC3126EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3126EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3126EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3126EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3126EFE#TRPBF?
LTC3126EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3126EFE#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 LTC3126EFE#TRPBF?
For technical support, including LTC3126EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3126EFE#TRPBF requirements.
6.How does Aetrix verify that LTC3126EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3126EFE#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 LTC3126EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3126EFE#TRPBF?
All LTC3126EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3126EFE#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 LTC3126EFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3126EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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