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Analog Devices Inc. LTC3126IFE#TRPBF
- Part No.:
- LTC3126IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3126IFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 2.5A 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,558
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Product details
Overview
LTC3126IFE#TRPBF from Analog Devices (formerly Linear Technology) is a 42V, 2.5A synchronous step-down regulator with dual-input no-loss PowerPath™ for seamless switchover between two independent power sources. It supports pin-selectable priority and ideal diode-OR modes, programmable UVLO thresholds, and delivers 95% efficiency at 1A/12VIN/5VOUT. Used in automotive battery backup systems where transient robustness and uninterrupted output are critical.
For engineers reviewing the LTC3126IFE#TRPBF datasheet, LTC3126IFE#TRPBF pinout, LTC3126IFE#TRPBF application, or LTC3126IFE#TRPBF equivalent, key selection factors include its 2.4V–42V input range, 2µA Burst Mode quiescent current, 200kHz–2.2MHz programmable switching frequency, dual-input status indicators (VALID1/VALID2), and thermal performance in the TSSOP package.
Technical Context
The LTC3126IFE#TRPBF integrates dual-input PowerPath control with current-mode synchronous buck regulation. Its internal architecture includes two independent UVLO comparators (programmable via VSET1/VSET2), fast automatic switchover logic, and separate high-side (200mΩ) and low-side (70mΩ) MOSFET drivers with 46ns minimum on-time.
It features three operating modes controlled by the DIODE pin: priority mode (VIN1 preferred), ideal diode-OR mode (highest valid input selected), and shutdown (ENA low). The device supports external clock synchronization via PWM/SYNC and maintains regulation down to 0.818V output with ±1% FB voltage accuracy over temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.4V to 42V - supports automotive transients (42V), supercapacitors, and multi-cell battery stacks without external protection. |
| Max Output Current | 2.5A continuous - sufficient for powering FPGA I/O banks, microcontroller cores, or industrial sensors under full load. |
| 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 - adjustable via RT resistor; higher frequencies allow smaller inductors (e.g., 2.2µH at 2MHz) for space-constrained layouts. |
| Feedback Voltage | 818mV ±1% - sets precise output voltage with minimal external resistor tolerance impact; supports 0.818V–VIN output range. |
| UVLO Thresholds | Programmable from 0V to 20V via VSET1/VSET2 - enables custom brown-out behavior for VIN1 and VIN2 independently. |
| Thermal Rating | –40°C to 125°C junction - qualified for under-hood automotive and industrial environments with derated power handling. |
Pinout & Package
Package: 28-lead plastic TSSOP (4.4mm width), exposed pad (Pin 29) connected to PGND for thermal dissipation. θJA = 30°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1 / VIN2 | Kelvin sense inputs | Low-impedance sensing paths for priority and secondary inputs; must be short-traced to PVIN1/PVIN2 to reject PCB trace resistance errors. |
| PVIN1 / PVIN2 | Main power inputs | High-current paths requiring ≥4.7µF ceramic bypass capacitors; Schottky diodes needed if inductive shorts possible. |
| VALID1 / VALID2 | Open-drain status outputs | Indicate real-time validity of each input above programmed UVLO; pulled low only when enabled and voltage exceeds threshold. |
| PRIORITY | Open-drain mode indicator | Asserted low only during active priority-mode operation from VIN1; floats in shutdown or ideal-diode mode. |
| DIODE | Mode select logic input | High = ideal diode-OR; low = priority mode; no pull-up/pull-down required - driven directly by MCU GPIO or hardwired. |
| SW | Power switch node | Connects to buck inductor; requires tight layout with low-inductance PGND return path to minimize EMI and switching losses. |
| BST1 / BST2 | Bootstrap rails | Drive high-side MOSFET gates; require 0.1µF/5V ceramic caps between BSTx and COMx for reliable gate drive. |
| PGND (Pins 18,19,21,22,29) | Power ground | Multiple dedicated pins plus exposed pad - must be soldered to large copper area with ≥6 thermal vias to inner ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| No-loss PowerPath™ switchover | Eliminates hold-up capacitors by enabling sub-50µs transition between inputs without output droop or glitch. |
| Programmable dual-input UVLO | VSET1/VSET2 pins accept 0–1V to set 0–20V thresholds - allows asymmetric brown-out behavior for battery vs. wall adapter inputs. |
| 2.5A integrated power stage | Combines 200mΩ high-side and 70mΩ low-side MOSFETs - achieves 95% peak efficiency at 1A/12V→5V without external switches. |
| 2µA Burst Mode quiescent current | Reduces standby power in always-on systems - e.g., 2.5µA total system current enables >12-year CR2032 coin cell lifetime at 25µA average load. |
| 200kHz–2.2MHz frequency programming | RT resistor sets exact switching frequency - enables EMI optimization and inductor size reduction (e.g., 2.2µH at 2MHz vs. 10µH at 700kHz). |
| Independent PGOOD, VALID1, VALID2, PRIORITY | Four open-drain status signals provide complete real-time visibility into power rail health and source selection state for system-level fault logging. |
Applications
| Automotive Battery Backup | Industrial Uninterruptible Supply |
|---|---|
Use Scenario: Maintaining 3.3V rail during engine cranking when battery dips to 6V while alternator is offline. IC Role / Device Role / Timing Role: Dual-input buck controller managing seamless transition from main battery (VIN1) to supercapacitor backup (VIN2) with <50µs switchover. Use Value: Prevents microcontroller reset and preserves SRAM contents without bulky hold-up capacitors or complex sequencing logic. | Use Scenario: Powering PLC I/O modules during AC mains failure using LiFePO4 battery stack (24V–36V) as secondary source. IC Role / Device Role / Timing Role: Priority-mode regulator selecting main 24V DC supply (VIN1), then automatically switching to battery (VIN2) upon undervoltage detection. Use Value: Enables zero-interruption operation with programmable 24.18V/23.83V hysteresis on VIN1 to reject noise-induced false triggers. |
| Portable Test Equipment | Communications Base Station Backup |
Use Scenario: Handheld multimeter powered by USB (VIN1) or internal Li-ion (VIN2), requiring stable 3.3V for ADC and display during hot-swap. IC Role / Device Role / Timing Role: Ideal diode-OR mode controller selecting highest valid input; VSET1/VSET2 configured for 4.2V/3.0V thresholds respectively. Use Value: Eliminates reverse current and ensures smooth handoff without output voltage sag or software intervention. | Use Scenario: 48V telecom system maintaining 12V management rail during rectifier failure using 48V battery bank (VIN2) as backup. IC Role / Device Role / Timing Role: High-voltage synchronous buck (42V abs max) operating in priority mode with EXTVCC bootstrapped to VOUT for ultra-low IQ. Use Value: Achieves 2µA no-load current and 94% efficiency at 1A, extending backup runtime while minimizing heat in sealed enclosures. |
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 |
|---|---|---|---|
| LTC3122IFE#TRPBF | Lower 36V max input, 1.5A output, no programmable UVLO - fixed 2.5V threshold on both inputs. | Suitable only for ≤36V systems with symmetric input requirements and lower current needs. | Select when cost sensitivity outweighs need for 42V rating, 2.5A capability, or independent UVLO tuning. |
| TPS63020DSJR | Single-input buck-boost, no dual-source switchover logic, 96% peak efficiency, 2.5A output. | Cannot replace PowerPath functionality - requires external OR-ing FETs and control logic for dual-input operation. | Choose only if input voltage may fall below output (buck-boost needed) and dual-source autonomy is handled externally. |
Compared with LTC3122IFE#TRPBF and TPS63020DSJR, the LTC3126IFE#TRPBF uniquely integrates programmable dual-input UVLO, no-loss switchover, and 42V operation - making it the only solution that eliminates hold-up capacitors and external control logic in automotive and industrial backup designs.
Availability
LTC3126IFE#TRPBF is available at Aetrix Electronics and suitable for automotive battery backup, industrial uninterruptible supplies, and portable test equipment requiring stable component supply across extended temperature ranges.
Supply support for LTC3126IFE#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 high-performance analog IC portfolio, emphasizing precision, reliability, and ruggedized design for demanding applications.
The LTC3126IFE#TRPBF belongs to Linear's PowerPath™ regulator family, engineered specifically for mission-critical dual-input power systems where seamless source transition, wide input range, and ultra-low quiescent current are mandatory.
FAQ
What is the maximum allowable voltage on the PVIN1 and PVIN2 pins of the LTC3126IFE#TRPBF?
The absolute maximum rating for PVIN1 and PVIN2 is 42V. This rating applies regardless of operating mode or input source configuration. Exceeding 42V risks permanent damage. Transient spikes up to 42V are tolerated per specification, but sustained operation above 42V violates Absolute Maximum Ratings and voids reliability guarantees. The LTC3126IFE#TRPBF is designed for automotive 24V systems with load-dump protection.
How does the LTC3126IFE#TRPBF handle switchover between VIN1 and VIN2 in priority mode?
In priority mode (DIODE = low), the LTC3126IFE#TRPBF continuously monitors VIN1 against its UVLO threshold. If VIN1 drops below the threshold (e.g., 23.83V with 24.18V rising threshold), the device transitions to VIN2 within 50µs while maintaining regulated output. The VBEST comparator provides hysteresis (280–450mV) to prevent oscillation near the threshold. The LTC3126IFE#TRPBF asserts PRIORITY low only when actively sourcing from VIN1.
Can the LTC3126IFE#TRPBF operate with only one input connected?
Yes. If only VIN1 is connected and valid (above its UVLO threshold), the LTC3126IFE#TRPBF operates normally in priority mode. If only VIN2 is connected and VIN1 is floating or below UVLO, the device will use VIN2 - provided DIODE is high (ideal diode-OR mode) or VIN1 is invalid in priority mode. Floating inputs must be avoided; unused VINx pins should be tied to GND or biased below UVLO to prevent noise coupling. The LTC3126IFE#TRPBF requires at least one valid input to enable regulation.
What is the purpose of the EXTVCC pin on the LTC3126IFE#TRPBF, and how should it be used?
The EXTVCC pin powers the internal VCC LDO rail. When driven ≥3.15V (e.g., from VOUT), it reduces quiescent current and improves efficiency - especially in high-VIN/low-VOUT applications. If left open, VCC is powered from VIN1/VIN2, increasing no-load current. The LTC3126IFE#TRPBF draws only 0.2µA from EXTVCC in shutdown and 8.8mA during switching at 1MHz, making it optimal for battery-backed systems.
Does the LTC3126IFE#TRPBF support external clock synchronization, and what are the timing requirements?
Yes. The PWM/SYNC pin accepts an external clock (200kHz–2.2MHz) to synchronize switching. Minimum high/low pulse widths are 100ns/150ns respectively. Synchronization forces PWM mode (disabling Burst Mode) and aligns phase across multiple converters to reduce EMI peaks. The LTC3126IFE#TRPBF tolerates clock jitter <1ns RMS and maintains regulation even with ±5% frequency variation - critical for noise-sensitive instrumentation.
LTC3126IFE#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
LTC3126IFE#TRPBF FAQ
1.How can I place an order for LTC3126IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3126IFE#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 LTC3126IFE#TRPBF reliable?
The price and inventory of LTC3126IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3126IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3126IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3126IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3126IFE#TRPBF?
LTC3126IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3126IFE#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 LTC3126IFE#TRPBF?
For technical support, including LTC3126IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3126IFE#TRPBF requirements.
6.How does Aetrix verify that LTC3126IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3126IFE#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 LTC3126IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3126IFE#TRPBF?
All LTC3126IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3126IFE#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 LTC3126IFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3126IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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