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Analog Devices Inc. LT1976BIFE#TRPBF
- Part No.:
- LT1976BIFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1976BIFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.2A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,048
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Product details
Overview
LT1976BIFE#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode step-down switching regulator IC designed for automotive and industrial power conversion. It operates from 3.3V to 60V input, delivers up to 1.5A peak switch current, features 1.6mA quiescent current (non-Burst Mode), 200kHz fixed switching frequency, and integrates a 0.2Ω on-resistance NPN power switch. It is used in 14V/42V automotive systems requiring load dump protection and stable regulation under wide VIN transients.
For engineers reviewing the LT1976BIFE#TRPBF datasheet, LT1976BIFE#TRPBF pinout, LT1976BIFE#TRPBF application, or LT1976BIFE#TRPBF equivalent, key selection considerations include its 60V absolute max input rating, programmable Power Good flag with CT delay timing, absence of Burst Mode (enabling low-ripple light-load operation), thermal shutdown, and compatibility with external synchronization - all within a thermally enhanced 16-pin TSSOP package with exposed pad.
Technical Context
The LT1976BIFE#TRPBF employs current-mode control with cycle-by-cycle peak current limiting and an internal 1.25V reference, enabling fast transient response and stable loop compensation. Its architecture uses BOOST pin voltage boosting to saturate the integrated NPN switch, achieving FET-like conduction loss (0.2Ω typical) despite bipolar construction.
Unlike the LT1976, the LT1976B variant disables Burst Mode operation, maintaining fixed-frequency pulse-skipping at light loads to eliminate low-frequency output ripple - critical for noise-sensitive analog or RF subsystems. It supports programmable Power Good threshold via PGFB divider and soft-start via CSS capacitor, with shutdown current <1μA and full -40°C to +125°C junction temperature operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V - supports 12V/24V/42V automotive battery rails and industrial DC distribution without pre-regulation. |
| Switch Current Limit | 1.2A (min), 2.5A (typ), 4A (max) - ensures robust overload handling while maintaining regulation across duty cycle range. |
| Quiescent Current | 1.6mA (typ) - fixed-frequency operation eliminates Burst Mode, avoiding sub-audio ripple but increasing no-load power draw vs LT1976. |
| Switch On-Resistance | 0.2Ω (typ) - achieved via BOOST pin voltage boost, minimizing conduction loss and thermal stress in high-current applications. |
| Feedback Reference | 1.25V ±2.4% (–40°C to +125°C) - precise setpoint enables accurate output voltage programming with standard resistor dividers. |
| Power Good Flag | Programmable threshold (87–93% of VREF) with CT-based delay - allows customizable output voltage monitoring and system sequencing. |
| Thermal Protection | Internal thermal shutdown - prevents damage during sustained overload or poor PCB heatsinking conditions. |
Pinout & Package
LT1976BIFE#TRPBF is housed in a 16-pin thermally enhanced TSSOP package (FE) with exposed pad (Pin 17), soldered to PCB ground for low θJC(PAD) = 10°C/W. The exposed pad is electrically GND and must be connected to system ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 2) | Switch Emitter | Connects to inductor and catch diode cathode; swings from –0.3V to VIN during operation; requires low-inductance layout. |
| VIN (Pin 4) | Switch Collector & Supply Input | Primary power input for internal circuitry when BIAS is unconnected; handles high di/dt; bypass capacitor required. |
| BOOST (Pin 6) | Switch Drive Boost | Accepts externally boosted voltage (≥VIN + 3.3V) to fully saturate internal NPN switch and minimize VCE(sat). |
| CT (Pin 7) | Power Good Timing | Sources/sinks current to external capacitor to program PG flag delay time; clamps at 1.2V for PG assertion. |
| GND (Pins 8, 17) | Signal & Thermal Reference | Pins 8 and 17 are common ground; exposed pad (Pin 17) must be soldered to PCB ground plane for thermal performance. |
| CSS (Pin 9) | Soft-Start Control | Sinks current proportional to FB voltage; controls output ramp rate via external capacitor to limit inrush current. |
| BIAS (Pin 10) | Efficiency Boost Supply | Accepts regulated output voltage ≥3V to power internal circuitry, reducing VIN current and improving efficiency at high VIN. |
| VC (Pin 11) | Error Amplifier Output | Provides error amplifier output for compensation; also serves as current limit comparator input and override point. |
| FB (Pin 12) | Feedback Input | Compares divided output voltage to 1.25V reference; enables frequency foldback and soft-start when below 0.9V. |
| PGFB (Pin 13) | Power Good Threshold Input | Resistive divider input for programmable PG activation; triggers CT timing when exceeding 90% of VREF. |
| SYNC (Pin 14) | External Clock Input | Accepts logic-level signal (230–600kHz) to synchronize switching frequency; disabled if FB < 0.9V. |
| SHDN (Pin 15) | Shutdown Control | Active-high enable; >1.3V activates regulator; <1.2V forces shutdown with <1μA supply current. |
| PG (Pin 16) | Power Good Output | Open-drain active-low flag; sinks 200μA when asserted; high-impedance when CT clamp is active (PG delay complete). |
Key Features
| Feature | Design Value |
|---|---|
| High-Voltage Input Capability | 60V absolute maximum input rating with load dump protection - suitable for 42V automotive transients per ISO 7637-2. |
| No-Burst-Mode Operation | Fixed-frequency pulse-skipping replaces Burst Mode, eliminating 20–200Hz output ripple critical for analog sensor or RF power supply rails. |
| Integrated Power Good Flag | Programmable threshold and delay via external CT capacitor - enables reliable system power sequencing and fault detection. |
| Thermally Optimized Package | 16-pin TSSOP with exposed GND pad (θJC = 10°C/W) - supports 1.5A continuous output with minimal external heatsinking. |
| External Synchronization | Logic-compatible SYNC pin accepts 230–600kHz input - allows EMI reduction via frequency dithering or multi-rail synchronization. |
| Soft-Start with Programmable Ramp | CSS pin current scales with FB voltage - provides controlled output rise time using single capacitor, preventing inrush-induced rail collapse. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module Regulator |
|---|---|
|
Use Scenario: Powers DSP, audio codec, and display controller in head unit with 12V/24V battery input subject to load dump and cold-crank events. IC Role / Device Role / Timing Role: Primary 3.3V/5V buck regulator providing stable, low-noise DC power; PG flag sequences downstream logic after valid output. Use Value: 60V input tolerance and integrated load dump protection eliminate need for external TVS; non-Burst Mode avoids audible noise in audio subsystems. |
Use Scenario: Generates isolated 5V rail for digital I/O conditioning circuits in programmable logic controller modules operating from 24VDC field bus. IC Role / Device Role / Timing Role: High-efficiency, thermally robust step-down converter with programmable PG for safe startup of FPGA-based control logic. Use Value: 0.2Ω switch RDS(on) and exposed-pad TSSOP enable 1.5A output without forced air; BIAS pin improves efficiency at 24V→5V conversion. |
| Ruggedized Battery-Powered Instrumentation | Distributed Telecom Power System |
|
Use Scenario: Supplies precision ADC, op-amps, and microcontroller in portable test equipment powered by 3S Li-ion (9–12.6V) or 24V sealed lead-acid packs. IC Role / Device Role / Timing Role: Main system regulator with soft-start and thermal shutdown; PG flag confirms stable rail before enabling sensitive analog front-end. Use Value: Wide 3.3–60V input range accommodates battery chemistries and aging; 1.6mA IQ balances runtime vs. low-noise requirements. |
Use Scenario: Provides intermediate 5V/3.3V rails in telecom remote radio head (RRH) powered from 48V backplane with strict EMI limits. IC Role / Device Role / Timing Role: Synchronized buck converter operating at 200kHz with external clock to avoid interference with RF bands. Use Value: SYNC pin enables deterministic switching frequency placement; BOOST-assisted saturation minimizes heat in confined RRH enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | 40V max input, 1.2A output, 3mm × 4mm MSOP, 17μA IQ in Burst Mode | Better light-load efficiency but lower voltage rating; lacks PG flag and SYNC | Select for space-constrained, low-IQ designs where 40V input suffices and PG/SYNC not required. |
| LM5164QPWPRQ1 | 100V max input, 1A output, 1.5MHz switching, integrated MOSFETs, 15μA IQ | Higher voltage, higher frequency, smaller inductor; no BOOST pin or programmable PG | Select for ultra-wide VIN (up to 100V) and compact designs where fixed 1.5MHz simplifies filtering. |
Compared with LTC3631EMSE#PBF and LM5164QPWPRQ1, LT1976BIFE#TRPBF uniquely combines 60V operation, programmable Power Good, external synchronization, and non-Burst Mode low-noise regulation - making it optimal for automotive and industrial systems demanding both ruggedness and signal integrity.
Availability
LT1976BIFE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC power modules, and ruggedized battery-powered instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1976BIFE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LT1976/LT1976B product line was designed specifically for high-input-voltage DC/DC conversion in harsh environments - emphasizing reliability, thermal robustness, and feature-rich control (PG, SYNC, soft-start) for automotive and industrial power systems.
FAQ
What is the maximum input voltage rating for LT1976BIFE#TRPBF?
The LT1976BIFE#TRPBF has an absolute maximum input voltage rating of 60V on the VIN and SHDN pins, with load dump protection rated to 60V. This makes LT1976BIFE#TRPBF suitable for 42V automotive systems per ISO 7637-2, though continuous operation above 40V requires careful thermal design due to increased power dissipation.
Does LT1976BIFE#TRPBF support Burst Mode operation?
No, LT1976BIFE#TRPBF does not support Burst Mode operation. Unlike the LT1976, the LT1976B variant uses pulse-skipping at light loads to maintain fixed-frequency switching and eliminate low-frequency output ripple. As a result, LT1976BIFE#TRPBF draws 1.6mA quiescent current instead of 100μA, trading efficiency for noise performance.
How is the Power Good flag programmed on LT1976BIFE#TRPBF?
The Power Good flag on LT1976BIFE#TRPBF is programmed using two external components: a resistive divider from VOUT to GND connected to PGFB (Pin 13) sets the activation threshold (typically 90% of 1.25V), and a capacitor from CT (Pin 7) to GND determines the delay time before PG asserts. LT1976BIFE#TRPBF's PG pin is open-drain and sinks 200μA when active.
What is the purpose of the BOOST pin on LT1976BIFE#TRPBF?
The BOOST pin on LT1976BIFE#TRPBF supplies an elevated gate drive voltage to the internal NPN power switch, enabling full saturation and minimizing VCE(sat). A charge pump formed by an external diode and capacitor connects BOOST to SW, generating ~VIN + 3.3V. This reduces effective on-resistance to 0.2Ω, significantly lowering conduction losses compared to standard bipolar operation.
Can LT1976BIFE#TRPBF be synchronized to an external clock?
Yes, LT1976BIFE#TRPBF supports external synchronization via the SYNC pin (Pin 14), which accepts logic-level inputs from 230kHz to 600kHz with 20–80% duty cycle. Synchronization is disabled when FB voltage drops below 0.9V (e.g., during startup or fault). This capability allows EMI reduction and multi-rail coordination in complex power systems using LT1976BIFE#TRPBF.
LT1976BIFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-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):
- 3.3V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 55.2V
- Current - Output:
- 1.2A (Switch)
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT1976BIFE#TRPBF FAQ
1.How can I place an order for LT1976BIFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1976BIFE#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 LT1976BIFE#TRPBF reliable?
The price and inventory of LT1976BIFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1976BIFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1976BIFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1976BIFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1976BIFE#TRPBF?
LT1976BIFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1976BIFE#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 LT1976BIFE#TRPBF?
For technical support, including LT1976BIFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1976BIFE#TRPBF requirements.
6.How does Aetrix verify that LT1976BIFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1976BIFE#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 LT1976BIFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1976BIFE#TRPBF?
All LT1976BIFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1976BIFE#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 LT1976BIFE#TRPBF part is unused and in its original packaging.
Return procedure for LT1976BIFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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