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Analog Devices Inc. LT1976BIFE#PBF
- Part No.:
- LT1976BIFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1976BIFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.2A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:155
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Product details
Overview
LT1976BIFE#PBF 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 200kHz fixed-frequency operation, 0.2Ω on-resistance, and 1.25V feedback reference. It is used in 14V/42V automotive systems and battery-powered industrial equipment requiring robust load-dump protection.
For engineers reviewing the LT1976BIFE#PBF datasheet, LT1976BIFE#PBF pinout, LT1976BIFE#PBF application, or LT1976BIFE#PBF equivalent, key selection criteria include its non-Burst Mode operation (1.6mA quiescent current), programmable Power Good flag, soft-start capability via CSS pin, and thermally enhanced 16-pin TSSOP package with exposed pad.
Technical Context
The LT1976BIFE#PBF implements a constant-frequency current-mode control architecture with an internal 200kHz oscillator, error amplifier output at VC pin, and cycle-by-cycle peak current limiting. Its BOOST pin enables full saturation of the integrated NPN switch, achieving low conduction loss comparable to a 0.2Ω FET despite bipolar construction.
Unlike the LT1976, the LT1976B variant disables Burst Mode operation-eliminating low-frequency output ripple but maintaining higher light-load quiescent current (1.6mA vs. 100μA). It supports external synchronization (230–600kHz), programmable PG delay via CT capacitor, and soft-start ramp control via CSS pin current threshold (7–20μA).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V - supports direct connection to 42V automotive batteries and industrial HV rails without pre-regulation. |
| Switch Current Limit | 1.2A (min), 2.5A (typ) - ensures reliable overcurrent protection across temperature; lower than LT1976's 1.5A min due to B-variant optimization. |
| Quiescent Current | 1.6mA - fixed operating current independent of load; avoids Burst Mode ripple but increases standby power vs. LT1976. |
| Feedback Reference | 1.25V ±2.4% - precise voltage setpoint enabling accurate output regulation with standard resistor dividers (R2 ≤10kΩ recommended). |
| Switch On-Resistance | 0.2Ω (typ) - achieved via BOOST-driven saturation; reduces conduction loss and thermal stress at 1.5A peak. |
| Power Good Flag | Programmable threshold (87–93% of VREF) with CT-based delay - enables system-level power sequencing and fault detection. |
| Shutdown Current | <1μA - enables ultra-low-power system sleep states with SHDN pin assertion. |
Pinout & Package
LT1976BIFE#PBF is housed in a 16-pin thermally enhanced TSSOP package with exposed pad (Pin 17), requiring soldering to PCB ground plane for thermal management (θJC = 10°C/W). Pins 1, 3, 5 are NC and electrically isolated.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 2) | Switch emitter node | Connects to inductor; swings negative during off-time; requires Schottky catch diode clamping. |
| VIN (Pin 4) | Power switch collector & primary supply | Supplies internal circuitry when BIAS is unconnected; subject to high di/dt; demands short, low-inductance input path. |
| BOOST (Pin 6) | Switch drive voltage boost | Enables NPN saturation via external capacitor/diode; must exceed VIN by ≥3.3V; minimum 1.8V boost voltage required. |
| GND (Pins 8, 17) | Signal & thermal reference | Exposed pad (Pin 17) must be soldered to ground plane; serves as both electrical return and primary heat sink. |
| CSS (Pin 9) | Soft-start control input | Current-source threshold (7–20μA) sets output voltage ramp rate; disabled above 0.9V FB voltage. |
| FB (Pin 12) | Feedback sense input | Compares divided output to 1.25V reference; controls regulation; triggers frequency foldback and soft-start below 0.9V. |
| PGFB (Pin 13) | Power Good comparator input | Resistive divider from output sets PG activation threshold (87–93% of VREF); initiates CT timing delay. |
| SHDN (Pin 15) | Enable/disable control | Active-high logic input (1.2–1.4V threshold); pulls supply current below 1μA when low. |
Key Features
| Feature | Design Value |
|---|---|
| Load Dump Protection | Withstands 60V transients per ISO 7637-2 - eliminates need for external TVS in 42V automotive designs. |
| Pulse-Skipping Light-Load Operation | Eliminates low-frequency output ripple (vs. Burst Mode) - critical for noise-sensitive analog/RF subsystems. |
| Thermally Enhanced Package | 16-pin TSSOP with exposed GND pad (θJA = 45°C/W) - enables 1.5A operation in compact industrial layouts without heatsinks. |
| Programmable Power Good Delay | CT capacitor sets delay time (t = CCT × VCT / ICT) - allows precise power sequencing in multi-rail systems. |
| Synchronizable Oscillator | Accepts 230–600kHz external clock on SYNC pin - enables EMI reduction via spread-spectrum or system-level clock alignment. |
Applications
| Automotive Body Control Module | Industrial PLC I/O Power Supply |
|---|---|
|
Use Scenario: Regulating 12V battery input to 3.3V for microcontroller, CAN transceiver, and sensor interface in under-hood ECUs. IC Role / Device Role / Timing Role: Primary buck converter providing stable 3.3V rail with load-dump immunity and programmable Power Good signaling to MCU. Use Value: Eliminates need for external transient suppressors; PG flag enables safe boot sequencing after cold crank recovery. |
Use Scenario: Generating 5V/1A supply from 24V DC industrial bus for digital I/O isolation and fieldbus interface circuits. IC Role / Device Role / Timing Role: High-efficiency, wide-input buck regulator with soft-start to prevent inrush into capacitive loads on modular backplanes. Use Value: 0.2Ω switch resistance minimizes thermal rise at full load; CSS-controlled ramp prevents relay chatter during power-up. |
| Battery-Powered Test Equipment | Distributed Telecom Power |
|
Use Scenario: Converting 36V Li-ion stack voltage to 5V for FPGA, ADC, and display subsystem in portable instrumentation. IC Role / Device Role / Timing Role: High-voltage step-down regulator with shutdown current <1μA enabling long standby life between measurements. Use Value: 60V absolute max rating accommodates full battery charge voltage; exposed pad ensures thermal stability during burst measurement cycles. |
Use Scenario: Local 12V rail generation from 48V telecom plant supply in remote radio head enclosures with limited airflow. IC Role / Device Role / Timing Role: Robust buck converter supporting -40°C to 125°C junction operation with programmable PG for remote fault reporting. Use Value: Guaranteed performance over full temp range; PGFB/CT configuration enables remote monitoring of 12V rail health via baseband controller. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1976IFE#PBF | Includes Burst Mode operation (100μA IQ), same 200kHz frequency and pinout. | Preferred where ultra-low standby power is critical and low-frequency ripple is acceptable (e.g., infotainment memory retention). | Select LT1976IFE#PBF if light-load efficiency > ripple suppression; verify PG timing compatibility with existing CT network. |
| LTC3639EMSE#PBF | 40V max input, 1.5A, 3MHz sync capability, integrated MOSFETs, 2.5μA IQ in shutdown. | Better suited for space-constrained, high-density designs needing higher frequency and lower EMI filtering. | Choose LTC3639EMSE#PBF for compact 3.3V/5V rails with aggressive size targets; not suitable for 60V automotive transients. |
Compared with LT1976IFE#PBF, the LT1976BIFE#PBF trades 1.5mA higher quiescent current for elimination of Burst Mode ripple-critical in precision analog signal chains. Versus LTC3639EMSE#PBF, it offers superior 60V transient handling and higher temperature rating but requires external MOSFET and diode.
Availability
LT1976BIFE#PBF is available at Aetrix Electronics and suitable for 14V/42V automotive systems, industrial PLC power supplies, and battery-powered test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1976BIFE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving automotive, industrial, communications, and aerospace markets.
The LT1976BIFE#PBF belongs to Linear's high-voltage monolithic buck regulator product line, engineered specifically for harsh-environment power conversion where input transients, wide VIN range, and thermal reliability are paramount.
FAQ
What is the maximum input voltage rating for the LT1976BIFE#PBF?
The LT1976BIFE#PBF has an absolute maximum input voltage rating of 60V on the VIN pin, with guaranteed operation from 3.3V to 60V. It also provides load-dump protection up to 60V per ISO 7637-2, making it suitable for 42V automotive systems. Exceeding 60V risks permanent damage per Absolute Maximum Ratings.
How does the LT1976BIFE#PBF differ from the LT1976IFE#PBF in operation?
The LT1976BIFE#PBF disables Burst Mode operation entirely, maintaining fixed 200kHz switching even at light loads-eliminating low-frequency output ripple but drawing 1.6mA quiescent current. In contrast, the LT1976IFE#PBF enters Burst Mode below ~10mA load, reducing IQ to 100μA while introducing ~100Hz ripple. Both share identical pinout, package, and core regulation architecture.
What is the purpose of the BOOST pin on the LT1976BIFE#PBF?
The BOOST pin on the LT1976BIFE#PBF supplies an elevated voltage (≥VIN + 3.3V) to the internal NPN switch driver, enabling full saturation and achieving a typical on-resistance of 0.2Ω. This is implemented with an external capacitor and Schottky diode; insufficient BOOST voltage results in higher conduction losses and thermal stress.
Can the LT1976BIFE#PBF be synchronized to an external clock?
Yes, the LT1976BIFE#PBF supports external synchronization via the SYNC pin, accepting logic-level inputs (20–80% duty cycle) from 230kHz to 600kHz. Synchronization is disabled when the FB pin voltage falls below 0.9V. This feature enables EMI reduction and system-level clock alignment in multi-converter designs.
What thermal design considerations apply to the LT1976BIFE#PBF package?
The LT1976BIFE#PBF uses a 16-pin TSSOP with exposed pad (Pin 17), which must be soldered directly to a PCB ground plane to achieve θJC = 10°C/W. Failure to connect the exposed pad degrades thermal performance significantly. Layout must minimize thermal resistance between the pad and copper area, and avoid thermal vias under the pad unless filled and capped.
LT1976BIFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LT1976BIFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1976BIFE#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 LT1976BIFE#PBF reliable?
The price and inventory of LT1976BIFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1976BIFE#PBF is usually 5 days.
3.What payment methods are accepted for LT1976BIFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1976BIFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1976BIFE#PBF?
LT1976BIFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1976BIFE#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 LT1976BIFE#PBF?
For technical support, including LT1976BIFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1976BIFE#PBF requirements.
6.How does Aetrix verify that LT1976BIFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT1976BIFE#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 LT1976BIFE#PBF meets industry standards.
7.What is the process for return or replacement of LT1976BIFE#PBF?
All LT1976BIFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1976BIFE#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 LT1976BIFE#PBF part is unused and in its original packaging.
Return procedure for LT1976BIFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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