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Analog Devices Inc. LT1976IFE#PBF
- Part No.:
- LT1976IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1976IFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:563
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Product details
Overview
LT1976IFE#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 100μA quiescent current in Burst Mode, 0.2Ω switch on-resistance, and 200kHz fixed-frequency operation in a thermally enhanced 16-pin TSSOP package with exposed pad. It is used in 14V/42V automotive systems requiring load dump protection and stable regulation under wide VIN transients.
For engineers reviewing the LT1976IFE#PBF datasheet, LT1976IFE#PBF pinout, LT1976IFE#PBF application, or LT1976IFE#PBF equivalent, key selection criteria include its 60V absolute max input rating, programmable Power Good flag, soft-start via CSS pin, synchronous capability, and thermal shutdown protection - all critical for high-reliability 12V–48V embedded power rails.
Technical Context
The LT1976IFE#PBF implements constant-frequency current-mode control with an internal 200kHz oscillator, error amplifier output (VC pin), and cycle-by-cycle peak current limiting. Its NPN power switch is driven by a BOOST voltage generated externally to achieve saturation and low conduction loss (0.2Ω typical).
Burst Mode operation reduces quiescent current to 100μA at light loads by disabling switching and bias circuitry, while maintaining fast transient response via VC clamp recovery. The device supports programmable Power Good delay via CT capacitor and offers full-duty-cycle peak current maintenance - a patented feature ensuring consistent current limit across input/output conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V - supports direct connection to 42V automotive battery rails and withstands load dump transients up to 60V without external clamping. |
| Peak Switch Current | 1.5A - enables ≥1A continuous output at 3.3V–12V with standard 33μH inductors and proper thermal layout. |
| Quiescent Current | 100μA (Burst Mode) - sustains ultra-low standby power in always-on vehicle modules like telematics or CAN gateways. |
| Switch On-Resistance | 0.2Ω - minimizes conduction loss and thermal rise during high-current pulses, reducing need for oversized MOSFETs. |
| Feedback Reference | 1.25V ±2.5% - allows precise output voltage setting (e.g., 3.3V, 5V, 12V) using standard 1% resistor dividers with ≤100kΩ R2. |
| Power Good Flag | Programmable threshold (88–92% of VREF) and delay via CT capacitor - provides configurable rail validation for microcontroller reset sequencing. |
| Thermal Protection | Internal thermal shutdown - disables switching when junction temperature exceeds safe operating limit, preventing permanent damage during overload or poor heatsinking. |
Pinout & Package
LT1976IFE#PBF is housed in a 16-pin thermally enhanced TSSOP package (FE) with exposed pad (Pin 17), which must be soldered to PCB ground plane for optimal thermal resistance (θJC(PAD) = 10°C/W). Package dimensions: 5mm × 4.4mm × 1.1mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 2) | Switch emitter node | Connects to inductor and Schottky catch diode cathode; carries full switched current and experiences negative flyback voltage during off-time. |
| VIN (Pin 4) | Power switch collector & primary supply | Accepts 3.3V–60V input; powers internal circuitry when BIAS is unconnected; requires low-inductance path to input capacitor and SW. |
| BOOST (Pin 6) | Switch driver boost supply | Receives boosted voltage (≥VIN + 1.8V) from external capacitor/diode network to saturate internal NPN switch and minimize VCE(sat). |
| CT (Pin 7) | Power Good timer control | Current source/sink node that charges/discharges external capacitor to set PG flag delay time (t = CCT × VCT / ICT). |
| GND (Pins 8, 17) | Signal and thermal reference | Pins 8 and 17 (exposed pad) are internally connected; both must be soldered to large copper ground plane for stable regulation and thermal dissipation. |
| CSS (Pin 9) | Soft-start ramp control | Sinks current proportional to FB voltage; capacitor from CSS to VOUT sets controlled output voltage slew rate during startup. |
| BIAS (Pin 10) | Efficiency-boosting auxiliary supply | When tied to regulated output (≥3V), powers internal circuitry from VOUT instead of VIN - improves efficiency at high VIN/light load. |
| VC (Pin 11) | Error amplifier output & current limit input | Provides loop compensation node; voltage level (0.45V–2.2V) directly sets peak switch current; can be overridden for current limiting or shutdown. |
| FB (Pin 12) | Output voltage sensing input | Compares divided output against 1.25V reference; also triggers frequency foldback and enables CSS soft-start when VFB < 0.9V. |
| PGFB (Pin 13) | Power Good comparator input | Resistive divider from VOUT or VIN sets PG activation threshold; rising edge initiates CT timing sequence for delayed PG assertion. |
| SYNC (Pin 14) | External clock synchronization input | Accepts logic-level signals (20–80% duty, 230–600kHz) to align switching frequency with system clocks and reduce EMI beat frequencies. |
| SHDN (Pin 15) | Enable/disable control | Logic-high (>1.3V) enables regulation; logic-low (<1.2V) reduces input current to <1μA - ideal for deep-sleep system states. |
| PG (Pin 16) | Power Good open-drain output | Active-low signal indicating valid output; sinks 200μA when asserted; high-impedance when CT clamp is active (delayed PG condition). |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode Operation | Reduces no-load IQ to 100μA by disabling oscillator and bias circuitry - extends battery life in always-on automotive modules without sacrificing startup speed. |
| Load Dump Protection | Withstands 60V transients on VIN per ISO 7637-2 Pulse 5a - eliminates need for external TVS diodes in 12V/24V/42V vehicle subsystems. |
| Programmable Power Good | Configurable threshold (88–92% of 1.25V) and delay (via CT capacitor) enable precise power-rail sequencing for MCUs, FPGAs, and communication ICs. |
| Thermally Enhanced TSSOP | 16-pin TSSOP with exposed pad achieves θJA = 45°C/W - supports 1.5A operation at ambient up to 85°C with minimal copper area. |
| Soft-Start Control | Single capacitor from CSS to VOUT sets monotonic output ramp rate - prevents inrush current and overshoot during cold start or hot-plug events. |
| Current-Mode Control | Provides inherent cycle-by-cycle overcurrent protection, fast transient response, and simplified loop compensation versus voltage-mode architectures. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powers DSP, display controller, and audio codec in head unit with 12V battery input subject to cranking dips and load dump spikes. IC Role / Device Role / Timing Role: Primary 3.3V/5V buck regulator providing regulated rail with Burst Mode for low-power standby and programmable PG for MCU reset coordination. Use Value: 60V input rating and integrated load dump tolerance eliminate external protection components; 100μA IQ extends parking mode battery life. |
Use Scenario: Generates isolated 5V and 3.3V rails for digital I/O and fieldbus interfaces in DIN-rail mounted controllers operating from 24VDC industrial supply. IC Role / Device Role / Timing Role: High-efficiency step-down converter delivering stable output despite wide input variation (18–36V) and ambient temperatures up to 70°C. Use Value: 0.2Ω switch RDS(on) and thermally enhanced TSSOP enable >85% efficiency at 1A without heatsink; SYNC pin allows EMI reduction via system clock alignment. |
| Telecom Remote Radio Unit (RRU) | Medical Portable Diagnostic Device |
Use Scenario: Supplies FPGA, ADC, and RF front-end in outdoor base station equipment powered from -48V DC telecom supply via intermediate 12V bus. IC Role / Device Role / Timing Role: Intermediate 12V-to-3.3V regulator supporting burst-mode sleep during idle periods and fast wake-up for data transmission bursts. Use Value: 200kHz fixed frequency simplifies EMI filter design; programmable PG ensures clean power-up sequencing before RF calibration routines begin. |
Use Scenario: Powers microcontroller, sensor interface, and Bluetooth radio in handheld ultrasound or glucose monitor running from single-cell Li-ion (3.0–4.2V) or dual-cell pack (6–8.4V). IC Role / Device Role / Timing Role: Wide-input buck converter enabling direct battery connection without pre-regulation; soft-start prevents sensor offset drift during power-on. Use Value: 3.3V minimum input allows operation down to near-empty battery; CSS-controlled ramp avoids false triggers in analog front-end during startup. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | 40V max input, 1.5A, 3.5MHz sync-capable, 2.5μA IQ - uses external MOSFETs and requires more external components. | Targeted at space-constrained, high-frequency designs where small inductors are prioritized over ultra-wide VIN range. | Select LTC3631EMSE#PBF when board area is critical and input stays below 40V; avoid if load dump immunity or 60V operation is required. |
| LM5164QPWPRQ1 | 65V max input, 1A, 100kHz–2.2MHz adjustable frequency, 14μA IQ - includes integrated high-side MOSFET and valley current mode control. | Designed for automotive AEC-Q100 Grade 1; supports lower output currents but offers wider frequency tuning and better light-load efficiency. | Choose LM5164QPWPRQ1 for new automotive designs requiring AEC-Q100 qualification and flexible frequency optimization; retain LT1976IFE#PBF for legacy 60V/1.5A Burst Mode use cases. |
Compared with LTC3631EMSE#PBF and LM5164QPWPRQ1, the LT1976IFE#PBF delivers superior 60V-rated robustness and proven Burst Mode performance in existing 12V/24V/42V platforms, while trading off higher IQ than LM5164QPWPRQ1 and lower integration than LTC3631EMSE#PBF.
Availability
LT1976IFE#PBF is available at Aetrix Electronics and suitable for 14V and 42V automotive systems, industrial power supplies, and battery-powered instrumentation requiring stable component supply across extended temperature ranges (–40°C to 125°C).
Supply support for LT1976IFE#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 healthcare markets.
The LT1976IFE#PBF belongs to Linear's high-voltage monolithic buck regulator family, engineered specifically for ruggedized power conversion in automotive and industrial environments where input transients, thermal stress, and long-term reliability are critical design constraints.
FAQ
What is the maximum input voltage rating for the LT1976IFE#PBF?
The LT1976IFE#PBF has an absolute maximum input voltage rating of 60V on the VIN pin, enabling direct use in 42V automotive systems and compatibility with ISO 7637-2 Load Dump Pulse 5a transients. Continuous operation is specified from 3.3V to 60V, with guaranteed performance over –40°C to 125°C junction temperature.
Does the LT1976IFE#PBF support Burst Mode operation?
Yes, the LT1976IFE#PBF supports Burst Mode operation, reducing quiescent current to 100μA at light loads by disabling the oscillator and internal bias circuitry. This feature is intrinsic to the LT1976 variant (as opposed to LT1976B), making it ideal for battery-backed or always-on automotive subsystems where standby power is critical.
How is the Power Good (PG) flag configured on the LT1976IFE#PBF?
The Power Good flag on the LT1976IFE#PBF is configured using the PGFB pin (resistive divider from VOUT or VIN) and the CT pin (external capacitor). When PGFB exceeds 88–92% of the 1.25V reference, the CT capacitor begins charging; once its voltage reaches 1.2V, the PG pin transitions to high-impedance. The delay time is calculated as t = CCT × 1.2V / 3.6μA.
What thermal considerations apply to the LT1976IFE#PBF package?
The LT1976IFE#PBF uses a 16-pin TSSOP with exposed pad (Pin 17), which must be soldered to a PCB ground plane to achieve θJC(PAD) = 10°C/W. Without proper thermal anchoring, junction temperature rise will exceed specifications under 1.5A load. Recommended layout includes ≥250mm² copper area connected via ≥4 thermal vias to inner ground planes.
Can the LT1976IFE#PBF be synchronized to an external clock?
Yes, the LT1976IFE#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 (e.g., during startup or fault conditions), ensuring reliable operation during soft-start and fault recovery sequences.
LT1976IFE#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:
- 1.5A (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
LT1976IFE#PBF FAQ
1.How can I place an order for LT1976IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1976IFE#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 LT1976IFE#PBF reliable?
The price and inventory of LT1976IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1976IFE#PBF is usually 5 days.
3.What payment methods are accepted for LT1976IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1976IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1976IFE#PBF?
LT1976IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1976IFE#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 LT1976IFE#PBF?
For technical support, including LT1976IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1976IFE#PBF requirements.
6.How does Aetrix verify that LT1976IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT1976IFE#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 LT1976IFE#PBF meets industry standards.
7.What is the process for return or replacement of LT1976IFE#PBF?
All LT1976IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1976IFE#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 LT1976IFE#PBF part is unused and in its original packaging.
Return procedure for LT1976IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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