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Analog Devices Inc. LT1976EFE#PBF
- Part No.:
- LT1976EFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1976EFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:432
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Product details
Overview
LT1976EFE#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 internal NPN switch on-resistance, and 200kHz fixed switching frequency. It is used in 14V/42V automotive systems requiring load dump protection and stable regulation under wide VIN transients.
For engineers reviewing the LT1976EFE#PBF datasheet, LT1976EFE#PBF pinout, LT1976EFE#PBF application, or LT1976EFE#PBF equivalent, key selection criteria include its 60V absolute maximum input rating, programmable Power Good flag with threshold and delay, soft-start via CSS pin, thermal shutdown, and compatibility with external synchronization - all critical for robust high-voltage DC/DC design in harsh environments.
Technical Context
The LT1976EFE#PBF implements constant-frequency current-mode control using an internal 200kHz oscillator and dual-loop feedback: the error amplifier sets the peak switch current threshold, while the current comparator monitors SW node current cycle-by-cycle. This architecture ensures fast transient response and stable loop compensation across wide load and input ranges.
It integrates a high-voltage NPN power switch with BOOST-driven saturation, achieving low conduction loss (0.2Ω typical), and employs Burst Mode operation below ~10mA load to maintain 100μA no-load quiescent current. The BIAS pin enables output-sourced biasing for improved efficiency at high VIN/VOUT ratios, and the PGFB/CT interface provides fully programmable Power Good timing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V - supports direct connection to 42V automotive batteries and industrial 48V rails without pre-regulation. |
| Peak Switch Current | 1.5A - defines maximum continuous inductor current capability before cycle-by-cycle current limiting engages. |
| Quiescent Current | 100μA (Burst Mode) - enables >10-year battery life in always-on automotive modules (e.g., CAN gateways, telematics). |
| Switch On-Resistance | 0.2Ω (typ) - reduces conduction loss and thermal stress at full load; enabled by BOOST pin voltage boosting. |
| Feedback Reference | 1.25V ±1.2% - sets output voltage accuracy; allows precise 3.3V, 5V, or custom outputs using standard resistor dividers. |
| Power Good Flag | Programmable threshold (87–93% of VREF) and delay via CT capacitor - provides reliable system-level power sequencing and fault detection. |
| Thermal Shutdown | Active at TJ ≥165°C - protects device during overload or poor PCB heatsinking; auto-recovery on cooldown. |
| Operating Junction Temp | –40°C to +125°C - qualified for under-hood automotive applications and industrial control cabinets. |
Pinout & Package
LT1976EFE#PBF is housed in a 16-pin thermally enhanced TSSOP package with exposed pad (Pin 17 = GND), optimized for low θJA (45°C/W) and θJC(PAD) (10°C/W). The exposed pad must be soldered to a PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 2) | Switch emitter node | Connects to inductor and catch diode cathode; carries full switching current and negative flyback voltage - requires low-inductance layout. |
| VIN (Pin 4) | High-voltage input supply | Powers internal circuitry when BIAS is inactive; withstands 60V absolute max; source of high di/dt noise - bypass directly to GND. |
| BOOST (Pin 6) | Switch driver boost supply | Accepts voltage ≥VIN+3.3V to saturate internal NPN; enables 0.2Ω RON - requires external boost capacitor and Schottky diode. |
| CT (Pin 7) | Power Good timing capacitor | Sets PG delay time (t = CCT × VCT / ICT); clamped at 1.2V - determines how long PG remains active after startup or fault recovery. |
| GND (Pins 8, 17) | Signal and thermal reference | Reference for FB, PGFB, and output regulation; exposed pad (Pin 17) must be soldered to PCB ground plane for thermal management. |
| CSS (Pin 9) | Soft-start control | Current-source input; controls output voltage ramp rate during startup - prevents inrush current and overshoot. |
| BIAS (Pin 10) | Efficiency-boosting bias supply | When connected to VOUT ≥3V, powers internal circuitry from output instead of VIN - improves light-load efficiency at high VIN/VOUT ratios. |
| VC (Pin 11) | Error amplifier output | Direct access to control loop; used for compensation, current limiting override, or disabling switching by pulling to GND. |
| FB (Pin 12) | Feedback input | Monitors output via resistive divider; 1.25V reference sets regulation point; also enables frequency foldback and soft-start when VFB < 0.9V. |
| PGFB (Pin 13) | Power Good sense input | Compares against internal 90% VREF threshold; initiates PG delay when exceeded - supports flexible monitoring of VIN, VOUT, or intermediate rails. |
| SYNC (Pin 14) | External clock input | Accepts 230–600kHz logic-level signal; synchronizes internal oscillator to reduce EMI - disabled if FB < 0.9V. |
| SHDN (Pin 15) | Shutdown control | Active-high enable; 1.3V threshold; draws only 5μA - reduces total input current to <1μA in shutdown mode. |
| PG (Pin 16) | Power Good open-drain output | Active-low flag with 200μA sink capability; high-impedance when PGFB > threshold and CT clamp active - signals valid output. |
Key Features
| Feature | Design Value |
|---|---|
| Load Dump Protection | Withstands 60V transients per ISO 7637-2 - eliminates need for external TVS in 12V/24V/42V automotive designs. |
| Burst Mode Operation | Reduces IQ to 100μA at light loads - extends battery runtime in always-on vehicle modules without sacrificing regulation accuracy. |
| Programmable Power Good | Adjustable threshold (87–93% VREF) and delay (via CT capacitor) - enables precise power sequencing for microcontrollers and FPGAs. |
| Thermally Enhanced TSSOP | 16-pin package with exposed GND pad - achieves θJC(PAD) = 10°C/W, enabling 1.5A operation without heatsink in compact layouts. |
| Internal Saturating NPN Switch | 0.2Ω RON with BOOST-assisted drive - delivers higher efficiency than comparable MOSFET-based regulators at 60V input. |
| Soft-Start Control | Single external capacitor (CSS-to-VOUT) sets controlled output ramp - prevents inrush current and stabilizes upstream supplies. |
Applications
| Automotive Body Control Module (BCM) | Industrial 48V DC Power Distribution |
|---|---|
Use Scenario: Regulating 12V battery input to 3.3V for CAN transceivers, microcontrollers, and sensor interfaces in engine bay or chassis locations. IC Role / Device Role / Timing Role: Primary step-down regulator with integrated load dump protection and programmable Power Good for MCU reset coordination. Use Value: Eliminates external TVS and discrete power sequencing logic; 100μA IQ enables >15-year battery standby life in parked-vehicle monitoring systems. |
Use Scenario: Converting 48V industrial bus to 5V/3.3V for PLC I/O modules, motor drivers, and fieldbus gateways operating in factory environments. IC Role / Device Role / Timing Role: High-efficiency, high-reliability buck converter with thermal shutdown and wide input range tolerance. Use Value: 60V absolute max rating handles 48V rail surges; 0.2Ω RON minimizes heat generation in enclosed enclosures; exposed-pad TSSOP simplifies thermal design. |
| Telecom Remote Radio Unit (RRU) | Off-Grid Solar Charge Controller |
Use Scenario: Generating stable 5V supply from -48V telecom rectifier output (with polarity inversion) for FPGA configuration and RF front-end biasing. IC Role / Device Role / Timing Role: Input-referred buck regulator supporting reverse-polarity input via external diode; synchronized to system clock via SYNC pin. Use Value: 200kHz fixed frequency enables predictable EMI filtering; synchronization capability aligns switching noise away from sensitive RF bands. |
Use Scenario: Stepping down variable PV array voltage (up to 60V) to charge 12V/24V lead-acid or LiFePO₄ batteries with minimal quiescent loss. IC Role / Device Role / Timing Role: Wide-input buck controller with Burst Mode for nighttime standby and high-efficiency MPPT stage support. Use Value: 100μA IQ preserves battery capacity during extended low-light periods; programmable PGFB monitors battery voltage for charge-state signaling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3639EMSE#PBF | 40V max input, 1.5A, 3mm × 4mm MSOP, 2.5μA IQ (no Burst Mode) | Lower voltage range; ultra-low IQ but no load dump protection or BOOST-assisted switch | Select for space-constrained, low-noise 24V systems where 60V transients are absent and lowest possible sleep current is critical. |
| LM5164QPWPRQ1 | 65V max input, 1A, 2.1μA shutdown IQ, integrated MOSFETs, spread-spectrum EMI reduction | Lower peak current; no programmable PG; uses external MOSFETs in LT1976EFE#PBF offers higher reliability in high-temp automotive zones | Select for AEC-Q100 Grade 1 automotive applications needing spread-spectrum EMI control, but verify 1A limit suffices for load. |
Compared with LTC3639EMSE#PBF and LM5164QPWPRQ1, the LT1976EFE#PBF uniquely combines 60V input tolerance, integrated NPN switch with BOOST saturation, programmable Power Good, and automotive-grade thermal performance - making it optimal for high-reliability 42V/60V transient-prone systems where discrete switch control and precise sequencing are required.
Availability
LT1976EFE#PBF is available at Aetrix Electronics and suitable for automotive body control modules, industrial 48V power distribution units, and off-grid solar charge controllers requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LT1976EFE#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 and maintains full support for legacy Linear power products, including rigorous qualification, long-term manufacturing commitment, and comprehensive technical documentation.
The LT1976EFE#PBF belongs to Linear's high-voltage monolithic buck regulator family, engineered specifically for automotive and industrial applications demanding robustness against load dump, wide input range, and low quiescent current in harsh thermal environments.
FAQ
What is the maximum input voltage rating for the LT1976EFE#PBF?
The LT1976EFE#PBF has an absolute maximum input voltage rating of 60V on the VIN pin, and it is specifically designed to withstand automotive load dump transients up to this level per ISO 7637-2. Its operational input range is 3.3V to 60V, making it suitable for 12V, 24V, and 42V vehicle electrical systems as well as industrial 48V DC distribution networks. Exceeding 60V may cause permanent damage.
Does the LT1976EFE#PBF support external synchronization, and what is its sync frequency range?
Yes, the LT1976EFE#PBF supports external synchronization via the SYNC pin (Pin 14), which accepts logic-level inputs with 20%–80% duty cycle. Its synchronization frequency range is 230kHz to 600kHz - wider than its native 200kHz oscillator - enabling EMI reduction by aligning switching edges to system clocks or avoiding sensitive frequency bands. The SYNC function is automatically disabled when the FB pin voltage drops below 0.9V.
How does the LT1976EFE#PBF achieve 100μA quiescent current, and under what conditions?
The LT1976EFE#PBF achieves 100μA typical quiescent current through Burst Mode operation, which disables most internal circuitry during light-load conditions (typically below ~10mA). In this mode, the IC delivers energy in short bursts, then enters deep sleep - drawing only 45–100μA depending on temperature and BIAS pin state. This behavior is inherent to the LT1976 variant (not LT1976B) and is confirmed over the full –40°C to 125°C junction temperature range.
What is the purpose of the BOOST pin on the LT1976EFE#PBF, and how is it implemented?
The BOOST pin (Pin 6) on the LT1976EFE#PBF provides a voltage higher than VIN to fully saturate the internal NPN power switch, reducing its on-resistance to 0.2Ω (typ). It is implemented using an external bootstrap capacitor and Schottky diode connected between VIN and BOOST. During switch-off, the diode charges the capacitor; during switch-on, the capacitor drives BOOST above VIN, enabling low-loss conduction - a key differentiator versus standard MOSFET-based buck controllers at high input voltages.
Can the LT1976EFE#PBF be used without connecting the BIAS pin, and what is the impact?
Yes, the LT1976EFE#PBF operates fully functional with the BIAS pin (Pin 10) left unconnected or tied to GND. In this configuration, all internal circuitry is powered from VIN, resulting in higher quiescent current - typically 2.6–4.1mA depending on load and input voltage. Connecting BIAS to VOUT ≥3V shifts bias current sourcing to the output rail, improving efficiency by up to 15% at high VIN/VOUT ratios (e.g., 48V-to-3.3V), especially under light loads.
LT1976EFE#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:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT1976EFE#PBF FAQ
1.How can I place an order for LT1976EFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1976EFE#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 LT1976EFE#PBF reliable?
The price and inventory of LT1976EFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1976EFE#PBF is usually 5 days.
3.What payment methods are accepted for LT1976EFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1976EFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1976EFE#PBF?
LT1976EFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1976EFE#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 LT1976EFE#PBF?
For technical support, including LT1976EFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1976EFE#PBF requirements.
6.How does Aetrix verify that LT1976EFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT1976EFE#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 LT1976EFE#PBF meets industry standards.
7.What is the process for return or replacement of LT1976EFE#PBF?
All LT1976EFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1976EFE#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 LT1976EFE#PBF part is unused and in its original packaging.
Return procedure for LT1976EFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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