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Analog Devices Inc. LT1976HFE#TRPBF
- Part No.:
- LT1976HFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1976HFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,296
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Product details
Overview
LT1976HFE#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 100μA quiescent current in Burst Mode, 200kHz fixed switching frequency, and integrates a 0.2Ω NPN power switch. It is used in 14V/42V automotive systems requiring load dump protection and stable regulation under wide input transients.
For engineers reviewing the LT1976HFE#TRPBF datasheet, LT1976HFE#TRPBF pinout, LT1976HFE#TRPBF application, or LT1976HFE#TRPBF equivalent, key selection criteria include its –40°C to 140°C junction temperature rating, programmable Power Good flag with CT delay timing, soft-start via CSS pin, BOOST-driven saturation architecture, and compatibility with external synchronization up to 600kHz.
Technical Context
The LT1976HFE#TRPBF employs current-mode control with cycle-by-cycle peak current limiting and an internal 200kHz oscillator. Its error amplifier output (VC pin) directly sets the switch current trip threshold, enabling fast transient response and simplified loop compensation. The integrated NPN switch uses BOOST voltage (≥1.8V above SW) to achieve low VCE(sat) (~0.2Ω), reducing conduction loss across wide duty cycles.
Burst Mode operation-active in LT1976 variants but not LT1976B-is enabled at light loads to maintain 100μA quiescent current; the HFE grade extends full-spec operation to 140°C junction temperature. Shutdown reduces supply current to <1μA, and the PGFB/CT circuitry provides user-programmable power-good delay with 87–93% VREF threshold accuracy.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V - supports direct connection to 42V automotive battery rails and industrial 48V systems without pre-regulation. |
| Peak Switch Current | 1.5A (min) - enables ≥1A continuous output with margin for transient surges in 12V–48V buck applications. |
| Quiescent Current | 100μA (typ, Burst Mode) - sustains ultra-low standby power in always-on vehicle modules (e.g., CAN gateways, telematics). |
| Switch On-Resistance | 0.2Ω (typ) - achieved via BOOST-assisted saturation, minimizing conduction loss and thermal rise at full load. |
| Reference Voltage | 1.25V ±2.5% (–40°C to 140°C) - ensures accurate, temperature-stable output regulation across extended automotive thermal range. |
| Operating Junction Temp | –40°C to 140°C - qualified for under-hood automotive locations and high-ambient industrial enclosures. |
| Power Good Threshold | 87–93% of VREF (i.e., ~1.09–1.16V) - allows precise output voltage monitoring with externally adjustable delay via CT capacitor. |
Pinout & Package
LT1976HFE#TRPBF 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 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; swings from –0.3V (clamped) to VIN during operation; requires low-inductance layout. |
| VIN (Pin 4) | Power switch collector & bias source | Supplies internal circuitry when BIAS pin is unconnected; handles high di/dt; must be decoupled with low-ESR ceramic capacitor. |
| BOOST (Pin 6) | Switch drive boost supply | Accepts ≥1.8V above SW to saturate internal NPN; requires external boost capacitor + Schottky diode (e.g., B1100). |
| CT (Pin 7) | Power Good delay timing | Sinks/source current to external capacitor; delay t = CCT × VCT/ICT; clamps at 1.2V to assert PG high-impedance state. |
| GND (Pins 8, 17) | Signal & thermal reference | Pins 8 and 17 are internally connected; exposed pad (pin 17) must be soldered to large copper area for thermal dissipation and noise immunity. |
| CSS (Pin 9) | Soft-start ramp control | Sources current into external capacitor to limit dVOUT/dt; threshold scales with FB voltage; disabled above 0.9V FB. |
| BIAS (Pin 10) | Efficiency-boosting auxiliary supply | When tied to VOUT ≥3V, powers internal circuitry from output rail-reducing VIN current and improving efficiency at high VIN/VOUT ratios. |
| VC (Pin 11) | Error amplifier output & current limit input | 0.45V (light load) to 2.2V (current limit); used for loop compensation, current clamping, or external override. |
| FB (Pin 12) | Feedback sensing input | Compares resistive divider output to 1.25V reference; triggers frequency foldback and disables SYNC when FB < 0.9V. |
| PGFB (Pin 13) | Power Good comparator input | Monitors output (or input) via resistor divider; rising edge initiates CT delay; falling edge resets PG and asserts active-low sink. |
| SYNC (Pin 14) | External clock synchronization | Accepts 20–80% duty cycle logic-level signal up to 600kHz; disabled when FB < 0.9V to prevent instability during startup/fault. |
| SHDN (Pin 15) | Enable/disable control | Active-high; 1.2–1.4V threshold; draws ≤20μA; pulls VIN supply current to <1μA in shutdown. |
| PG (Pin 16) | Power Good open-drain output | Active-low (200μA sink) when CT clamp inactive; high-Z when CT clamped - signals valid output after programmable delay. |
Key Features
| Feature | Design Value |
|---|---|
| Load Dump Protection | Withstands 60V transients on VIN - meets ISO 7637-2 Pulse 5a requirements for 12V/24V automotive systems. |
| Burst Mode Operation | Reduces no-load IQ to 100μA while maintaining regulation - critical for always-on ECUs with strict battery drain limits. |
| Programmable Power Good | Adjustable delay (via CT cap) and threshold (via PGFB divider) enable system-level sequencing and fault detection. |
| Thermally Enhanced Package | 16-pin TSSOP with exposed pad achieves θJC = 10°C/W - supports 1.5A operation at 140°C ambient with proper PCB copper. |
| BOOST-Driven Saturation | External BOOST circuit reduces effective switch RDS(on) to 0.2Ω - cuts conduction loss by >50% vs. non-boosted bipolar designs. |
| Current-Mode Control | Inherent cycle-by-cycle current limiting and simplified compensation - enables stable operation with wide input/output ranges and varied output capacitors. |
Applications
| Automotive Body Control Module (BCM) | Industrial 24V PLC I/O Power Supply |
|---|---|
|
Use Scenario: Powers microcontroller, CAN transceiver, and sensor interface circuits in vehicle door modules exposed to cold-crank (4.5V) and load dump (60V) events. IC Role / Device Role / Timing Role: Primary 5V/3.3V buck regulator with integrated overvoltage protection and programmable power-good signaling for MCU reset coordination. Use Value: Eliminates need for external TVS and discrete enable logic; 100μA quiescent current prevents battery drain during 30-day parking mode. |
Use Scenario: Generates isolated 5V rail for digital I/O expansion cards in DIN-rail mounted programmable logic controllers operating in factory environments up to 85°C ambient. IC Role / Device Role / Timing Role: High-efficiency, wide-input DC-DC converter delivering 1A continuous output from unregulated 24VDC field supply. Use Value: 0.2Ω switch RON and BOOST architecture sustain >88% efficiency at full load; 140°C rating avoids derating in enclosed cabinets. |
| 42V Mild Hybrid Vehicle Telematics | Distributed Power System for Test Equipment |
|
Use Scenario: Supplies 3.3V to LTE modem and GNSS receiver in telematics control unit connected to 42V starter-generator bus. IC Role / Device Role / Timing Role: Input-robust buck regulator with soft-start and synchronized switching to minimize EMI in RF-sensitive subsystems. Use Value: SYNC pin enables alignment with system master clock; CSS-controlled ramp prevents inrush into modem's LDO input caps. |
Use Scenario: Provides local 12V/1A bias for analog front-end modules in modular automated test equipment where multiple independent supplies are distributed across backplane. IC Role / Device Role / Timing Role: Compact, thermally efficient point-of-load regulator with programmable PG signaling for inter-module power sequencing. Use Value: TSSOP-16 package fits dense layouts; PGFB/CT delay ensures downstream ADCs power up only after stable 12V is confirmed. |
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 |
|---|---|---|---|
| LTC3642EMSE#PBF | 40V max input, 2A output, 3MHz sync capability, 2.5μA quiescent current; no BOOST pin or load dump rating. | Targeted at space-constrained, high-frequency applications where EMI filtering is prioritized over 60V transient robustness. | Select when input stays below 40V and ultra-low IQ (<5μA) is required; avoid for automotive load dump or >42V industrial use. |
| LM5164QPWPRQ1 | 65V max input, 1A output, 100μA IQ, integrated MOSFETs, spread-spectrum EMI reduction; no programmable PG or BOOST architecture. | Designed for AEC-Q100 automotive qualification with lower peak current and no external BOOST diode requirement. | Choose for production automotive programs needing AEC-Q100 compliance and simplified BOM; accept 1A limit and fixed PG behavior. |
Compared with LTC3642EMSE#PBF and LM5164QPWPRQ1, the LT1976HFE#TRPBF uniquely combines 60V load dump tolerance, 1.5A peak current, BOOST-enabled 0.2Ω switch performance, and fully programmable Power Good timing - making it optimal for ruggedized 12V/24V/42V systems where reliability under extreme transients is non-negotiable.
Availability
LT1976HFE#TRPBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power supplies, and distributed test equipment requiring stable component supply across extended temperature and high-reliability environments.
Supply support for LT1976HFE#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, Inc. (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 product line was developed specifically for high-input-voltage DC-DC conversion in harsh environments, emphasizing robustness against automotive transients, extended temperature operation, and minimal external component count for cost-sensitive power designs.
FAQ
What is the maximum input voltage rating for LT1976HFE#TRPBF, and does it support load dump conditions?
The LT1976HFE#TRPBF has an absolute maximum input voltage rating of 60V and is explicitly designed to withstand automotive load dump transients up to 60V per ISO 7637-2 Pulse 5a. Its internal circuitry and BOOST architecture remain functional during these events, ensuring uninterrupted regulation without external TVS clamping in many implementations.
How does the LT1976HFE#TRPBF achieve 100μA quiescent current, and is this guaranteed across temperature?
The LT1976HFE#TRPBF achieves 100μA typical quiescent current through Burst Mode operation, which shuts down non-essential circuitry during light loads. This specification is validated over the full –40°C to 140°C junction temperature range per the LT1976HFE electrical characteristics table, with sleep current specified at 45–100μA (typ–max) at TJ = 140°C.
Can the LT1976HFE#TRPBF be synchronized to an external clock, and what are the valid frequency and logic levels?
Yes, the LT1976HFE#TRPBF supports external synchronization via the SYNC pin, accepting logic-level inputs from 230kHz to 600kHz with 20–80% duty cycle. The pin is compatible with standard CMOS/TTL logic (0.5V low, ≥1.5V high), and synchronization is automatically disabled when FB voltage falls below 0.9V to prevent instability during startup or fault conditions.
What is the role of the BOOST pin, and what external components are required?
The BOOST pin supplies elevated drive voltage to the internal NPN switch base, enabling saturation and achieving 0.2Ω effective on-resistance. It requires an external bootstrap capacitor (typically 10nF–100nF) and Schottky diode (e.g., Diodes Inc. B1100) connected between SW and BOOST. Minimum BOOST voltage is 1.8V above SW; typical boost current is 40–50mA at 1.5A switch current.
How is the Power Good (PG) function configured, and can its delay be adjusted?
The PG function is configured using the PGFB pin (connected to a resistor divider from VOUT or VIN) and the CT pin (connected to a timing capacitor to GND). When PGFB exceeds 87–93% of VREF, CT begins charging; PG goes high-impedance when CT reaches 1.2V. Delay time is calculated as t = CCT × 1.2V / ICT, where ICT = 1.5–5.5μA (typ–max), enabling precise, user-adjustable power-good assertion timing.
LT1976HFE#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:
- 1.5A (Switch)
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT1976HFE#TRPBF FAQ
1.How can I place an order for LT1976HFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1976HFE#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 LT1976HFE#TRPBF reliable?
The price and inventory of LT1976HFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1976HFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1976HFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1976HFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1976HFE#TRPBF?
LT1976HFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1976HFE#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 LT1976HFE#TRPBF?
For technical support, including LT1976HFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1976HFE#TRPBF requirements.
6.How does Aetrix verify that LT1976HFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1976HFE#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 LT1976HFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1976HFE#TRPBF?
All LT1976HFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1976HFE#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 LT1976HFE#TRPBF part is unused and in its original packaging.
Return procedure for LT1976HFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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