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Analog Devices Inc. LT1766HFE#PBF
- Part No.:
- LT1766HFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1766HFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,250
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Product details
Overview
LT1766HFE#PBF from Analog Devices (formerly Linear Technology) is a 200kHz monolithic step-down switching regulator with integrated 1.5A/0.2Ω NPN power switch, 5.5V–60V input range, and 1.219V feedback reference. It delivers regulated DC output in high-voltage industrial and automotive power supplies where thermal robustness and wide VIN tolerance are critical.
For engineers reviewing the LT1766HFE#PBF datasheet, LT1766HFE#PBF pinout, LT1766HFE#PBF application, or LT1766HFE#PBF equivalent, key selection factors include its –40°C to 140°C guaranteed junction temperature rating, exposed-pad TSSOP-16 thermal performance, cycle-by-cycle current limiting, and external synchronization capability from 228kHz to 700kHz.
Technical Context
The LT1766HFE#PBF implements current-mode control with an internal 200kHz oscillator, error amplifier (gm = 2000 μmho, gain = 400 V/V), and peak-current comparator referenced to the VC pin. Its patented boost-capacitor-driven switch driver enables saturation of the on-die NPN transistor, achieving low 0.2Ω on-resistance across full duty cycle and temperature.
Thermal design is enabled by the exposed backside pad (Pin 17, GND) soldered to PCB copper, delivering θJC = 10°C/W. Shutdown logic includes dual thresholds: 2.38V UVLO lockout and 0.4V micropower shutdown, with 25μA shutdown supply current confirmed over –40°C to 140°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.5V to 60V - supports direct connection to 24V/48V industrial buses and automotive battery systems without pre-regulation. |
| Switch Current Limit | 1.5A peak - maintains rated current delivery across full duty cycle and up to 140°C junction temperature. |
| Switch On-Resistance | 0.2Ω (typ) at 1.5A - minimizes conduction loss and thermal rise in high-current buck stages. |
| Feedback Reference | 1.219V (LT1766 variant) - enables precise output voltage setting via external resistor divider; stable over full temperature range. |
| Operating Junction Temp | –40°C to 140°C - fully specified and guaranteed, enabling use in under-hood automotive and high-ambient industrial environments. |
| Shutdown Current | 25μA (max) - ensures ultra-low system standby power in battery-backed or energy-sensitive applications. |
| SYNC Frequency Range | 228kHz to 700kHz - allows EMI reduction via spread-spectrum or noise-avoidance frequency alignment with other system clocks. |
Pinout & Package
LT1766HFE#PBF is housed in a 16-lead plastic TSSOP package with exposed backside thermal pad (Pin 17, GND). The package provides θJA = 45°C/W and θJC = 10°C/W when the exposed pad is soldered to a PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 8, 9, 16, 17) | Power and signal reference ground | Multiple GND pins plus exposed pad reduce ground impedance and thermal resistance; must be soldered to large copper area for thermal and regulation stability. |
| SW (Pin 2) | Emitter of internal NPN power switch | Carries full inductor current; swings from near 0V (off) to VIN (on); requires low-inductance path to catch diode and input capacitor. |
| VIN (Pin 4) | Collector of internal NPN switch & primary bias source | Supplies internal circuitry when BIAS pin is unconnected; high dI/dt node requiring short, low-inductance layout. |
| BOOST (Pin 6) | Switch driver bootstrap supply | Must be biased ~5V above VIN via external capacitor/diode to saturate internal NPN and achieve 0.2Ω RON. |
| BIAS (Pin 10) | Secondary bias supply input | Connect to regulated output (≥3V) to improve efficiency at high VIN/light load by shifting bias current from VIN to VOUT. |
| VC (Pin 11) | Error amplifier output / current limit threshold | Controls switch peak current; clamped between 0.9V (light load) and 2.1V (full load); can be driven to GND for shutdown. |
| FB (Pin 12) | Feedback input / reference sense node | Accepts 1.219V reference for adjustable output; also enables frequency foldback and current limit reduction below 0.8V/0.6V respectively. |
| SYNC (Pin 14) | External oscillator synchronization input | Logic-level compatible (1.5V–2.2V min amplitude); accepts 228–700kHz signals with 10%–90% duty cycle for EMI control. |
| SHDN (Pin 15) | Enable/disable control with dual thresholds | 2.38V = UVLO lockout; 0.4V = deep shutdown; open-circuit defaults to active via internal bias current. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1.5A NPN switch with 0.2Ω RON | Eliminates external MOSFET and gate driver; reduces BOM count and layout complexity in space-constrained 5–60V buck designs. |
| Current-mode control architecture | Delivers fast transient response and inherent cycle-by-cycle overcurrent protection without external sensing resistors. |
| Exposed thermal pad (Pin 17) | Enables θJC = 10°C/W - critical for maintaining <140°C junction temperature in continuous 1A+ operation at 60VIN. |
| Dual-threshold SHDN pin | Provides both precision undervoltage lockout (2.38V) and ultra-low-power shutdown (0.4V), simplifying system power sequencing. |
| Frequency foldback below 0.8V FB | Reduces switching frequency 5:1 during short-circuit or startup, limiting power dissipation in IC, diode, and inductor without external circuitry. |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
Use Scenario: Regulating 48V rail down to 5V for PLC I/O modules operating in factory environments up to 85°C ambient. IC Role / Device Role / Timing Role: Primary non-isolated buck converter delivering 1A continuous output with input transients up to 60V. Use Value: Guaranteed 140°C junction rating and 0.2Ω switch enable reliable operation without derating, while SYNC input allows coordination with CAN bus timing. | Use Scenario: Powering microcontroller, sensors, and LIN transceivers in under-hood BCMs exposed to 125°C under-hood temperatures. IC Role / Device Role / Timing Role: High-input-voltage buck regulator converting battery (9–16V) or load-dump (up to 60V) to stable 5V. Use Value: Dual SHDN thresholds provide robust start-up sequencing and fail-safe shutdown during brownout; exposed pad ensures thermal survival at 140°C junction. |
| Portable Test Equipment | Battery Charger Auxiliary Supply |
Use Scenario: Generating 5V from 12–36V Li-ion battery packs in handheld oscilloscopes and multimeters with strict standby current limits. IC Role / Device Role / Timing Role: Main system supply with ultra-low 25μA shutdown current and BIAS pin efficiency optimization. Use Value: 25μA shutdown current extends battery life; BIAS connection to 5V output reduces total input current by >30% at light loads. | Use Scenario: Providing isolated 5V bias for charger controller ICs and gate drivers in multi-cell Li-ion chargers with 30–60V input. IC Role / Device Role / Timing Role: Auxiliary buck stage powering control circuitry independent of main charging path. Use Value: Wide 5.5–60V input accommodates variable charger input; frequency foldback protects during output short during hot-plug events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | 42V max input, 1.2A switch, 3mm × 4mm MSOP, no BOOST pin required (integrated charge pump) | Lower voltage range; better suited for 24V systems with tighter board space; lacks 60V tolerance and 140°C rating | Select when input ≤42V and board area is constrained; avoid for 48V+ or under-hood use. |
| LM5164QDRCRQ1 | 65V max input, 1A switch, integrated high-side FET, 2.2MHz fixed frequency, AEC-Q100 Grade 1 | Higher frequency enables smaller magnetics; lower current rating; automotive-qualified but only to 125°C junction | Select for automotive production requiring AEC-Q100; not suitable for 140°C continuous operation or 1.5A loads. |
Compared with LTC3631EMSE#PBF and LM5164QDRCRQ1, LT1766HFE#PBF uniquely combines 60V input, 1.5A current, 0.2Ω switch, and guaranteed 140°C operation in a thermally enhanced TSSOP - making it optimal for high-reliability industrial and extended-temperature automotive auxiliary supplies where thermal headroom and voltage margin are non-negotiable.
Availability
LT1766HFE#PBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and portable test equipment requiring stable component supply with guaranteed high-temperature performance and long-term lifecycle support.
Supply support for LT1766HFE#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT1766 product line was designed by Linear Technology as a family of high-voltage, thermally robust monolithic buck regulators targeting industrial, automotive, and distributed power applications where wide input range and guaranteed high-temperature operation are essential.
FAQ
What is the maximum guaranteed junction temperature for LT1766HFE#PBF?
The LT1766HFE#PBF is fully specified and guaranteed over an operating junction temperature range of –40°C to 140°C. This rating is explicitly confirmed in the Absolute Maximum Ratings table and Order Information section of the datasheet, distinguishing it from E-grade (0°C–125°C) and I-grade (–40°C–125°C) variants. Thermal design must ensure the exposed pad (Pin 17) is soldered to a sufficient copper area to maintain this rating under full load.
Does LT1766HFE#PBF require an external boost capacitor, and why?
Yes, LT1766HFE#PBF requires an external boost capacitor connected between BOOST (Pin 6) and SW (Pin 2) via a small-signal diode. This capacitor provides a voltage ~5V above VIN to drive the base of the internal NPN power switch into saturation, enabling its low 0.2Ω on-resistance. Without it, switch conduction losses increase significantly, degrading efficiency and thermal performance - especially critical given the device's 140°C rating and high-VIN operation.
How does the SHDN pin function on LT1766HFE#PBF, and what are its two thresholds?
The SHDN pin on LT1766HFE#PBF has two distinct voltage thresholds: 2.38V (UVLO lockout) and 0.4V (micropower shutdown). At ≥2.38V, the device operates normally; between 0.4V and 2.38V, switching is disabled but bias circuitry remains active; at ≤0.4V, supply current drops to 25μA. This dual-threshold behavior enables robust power sequencing and brownout protection - a key feature for automotive and industrial systems where input voltage instability is common.
Can LT1766HFE#PBF synchronize to an external clock, and what is its valid frequency range?
Yes, LT1766HFE#PBF supports external synchronization via the SYNC pin (Pin 14). It accepts logic-level inputs (1.5V–2.2V minimum amplitude) with 10%–90% duty cycle across a frequency range of 228kHz to 700kHz. This capability allows EMI reduction by aligning switching noise to non-sensitive bands or coordinating with other system clocks - particularly valuable in dense, noise-sensitive applications like test equipment and automotive ECUs.
What is the purpose of the FB pin's frequency and current foldback features in LT1766HFE#PBF?
The FB pin on LT1766HFE#PBF enables automatic protection during fault conditions: when FB voltage falls below 0.8V, switching frequency folds back ~5:1 to limit power dissipation; below 0.6V, peak switch current is reduced to further constrain thermal stress in the IC, catch diode, and inductor. These features operate transparently during normal regulation but are critical for surviving output shorts and startup into heavy capacitive loads - eliminating need for external foldback circuitry.
LT1766HFE#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):
- 5.5V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 57.6V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 140°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT1766HFE#PBF FAQ
1.How can I place an order for LT1766HFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1766HFE#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 LT1766HFE#PBF reliable?
The price and inventory of LT1766HFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1766HFE#PBF is usually 5 days.
3.What payment methods are accepted for LT1766HFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1766HFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1766HFE#PBF?
LT1766HFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1766HFE#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 LT1766HFE#PBF?
For technical support, including LT1766HFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1766HFE#PBF requirements.
6.How does Aetrix verify that LT1766HFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT1766HFE#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 LT1766HFE#PBF meets industry standards.
7.What is the process for return or replacement of LT1766HFE#PBF?
All LT1766HFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1766HFE#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 LT1766HFE#PBF part is unused and in its original packaging.
Return procedure for LT1766HFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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