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Analog Devices Inc. LT3682EDD#PBF
- Part No.:
- LT3682EDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LT3682EDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 1A 12DFN
- Quantity:
- Payment:
- Shipping:
Inventory:926
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Product details
Overview
LT3682EDD#PBF from Analog Devices (formerly Linear Technology) is a 1A, adjustable-frequency (250kHz–2.2MHz) monolithic buck switching regulator with integrated 0.5Ω bipolar NPN switch, boost diode, and current-mode control architecture. It operates from 3.6V to 36V input, delivers 0.8V–20V output, and features Low Ripple Burst Mode™ (75μA IQ, <15mV ripple), power good flag, soft-start, and overvoltage lockout up to 60V transients - used in automotive battery regulation and industrial distributed supplies.
For engineers reviewing the LT3682EDD#PBF datasheet, LT3682EDD#PBF pinout, LT3682EDD#PBF application, or LT3682EDD#PBF equivalent, key selection criteria include its 12-pin 3mm × 3mm DFN package with exposed PGND pad, SYNC-controlled mode selection (Burst vs. PWM), VC-based loop compensation, and validated short-circuit protection via DA-pin current sensing.
Technical Context
The LT3682EDD#PBF implements constant-frequency current-mode control using an internal error amplifier (gm = 430μS, gain = 1300 V/V) that drives the VC pin to regulate peak switch current. Its oscillator frequency is set by an external RT resistor (250kHz–2.2MHz), with SYNC pin enabling external clock synchronization or Burst Mode activation.
Protection includes cycle-by-cycle current limiting (1.45A min at low duty cycle, reduced under slope compensation), frequency foldback during startup/overload, thermal shutdown, and overvoltage lockout (36V continuous, 60V transient). The BOOST/SW/DA pins enable high-efficiency bipolar switch drive and catch-diode current monitoring for fault containment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V continuous; withstands 60V nonrepetitive transients - enables direct connection to 24V/36V automotive and industrial rails without pre-regulation. |
| Output Current | 1A maximum continuous - supports mid-power point-of-load conversion for microcontrollers, sensors, and interface ICs. |
| Switching Frequency | 250kHz to 2.2MHz, set by RT resistor - allows optimization of inductor size (e.g., 4.7μH at 2MHz) versus efficiency and EMI. |
| Feedback Reference | 0.8V ±12mV over temp - enables precise output programming from 0.8V to 20V using standard resistor dividers. |
| Quiescent Current | 75μA in Low Ripple Burst Mode at 12VIN/3.3VOUT - extends battery life in always-on portable or telematics systems. |
| Power Good Threshold | 90% of programmed VOUT with 12mV hysteresis - provides reliable system power sequencing and fault detection. |
| Thermal Package | 12-lead 3mm × 3mm DFN with exposed PGND pad (θJA = 43°C/W) - supports >1A operation at 125°C junction temperature with minimal PCB copper. |
Pinout & Package
LT3682EDD#PBF is housed in a thermally enhanced 12-lead 3mm × 3mm plastic DFN package with exposed pad (Pin 13), which must be soldered to PCB for PGND connection and thermal dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC (Pin 1) | Error amplifier output | Controls peak switch current; requires RC network to ground for loop stability and compensation. |
| FB (Pin 2) | Feedback input | Regulated to 0.8V reference; connects to resistor divider tap for output voltage programming. |
| PG (Pin 3) | Open-collector power good flag | Asserts high when VOUT reaches 90% of target; requires external pull-up for system monitoring. |
| GND (Pin 4) | Analog ground | Reference for internal circuitry; must tie directly to local ground plane, separate from PGND where possible. |
| BD (Pin 5) | Boost diode anode supply | Provides bias current to internal regulator; improves efficiency when connected to regulated output. |
| BOOST (Pin 6) | Bootstrap drive voltage | Connects to SW via 0.22μF capacitor to generate >VIN voltage for full saturation of NPN switch. |
| DA (Pin 7) | Catch diode current sense | Monitors valley current in external Schottky diode; triggers frequency foldback during overload/short-circuit. |
| SW (Pin 8) | Switch node | Connects to inductor, catch diode cathode, and BOOST capacitor; carries high di/dt switching current. |
| RUN/SS (Pin 9) | Enable & soft-start control | Pull ≥2.5V to enable; apply RC ramp for controlled VOUT rise; pull ≤0.2V to shut down (<1μA IQ). |
| RT (Pin 10) | Oscillator frequency set | Resistor to ground sets switching frequency (e.g., 40.2kΩ = 800kHz); tolerance affects accuracy. |
| SYNC (Pin 11) | External clock input / mode select | Ground = Burst Mode; ≥0.8V = pulse-skipping; external clock = synchronization (300kHz–2.2MHz). |
| VIN (Pin 12) | Main power input | Supplies internal regulator and switch; requires local ceramic bypass (≥10μF) near pin. |
| Exposed Pad (Pin 13) | Power ground (PGND) | Mandatory solder connection to PCB thermal plane; serves as return path for catch diode current. |
Key Features
| Feature | Design Value |
|---|---|
| Low Ripple Burst Mode™ | Maintains 75μA quiescent current and <15mVP-P output ripple at light loads - eliminates audible noise while preserving efficiency in standby. |
| Integrated Boost Diode | On-chip Schottky diode supplies BD pin - reduces BOM count and PCB area; reverse leakage <1μA at 10V. |
| Synchronized Operation | Accepts external clock (300kHz–2.2MHz) with <1μs edge rate - enables EMI reduction via fixed-frequency coordination across multiple rails. |
| Robust Short-Circuit Protection | Combines switch current limit (1.45A min), DA-pin valley-current foldback, and thermal shutdown - survives sustained output shorts without damage. |
| Wide Input Transient Tolerance | Withstands 60V/1s transients with automatic shutdown - meets ISO 7637-2 Pulse 5a requirements for 24V automotive systems. |
| Programmable Soft-Start | RUN/SS pin accepts RC network to control VOUT ramp rate - prevents inrush current and stabilizes upstream supplies during power-up. |
Applications
| Automotive Battery Regulation | Industrial Distributed Supply |
|---|---|
|
Use Scenario: Regulating 12V/24V vehicle battery to 3.3V/5V for infotainment head units and ADAS ECUs under cold-crank (4.5V) and load-dump (60V) conditions. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, regulated DC-DC conversion with overvoltage lockout and thermal protection. Use Value: Eliminates need for external TVS and pre-regulator stages; maintains regulation through ISO 16750-2 transients without shutdown. |
Use Scenario: Powering PLC I/O modules and fieldbus gateways from unregulated 24V industrial rails subject to brownouts and surges. IC Role / Device Role / Timing Role: High-input-voltage step-down regulator delivering stable 5V/12V outputs with power-good signaling for system reset control. Use Value: Enables single-stage conversion from 36V max input; PG flag ensures deterministic boot sequence after input recovery. |
| Portable Product Power | Power for Sensor Nodes |
|
Use Scenario: Supplying 1.8V/3.3V to battery-powered handheld test equipment with multi-day runtime requirements. IC Role / Device Role / Timing Role: Micropower buck regulator operating in Low Ripple Burst Mode during sleep cycles and PWM during active measurement. Use Value: Achieves 75μA no-load IQ and <15mV ripple - extends Li-ion battery life while avoiding audible coil whine in sensitive audio environments. |
Use Scenario: Powering ultra-low-power IoT sensor nodes (e.g., temperature/humidity) with intermittent wake-up and wireless transmission bursts. IC Role / Device Role / Timing Role: Efficient point-of-load regulator with programmable soft-start and precise 0.8V feedback for accurate low-voltage rail generation. Use Value: Supports 0.8V–20V output range and 125°C operation - accommodates diverse sensor supply needs in compact, thermally constrained enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8609SIV#PBF | 42V input, 2.5A, Silent Switcher® architecture; lower EMI, higher current, but larger 16-lead 3mm × 4mm LQFN package. | Better suited for noise-sensitive RF/analog circuits; requires more PCB area and lacks BD pin for bias optimization. | Select when EMI compliance (CISPR 25 Class 5) is critical and 2.5A output is needed; not drop-in due to pinout and layout changes. |
| TPS54332DDAR | 28V input, 3A, integrated MOSFETs; higher current, but fixed 500kHz/1MHz freq, no SYNC or Burst Mode - higher light-load IQ (120μA). | Targets cost-sensitive industrial supplies; lacks overvoltage lockout beyond 28V and has no PG flag. | Select for higher output current and simpler design where 60V transient tolerance and ultra-low IQ are not required. |
Compared with LT3682EDD#PBF, LT8609SIV#PBF offers superior EMI performance and current capability but demands larger layout space and forfeits BD-pin efficiency optimization; TPS54332DDAR provides higher current at lower cost but sacrifices transient robustness, precision PG signaling, and micropower operation.
Availability
LT3682EDD#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed supplies, and portable product power requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LT3682EDD#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 aerospace, automotive, industrial, and communications markets.
The LT3682EDD#PBF belongs to Linear's micropower monolithic buck regulator family, designed specifically for wide-input industrial and automotive applications demanding high transient immunity, low quiescent current, and robust fault protection.
FAQ
What is the minimum input voltage for stable operation of the LT3682EDD#PBF?
The LT3682EDD#PBF requires a minimum input voltage of 3.6V for continuous operation when the BD pin voltage exceeds 3.0V. Below this threshold, the internal bias regulator may not sustain control circuitry, leading to dropout or shutdown. This value is confirmed in the Electrical Characteristics table under "Minimum Operating Voltage" and applies across the full −40°C to 125°C junction temperature range.
How does the SYNC pin affect current limit and maximum output capability in the LT3682EDD#PBF?
When the SYNC pin of the LT3682EDD#PBF is grounded, the switch current limit is ≥1.45A at low duty cycles, decreasing to ≥1.1A at 90% duty cycle. When SYNC is tied to ≥0.8V or an external clock, the limit drops to ≥1.18A (low DC) and ≥0.85A (90% DC). This directly reduces maximum sustainable output current - especially critical in high-VIN/low-VOUT designs where duty cycle is high.
Can the LT3682EDD#PBF safely operate with a 60V input transient, and what happens during such an event?
Yes, the LT3682EDD#PBF is rated to safely withstand 60V/1-second input transients per Absolute Maximum Ratings. During such events, its overvoltage lockout circuit disables switching when VIN exceeds ~39V (typical), causing VOUT to fall out of regulation until VIN recovers below the threshold. The device remains undamaged and resumes normal operation automatically once input voltage returns within spec.
What is the role of the DA pin in the LT3682EDD#PBF, and how does it contribute to protection?
The DA pin on the LT3682EDD#PBF senses current through the external catch diode's anode. When valley current exceeds ~1.6A, it triggers frequency foldback - delaying subsequent switch pulses to limit inductor energy and prevent thermal runaway during short-circuit or overload. This complements the primary switch current limit and enhances system-level fault resilience without requiring additional sensing components.
Is the exposed pad of the LT3682EDD#PBF electrically connected, and what is its function?
Yes, the exposed pad (Pin 13) of the LT3682EDD#PBF is electrically connected to PGND - the power ground node for the catch diode return path. It must be soldered to a dedicated PCB thermal plane to ensure low-impedance grounding, effective heat dissipation (θJA = 43°C/W), and proper operation of the DA-pin current-sensing circuitry. Omitting this connection risks thermal failure and protection malfunction.
LT3682EDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-WFDFN 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):
- 3.6V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 20V
- Current - Output:
- 1A
- Frequency - Switching:
- 250kHz ~ 2.2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-DFN (3x3)
LT3682EDD#PBF FAQ
1.How can I place an order for LT3682EDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3682EDD#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 LT3682EDD#PBF reliable?
The price and inventory of LT3682EDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3682EDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3682EDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3682EDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3682EDD#PBF?
LT3682EDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3682EDD#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 LT3682EDD#PBF?
For technical support, including LT3682EDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3682EDD#PBF requirements.
6.How does Aetrix verify that LT3682EDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3682EDD#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 LT3682EDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3682EDD#PBF?
All LT3682EDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3682EDD#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 LT3682EDD#PBF part is unused and in its original packaging.
Return procedure for LT3682EDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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