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Analog Devices Inc. LT3693IDD#PBF
- Part No.:
- LT3693IDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3693IDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,675
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Product details
Overview
LT3693IDD#PBF from Analog Devices (formerly Linear Technology) is a monolithic current-mode step-down switching regulator with integrated 95mΩ NPN power switch and boost Schottky diode, supporting 3.6V–36V input, 0.79V–30V adjustable output, up to 3.5A load, and programmable 200kHz–2.4MHz switching frequency. It delivers automotive battery regulation and industrial distributed supply in thermally enhanced 10-pin 3mm × 3mm DFN.
For engineers reviewing the LT3693IDD#PBF datasheet, LT3693IDD#PBF pinout, LT3693IDD#PBF application, or LT3693IDD#PBF equivalent, key selection considerations include its 91% power-good threshold, soft-start via RUN/SS pin, thermal shutdown protection, exposed-pad thermal management, and synchronization capability across 250kHz–2MHz - all critical for high-reliability 12V/24V embedded power rails.
Technical Context
The LT3693IDD#PBF implements constant-frequency current-mode control with internal error amplifier (525 μ℧ transconductance), slope compensation, and VC-pin-based peak-current limiting. Its oscillator uses an external RT resistor to set frequency, with foldback during low FB voltage to limit startup current.
Power delivery relies on bipolar NPN switch driven by BOOST pin voltage (up to 56V absolute max), requiring external boost capacitor and Schottky diode. The BD pin supplies bias current to the internal regulator, enabling efficiency optimization when tied to regulated output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V - supports wide-range industrial and automotive batteries without pre-regulation. |
| Max Output Current | 3.5A - sustained load capability with internal switch rated for 4.6A–6.0A current limit depending on duty cycle. |
| Switching Frequency | 200kHz to 2.4MHz - adjustable via RT resistor; enables tradeoff between inductor size (high-freq) and efficiency/dropout (low-freq). |
| Feedback Reference | 0.790V ±15mV - precise reference enabling accurate output programming with standard resistor dividers. |
| Power Good Threshold | 91% of VOUT - open-collector PG flag asserts when output reaches regulation, with 65mV offset and 10mV hysteresis. |
| Shutdown Quiescent Current | <1μA - ultra-low IQ enables always-on systems with minimal standby drain. |
| Thermal Protection | Integrated junction thermal shutdown - disables switching above safe temperature, auto-recovering on cooldown. |
Pinout & Package
LT3693IDD#PBF is housed in a 10-lead, 3mm × 3mm plastic DFN package with exposed pad (Pin 11) that must be soldered to PCB for thermal and electrical grounding. θJA = 45°C/W, θJC = 10°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Bias Diode Anode Input | Connects to boost Schottky anode; supplies bias current to internal regulator - improves efficiency when tied to VOUT. |
| BOOST (Pin 2) | Boost Drive Voltage | Provides >VIN voltage to saturate internal NPN switch; requires external boost capacitor and diode. |
| SW (Pin 3) | Switch Node | Output of internal power switch; connects to inductor, catch diode, and boost capacitor - high dv/dt node requiring careful layout. |
| VIN (Pin 4) | Main Power Input | Supplies current to internal regulator and switch; must be locally bypassed with ≥10μF X7R/X5R ceramic capacitor. |
| RUN/SS (Pin 5) | Enable & Soft-Start Control | Logic-level enable (≥2.5V = ON); RC network here sets controlled VOUT ramp rate during startup. |
| SYNC (Pin 6) | External Clock Input | Accepts TTL/CMOS clock for synchronization between 250kHz–2MHz; must not float - tie to GND if unused. |
| PG (Pin 7) | Power Good Flag | Open-collector output active-low until VFB ≥ 91% of target; valid only when VIN > 3.6V and RUN/SS high. |
| FB (Pin 8) | Feedback Input | Regulated to 0.790V; connects to resistor divider tap - determines output voltage with ±15mV tolerance over temp. |
| VC (Pin 9) | Error Amplifier Output | Controls peak switch current; RC network to ground sets loop compensation - critical for stability with ceramic output caps. |
| RT (Pin 10) | Oscillator Frequency Set | Resistor-to-GND sets switching frequency per published RT vs. fSW table (e.g., 34kΩ = ~1MHz). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode | Eliminates external boost diode - reduces BOM count and board area while maintaining efficient NPN switch saturation. |
| Synchronizable Switching | Enables noise-sensitive systems (e.g., RF, audio) to align switching edges with master clock - avoids beat frequencies and EMI peaks. |
| Thermally Enhanced DFN | 3mm × 3mm footprint with exposed GND pad achieves θJC = 10°C/W - supports 3.5A continuous operation with minimal heatsinking. |
| Current-Mode Control | Delivers fast transient response and inherent cycle-by-cycle current limiting - simplifies compensation and improves fault robustness. |
| Programmable Soft-Start | RC network on RUN/SS pin provides user-defined output voltage ramp - prevents inrush current and stabilizes upstream supplies. |
Applications
| Automotive Battery Regulation | Industrial Distributed Supply |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to stable 3.3V or 5V for infotainment MCU and CAN transceivers under cold-crank (4.5V) and load-dump (36V) conditions. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, ripple-controlled power domain with PG signaling for system boot sequencing. Use Value: 3.6V–36V input range and thermal shutdown ensure reliable operation across automotive temperature extremes (–40°C to 125°C). |
Use Scenario: Generating local 5V/12V rails from 24V factory bus for PLC I/O modules, sensor interfaces, and fieldbus gateways. IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator with SYNC input to align switching with central controller clock - reducing conducted EMI in dense control cabinets. Use Value: 3.5A output and 95mΩ switch enable compact, fanless designs; exposed pad ensures thermal reliability in sealed enclosures. |
| Portable Product Power | Wall Transformer Regulation |
Use Scenario: Powering FPGA core logic and DDR memory in handheld test equipment powered by 12V Li-ion pack or universal AC adapter. IC Role / Device Role / Timing Role: Adjustable-output buck regulator with soft-start and PG flag - coordinates power-up sequence with FPGA configuration manager. Use Value: 200kHz–2.4MHz frequency range allows optimization for size (2.4MHz + 1μH inductor) or efficiency (400kHz + 4.7μH) based on battery life requirements. |
Use Scenario: Replacing linear regulators in wall adapters supplying 5V/3A to USB-C PD accessories or IoT hubs, improving efficiency and thermal performance. IC Role / Device Role / Timing Role: High-input-voltage buck converter accepting unregulated 9–36V DC from transformer rectifier - eliminating need for bulky pre-regulators. Use Value: Integrated boost diode and 36V VIN rating reduce component count; <1μA shutdown current enables zero-power standby mode. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630EMSE#PBF | Lower 3.1A max output; 3.5V–40V input; no integrated boost diode - requires external bootstrap circuit. | Targeted at higher-VIN industrial apps where 40V abs max suffices; less suitable for space-constrained automotive layouts. | Select when input exceeds 36V or when external bootstrap design flexibility is preferred over integration. |
| MP2451DT-LF-Z | 3A max output; 4.5V–36V input; 2MHz fixed freq; no PG flag or SYNC; smaller 8-pin SOIC package. | Cost-optimized for consumer-grade power rails where PG sequencing and EMI control are non-critical. | Choose for high-volume, non-automotive applications prioritizing cost and footprint over PG signaling and synchronization. |
Compared with LTC3630EMSE#PBF and MP2451DT-LF-Z, the LT3693IDD#PBF uniquely combines 3.5A capability, integrated boost diode, PG flag, and full 200kHz–2.4MHz programmability in a thermally optimized DFN - making it optimal for automotive and industrial designs demanding reliability, feature completeness, and layout simplicity.
Availability
LT3693IDD#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed supply, and portable product power applications requiring stable component supply, long-term lifecycle support, and guaranteed –40°C to 125°C operation.
Supply support for LT3693IDD#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 its legacy of high-performance analog and power management ICs with rigorous automotive and industrial qualification.
The LT3693 belongs to Linear's monolithic buck regulator product line, designed specifically for wide-input, high-reliability power conversion in harsh environments - emphasizing thermal robustness, integrated functionality, and ease of use in safety-critical systems.
FAQ
What is the maximum input voltage rating for LT3693IDD#PBF?
The LT3693IDD#PBF has an absolute maximum VIN rating of 36V and BOOST pin rating of 56V. Under normal regulation, it safely handles 36V transients. During startup or overload, maximum allowable VIN depends on switching frequency and minimum on-time - e.g., at 2.4MHz, max VIN drops to ~24V to avoid violating tON(MIN) limits. Always verify using the VINMAX equation in the datasheet for your specific fSW and VOUT.
Does LT3693IDD#PBF require an external boost diode?
No, the LT3693IDD#PBF integrates a boost Schottky diode internally - unlike many buck controllers, it does not require an external diode for bootstrap operation. However, an external boost capacitor is mandatory between BOOST and SW pins to generate the required gate-drive voltage above VIN for NPN switch saturation.
How is the power good (PG) flag of LT3693IDD#PBF configured and used?
The LT3693IDD#PBF PG pin is an open-collector output that pulls low until the FB voltage reaches 91% of the programmed output voltage, with 65mV offset and 10mV hysteresis. It is valid only when VIN > 3.6V and RUN/SS is high. Use a pull-up resistor (typically 10kΩ to 5V or 3.3V) to interface with microcontroller reset or enable logic for safe system boot sequencing.
Can LT3693IDD#PBF synchronize to an external clock, and what are the voltage thresholds?
Yes, the LT3693IDD#PBF supports external clock synchronization via the SYNC pin. It accepts TTL/CMOS-compatible signals from 250kHz to 2MHz. The SYNC pin has a low threshold of 0.5V and high threshold of 0.8V, with bias current <0.1μA. Do not leave SYNC floating - tie to GND if unused to prevent erratic behavior.
What thermal considerations apply to LT3693IDD#PBF in the 3mm × 3mm DFN package?
The LT3693IDD#PBF in the 3mm × 3mm DFN uses an exposed pad (Pin 11) that must be soldered to a thermal pad on the PCB for effective heat dissipation. With θJC = 10°C/W and θJA = 45°C/W, full 3.5A output requires ≥2 cm² copper area and ≥4 thermal vias under the pad. Derate output current above 85°C ambient unless additional airflow or heatsinking is provided.
LT3693IDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-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):
- 0.79V
- Voltage - Output (Max):
- 30V
- Current - Output:
- 3.5A
- Frequency - Switching:
- 230kHz ~ 2.45MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3693IDD#PBF FAQ
1.How can I place an order for LT3693IDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3693IDD#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 LT3693IDD#PBF reliable?
The price and inventory of LT3693IDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3693IDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3693IDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3693IDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3693IDD#PBF?
LT3693IDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3693IDD#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 LT3693IDD#PBF?
For technical support, including LT3693IDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3693IDD#PBF requirements.
6.How does Aetrix verify that LT3693IDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3693IDD#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 LT3693IDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3693IDD#PBF?
All LT3693IDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3693IDD#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 LT3693IDD#PBF part is unused and in its original packaging.
Return procedure for LT3693IDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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