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Analog Devices Inc. LT3502IDC#TRPBF
- Part No.:
- LT3502IDC#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3502IDC#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,914
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Product details
Overview
LT3502IDC#TRPBF from Analog Devices (formerly Linear Technology) is a 2.2MHz, 500mA current-mode PWM step-down DC/DC converter with integrated 500mA bipolar NPN power switch, 0.8V feedback reference, internal boost diode, and cycle-by-cycle current limiting. It operates from 3V to 40V input and delivers regulated 3.3V or 5V outputs in automotive battery and industrial 24V supply systems.
For engineers reviewing the LT3502IDC#TRPBF datasheet, LT3502IDC#TRPBF pinout, LT3502IDC#TRPBF application, or LT3502IDC#TRPBF equivalent, key selection criteria include its 2.2MHz switching frequency for compact magnetics, –40°C to 125°C junction temperature rating, 8-lead 2mm × 2mm DFN package with exposed GND pad, and DA-pin-based frequency foldback for short-circuit robustness.
Technical Context
The LT3502IDC#TRPBF implements constant-frequency current-mode control using an RS flip-flop–driven oscillator and slope-compensated peak current sensing. Its internal bipolar NPN switch requires BOOST voltage ≥2.2V above SW for full saturation, enabled by an integrated Schottky diode and external BOOST capacitor.
Protection architecture combines cycle-by-cycle switch current limit (0.75A min), DA-pin valley current monitoring (650mA threshold), soft-start via SHDN pin ramping, and undervoltage lockout (~2.8V). Frequency foldback activates under overload or short-circuit to maintain inductor valley current ≤650mA while reducing switching frequency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 2.2MHz - enables use of sub-10µH inductors and 1µF ceramic input caps; avoids AM band interference. |
| Input Voltage Range | 3V to 40V - supports direct connection to automotive batteries (12V/24V) and industrial supplies without pre-regulation. |
| Output Current | 500mA continuous - sustained at VOUT = 3.3V/5V with appropriate inductor (e.g., 6.8µH/10µH) and thermal layout. |
| Feedback Reference | 0.8V ±13mV - sets output via resistor divider (e.g., R2 = 10kΩ, R1 = 32.4kΩ for 3.3V); low tolerance minimizes output error. |
| Shutdown Current | <2µA - enables ultra-low-power system sleep modes; SHDN pin pulled to GND disables switching and disconnects output. |
| Thermal Resistance | θJA = 102°C/W - achieved via exposed GND pad soldered to PCB plane; requires minimum 120mm² copper area for 125°C operation. |
| Current Limit Threshold | 0.75A to 1.1A - protects against overloads; actual trip level varies with duty cycle due to slope compensation. |
Pinout & Package
LT3502IDC#TRPBF uses an 8-lead 2mm × 2mm plastic DFN package with exposed GND pad (Pin 9), which must be soldered to PCB for thermal and electrical performance. Package outline and thermal pad layout comply with JEDEC MO-229 standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main power input | Supplies internal regulator and power switch; requires local 1µF X7R ceramic bypass within 3mm of pin. |
| BD (Pin 2) | Boost diode anode | Connects to internal Schottky diode; ties to BOOST cap cathode; optional external BD voltage improves low-VOUT startup. |
| FB (Pin 3) | Feedback sense node | Regulated to 0.8V; connects to resistor divider midpoint; bias current ≤50nA minimizes divider error. |
| SHDN (Pin 4) | Enable/soft-start control | Pulled low to disable; ≥2V enables operation; RC network here provides programmable soft-start ramp and frequency foldback. |
| GND (Pin 5) | Power and signal ground | Common return for switch, driver, and control circuits; exposed pad (Pin 9) is electrically GND and mandatory for thermal path. |
| DA (Pin 6) | Diode anode monitor | Detects catch diode conduction; triggers frequency foldback when valley current exceeds 650mA during fault conditions. |
| BOOST (Pin 7) | Switch driver supply | Must be ≥2.2V above SW for full switch saturation; driven by external capacitor charged via internal BD diode. |
| SW (Pin 8) | Switch node | Connects to inductor, catch diode cathode, and BOOST capacitor; high dv/dt node requiring tight loop layout and guard ring. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost diode | Eliminates external Schottky diode in BOOST path, reducing BOM count and PCB area in 2mm × 2mm footprint. |
| DA-pin frequency foldback | Automatically reduces switching frequency under short-circuit to hold inductor valley current ≤650mA, preventing thermal runaway. |
| Internally compensated | Requires no external compensation components; stable with standard output capacitor types (ceramic, polymer, low-ESR electrolytic). |
| 2.2MHz fixed frequency | Enables <10µH inductors and 1µF input capacitors, achieving total solution size <25mm² for 3.3V/500mA output. |
| –40°C to 125°C operation | Qualified across full junction temperature range; electrical specs guaranteed per data sheet Table 3 for LT3502I grade. |
Applications
| Automotive Infotainment Power | Industrial Sensor Node Supply |
|---|---|
Use Scenario: Regulating 12V vehicle battery to 3.3V for MCU, CAN transceiver, and display logic in head units. IC Role / Device Role / Timing Role: Primary buck converter providing clean, ripple-controlled 3.3V rail with AM-band–free 2.2MHz switching. Use Value: Eliminates need for EMI filters; survives load dump transients up to 40V; DA-foldback prevents thermal failure during display backlight short. |
Use Scenario: Powering low-power wireless sensor nodes (LoRaWAN, NB-IoT) from 24V factory wiring or 12V backup battery. IC Role / Device Role / Timing Role: High-input-voltage buck regulator delivering 500mA at 3.3V/5V with <2µA shutdown current for multi-year battery life. Use Value: 3V–40V range accommodates wide input variance; exposed pad ensures reliability in unventilated enclosures; soft-start prevents inrush into large sensor capacitance. |
| Medical Portable Equipment | Test & Measurement Front-End |
Use Scenario: Generating isolated 5V rail for ADC drivers and op-amps in handheld ultrasound or ECG devices powered by Li-ion packs. IC Role / Device Role / Timing Role: Compact, low-noise step-down stage preceding LDO post-regulation; 2.2MHz allows small LC filter before sensitive analog circuitry. Use Value: 0.8V FB reference enables precise output setting; internal compensation simplifies layout near noise-sensitive analog sections. |
Use Scenario: Supplying 3.3V to FPGA configuration I/O banks and 5V to analog front-end amplifiers in benchtop oscilloscopes and signal generators. IC Role / Device Role / Timing Role: Main intermediate converter stepping down 12V/24V system rail to distributed point-of-load voltages. Use Value: 500mA output supports multiple ICs; thermal enhancement sustains full load at 70°C ambient; frequency foldback protects during probe short events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3502AIDC#TRPBF | Same pinout, same 2.2MHz frequency, but guaranteed over full –40°C to 125°C range with tighter FB tolerance (±1.25% vs ±1.6%). | Better suited for automotive under-hood or industrial environments requiring extended temp validation. | Select LT3502AIDC#TRPBF when full-temperature-range parametric guarantees are required; otherwise LT3502IDC#TRPBF offers identical functionality at lower cost. |
| MP2451DT-LF-Z | 3.5A switch, 2MHz, 4.5–36V input, but no DA-foldback or internal boost diode; requires external BOOT diode and compensation. | Larger solution size; lacks short-circuit robustness features critical for unattended industrial systems. | Choose MP2451DT-LF-Z only if higher output current (>500mA) is needed and board space permits larger inductor/capacitor; not drop-in compatible. |
Compared with LT3502AIDC#TRPBF, the LT3502IDC#TRPBF trades minor FB tolerance and temp-range validation for cost efficiency, while MP2451DT-LF-Z sacrifices integrated protection and compactness for raw current capability-making LT3502IDC#TRPBF optimal for space-constrained, fault-tolerant 500mA designs.
Availability
LT3502IDC#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor nodes, and medical portable equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3502IDC#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 acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for all LT® products, including rigorous AEC-Q200–aligned qualification for automotive-grade variants.
The LT3502/LT3502A product line was designed specifically for high-input-voltage, space-constrained DC/DC conversion in automotive, industrial, and medical systems where reliability under fault conditions and minimal external component count are critical.
FAQ
What is the maximum input voltage supported by the LT3502IDC#TRPBF?
The LT3502IDC#TRPBF has an absolute maximum VIN rating of 40V and operates continuously from 3V to 40V. For fixed-frequency operation, maximum practical input depends on output voltage and inductor value-for example, at 3.3V output with 6.8µH inductor, VIN(MAX) ≈ 33V before pulse-skipping begins. Transient inputs up to 40V are tolerated, though output ripple increases above VIN(MAX).
Does the LT3502IDC#TRPBF require an external bootstrap diode?
No, the LT3502IDC#TRPBF integrates a BOOST Schottky diode (BD pin), eliminating the need for an external bootstrap diode. The internal diode charges the BOOST capacitor from VIN, enabling the driver to fully saturate the bipolar NPN switch. External BD voltage can be applied for improved low-VOUT startup, but is optional.
How does the DA pin protect the LT3502IDC#TRPBF during output short-circuit?
The DA pin monitors catch diode conduction and triggers frequency foldback when valley current exceeds 650mA. During a short, the LT3502IDC#TRPBF reduces switching frequency to maintain inductor valley current at ~650mA, limiting power dissipation and preventing thermal runaway-enabling indefinite short-circuit survival with proper thermal design.
Can the LT3502IDC#TRPBF be used with ceramic output capacitors?
Yes, the LT3502IDC#TRPBF is internally compensated and stable with ceramic output capacitors. Recommended COUT = 33/VOUT µF (e.g., 10µF for 3.3V); X5R or X7R dielectrics are preferred. Low-ESR ceramics provide best ripple suppression and transient response without requiring external compensation.
What is the purpose of the exposed pad on the LT3502IDC#TRPBF DFN package?
The exposed pad (Pin 9) on the LT3502IDC#TRPBF is electrically connected to GND and serves as the primary thermal path. It must be soldered to a minimum 120mm² PCB copper area to achieve θJA = 102°C/W and sustain 500mA output at 125°C junction temperature. Omitting this connection risks thermal shutdown or reduced lifetime.
LT3502IDC#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN 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):
- 3V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 36V
- Current - Output:
- 500mA
- Frequency - Switching:
- 1.1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (2x2)
LT3502IDC#TRPBF FAQ
1.How can I place an order for LT3502IDC#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3502IDC#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 LT3502IDC#TRPBF reliable?
The price and inventory of LT3502IDC#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3502IDC#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3502IDC#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3502IDC#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3502IDC#TRPBF?
LT3502IDC#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3502IDC#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 LT3502IDC#TRPBF?
For technical support, including LT3502IDC#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3502IDC#TRPBF requirements.
6.How does Aetrix verify that LT3502IDC#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3502IDC#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 LT3502IDC#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3502IDC#TRPBF?
All LT3502IDC#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3502IDC#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 LT3502IDC#TRPBF part is unused and in its original packaging.
Return procedure for LT3502IDC#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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