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Analog Devices Inc. LT3502AIDC#TRPBF
- Part No.:
- LT3502AIDC#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3502AIDC#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:10,224
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Product details
Overview
LT3502AIDC#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 thermally enhanced 2mm × 2mm 8-lead DFN package. It operates from 3V to 40V input and delivers regulated 3.3V or 5V output in automotive battery and industrial 24V supply systems.
For engineers reviewing the LT3502AIDC#TRPBF datasheet, LT3502AIDC#TRPBF pinout, LT3502AIDC#TRPBF application, or LT3502AIDC#TRPBF equivalent, key selection criteria include its 2.2MHz switching frequency for compact magnetics, cycle-by-cycle current limit with DA-pin valley-current foldback, soft-start via SHDN pin, <2µA shutdown current, and guaranteed –40°C to 125°C operation in DFN packaging.
Technical Context
The LT3502AIDC#TRPBF uses constant-frequency current-mode control with an internal oscillator, slope-compensated PWM comparator, and error amplifier servoing the VC node to maintain 0.8V at FB. Its bipolar NPN switch requires BOOST voltage > VIN to ensure saturation, generated via internal Schottky diode and external BOOST capacitor.
Protection includes undervoltage lockout (~2.8V), cycle-by-cycle peak current limiting (typ. 0.9A), DA-pin–monitored valley current foldback (650mA threshold), and thermal shutdown. Soft-start is implemented by ramping the SHDN pin voltage, which simultaneously controls startup current and reduces oscillator frequency to avoid overcurrent during turn-on.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 2.2MHz - enables use of sub-10µH inductors and 1–10µF ceramic output capacitors; avoids AM band interference. |
| Input Voltage Range | 3V to 40V - supports direct regulation from automotive batteries (12V/24V) and industrial supplies without pre-regulation. |
| Output Current | 500mA continuous - sustained under thermal limits in DFN package with θJA = 102°C/W and exposed pad soldered to PCB. |
| Feedback Reference | 0.8V ±13mV - sets output voltage via resistor divider (VOUT = 0.8 × (1 + R1/R2)); enables precise 3.3V or 5V regulation. |
| Shutdown Current | <2µA - minimizes system standby power loss; SHDN pin pulled low disables switching and disconnects output. |
| Current Limit | 0.75A to 1.1A (peak), 650mA (valley via DA pin) - provides short-circuit robustness with frequency foldback to limit power dissipation. |
| Package | 8-lead 2mm × 2mm DFN with exposed GND pad - thermally enhanced for high-power density; requires PCB thermal relief and soldering of pin 9 (GND). |
Pinout & Package
LT3502AIDC#TRPBF is housed in an 8-lead 2mm × 2mm plastic DFN package with exposed thermal pad (pin 9) that must be soldered to PCB ground for thermal performance. Pin 1 is VIN; pin 9 is GND (exposed pad); pin numbering follows standard DFN top-view orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input | Supplies internal regulator and power switch; requires local 1µF X7R/X5R ceramic bypass close to pin. |
| BD (Pin 2) | Boost diode anode | Connects to internal Schottky diode anode; used to charge BOOST capacitor when tied to VIN or external bias source. |
| FB (Pin 3) | Feedback sense | Regulated to 0.8V; connects to resistor divider tap; determines output voltage accuracy and loop stability. |
| SHDN (Pin 4) | Shutdown & soft-start control | Pulled low to disable IC (<2µA IQ); driven with RC ramp for controlled start-up and frequency foldback. |
| GND (Pin 5) | Ground reference | Power and signal ground; exposed pad (pin 9) is electrically connected and must be soldered to PCB GND plane. |
| DA (Pin 6) | Diode anode monitor | Detects catch diode current; triggers frequency foldback when valley current exceeds 650mA during fault conditions. |
| BOOST (Pin 7) | Switch driver boost | Provides >VIN gate drive to bipolar NPN switch; requires 0.1µF ceramic capacitor to SW pin for proper saturation. |
| SW (Pin 8) | Switch node | Drives external inductor and catch diode; high dV/dt node requiring tight layout and minimal trace length. |
Key Features
| Feature | Design Value |
|---|---|
| 2.2MHz fixed switching frequency | Enables ultra-compact 2mm × 2mm solution size with 6.8µH inductor and 10µF output capacitor; eliminates need for EMI filtering in AM band. |
| Integrated boost diode | Reduces BOM count by eliminating external Schottky diode for BOOST capacitor charging; simplifies layout and improves reliability. |
| DA-pin valley current foldback | Actively limits output current during short-circuit by reducing switching frequency to hold inductor valley current ≤650mA, preventing thermal runaway. |
| Internally compensated | Eliminates need for external compensation network; supports stable operation with standard ceramic output capacitors across full load and line range. |
| Thermally enhanced DFN | Exposed GND pad and low θJA (102°C/W) enable 500mA continuous output at 125°C junction temperature without heatsink or airflow. |
Applications
| Automotive Infotainment Power Supply | Industrial Sensor Node Regulator |
|---|---|
|
Use Scenario: Powering 3.3V microcontroller, CAN transceiver, and analog front-end from 12V vehicle battery with cold-crank (6V) and load-dump (40V) transients. IC Role / Device Role / Timing Role: Primary step-down regulator providing stable 3.3V rail; handles wide VIN range and transient immunity via UVLO and BOOST pin robustness. Use Value: 2.2MHz operation avoids AM radio interference; DA-foldback prevents thermal failure during ECU short-circuit events; <2µA shutdown extends battery life in sleep mode. |
Use Scenario: Converting 24V factory bus to 5V for PLC I/O modules operating in ambient temperatures up to 85°C. IC Role / Device Role / Timing Role: High-input-voltage buck converter delivering 500mA with minimal external components; operates continuously across industrial temperature range. Use Value: 40V absolute max rating withstands 24V bus surges; DFN package fits dense PCB layouts; internal compensation ensures stability with low-ESR ceramics. |
| Portable Medical Device Power | Smart Building Controller Supply |
|
Use Scenario: Regulating 3.3V for Bluetooth LE module and ADC in handheld diagnostic tool powered by dual-cell Li-ion (6–8.4V). IC Role / Device Role / Timing Role: Efficient, low-noise DC/DC converter enabling battery runtime extension and clean analog measurement. Use Value: 2.2MHz switching allows tiny 2.2µH inductor and 4.7µF output cap; soft-start via SHDN prevents inrush into large capacitive loads; 0.8V FB enables accurate 3.3V setpoint. |
Use Scenario: Providing 5V rail for Zigbee/Wi-Fi SoC and environmental sensors in wall-mounted HVAC controller with 24VAC/DC input. IC Role / Device Role / Timing Role: Compact, reliable buck regulator supporting long-life deployment in unventilated enclosures. Use Value: Guaranteed –40°C to 125°C operation ensures reliability in attic or outdoor installations; low shutdown current preserves backup battery; DFN package resists vibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3502AEDC#TRPBF | Same silicon, E-grade (0°C to 125°C junction) vs. I-grade (–40°C to 125°C); identical electrical specs and pinout. | Suitable only where ambient temperature stays ≥0°C; not qualified for automotive cold-start or extended industrial environments. | Select LT3502AIDC#TRPBF for full –40°C operation; choose LT3502AEDC#TRPBF only if cost-sensitive and temperature range permits. |
| MP2315DJ-LF-Z | Monolithic 2A buck; 2MHz freq; 4.5–28V input; no DA-foldback; requires external compensation; different pinout. | Lacks valley-current foldback protection; higher current capability but larger solution size and less fault robustness in short-circuit scenarios. | Use MP2315DJ-LF-Z only when >500mA output is required and DA-foldback is not critical; LT3502AIDC#TRPBF preferred for automotive-grade fault tolerance. |
Compared with LT3502AEDC#TRPBF, the LT3502AIDC#TRPBF adds guaranteed operation down to –40°C and tighter parametric testing across temperature; compared with MP2315DJ-LF-Z, it offers superior short-circuit resilience via DA-pin foldback and smaller 2mm × 2mm footprint despite lower current rating.
Availability
LT3502AIDC#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial sensor nodes, and portable medical devices requiring stable component supply with guaranteed –40°C to 125°C performance and AEC-Q200–compatible reliability.
Supply support for LT3502AIDC#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 industrial, automotive, communications, and healthcare markets.
The LT3502/LT3502A product line was designed specifically for compact, high-voltage step-down regulation in space-constrained and thermally demanding applications-emphasizing fault robustness, wide input range, and minimal external component count.
FAQ
What is the guaranteed operating temperature range for LT3502AIDC#TRPBF?
The LT3502AIDC#TRPBF is specified and guaranteed over the full –40°C to 125°C junction temperature range. This I-grade qualification ensures reliable operation in automotive engine compartments, industrial control cabinets, and outdoor equipment where ambient extremes occur. Electrical characteristics including feedback voltage, current limit, and switching frequency are characterized across this range.
Does LT3502AIDC#TRPBF require an external boost diode?
No, the LT3502AIDC#TRPBF integrates a Schottky diode between BD and BOOST pins, eliminating the need for an external boost diode. The internal diode charges the BOOST capacitor during each switching cycle, reducing component count and board area. External diodes are only needed in specialized configurations-for example, when using an external BD bias source below 3V.
How does the DA pin protect LT3502AIDC#TRPBF during output short-circuit?
The DA pin monitors catch diode current and triggers frequency foldback when valley current exceeds 650mA. During a short, the LT3502AIDC#TRPBF reduces switching frequency to maintain inductor valley current at ~650mA, limiting average power dissipation and preventing thermal runaway-unlike simple current-limit shutdown, this allows safe, sustained fault operation.
Can LT3502AIDC#TRPBF operate from a 40V input continuously?
Yes, the LT3502AIDC#TRPBF supports continuous operation up to 40V input, as confirmed by its Absolute Maximum Rating and validated in typical performance graphs (e.g., Figure 3502 G17). However, at high VIN and low VOUT, pulse-skipping occurs above VIN(MAX) for fixed-frequency operation, increasing output ripple-designers should verify ripple and thermal performance per application.
What is the minimum inductor value recommended for LT3502AIDC#TRPBF at 3.3V output?
For 3.3V output, the recommended minimum inductor is 6.8µH, as shown in the Typical Application schematic (Figure 3502 TA01a) and validated in maximum load current plots (Figure 3502 G05). This value balances efficiency, transient response, and discontinuous-mode avoidance; smaller values increase ripple and may trigger DA-foldback under heavy load.
LT3502AIDC#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):
- 32V
- Current - Output:
- 500mA
- Frequency - Switching:
- 2.25MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (2x2)
LT3502AIDC#TRPBF FAQ
1.How can I place an order for LT3502AIDC#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3502AIDC#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 LT3502AIDC#TRPBF reliable?
The price and inventory of LT3502AIDC#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3502AIDC#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3502AIDC#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3502AIDC#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3502AIDC#TRPBF?
LT3502AIDC#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3502AIDC#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 LT3502AIDC#TRPBF?
For technical support, including LT3502AIDC#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3502AIDC#TRPBF requirements.
6.How does Aetrix verify that LT3502AIDC#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3502AIDC#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 LT3502AIDC#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3502AIDC#TRPBF?
All LT3502AIDC#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3502AIDC#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 LT3502AIDC#TRPBF part is unused and in its original packaging.
Return procedure for LT3502AIDC#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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