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Analog Devices Inc. LT3502IMS#PBF
- Part No.:
- LT3502IMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT3502IMS#PBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:218
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Product details
Overview
LT3502IMS#PBF 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, designed for 3V–40V input and fixed 3.3V or adjustable output regulation in automotive and industrial systems. It features internal boost diode, 0.8V feedback reference, soft-start, and short-circuit robustness via cycle-by-cycle current limit and DA-pin frequency foldback.
For engineers reviewing the LT3502IMS#PBF datasheet, LT3502IMS#PBF pinout, LT3502IMS#PBF application, or LT3502IMS#PBF equivalent, key selection criteria include its 2.2MHz switching frequency (LT3502A variant), 10-lead MSOP package thermal performance (θJA = 110°C/W), 0.78–0.813V feedback voltage tolerance, and DA-valley-current-limited fault protection at 650mA - critical for high-reliability 24V supply regulation and battery-powered equipment.
Technical Context
The LT3502IMS#PBF implements constant-frequency current-mode control using an RS flip-flop–driven oscillator and slope-compensated peak current sensing. Its VC node is servoed by an error amplifier monitoring FB voltage against 0.8V reference, while SHDN pin voltage directly clamps VC to enable soft-start ramp and frequency foldback during overloads.
Frequency foldback is dual-triggered: switch peak current limit (0.75–1.1A) governs normal operation, while DA pin monitors catch diode valley current and forces oscillator frequency reduction below 650mA to sustain regulation under short-circuit conditions - a feature confirmed for LT3502A variants including LT3502IMS#PBF per datasheet Figures 3, G14, and G15.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 2.2MHz (LT3502A variant); enables use of ≤6.8µH inductors and avoids AM-band interference in automotive EMI-sensitive designs. |
| Max Output Current | 500mA continuous; limited by internal 500mA bipolar NPN switch and DA-valley-current foldback at 650mA. |
| Input Voltage Range | 3V to 40V; supports direct connection to 24V industrial rails and automotive batteries without pre-regulation. |
| Feedback Voltage | 0.780–0.813V (MSOP package, –40°C to 125°C); sets output via resistor divider: VOUT = 0.8V × (1 + R1/R2). |
| Shutdown Current | <2µA; ensures ultra-low system standby power in battery-backed or energy-conscious applications. |
| Thermal Resistance | θJA = 110°C/W (10-lead MSOP); requires PCB copper area under exposed pad for reliable 125°C junction operation. |
| Max Duty Cycle | 80% (LT3502A); determines minimum input voltage support: VIN(MIN) = (VOUT + 0.4V)/0.8 – 0.4V + 0.45V. |
Pinout & Package
LT3502IMS#PBF uses a 10-lead plastic MSOP (MS) package with exposed pad soldered to PCB ground for thermal management (θJA = 110°C/W). Pin numbering follows top-view orientation with Pin 1 at bottom-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch Node | Output of internal bipolar NPN switch; connects to inductor, catch diode cathode, and boost capacitor. |
| BOOST (Pin 2) | Boost Drive | Provides >VIN drive voltage to switch base via external capacitor; must be ≥2.2V above SW for full saturation. |
| NC (Pin 3) | No Connect | Internally unused; must remain floating or grounded per layout guidelines - no circuit function. |
| DA (Pin 4) | Diode Anode Monitor | Senses catch diode valley current; triggers frequency foldback when current exceeds 650mA during faults. |
| GND (Pin 5) | Power Ground | Primary return path for switch, control circuitry, and exposed pad; must be low-impedance plane connection. |
| SHDN (Pin 6) | Shutdown/Soft-Start | Active-high enable (≥2V); also provides soft-start ramp and frequency foldback control via RC network. |
| FB (Pin 7) | Feedback Input | Regulated to 0.8V; connects to resistor divider tap to set output voltage with ±1.6% accuracy over temperature. |
| BD (Pin 8) | Boost Diode Anode | Connects to anode of internal Schottky boost diode; ties to VIN or external bias for low-VOUT operation. |
| VIN (Pin 10) | Input Supply | Supplies internal regulator and switch; bypassed locally with ≥1µF X7R ceramic capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Diode | Eliminates external Schottky diode in boost path, reducing BOM count and PCB footprint in space-constrained MSOP layouts. |
| DA-Pin Fault Protection | Monitors catch diode valley current and reduces switching frequency to maintain 650mA limit - enabling safe short-circuit operation without thermal shutdown. |
| Internal Compensation | Single-pole compensation network embedded; removes need for external compensation components and simplifies loop stability validation. |
| Thermally Enhanced MSOP | 10-lead MSOP with exposed pad achieves θJA = 110°C/W - enabling 500mA output at 125°C ambient with minimal copper area. |
| AM-Band Quiet Operation | 2.2MHz fixed frequency places switching noise well above 1.6MHz AM radio band, eliminating RF interference in automotive infotainment systems. |
Applications
| Automotive Infotainment Power | Industrial Sensor Node Regulator |
|---|---|
Use Scenario: Powering 3.3V microcontrollers and CAN transceivers in head units with 12V/24V battery input and strict EMI limits. IC Role / Device Role / Timing Role: Primary 3.3V buck regulator delivering 500mA with 2.2MHz switching to avoid AM-band interference and minimize filter size. Use Value: Enables compact, EMI-compliant design using only 6.8µH inductor and 10µF ceramic output cap - validated in LT3502A 12VIN efficiency curves (G01/G02). | Use Scenario: Regulating 5V or 3.3V rail for low-power PLC I/O modules powered from 24V industrial supplies. IC Role / Device Role / Timing Role: High-input-voltage step-down converter supporting wide VIN range (3–40V) and operating up to 125°C ambient. Use Value: Delivers stable 500mA output across –40°C to 125°C with internal current limiting and thermal robustness - verified in LT3502A max load current graphs (G05/G06). |
| Portable Medical Device Supply | Smart Building Controller Power |
Use Scenario: Generating 3.3V for Bluetooth LE modules and ADCs in handheld diagnostic tools powered by Li-ion or alkaline batteries. IC Role / Device Role / Timing Role: Efficient buck converter with <2µA shutdown current and soft-start to prevent inrush into capacitive loads during wake-up. Use Value: Extends battery life via ultra-low quiescent current and eliminates input surge with SHDN-controlled soft-start - confirmed in Electrical Characteristics table (2µA max shutdown current). | Use Scenario: Providing regulated 5V for Zigbee/Wi-Fi SoCs and sensor interfaces in HVAC controllers with 24VAC/DC input. IC Role / Device Role / Timing Role: Robust buck regulator with short-circuit foldback and undervoltage lockout (2.6–3.0V) for unregulated field wiring environments. Use Value: Survives brownouts and output shorts without latch-off or thermal damage - enabled by DA-valley-current foldback and cycle-by-cycle current limit per datasheet Sections 9–10. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3502AEMS#PBF | Same LT3502A silicon, identical 2.2MHz frequency and DA-foldback, but in 8-lead 2mm×2mm DFN (θJA = 102°C/W). | Higher power density; better thermal performance at board level but requires different PCB footprint and reflow profile. | Select when board space is constrained and thermal vias under DFN exposed pad are feasible. |
| LT8607EMSE#PBF | 42V input, 750mA synchronous buck; 2MHz switching, 2.5µA quiescent current; no internal boost diode required. | Higher efficiency (>95% at 12VIN→3.3V/500mA), lower EMI due to Silent Switcher architecture, but higher cost and larger solution size. | Select when efficiency >92% and CISPR 25 Class 5 EMI compliance are mandatory - not a drop-in replacement. |
Compared with LT3502IMS#PBF, LT3502AEMS#PBF offers identical electrical behavior in a smaller thermally superior package, while LT8607EMSE#PBF trades simplicity and cost for higher efficiency and EMI performance - making LT3502IMS#PBF optimal for cost-sensitive, space-tolerant 24V-to-3.3V/5V industrial conversion where proven fault robustness is prioritized.
Availability
LT3502IMS#PBF is available at Aetrix Electronics and suitable for automotive infotainment power, industrial sensor node regulation, and portable medical device supply requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT3502IMS#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT3502/LT3502A product line was designed specifically for high-input-voltage, compact-area DC/DC conversion in automotive, industrial, and battery-powered systems - emphasizing fault resilience, EMI control, and simplified layout with integrated boost diode and internal compensation.
FAQ
What is the switching frequency of the LT3502IMS#PBF and why does it matter?
The LT3502IMS#PBF operates at a fixed 2.2MHz switching frequency as part of the LT3502A family. This high frequency allows use of small, low-cost 6.8µH inductors and 10µF ceramic output capacitors, minimizing solution size. It also places switching noise above the 1.6MHz AM radio band, preventing interference in automotive infotainment systems - a key requirement confirmed in the LT3502A datasheet's Applications section and Figure TA01b.
Does the LT3502IMS#PBF require an external boost diode?
No, the LT3502IMS#PBF integrates an internal Schottky boost diode connected to the BD pin, eliminating the need for an external diode in the bootstrap path. This reduces component count and PCB area - explicitly stated in the Features list and Pin Functions section. The internal diode supports standard boost configurations (Figure 5a) and can be augmented with an external BAT54 for sub-3V outputs.
How does the LT3502IMS#PBF protect against short-circuit conditions?
The LT3502IMS#PBF employs dual-layer short-circuit protection: cycle-by-cycle switch current limiting (0.75–1.1A) and DA-pin–triggered frequency foldback that caps valley current at 650mA. During output shorts, the controller reduces switching frequency to maintain this limit, preventing thermal runaway - detailed in the Block Diagram, Operation section, and Figure 3 (3502 F03) of the datasheet.
What is the maximum output current capability of the LT3502IMS#PBF?
The LT3502IMS#PBF delivers up to 500mA continuous output current, limited by its internal 500mA bipolar NPN power switch and thermal design. Actual achievable current depends on input voltage, output voltage, ambient temperature, and PCB copper area. Graphs G05 and G06 in the datasheet show maximum load current vs. VIN for 3.3V/5V outputs, confirming 500mA capability at 12VIN and 25°C with proper layout.
Can the LT3502IMS#PBF be used in automotive applications?
Yes, the LT3502IMS#PBF is qualified for automotive applications: it operates across –40°C to 125°C junction temperature, supports 12V/24V battery inputs (3V–40V range), features AM-band–quiet 2.2MHz switching, and includes robust fault protection (UVLO, short-circuit foldback, thermal shutdown). These attributes are explicitly cited in the Applications list and Typical Application schematic (TA01a) for automotive systems.
LT3502IMS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- 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:
- 10-MSOP
LT3502IMS#PBF FAQ
1.How can I place an order for LT3502IMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3502IMS#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 LT3502IMS#PBF reliable?
The price and inventory of LT3502IMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3502IMS#PBF is usually 5 days.
3.What payment methods are accepted for LT3502IMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3502IMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3502IMS#PBF?
LT3502IMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3502IMS#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 LT3502IMS#PBF?
For technical support, including LT3502IMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3502IMS#PBF requirements.
6.How does Aetrix verify that LT3502IMS#PBF is sourced from the original manufacturer or authorized distributors?
All LT3502IMS#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 LT3502IMS#PBF meets industry standards.
7.What is the process for return or replacement of LT3502IMS#PBF?
All LT3502IMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3502IMS#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 LT3502IMS#PBF part is unused and in its original packaging.
Return procedure for LT3502IMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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