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Analog Devices Inc. LT3502EMS#TRPBF
- Part No.:
- LT3502EMS#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT3502EMS#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 500MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,671
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Product details
Overview
LT3502EMS#TRPBF from Analog Devices (formerly Linear Technology) is a current-mode PWM step-down DC/DC converter with an integrated 500mA bipolar NPN power switch, designed for industrial and automotive power regulation in compact MSOP-10 packages. It operates from 3V to 40V input, delivers up to 500mA output at 3.3V or 5V, switches at 1.1MHz (LT3502 variant), and features internal compensation, soft-start, and cycle-by-cycle current limiting - enabling robust 24V rail conversion in space-constrained control modules.
For engineers reviewing the LT3502EMS#TRPBF datasheet, LT3502EMS#TRPBF pinout, LT3502EMS#TRPBF application, or LT3502EMS#TRPBF equivalent, key selection considerations include its 1.1MHz fixed-frequency operation (vs. 2.2MHz LT3502A), MSOP-10 thermal performance (θJA = 110°C/W), 0.8V feedback reference, and DA-pin–enabled frequency foldback for short-circuit resilience in battery-fed systems.
Technical Context
The LT3502EMS#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, supplied via an external capacitor and internal Schottky diode connected to the BD pin.
Protection architecture combines cycle-by-cycle switch current limit (typ. 0.9A), DA-pin–monitored valley current foldback (650mA threshold), and undervoltage lockout (~2.8V). Soft-start is implemented by ramping the SHDN pin voltage, which simultaneously controls VC node clamping and oscillator frequency reduction during startup.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 40V - supports direct connection to 24V industrial rails and automotive batteries without pre-regulation. |
| Output Current | 500mA continuous - sufficient for powering microcontrollers, sensors, and interface ICs in embedded systems. |
| Switching Frequency | 1.1MHz - enables use of sub-10µH inductors and reduces EMI above AM band (530–1710kHz). |
| Feedback Voltage | 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 - preserves battery life in always-on monitoring nodes during deep sleep. |
| Max Duty Cycle | 90% - allows regulation down to ~3.7V input for 3.3V output (accounting for VSW and diode drops). |
| Junction Temp Range | –40°C to 125°C - qualified for under-hood automotive and industrial control environments. |
Pinout & Package
LT3502EMS#TRPBF uses a thermally enhanced 10-lead plastic MSOP package (3mm × 3mm, 0.85mm height) with exposed pad soldered to PCB ground for θJA = 110°C/W. Pin numbering follows top-view MSOP standard (Pin 1 = SW, Pin 10 = VIN).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 10) | Main power input | Supplies internal regulator and switch; must be bypassed with ≥1µF X7R ceramic close to pin. |
| SW (Pin 1) | Switch node | Connects to inductor, catch diode cathode, and BOOST capacitor; carries high di/dt switching current. |
| BOOST (Pin 2) | Boost drive supply | Provides >VIN voltage to switch driver; requires capacitor to SW (min. 0.1µF) for NPN saturation. |
| BD (Pin 8) | Boost diode anode | Internal Schottky anode; tie to VIN or external bias source ≥2.2V above SW for low-VOUT designs. |
| FB (Pin 7) | Feedback input | Servo point for 0.8V reference; connects to resistor divider tap; bias current ≤50nA minimizes error. |
| SHDN (Pin 6) | Enable/soft-start control | Logic-high (>2V) enables operation; RC ramp here controls startup current and prevents overshoot. |
| GND (Pin 5) | Power and signal ground | Common return for switch, feedback, and internal regulator; exposed pad must be soldered to PCB GND plane. |
| DA (Pin 4) | Diode anode monitor | Detects catch diode conduction; triggers frequency foldback when valley current exceeds 650mA. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated | Eliminates need for external compensation network - reduces BOM count and layout sensitivity in cost-sensitive designs. |
| Internal boost diode | Reduces component count by integrating Schottky diode for BOOST capacitor charging - simplifies layout and improves reliability. |
| Frequency foldback | Automatically lowers switching frequency during overload or short-circuit to limit power dissipation and maintain regulation. |
| Soft-start via SHDN pin | Enables controlled output ramp-up using external RC; prevents inrush current and output overshoot in battery-powered systems. |
| Short-circuit robustness | Withstands sustained output shorts via combined peak switch limit (0.9A) and DA-valley foldback (650mA) - no external current sense needed. |
Applications
| Industrial Sensor Node Power | Automotive Body Control Module |
|---|---|
|
Use Scenario: Regulating 24V vehicle battery to 3.3V for CAN transceiver and microcontroller in door module. IC Role / Device Role / Timing Role: Primary buck converter supplying core logic power; operates continuously across cold-crank (6V) to load-dump (40V) conditions. Use Value: 1.1MHz switching avoids AM-band interference; frequency foldback maintains safe junction temperature during lamp-load surges. |
Use Scenario: Powering HVAC controller from 12V battery with transient immunity during ignition. IC Role / Device Role / Timing Role: Input-stage DC/DC regulator handling wide VIN range (6V–36V) and reverse-polarity protection via external diode. Use Value: 0.8V FB reference enables precise 3.3V/5V outputs; shutdown current <2µA extends battery life in sleep mode. |
| Programmable Logic Controller I/O Supply | Factory Automation Fieldbus Interface |
|
Use Scenario: Generating isolated 5V rail for digital I/O drivers in DIN-rail mounted PLC. IC Role / Device Role / Timing Role: Non-isolated intermediate regulator feeding isolated DC/DC; handles 24V nominal with 40V surge tolerance. Use Value: MSOP-10 package fits dense PCB layouts; internal compensation eliminates tuning effort during production ramp. |
Use Scenario: Powering RS-485 transceivers and optocouplers in PROFIBUS DP slave node. IC Role / Device Role / Timing Role: Point-of-load regulator delivering clean 3.3V with low noise and fast transient response. Use Value: 100mV p-p output ripple (typ.) at 500mA ensures signal integrity; DA-pin foldback prevents latch-up during bus faults. |
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#TRPBF | 2.2MHz switching frequency, 80% max duty cycle, tighter FB tolerance (±1.5% vs. ±1.6%). | Better suited for ultra-compact designs requiring <4.7µH inductors and stricter EMI control above 2MHz. | Select LT3502AEMS#TRPBF when board area is constrained and higher frequency improves filter size/cost. |
| LMR14050SDDAR | 500mA synchronous buck, 40V max VIN, 2.1MHz freq, integrated high/low-side MOSFETs, 45µA quiescent current. | Lacks DA-pin foldback; relies on hiccup-mode overcurrent protection; lower IQ benefits always-on IoT nodes. | Choose LMR14050SDDAR where efficiency at light loads matters more than short-circuit survival under high VIN. |
Compared with LT3502EMS#TRPBF, LT3502AEMS#TRPBF trades higher frequency for reduced solution size but sacrifices maximum duty cycle headroom, while LMR14050SDDAR offers superior light-load efficiency and integration at the cost of fault-handling granularity and bipolar-switch ruggedness.
Availability
LT3502EMS#TRPBF is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body controllers, and factory automation interfaces requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for LT3502EMS#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 its legacy of high-performance analog and power management ICs for demanding applications.
The LT3502 series was developed specifically for wide-input industrial and automotive DC/DC conversion where reliability under voltage transients and compact solution size are critical design constraints.
FAQ
What is the switching frequency of the LT3502EMS#TRPBF?
The LT3502EMS#TRPBF operates at a fixed 1.1MHz switching frequency. This frequency is inherent to the LT3502 variant (as opposed to the LT3502A's 2.2MHz) and is not adjustable. It enables use of small inductors and capacitors while staying above the AM radio band to avoid interference - a key requirement in automotive and industrial environments where the LT3502EMS#TRPBF is commonly deployed.
Does the LT3502EMS#TRPBF require an external catch diode?
Yes, the LT3502EMS#TRPBF requires an external Schottky catch diode connected between SW and GND. The device does not integrate a synchronous rectifier; instead, it relies on an external diode (e.g., Diodes Inc. DFLS140 or ON Semi MBRM140) rated for ≥40V reverse voltage and ≥500mA average current. This diode works with the DA pin to enable valley-current–based frequency foldback during overload conditions - a core protection feature of the LT3502EMS#TRPBF.
What is the purpose of the DA pin on the LT3502EMS#TRPBF?
The DA (Diode Anode) pin on the LT3502EMS#TRPBF monitors current through the external catch diode. When valley current exceeds 650mA, the DA comparator triggers frequency foldback - reducing switching frequency to limit power dissipation during short-circuit or heavy overload. This behavior is distinct from the cycle-by-cycle peak current limit and provides graded fault response without shutdown, enhancing system robustness. The DA pin must be connected directly to the cathode of the catch diode in all LT3502EMS#TRPBF applications.
Can the LT3502EMS#TRPBF be used with a 3.3V input?
No, the LT3502EMS#TRPBF cannot regulate from a 3.3V input. Its undervoltage lockout activates below ~2.8V, and minimum operating input is specified as 3V. More critically, with a 3.3V input and typical 0.45V switch drop + 0.4V diode drop, the achievable output is limited to ~2.45V - below the 3.3V or 5V targets it's designed for. For low-input applications, consider the LT3502EMS#TRPBF only with VIN ≥5V (for 3.3V output) or ≥7V (for 5V output), per its duty-cycle and dropout constraints.
How is soft-start implemented on the LT3502EMS#TRPBF?
Soft-start on the LT3502EMS#TRPBF is implemented by applying a voltage ramp to the SHDN pin using an external resistor and capacitor. When SHDN rises from 0V to >2V, the internal VC node is clamped to this ramp, delaying full regulation and limiting peak inrush current. A typical RC network (e.g., 100kΩ + 100nF) yields ~10ms ramp time. This method avoids output overshoot and reduces stress on input capacitors - especially valuable in battery-powered systems where the LT3502EMS#TRPBF supplies microcontrollers or RF modules.
LT3502EMS#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- 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:
- 10-MSOP
LT3502EMS#TRPBF FAQ
1.How can I place an order for LT3502EMS#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3502EMS#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 LT3502EMS#TRPBF reliable?
The price and inventory of LT3502EMS#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3502EMS#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3502EMS#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3502EMS#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3502EMS#TRPBF?
LT3502EMS#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3502EMS#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 LT3502EMS#TRPBF?
For technical support, including LT3502EMS#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3502EMS#TRPBF requirements.
6.How does Aetrix verify that LT3502EMS#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3502EMS#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 LT3502EMS#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3502EMS#TRPBF?
All LT3502EMS#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3502EMS#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 LT3502EMS#TRPBF part is unused and in its original packaging.
Return procedure for LT3502EMS#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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