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Analog Devices Inc. LT3503EDCB#TRPBF
- Part No.:
- LT3503EDCB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 6-WFDFN Exposed Pad
- Datasheet:
-
LT3503EDCB#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1A 6DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,188
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Product details
Overview
LT3503EDCB#TRPBF from Analog Devices (formerly Linear Technology) is a 1.45A, 2.2MHz current-mode PWM step-down DC/DC converter with integrated bipolar NPN power switch, designed for compact, high-efficiency regulation from 3.6V to 20V inputs. It delivers up to 1.2A at 3.3V (VIN ≥ 5.5V) or 1A at 5V (VIN ≥ 7.2V), features 780mV feedback reference, <2µA shutdown current, and thermally enhanced 2mm × 3mm 6-pin DFN package - ideal for space-constrained industrial control supplies and battery-powered equipment.
For engineers reviewing the LT3503EDCB#TRPBF datasheet, LT3503EDCB#TRPBF pinout, LT3503EDCB#TRPBF application, or LT3503EDCB#TRPBF equivalent, key selection considerations include its fixed 2.2MHz switching frequency, internal compensation, soft-start via SHDN pin, cycle-by-cycle current limit, and thermal pad grounding requirement for reliable 1.2A continuous operation.
Technical Context
The LT3503EDCB#TRPBF employs constant-frequency current-mode control with slope compensation and an internal 1.45A/400mV VCE(SAT) bipolar NPN switch. Its oscillator operates at 2.2MHz under normal conditions but folds back to ~36kHz when FB voltage drops low - enabling controlled start-up and overload protection.
Regulation relies on a 780mV precision feedback reference, error amplifier servoing the VC node, and active clamp-based current limiting. The BOOST pin supplies elevated gate drive (≥2.3V above SW) via external capacitor/diode to ensure full saturation of the internal switch, while undervoltage lockout (UVLO = 3.4V typ.) prevents operation below 3.6V input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports wide-source regulation including wall adapters, automotive batteries, and distributed supplies. |
| Switching Frequency | 2.2MHz (typ.) - enables use of sub-3mm inductors and ceramic capacitors for ultra-compact layouts. |
| Feedback Reference | 780mV (±15mV) - sets output voltage via resistor divider; allows adjustable outputs down to 780mV. |
| Max Output Current | 1.2A continuous (at 3.3V, VIN ≥ 8.5V) - limited by thermal performance in 2mm × 3mm DFN with exposed GND pad. |
| Shutdown Current | <2µA - ensures true output disconnect and minimal battery drain in portable systems. |
| Current Limit | 1.45A (typ.), 1.75A (min.) - cycle-by-cycle protection against shorted outputs without external sensing. |
| Thermal Package | 6-pin DFN (2mm × 3mm, 0.75mm height) with exposed GND pad - requires PCB soldering for θJA = 64°C/W. |
Pinout & Package
LT3503EDCB#TRPBF is housed in a thermally enhanced 6-pin plastic DFN (2mm × 3mm) with exposed GND pad (Pin 7), which must be soldered to PCB ground for thermal and electrical integrity. Pin numbering follows top-view orientation per Linear Technology Datasheet 3503f.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Feedback input | Regulated to 780mV; sets output voltage via R1/R2 divider; bias current ≤150nA affects high-R divider accuracy. |
| GND (Pin 2) | Power and signal ground | Reference for FB, SHDN, and internal regulators; must connect to local low-impedance ground plane. |
| BOOST (Pin 3) | Bootstrap drive supply | Must be ≥2.3V above SW to fully saturate internal NPN switch; max voltage = 40V absolute. |
| SW (Pin 4) | Switch node | Connects to inductor, catch diode, and BOOST capacitor; carries high di/dt switching current. |
| VIN (Pin 5) | Main power input | Supplies internal regulator and power switch; requires local 1µF ceramic bypass near pin. |
| SHDN (Pin 6) | Shutdown and soft-start control | Logic-high (≥2.3V) enables operation; ramping voltage provides programmable soft-start; draws ≤15µA. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated current-mode control | Eliminates external compensation components; stable with ceramic output capacitors regardless of ESR. |
| 2.2MHz fixed-frequency operation | Reduces inductor size to ≤3.3µH and enables <1mm profile designs without sacrificing transient response. |
| Soft-start via SHDN pin | External RC network ramps SHDN voltage to limit inrush current; avoids input surge during power-up. |
| Cycle-by-cycle current limit | Protects against sustained short-circuit loads without foldback or hiccup; maintains regulation under overload. |
| Thermally optimized DFN package | Exposed GND pad enables direct thermal path to PCB; supports 1.2A continuous load at TA ≤ 85°C. |
Applications
| Industrial Control Supply | Battery-Powered Equipment |
|---|---|
|
Use Scenario: Powering microcontrollers, sensors, and I/O interfaces in programmable logic controllers (PLCs) with 12–24V DC rails. IC Role / Device Role / Timing Role: Primary 3.3V/5V point-of-load regulator delivering up to 1.2A with tight output ripple (<20mVPP) at 2.2MHz. Use Value: Enables compact, fanless enclosure design due to high-frequency operation and no need for heatsinking. |
Use Scenario: Regulating Li-ion battery (3.0–4.2V) or 9V alkaline input to stable 3.3V for portable medical monitors or handheld test instruments. IC Role / Device Role / Timing Role: High-efficiency buck converter with <2µA shutdown current to extend battery life between measurements. Use Value: Maintains >85% efficiency at 100mA–1A loads across battery discharge curve, minimizing heat and runtime loss. |
| Wall Transformer Regulation | Distributed Supply Regulation |
|
Use Scenario: Down-converting unregulated 9–18V AC/DC adapter outputs to clean 5V for USB peripherals or embedded gateways. IC Role / Device Role / Timing Role: Input-tolerant step-down regulator accepting up to 20V transient surges while maintaining regulated output. Use Value: Eliminates need for pre-regulator LDO stages; reduces BOM count and improves system efficiency by >15% vs. linear solution. |
Use Scenario: Local regulation of 12V or 24V backplane supplies to 3.3V for FPGA I/O banks or high-speed SerDes interfaces. IC Role / Device Role / Timing Role: Low-noise, fast-transient-response DC/DC converter with minimized layout-sensitive EMI emissions. Use Value: Achieves <100mV output deviation during 1A load steps (200ns rise time) using only 10µF ceramic output capacitance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8609ES5#TRPBF | 42V input, 2A sync rectified, 2MHz, 2.5µA quiescent current; requires external compensation. | Better suited for higher-input-voltage industrial or automotive systems requiring >20V tolerance. | Select if input exceeds 20V or synchronous rectification is required for >90% efficiency at light loads. |
| TPS62130ARGTR | 3–17V input, 3A sync buck, 2.5MHz, 17µA quiescent current; integrated MOSFETs, different pinout. | Higher current capability and smaller solution size, but lacks bipolar switch robustness under short-circuit stress. | Prefer for cost-sensitive consumer applications where 3A output and smaller footprint outweigh bipolar switch ruggedness. |
Compared with LT3503EDCB#TRPBF, LT8609ES5#TRPBF offers wider input range and lower IQ but demands external loop compensation, while TPS62130ARGTR delivers higher current and integration at the expense of reduced short-circuit robustness and non-pin-compatible layout.
Availability
LT3503EDCB#TRPBF is available at Aetrix Electronics and suitable for industrial control supplies, battery-powered equipment, and wall transformer regulation requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LT3503EDCB#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 with rigorous characterization and automotive-grade reliability testing.
The LT3503EDCB#TRPBF belongs to Linear's monolithic current-mode buck regulator product line, engineered for compact, high-frequency DC/DC conversion in space- and thermal-constrained environments where bipolar switch robustness is critical.
FAQ
What is the maximum continuous output current of the LT3503EDCB#TRPBF?
The LT3503EDCB#TRPBF delivers up to 1.2A continuously at 3.3V output when input voltage is ≥8.5V, and 1A at 5V output when input is ≥7.2V. This assumes proper PCB thermal design with the exposed GND pad soldered to a ≥1cm² copper area and ambient temperature ≤85°C. Derating applies above 85°C ambient.
Does the LT3503EDCB#TRPBF require external compensation components?
No, the LT3503EDCB#TRPBF is internally compensated and does not require external compensation components. Its current-mode architecture and built-in slope compensation ensure stability with ceramic output capacitors of any ESR value, simplifying design and reducing bill-of-materials cost.
How is soft-start implemented on the LT3503EDCB#TRPBF?
Soft-start on the LT3503EDCB#TRPBF is implemented by applying a voltage ramp to the SHDN pin using an external resistor and capacitor. When SHDN voltage rises slowly from 0V to ≥2.3V, the internal VC node ramps proportionally, limiting peak inductor current and preventing input current surge during startup.
What is the purpose of the BOOST pin on the LT3503EDCB#TRPBF?
The BOOST pin on the LT3503EDCB#TRPBF provides elevated gate drive voltage (≥2.3V above SW) to fully saturate the internal bipolar NPN power switch. It is charged via an external capacitor and diode from the SW node, enabling low VCE(SAT) (400mV at 1A) and high efficiency across the input range.
Can the LT3503EDCB#TRPBF operate with input voltages below 3.6V?
No, the LT3503EDCB#TRPBF has an undervoltage lockout threshold of 3.4V (typ.) and will not operate reliably below 3.6V input. Attempting to operate below this level disables switching and places the device in UVLO state, preventing regulation and protecting internal circuitry from unstable operation.
LT3503EDCB#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 6-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):
- 3.6V
- Voltage - Input (Max):
- 20V
- Voltage - Output (Min/Fixed):
- 0.78V
- Voltage - Output (Max):
- 16.2V
- Current - Output:
- 1A
- Frequency - Switching:
- 2.2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-DFN (2x3)
LT3503EDCB#TRPBF FAQ
1.How can I place an order for LT3503EDCB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3503EDCB#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 LT3503EDCB#TRPBF reliable?
The price and inventory of LT3503EDCB#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3503EDCB#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3503EDCB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3503EDCB#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3503EDCB#TRPBF?
LT3503EDCB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3503EDCB#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 LT3503EDCB#TRPBF?
For technical support, including LT3503EDCB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3503EDCB#TRPBF requirements.
6.How does Aetrix verify that LT3503EDCB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3503EDCB#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 LT3503EDCB#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3503EDCB#TRPBF?
All LT3503EDCB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3503EDCB#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 LT3503EDCB#TRPBF part is unused and in its original packaging.
Return procedure for LT3503EDCB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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