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Analog Devices Inc. LT3470AEDDB#TRMPBF
- Part No.:
- LT3470AEDDB#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3470AEDDB#TRMPBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:272
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Product details
Overview
LT3470AEDDB#TRMPBF from Analog Devices (formerly Linear Technology) is a micropower step-down DC/DC converter with integrated 440mA bipolar NPN power switch, catch diode, and boost Schottky diode in a thermally enhanced 8-lead 2mm × 3mm DFN package. It delivers up to 250mA at 3.3V or 5V output across 4V–40V input, achieves <10mV output ripple via Burst Mode®/hysteretic control, and draws only 35μA quiescent current - enabling long battery life in portable industrial sensors and automotive body electronics.
For engineers reviewing the LT3470AEDDB#TRMPBF datasheet, LT3470AEDDB#TRMPBF pinout, LT3470AEDDB#TRMPBF application, or LT3470AEDDB#TRMPBF equivalent, key selection criteria include its 4V–40V wide input range, integrated diodes eliminating external components, 35μA operating quiescent current, <1μA shutdown current, and guaranteed operation from –40°C to +85°C in the E-grade variant.
Technical Context
The LT3470AEDDB#TRMPBF employs hysteretic mode control with dual current comparators and an RS latch to regulate output voltage by dynamically adjusting switching frequency based on load, input, and output conditions - no external compensation required. Its Burst Mode® operation enables low-noise, low-ripple regulation at light loads while transitioning seamlessly to continuous conduction above ~20mA.
Internal bipolar NPN switch saturation is actively managed via BOOST pin voltage monitoring: when boost capacitor voltage falls below ~1.8V, a 50mA internal current source pulls from BIAS to recharge it, ensuring reliable high-side drive across full input range. The device implements fast current limiting (top limit = 440mA typ, bottom limit = 280mA typ) and inherent short-circuit protection even at 40V input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 40V - supports 2-cell Li-ion, lead-acid, and unregulated wall adapters without external pre-regulation. |
| Output Current | 250mA max - sufficient for powering microcontrollers, RF transceivers, and analog front-ends in space-constrained systems. |
| Quiescent Current | 35μA at 12VIN/3.3VOUT - extends battery runtime in always-on sensor nodes and IoT edge devices. |
| Shutdown Current | <1μA - fully isolates load from input during system sleep, simplifying power sequencing. |
| Output Ripple | <10mV peak-to-peak - meets noise-sensitive analog supply requirements without additional LDO post-regulation. |
| Feedback Reference | 1.25V ±1.0% - enables precise programmable output from 1.25V to 16V using two external resistors. |
| Switch Current Limit | 440mA typical - provides robust overcurrent protection while supporting 33μH inductor designs for 40V input short-circuit resilience. |
| Package | 8-lead 2mm × 3mm DFN (DDB8), 0.75mm height - enables compact, thermally efficient layouts with exposed GND pad soldered to PCB. |
Pinout & Package
LT3470AEDDB#TRMPBF uses an 8-lead plastic DFN package (3mm × 2mm, 0.75mm height) with exposed thermal pad (Pin 9) that must be soldered to PCB ground for thermal and electrical performance. Pin 7 (NC) may be left floating, tied to VIN, or grounded per layout needs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (1) | Feedback input | Regulates output by holding voltage at 1.25V; connects to resistor divider tap - sets VOUT = 1.25V × (1 + R1/R2). |
| BIAS (2) | Boost regulator supply | Connects to VOUT if >2.5V (enables bias current sourcing); otherwise tie to VIN - powers internal regulator and BOOST circuit. |
| BOOST (3) | Charge pump drive | Provides >VIN voltage to saturate internal NPN switch; requires 0.22μF capacitor to SW - critical for efficiency at low VIN/VOUT ratios. |
| SW (4) | Switch node | Drives external inductor and catch diode; carries high dI/dt - must be routed with minimal loop area to reduce EMI. |
| GND (5) | Power and signal ground | Primary return path; connects to exposed pad (Pin 9) - must be solidly soldered to large PCB ground plane. |
| VIN (6) | Main input supply | Powers internal regulator and switch; requires local 1–2.2μF ceramic bypass - high-impedance sources need larger bulk capacitance. |
| NC (7) | No connect | Unused terminal - may float, tie to VIN, or ground; no internal connection or function. |
| SHDN (8) | Enable/shutdown control | Logic-high ≥2V enables operation; grounding disables all circuitry and reduces IIN to ~100nA - simplifies system-level power management. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost & catch diodes | Eliminates 2 external Schottky diodes - reduces solution size to ≤50mm² and component count in battery-powered designs. |
| Hysteretic + Burst Mode control | Delivers <10mV ripple at light loads without external compensation - ideal for noise-sensitive analog rails and low-power wake-up circuits. |
| Wide 4V–40V input range | Accepts direct connection to automotive batteries (cold crank), industrial 24V rails, and unregulated AC/DC adapters - avoids pre-regulator stage. |
| Thermally enhanced DFN package | θJA = 80°C/W with exposed pad soldered - sustains 250mA output at +85°C ambient without heatsink or airflow. |
| Fast current limiting & short-circuit protection | Withstands sustained 40V input short-circuit using ≥33μH inductor - protects IC and downstream circuitry without external current-sense components. |
| Low-profile 2mm × 3mm footprint | Enables placement under connectors or in stacked modules - critical for ultra-thin portable medical and handheld test equipment. |
Applications
| Automotive Body Electronics | Portable Industrial Sensors |
|---|---|
Use Scenario: Powering CAN transceiver, door module MCU, and LIN bus interface from vehicle battery (9V–16V nominal, up to 40V during load dump). IC Role / Device Role / Timing Role: Primary 3.3V/5V buck regulator supplying logic and communication ICs with tight ripple and high input voltage tolerance. Use Value: Eliminates need for discrete boost diode and external current-limiting circuitry - reduces BOM cost and improves reliability in harsh automotive environments. | Use Scenario: Regulating 3.3V for ultra-low-power wireless sensor node (BLE/Zigbee) powered by 2xAA alkaline or Li-SOCl₂ primary battery. IC Role / Device Role / Timing Role: Micropower DC/DC converter maintaining stable rail during 10μA sleep and 25mA transmit bursts. Use Value: 35μA quiescent current extends battery life to >10 years in duty-cycled sensing applications - outperforms standard buck controllers by 3×. |
| Distributed Power Supplies | Wall Adapter-Fed Embedded Systems |
Use Scenario: Local 5V regulation for FPGA I/O banks or ADC reference supplies in multi-rail industrial PLC backplane. IC Role / Device Role / Timing Role: Point-of-load converter accepting 12V–24V intermediate bus and delivering clean, low-noise 5V. Use Value: Integrated diodes and hysteretic control eliminate external compensation and reduce layout sensitivity - accelerates design validation. | Use Scenario: Stepping down noisy, unregulated 9V–12V wall adapter output to stable 3.3V for embedded Linux SBC or network controller. IC Role / Device Role / Timing Role: Input-tolerant buck regulator providing regulated rail despite poor line regulation and high ripple from low-cost adapters. Use Value: 40V absolute maximum rating and fast current limiting prevent failure during adapter plug-in transients - improves field reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3471EDDB#TRMPBF | Higher 600mA switch current limit; identical pinout and package; same 4V–40V input range but 50μA quiescent current. | Supports higher output current (350mA) and heavier transient loads - suitable where 250mA margin is insufficient. | Select LT3471EDDB#TRMPBF when load current exceeds 250mA or peak transients demand >440mA switch capability. |
| TPS63020DSJR | Buck-boost topology; 1.8V–5.5V input; 2.5V–5.5V output; 3A switch; 25μA quiescent current; 3mm × 2mm QFN. | Operates down to 1.8V input - supports single-cell Li-ion or NiMH battery operation where LT3470AEDDB#TRMPBF cannot start. | Choose TPS63020DSJR for single-cell battery systems requiring regulation across full discharge curve; not drop-in due to different topology and pinout. |
Compared with LT3470AEDDB#TRMPBF, LT3471EDDB#TRMPBF offers higher current headroom with identical footprint and voltage range, while TPS63020DSJR enables true single-cell compatibility at the cost of topology change and loss of 40V input tolerance - selection depends on whether input range or minimum startup voltage dominates the design requirement.
Availability
LT3470AEDDB#TRMPBF is available at Aetrix Electronics and suitable for automotive body electronics, portable industrial sensors, and distributed power supplies requiring stable component supply, extended temperature operation (–40°C to +85°C), and long-term lifecycle support.
Supply support for LT3470AEDDB#TRMPBF 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 precision power management portfolio with full datasheet, simulation model, and application support.
The LT3470A series was designed specifically for micropower, wide-input-voltage buck conversion in space- and energy-constrained systems - emphasizing integration (diodes, switch), ultra-low quiescent current, and robustness in automotive and industrial environments.
FAQ
What is the minimum input voltage required for LT3470AEDDB#TRMPBF to regulate 3.3V output?
The LT3470AEDDB#TRMPBF requires a minimum input voltage of approximately 4.0V to regulate 3.3V output at full 250mA load, constrained by its 4V undervoltage lockout and 90% maximum duty cycle. At lighter loads, startup is possible down to ~3.5V depending on boost capacitor charge state and inductor value - verified in Typical Performance Characteristic Figure 3a.
Can LT3470AEDDB#TRMPBF operate with a 2.5V output, and what are the BIAS pin requirements?
Yes, LT3470AEDDB#TRMPBF supports 2.5V output via FB resistor divider (VOUT = 1.25V × (1 + R1/R2)). For outputs ≤2.5V, the BIAS pin must be tied to VIN - not VOUT - because internal bias current sourcing requires VBIAS > 3V, which is unavailable at 2.5V output. This is explicitly specified in the PIN FUNCTIONS section.
How does the BOOST pin function in LT3470AEDDB#TRMPBF, and what capacitor value is recommended?
The BOOST pin in LT3470AEDDB#TRMPBF connects to an external 0.22μF capacitor between BOOST and SW to generate a voltage >VIN for full saturation of the internal bipolar NPN switch. For 3.3V+ outputs, the standard configuration (BOOST tied to SW via capacitor) is used; for 2.5V–3V outputs, 0.47μF is recommended per Applications Information Section.
Is LT3470AEDDB#TRMPBF pin-compatible with LT3470EDDB#TRMPBF, and what are the key improvements?
Yes, LT3470AEDDB#TRMPBF is pin-compatible and footprint-compatible with LT3470EDDB#TRMPBF. Key improvements include higher output current capability (250mA vs 200mA), improved startup behavior at low input voltages, lower dropout voltage, and enhanced thermal performance - all documented in the product description and Electrical Characteristics tables.
What is the thermal resistance (θJA) of LT3470AEDDB#TRMPBF, and how should the exposed pad be handled?
The LT3470AEDDB#TRMPBF has θJA = 80°C/W when the exposed pad (Pin 9) is soldered to a minimum 100mm² PCB copper area. The datasheet mandates soldering this pad to PCB ground for both thermal dissipation and electrical stability - leaving it unconnected degrades thermal performance by >40°C/W and risks oscillation.
LT3470AEDDB#TRMPBF 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):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 16V
- Current - Output:
- 250mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (3x2)
LT3470AEDDB#TRMPBF FAQ
1.How can I place an order for LT3470AEDDB#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3470AEDDB#TRMPBF 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 LT3470AEDDB#TRMPBF reliable?
The price and inventory of LT3470AEDDB#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3470AEDDB#TRMPBF is usually 5 days.
3.What payment methods are accepted for LT3470AEDDB#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3470AEDDB#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3470AEDDB#TRMPBF?
LT3470AEDDB#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3470AEDDB#TRMPBF 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 LT3470AEDDB#TRMPBF?
For technical support, including LT3470AEDDB#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3470AEDDB#TRMPBF requirements.
6.How does Aetrix verify that LT3470AEDDB#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LT3470AEDDB#TRMPBF 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 LT3470AEDDB#TRMPBF meets industry standards.
7.What is the process for return or replacement of LT3470AEDDB#TRMPBF?
All LT3470AEDDB#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3470AEDDB#TRMPBF, 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 LT3470AEDDB#TRMPBF part is unused and in its original packaging.
Return procedure for LT3470AEDDB#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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