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Analog Devices Inc. LT3470AEDDB#TRPBF
- Part No.:
- LT3470AEDDB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3470AEDDB#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:12,688
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Product details
Overview
LT3470AEDDB#TRPBF 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 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®/continuous hybrid control, and draws only 35μA quiescent current - enabling long battery life in portable industrial sensors and automotive body electronics.
For engineers reviewing the LT3470AEDDB#TRPBF datasheet, LT3470AEDDB#TRPBF pinout, LT3470AEDDB#TRPBF application, or LT3470AEDDB#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed efficiency vs load curves, exact thermal pad grounding requirement, and two field-tested alternative regulators for 4V–40V buck applications requiring <1μA shutdown and integrated diodes.
Technical Context
The LT3470AEDDB#TRPBF uses hysteretic mode control with dual current comparators and an RS latch to regulate output voltage by dynamically adjusting switching frequency based on inductor value, input/output voltage, and load - eliminating need for external compensation. Its internal bipolar NPN switch is driven either from VIN or from a charge-pumped BOOST voltage generated via external 0.22μF capacitor and integrated Schottky diode.
Burst Mode® operation engages below ~10mA load to maintain regulation while minimizing quiescent current; continuous conduction resumes above that threshold. Fast current limiting (top limit = 440mA typ, bottom limit = 280mA typ) and automatic duty cycle clamping (95% max) provide robust short-circuit protection even at 40V input, with minimum off-time of 500ns ensuring stable operation during start-up and overload.
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 - sustained delivery enabled by integrated 440mA switch and low-loss catch/boost Schottky diodes. |
| Quiescent Current | 35μA at 12VIN/3.3VOUT - enables >1-year battery life in always-on sensor nodes with intermittent wake-up. |
| Shutdown Current | <1μA - disconnects load from input source, simplifying power sequencing in multi-rail systems. |
| Output Ripple | <10mVPP - achieved via low-noise hysteretic control and optional 22pF phase-lead capacitor on FB node. |
| Feedback Reference | 1.25V ±1.4% - sets output via resistor divider (VOUT = 1.25V × (1 + R1/R2)), enabling adjustable 1.25V–16V outputs. |
| Operating Temp | –40°C to +85°C - specified performance over full range; junction temp limited to 125°C with θJA = 80°C/W. |
Pinout & Package
LT3470AEDDB#TRPBF is housed in a thermally enhanced 8-lead plastic DFN package (3mm × 2mm, 0.75mm height) with exposed GND pad (Pin 9) requiring soldering to PCB for thermal and electrical integrity. Pin 7 (NC) may be left floating, tied to VIN, or grounded per layout needs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Feedback input | Regulates output by sensing divider tap; internal comparator holds at 1.25V - sets VOUT accuracy and loop stability. |
| BIAS (Pin 2) | Boost supply path | Connects to VOUT if >2.5V or VIN otherwise; supplies current to internal regulator when VBIAS >3V. |
| BOOST (Pin 3) | Charge-pump drive node | Generates >VIN voltage to fully saturate bipolar switch; must exceed SW by ≥2.5V for optimal efficiency. |
| SW (Pin 4) | Switch node | Drives external inductor and connects to internal catch diode anode and BOOST capacitor cathode. |
| GND (Pin 5) | Power ground | Reference for feedback divider and internal circuits; must tie to local ground plane under IC and components. |
| VIN (Pin 6) | Main input supply | Powers internal regulator and switch; requires local 1–2.2μF ceramic bypass capacitor near pin. |
| NC (Pin 7) | No connect | Unused terminal - may float, connect to VIN, or tie to GND without functional impact. |
| SHDN (Pin 8) | Enable/disable control | Logic-high (≥2V) enables regulation; grounded forces <1μA shutdown - no external pull-up required. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost & Catch Diodes | Eliminates 2 external Schottky diodes - reduces BOM count, PCB area (~50mm² solution), and EMI from discrete routing. |
| Hysteretic + Burst Mode Control | Enables ultra-low IQ at light loads while maintaining <10mV ripple - avoids audible ceramic capacitor noise typical of fixed-frequency controllers. |
| Wide Input Range (4V–40V) | Supports direct connection to automotive batteries (cold crank), industrial 24V rails, and legacy wall adapters without input filtering. |
| Thermally Enhanced DFN | 0.75mm profile with exposed GND pad achieves θJA = 80°C/W - sustains 250mA output without heatsink in compact enclosures. |
| Robust Short-Circuit Protection | Fast current limiting and 500ns minimum off-time prevent switch failure during 40V input shorts - no external current-sense resistor needed. |
Applications
| Automotive Body Control Module | Industrial Sensor Node |
|---|---|
Use Scenario: Powering CAN transceiver, microcontroller, and analog front-end from 12V vehicle battery with cold-crank tolerance down to 4V. IC Role / Device Role / Timing Role: Primary buck regulator providing stable 3.3V/250mA rail with <1μA shutdown during sleep mode. Use Value: Eliminates need for external boost diode and reduces solution size by 30% versus discrete alternatives - critical for space-constrained BCM housings. |
Use Scenario: Battery-powered wireless temperature/humidity sensor operating for >2 years on AA cells with periodic BLE transmission. IC Role / Device Role / Timing Role: Micropower DC/DC converter delivering regulated 3.3V from 2×AA (2.4V–3.2V) boosted to 4V–40V input range via external charge pump. Use Value: 35μA quiescent current extends battery life beyond 24 months; integrated diodes reduce leakage paths that degrade shelf life. |
| Portable Medical Monitor | Distributed 24V-to-5V Conversion |
Use Scenario: Powering OLED display, ADC, and low-power MCU in handheld patient monitor powered by rechargeable Li-ion pack. IC Role / Device Role / Timing Role: Efficient 5V/250mA supply with low output ripple to avoid noise coupling into sensitive analog measurement paths. Use Value: <10mV ripple eliminates need for post-regulator LDO - saving board space and thermal overhead in sealed medical enclosure. |
Use Scenario: Local point-of-load regulation for FPGA I/O banks or communication PHYs in industrial PLC backplane with 24V distributed supply. IC Role / Device Role / Timing Role: Compact 5V buck stage accepting wide-input 24V±20% with fast transient response to digital load steps. Use Value: Hysteretic control enables immediate response to load changes without compensation network - improves system-level signal integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar micropower buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3642EMSE#TRPBF | Higher 100V input rating, 400mA output, but requires external MOSFET and diodes - larger solution size and higher BOM cost. | Preferred for 48V telecom or PoE-powered equipment where input surge immunity is critical. | Select LTC3642EMSE#TRPBF only if input exceeds 40V or >250mA output is required; not drop-in compatible due to different pinout and external component requirements. |
| TPS62130ARGTR | Lower 3.4V–17V input range, 3A output, synchronous rectification - higher efficiency above 100mA but no integrated boost diode. | Better suited for high-current, narrow-input applications like USB-powered instrumentation where 40V tolerance is unnecessary. | Choose TPS62130ARGTR when efficiency >90% at 500mA is prioritized over wide-input operation and minimal external parts - requires redesign of boost circuitry. |
Compared with LTC3642EMSE#TRPBF and TPS62130ARGTR, the LT3470AEDDB#TRPBF uniquely balances ultra-wide 4V–40V input, integrated diodes, and sub-40μA quiescent current in a 2mm × 3mm footprint - making it optimal for space- and battery-limited designs where input voltage variability is high and external component count must be minimized.
Availability
LT3470AEDDB#TRPBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, and portable medical monitors requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LT3470AEDDB#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 full product support, datasheets, and application engineering for legacy Linear parts including the LT3470A series.
The LT3470A belongs to Linear's micropower DC/DC converter family designed specifically for battery-powered and wide-input industrial systems where integration, low IQ, and ruggedness outweigh raw efficiency metrics.
FAQ
What is the maximum output current capability of the LT3470AEDDB#TRPBF?
The LT3470AEDDB#TRPBF delivers up to 250mA continuously at 3.3V or 5V output across its 4V–40V input range. This is enabled by its integrated 440mA bipolar NPN power switch and low-dropout catch/boost Schottky diodes. Performance is validated per Electrical Characteristics table with 33μH inductor and proper thermal layout - exceeding 250mA risks thermal shutdown or reduced lifetime.
Does the LT3470AEDDB#TRPBF require an external boost capacitor, and what value is recommended?
Yes, the LT3470AEDDB#TRPBF requires an external capacitor between BOOST and SW pins to generate gate-drive voltage above VIN. A 0.22μF ceramic capacitor is recommended for outputs ≥3.3V (Figure 2a); use 0.47μF for 2.5V–3V outputs. The capacitor must be placed adjacent to the IC with short traces - insufficient boost voltage causes increased switch VCE(SAT) and reduced efficiency.
How does the LT3470AEDDB#TRPBF achieve low output ripple despite using hysteretic control?
The LT3470AEDDB#TRPBF achieves <10mV output ripple through combined design elements: hysteretic control minimizes switching jitter, integrated low-VF Schottky diodes reduce conduction loss, and optional 22pF phase-lead capacitor across the feedback divider suppresses comparator delay-induced ripple. These features eliminate need for external LC filters in most 250mA applications.
Can the LT3470AEDDB#TRPBF operate with input voltage below 4V?
No - the LT3470AEDDB#TRPBF has a 4V undervoltage lockout (UVLO) and cannot start or regulate below that threshold. Even with external boost circuitry, the internal bias regulator and switch driver require ≥4V to function. For sub-4V inputs, consider the LT3471 or LTC3642 with external FETs and bootstrap solutions.
What is the role of the exposed pad (Pin 9) on the LT3470AEDDB#TRPBF DFN package?
The exposed pad (Pin 9) on the LT3470AEDDB#TRPBF is electrically and thermally connected to GND and must be soldered to a solid PCB ground plane. It provides the primary thermal path (θJA = 80°C/W) and reduces junction temperature rise by up to 30°C under full 250mA load - omitting this connection violates Absolute Maximum Ratings and risks premature failure.
LT3470AEDDB#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):
- 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#TRPBF FAQ
1.How can I place an order for LT3470AEDDB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3470AEDDB#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 LT3470AEDDB#TRPBF reliable?
The price and inventory of LT3470AEDDB#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3470AEDDB#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3470AEDDB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3470AEDDB#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3470AEDDB#TRPBF?
LT3470AEDDB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3470AEDDB#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 LT3470AEDDB#TRPBF?
For technical support, including LT3470AEDDB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3470AEDDB#TRPBF requirements.
6.How does Aetrix verify that LT3470AEDDB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3470AEDDB#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 LT3470AEDDB#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3470AEDDB#TRPBF?
All LT3470AEDDB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3470AEDDB#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 LT3470AEDDB#TRPBF part is unused and in its original packaging.
Return procedure for LT3470AEDDB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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