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Analog Devices Inc. LT3470AHDDB#TRPBF
- Part No.:
- LT3470AHDDB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3470AHDDB#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,679
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Product details
Overview
LT3470AHDDB#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 3mm × 2mm DFN package. It delivers up to 250mA at 3.3V or 5V over 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 LT3470AHDDB#TRPBF datasheet, LT3470AHDDB#TRPBF pinout, LT3470AHDDB#TRPBF application, or LT3470AHDDB#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed thermal performance (–40°C to 150°C), real-world efficiency curves, and two rigorously cross-checked alternative regulators for high-input-voltage buck conversion.
Technical Context
The LT3470AHDDB#TRPBF uses hysteretic mode control with dual current comparators and an RS latch to regulate output voltage by dynamically adjusting switching frequency and burst intervals. Its internal bipolar NPN switch is driven either from VIN or a charge-pumped BOOST voltage (>2.5V above SW), enabling full saturation even at low input voltages.
It combines low-ripple Burst Mode® operation at light loads (<10mA) with continuous conduction at higher loads, supported by independent top (440mA typ.) and bottom (280mA typ.) current limits. Startup and dropout are enhanced versus LT3470 via improved boost circuit sensitivity and reduced minimum input voltage requirements across 3.3V/5V outputs.
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 at 3.3V (4V–40V input) or 5V (5.7V–40V input) with thermal derating per junction temp. |
| Quiescent Current | 35μA typical at 12VIN→3.3VOUT - enables >1-year battery life in always-on sensor nodes. |
| Shutdown Current | <1μA - disconnects load from input, simplifying power sequencing in multi-rail systems. |
| Output Ripple | <10mVPP - achieved via low-ESR capacitor support and phase-lead compensation (22pF FB-to-VOUT). |
| Operating Temp | –40°C to +150°C (H-grade) - qualified for under-hood automotive and industrial motor control environments. |
| Switch VCE(SAT) | 150mV at 100mA - minimizes conduction loss and improves efficiency at mid-load conditions. |
| Feedback Reference | 1.25V ±1.0% - sets output via external resistor divider (VOUT = 1.25V × (1 + R1/R2)). |
Pinout & Package
LT3470AHDDB#TRPBF is housed in an 8-lead, 3mm × 2mm, 0.75mm-profile plastic DFN (DDB8) with exposed pad (Pin 9) soldered to PCB ground for thermal management (θJA = 80°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Feedback input | Regulates output by holding voltage at 1.25V; connects to resistor divider tap - determines VOUT accuracy and loop stability. |
| BIAS (Pin 2) | Bias supply input | Connects to VOUT if >2.5V (enables internal regulator preload); supplies current to boost circuit when VBIAS >3V. |
| BOOST (Pin 3) | Charge-pump drive node | Accepts externally charged capacitor (0.22μF) to generate >VIN voltage - ensures full NPN switch saturation for low VCE(SAT). |
| SW (Pin 4) | Switch node | Connects to inductor, catch diode cathode, and BOOST capacitor - carries high di/dt switching current; requires minimal loop area. |
| GND (Pin 5) | Power ground | Primary return path for switch, catch diode, and feedback network - must tie to local ground plane and output capacitor ground. |
| VIN (Pin 6) | Main input supply | Supplies internal regulator and power switch - requires local 1–2.2μF ceramic bypass near pin to suppress EMI and input ripple. |
| NC (Pin 7) | No-connect | May be left floating, tied to VIN, or grounded - no electrical function; used for mechanical symmetry in DFN layout. |
| SHDN (Pin 8) | Shutdown control | Logic-level enable: <0.2V = shutdown (<1μA IQ), ≥2V = active - ties to VIN if unused to ensure default operation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost & catch diodes | Eliminates 2 external Schottky diodes - reduces BOM count, PCB area (~50mm² solution), and assembly cost. |
| Hysteretic + Burst Mode control | Enables ultra-low IQ (35μA) while maintaining <10mV ripple - avoids audible ceramic capacitor noise and complex compensation. |
| Wide input range (4V–40V) | Supports direct regulation from automotive batteries (9V–16V), industrial 24V rails, and legacy 36V systems without pre-buck stage. |
| Thermally enhanced H-grade | Rated for –40°C to +150°C junction - enables placement near heat sources (e.g., motor drivers, power converters) without derating. |
| Fast short-circuit protection | Hysteretic current limiting and 500ns min off-time prevent switch overstress during 40V input faults - no external current sense needed. |
| Low-profile DFN package | 0.75mm height and 3mm × 2mm footprint - suitable for space-constrained modules like IoT edge nodes and automotive ECUs. |
Applications
| Automotive Body Control Module | Industrial Sensor Node |
|---|---|
Use Scenario: Powering microcontroller, CAN transceiver, and analog front-end in door module with 12V battery input subject to load dump (up to 40V). IC Role / Device Role / Timing Role: Primary 3.3V/250mA buck regulator providing stable rail during cold crank (4.5V) and load dump (40V). Use Value: Eliminates need for external TVS and pre-regulator; H-grade rating ensures operation at 150°C near door latch actuator. |
Use Scenario: Battery-powered vibration sensor with LoRaWAN radio, operating continuously on 2xAA alkaline cells (1.8V–3.2V) boosted to 4.5V input via external charge pump. IC Role / Device Role / Timing Role: Secondary 3.3V regulator delivering 150mA to MCU and RF IC with ultra-low IQ to extend 5-year battery life. Use Value: 35μA quiescent current and <1μA shutdown reduce average system IQ below 10μA - critical for energy harvesting compatibility. |
| Distributed Power Supply | Wall Adapter Regulation |
Use Scenario: Point-of-load regulation for FPGA I/O bank (1.8V/200mA) fed from 12V intermediate bus in telecom shelf. IC Role / Device Role / Timing Role: Compact, efficient buck converter replacing larger discrete solutions - placed directly on FPGA carrier board. Use Value: Integrated diodes and 50mm² solution size minimize PCB real estate; 80°C/W θJA allows natural convection cooling. |
Use Scenario: Regulating noisy, unregulated 9–24V AC/DC wall adapter output to clean 5V/250mA for USB peripheral hub. IC Role / Device Role / Timing Role: Input-tolerant buck converter absorbing line transients and reducing conducted EMI into downstream devices. Use Value: 40V absolute max input withstands adapter surges; low ESR capacitor support ensures <10mV ripple on USB data lines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar micropower buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3692EMSE#TRPBF | Higher 500mA output, wider 3.5V–60V input, but larger 16-lead MSOP package and 100μA IQ. | Preferred for >300mA loads or >40V inputs (e.g., 48V industrial buses); less suitable for ultra-low-power or space-constrained designs. | Select when output current >250mA or input exceeds 40V is required - not drop-in due to different pinout and layout. |
| TPS62840DRVR | Lower 1.8V–6.5V input, 1.8V–5.5V output, 750mA capability, 300nA IQ, but lacks integrated diodes and requires external catch diode. | Better for single-cell Li-ion (2.5V–4.2V) systems needing sub-μA sleep; unsuitable for 40V input or diode-integration requirement. | Choose for battery-only applications where ultra-low IQ dominates - requires redesign for diode placement and thermal management. |
Compared with LT3470AHDDB#TRPBF, LT3692EMSE#TRPBF trades higher current and input range for larger size and higher quiescent current, while TPS62840DRVR offers nanoscale IQ but sacrifices input voltage capability and integration - making LT3470AHDDB#TRPBF optimal for 4V–40V, 250mA, space-limited industrial and automotive use cases.
Availability
LT3470AHDDB#TRPBF is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor nodes, distributed power supplies, and wall adapter regulation requiring stable component supply across extended temperature and high-reliability production cycles.
Supply support for LT3470AHDDB#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 high-performance power management portfolio with rigorous automotive and industrial qualification standards.
The LT3470A series was designed specifically for micropower, wide-input-voltage buck conversion in harsh environments - targeting automotive subsystems, industrial sensors, and legacy power infrastructure where reliability across –40°C to +150°C is non-negotiable.
FAQ
What is the maximum ambient temperature for continuous operation of the LT3470AHDDB#TRPBF?
The LT3470AHDDB#TRPBF is rated for continuous operation from –40°C to +150°C junction temperature. With θJA = 80°C/W and typical PCB copper area, it supports ambient temperatures up to +105°C at full 250mA load. Derating is required above that point - full specifications are guaranteed only within the –40°C to +150°C junction range stated in the LT3470AHDDB#TRPBF datasheet.
Does the LT3470AHDDB#TRPBF require an external catch diode?
No, the LT3470AHDDB#TRPBF integrates a Schottky catch diode - confirmed in the "Features" section and Electrical Characteristics table (Catch Schottky Drop = 600mV at 100mA). This eliminates the need for an external diode, reducing solution size and BOM count. The BOOST and SW pins connect directly to the inductor and output capacitor as shown in the Typical Application schematic.
How does the LT3470AHDDB#TRPBF achieve 35μA quiescent current?
The LT3470AHDDB#TRPBF achieves 35μA quiescent current through Burst Mode® operation: at light loads, it enters micropower state where most internal circuitry is disabled, waking only periodically to deliver small energy packets. This is distinct from continuous PWM and is explicitly measured in the Electrical Characteristics table under "Quiescent Current from VIN" at TA = 25°C with VSHDN = 0.2V.
Can the LT3470AHDDB#TRPBF operate with a 3.3V output from a 4V input?
Yes - the LT3470AHDDB#TRPBF is specified to deliver 3.3V at 250mA from a 4V to 40V input, as stated in the "Features" list and validated in Figure 3a (Minimum Input Voltage, VOUT = 3.3V). At 4V input, it operates near maximum duty cycle (90%), relying on low VCE(SAT) (150mV) and integrated boost to maintain regulation without dropout.
What is the function of the NC pin (Pin 7) on the LT3470AHDDB#TRPBF?
The NC (No Connect) pin (Pin 7) on the LT3470AHDDB#TRPBF has no internal connection and serves only mechanical/thermal purposes in the DFN package. As documented in the Pin Functions section, it may be left floating, tied to VIN, or connected to GND - none of these configurations affect electrical performance, but grounding may slightly improve thermal dissipation in high-power layouts.
LT3470AHDDB#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:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (3x2)
LT3470AHDDB#TRPBF FAQ
1.How can I place an order for LT3470AHDDB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3470AHDDB#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 LT3470AHDDB#TRPBF reliable?
The price and inventory of LT3470AHDDB#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3470AHDDB#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3470AHDDB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3470AHDDB#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3470AHDDB#TRPBF?
LT3470AHDDB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3470AHDDB#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 LT3470AHDDB#TRPBF?
For technical support, including LT3470AHDDB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3470AHDDB#TRPBF requirements.
6.How does Aetrix verify that LT3470AHDDB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3470AHDDB#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 LT3470AHDDB#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3470AHDDB#TRPBF?
All LT3470AHDDB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3470AHDDB#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 LT3470AHDDB#TRPBF part is unused and in its original packaging.
Return procedure for LT3470AHDDB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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