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Analog Devices Inc. LT3470AHDDB#TRMPBF
- Part No.:
- LT3470AHDDB#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT3470AHDDB#TRMPBF.pdf
- Description:
- IC REG BUCK ADJ 250MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:449
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Product details
Overview
LT3470AHDDB#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 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, features 35μA quiescent current in regulation, <10mV output ripple, and hysteretic/Burst Mode® control for ultra-low-power portable battery systems.
For engineers reviewing the LT3470AHDDB#TRMPBF datasheet, LT3470AHDDB#TRMPBF pinout, LT3470AHDDB#TRMPBF application, or LT3470AHDDB#TRMPBF equivalent, this page provides verified technical context, validated pin functions, confirmed thermal grade (–40°C to 150°C), real-world efficiency curves, and two rigorously cross-checked alternative regulators for automotive battery regulation and industrial supply designs.
Technical Context
The LT3470AHDDB#TRMPBF uses a hysteretic control architecture with dual current comparators and an RS latch to regulate output by dynamically adjusting switching frequency based on inductor value, input/output voltage, and load-enabling both Burst Mode® operation at light loads (<10mA) and continuous conduction above ~50mA. Its internal bipolar NPN switch requires BOOST pin voltage ≥2.5V above SW to achieve full saturation (VCESAT ≤150mV at 100mA).
Startup and dropout performance are enhanced over LT3470 via improved minimum boost voltage (1.7V typ), higher top current limit (440mA typ), and tighter FB comparator trip voltage (1.250V ±12.5mV). The H-grade variant guarantees all electrical specifications over –40°C to 150°C junction temperature, with θJA = 80°C/W and exposed pad (Pin 9) required as GND connection for thermal management.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 40V - supports 2-cell Li-ion, lead-acid, and unregulated wall transformers 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 H-grade rating. |
| Quiescent Current | 35μA at 12VIN→3.3VOUT - enables multi-year battery life in always-on sensor nodes and low-duty-cycle IoT devices. |
| Shutdown Current | <1μA - disconnects load from input source, simplifying power sequencing in battery-powered systems. |
| FB Reference Voltage | 1.250V ±12.5mV - sets output via external resistor divider (VOUT = 1.25V × (1 + R1/R2)), stable over full H-grade temperature range. |
| Switch Top Current Limit | 440mA typical - provides short-circuit protection at 40V input when paired with ≥33μH inductor (ISAT ≥450mA). |
| Output Ripple | <10mV peak-to-peak - achieved with low-ESR output capacitor (≤150mΩ) and optional 22pF phase-lead capacitor on FB node. |
| Package | 8-lead 2mm × 3mm DFN (DDB8), 0.75mm height, exposed pad (Pin 9) - thermally enhanced for high ambient industrial environments. |
Pinout & Package
LT3470AHDDB#TRMPBF uses a low-profile 8-lead (3mm × 2mm) plastic DFN package (DDB8) with exposed thermal pad (Pin 9) that must be soldered to PCB ground for thermal and electrical integrity. θJA = 80°C/W. Maximum junction temperature: 150°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Feedback input | Regulates output by holding voltage at 1.25V; connects to resistor divider tap; bias current flows out (35nA typ at H-grade). |
| BIAS (Pin 2) | Boost regulator supply | Tied to VOUT if >2.5V or VIN otherwise; supplies current to internal regulator when VBIAS >3V; preload capability up to 50mA. |
| BOOST (Pin 3) | Boost capacitor node | Drives internal switch gate above VIN; requires ≥0.22μF capacitor to SW; must exceed SW by ≥2.5V for full saturation. |
| SW (Pin 4) | Switch node | Connects to inductor, catch diode cathode, and boost capacitor; carries pulsed high-current switching waveform. |
| GND (Pin 5) | Power and signal ground | Return path for feedback divider and internal circuits; must connect to local ground plane under IC and components. |
| VIN (Pin 6) | Main input supply | Supplies internal regulator and power switch; requires local 1–2.2μF ceramic bypass capacitor near pin. |
| NC (Pin 7) | No-connect | May be left floating, tied to VIN, or grounded; no internal connection; no electrical function. |
| SHDN (Pin 8) | Shutdown control | Logic-high (≥2V) enables operation; logic-low (≤0.2V) disables all circuitry, reducing VIN current to ~100nA. |
| Exposed Pad (Pin 9) | Thermal & electrical ground | Mandatory GND connection for heat dissipation and EMI reduction; must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated power train | 440mA bipolar NPN switch + monolithic catch Schottky + boost Schottky eliminates 3 external components and reduces solution size to 50mm². |
| Hysteretic + Burst Mode® control | Enables ultra-low-noise, low-ripple regulation at light loads while maintaining fast transient response and automatic short-circuit foldback. |
| Wide input range with robust protection | 4V–40V operation with fast current limiting, 47V BOOST pin rating, and 40V VIN absolute max withstands load dump and hot-plug transients. |
| H-grade temperature rating | Full specification guarantee from –40°C to 150°C junction temperature - qualified for under-hood automotive and industrial control cabinet use. |
| Low-profile thermally enhanced package | 2mm × 3mm DFN with exposed pad achieves θJA = 80°C/W - enables high-power density in space-constrained portable and embedded systems. |
Applications
| Automotive Battery Regulation | Portable Medical Sensors |
|---|---|
Use Scenario: Regulating 12V vehicle battery (8V–16V nominal, up to 40V during load dump) to 3.3V for microcontroller and CAN transceiver. IC Role / Device Role / Timing Role: Primary buck regulator providing isolated, low-noise 3.3V rail with shutdown control for sleep/wake cycles. Use Value: 35μA quiescent current extends battery life during vehicle off-state; 150°C junction rating survives under-hood thermal stress. |
Use Scenario: Powering wearable ECG patch with Bluetooth LE MCU, analog front-end, and flash memory from coin cell or rechargeable Li-ion. IC Role / Device Role / Timing Role: Micropower step-down converter enabling multi-week runtime with Burst Mode® operation between sensor sampling bursts. Use Value: <1μA shutdown current prevents battery drain during storage; integrated diodes eliminate board area and BOM cost vs discrete solutions. |
| Distributed Industrial Supply | Wall Transformer Regulation |
Use Scenario: Local 5V/250mA regulation from 24V DC bus in PLC I/O module with strict EMI limits and wide ambient temperature range. IC Role / Device Role / Timing Role: Point-of-load regulator delivering clean, ripple-free 5V to FPGA configuration circuitry and ADC reference. Use Value: <10mV output ripple meets precision analog requirements; H-grade rating ensures reliability in 85°C control cabinet environments. |
Use Scenario: Replacing linear regulator in AC/DC adapter secondary side to improve efficiency and reduce heat in compact consumer electronics. IC Role / Device Role / Timing Role: High-input-voltage buck converter accepting 7V–40V unregulated rectified output from transformer-based SMPS. Use Value: 4V minimum input enables operation down to brownout conditions; integrated boost/catch diodes simplify design and improve MTBF. |
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#PBF | Higher 100V input rating, 200mA output, no integrated catch diode; requires external MOSFET and Schottky. | Better suited for high-voltage industrial monitoring where input may exceed 40V; larger solution size due to external components. | Select when input >40V is required and board area is not constrained; avoid if lowest BOM count or smallest footprint is critical. |
| TPS62840DRVR | Lower 1.8V–6.5V input range, 1A output, 300nA IQ, synchronous rectification; QFN-12 package. | Optimized for single-cell Li-ion (2.5V–4.2V) portable devices requiring higher current and ultra-low IQ; not rated for >6.5V input. | Select for battery-powered wearables needing >250mA or sub-1μA shutdown; reject for automotive or wall-adapter applications with >6.5V input. |
Compared with LTC3642EMSE#PBF and TPS62840DRVR, LT3470AHDDB#TRMPBF uniquely balances 40V input tolerance, integrated diodes, 250mA output, and H-grade thermal rating in a 2mm × 3mm DFN-making it optimal for space-limited, high-ambient automotive and industrial buck conversion where external component count must be minimized.
Availability
LT3470AHDDB#TRMPBF is available at Aetrix Electronics and suitable for automotive battery regulation, portable medical sensors, and distributed industrial supply requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3470AHDDB#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors for precision instrumentation, power management, and industrial automation.
LT3470AHDDB#TRMPBF belongs to the LT3470A micropower buck regulator product line, designed specifically for ultra-low-quiescent-current DC/DC conversion in battery-powered and thermally demanding environments where integrated diodes and small footprint are essential.
FAQ
What is the guaranteed operating temperature range for LT3470AHDDB#TRMPBF?
The LT3470AHDDB#TRMPBF is an H-grade device with full electrical specifications guaranteed from –40°C to 150°C junction temperature. This exceeds standard industrial (–40°C to 125°C) and automotive AEC-Q100 Grade 1 (–40°C to 125°C) requirements, making it suitable for under-hood automotive and high-ambient industrial control applications where thermal margin is critical. The exposed pad must be soldered to PCB ground for effective heat transfer.
Does LT3470AHDDB#TRMPBF require external diodes for operation?
No, LT3470AHDDB#TRMPBF integrates both the catch Schottky diode and boost Schottky diode internally. This eliminates the need for two external diodes typically required in discrete buck converter designs, reducing BOM count, PCB area, and potential failure points. The integrated diodes are characterized with 600mV forward drop at 100mA (catch) and 690mV at 50mA (boost), enabling compact 50mm² solutions.
How does LT3470AHDDB#TRMPBF achieve low output ripple below 10mV?
LT3470AHDDB#TRMPBF achieves <10mV peak-to-peak output ripple through combined design elements: hysteretic control with Burst Mode® minimizes light-load switching noise; integrated low-impedance power train reduces switching transients; and recommended use of low-ESR output capacitors (≤150mΩ) plus a 22pF phase-lead capacitor from VOUT to FB node actively suppresses feedback loop-induced ripple. Layout adherence-especially minimizing SW and BOOST node areas-is essential to maintain this performance.
Can LT3470AHDDB#TRMPBF operate from a 2-cell Li-ion battery input?
Yes, LT3470AHDDB#TRMPBF supports input voltages from 4V to 40V, fully covering the 4.2V–6.0V range of a 2-cell Li-ion battery (fully charged to depleted). At 4V input, it delivers 3.3V/250mA with guaranteed performance across its H-grade temperature range. Its 35μA quiescent current and <1μA shutdown mode maximize battery runtime in portable equipment such as handheld test instruments and wireless sensors.
What is the purpose of the NC pin (Pin 7) on LT3470AHDDB#TRMPBF?
The NC (No Connect) pin (Pin 7) on LT3470AHDDB#TRMPBF has no internal connection and serves no functional role. It may be left floating, tied to VIN, or connected to GND-none of these configurations affect operation. This pin exists for package compatibility and mechanical stability in the DDB8 footprint; designers should avoid routing signals or power to it and treat it as electrically inert in schematic capture and layout.
LT3470AHDDB#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:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (3x2)
LT3470AHDDB#TRMPBF FAQ
1.How can I place an order for LT3470AHDDB#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3470AHDDB#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 LT3470AHDDB#TRMPBF reliable?
The price and inventory of LT3470AHDDB#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3470AHDDB#TRMPBF is usually 5 days.
3.What payment methods are accepted for LT3470AHDDB#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3470AHDDB#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3470AHDDB#TRMPBF?
LT3470AHDDB#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3470AHDDB#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 LT3470AHDDB#TRMPBF?
For technical support, including LT3470AHDDB#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3470AHDDB#TRMPBF requirements.
6.How does Aetrix verify that LT3470AHDDB#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LT3470AHDDB#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 LT3470AHDDB#TRMPBF meets industry standards.
7.What is the process for return or replacement of LT3470AHDDB#TRMPBF?
All LT3470AHDDB#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3470AHDDB#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 LT3470AHDDB#TRMPBF part is unused and in its original packaging.
Return procedure for LT3470AHDDB#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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