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Analog Devices Inc. LT3480IDD#PBF
- Part No.:
- LT3480IDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3480IDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 2A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,192
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Product details
Overview
LT3480IDD#PBF from Analog Devices (formerly Linear Technology) is a 36V, 2A, 2.4MHz monolithic step-down switching regulator with current-mode control, integrated 0.25Ω bipolar NPN switch, and on-chip boost Schottky diode. It operates from 3.6V to 36V input, delivers adjustable output from 0.79V to 20V, and maintains 70µA quiescent current in Burst Mode for portable power rails.
For engineers reviewing the LT3480IDD#PBF datasheet, LT3480IDD#PBF pinout, LT3480IDD#PBF application, or LT3480IDD#PBF equivalent, key selection considerations include its 10-lead 3mm × 3mm DFN package with exposed GND pad, 200kHz–2.4MHz programmable switching frequency via RT resistor, Power Good flag, soft-start via RUN/SS, and automotive-grade –40°C to 125°C operating range.
Technical Context
The LT3480IDD#PBF implements constant-frequency current-mode PWM control using an internal oscillator set by an external RT resistor, enabling precise duty-cycle regulation and fast transient response. Its error amplifier drives the VC pin to modulate peak switch current, with active clamping for overcurrent protection and soft-start ramping via RUN/SS.
Burst Mode operation reduces quiescent current to 70µA at light loads while limiting output ripple to <15mV; bias current can be drawn from VOUT (≥3V) to further improve efficiency. Overvoltage lockout disables switching above 38V (typ), allowing safe 60V transient tolerance without external protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V continuous; withstands 60V transients - enables direct connection to 24V industrial or automotive batteries. |
| Output Current | 2A maximum - supports high-current digital logic, FPGAs, and microcontrollers without external pass devices. |
| Switching Frequency | 200kHz to 2.4MHz (RT-programmable) - allows trade-off between small magnetics (high fSW) and high-input-voltage capability (low fSW). |
| Quiescent Current | 70µA at 12VIN → 3.3VOUT in Burst Mode - extends battery life in always-on IoT sensors and portable instrumentation. |
| Feedback Reference | 0.790V ±15mV - enables precise output regulation down to sub-1V levels with standard resistor dividers. |
| Power Good Flag | Open-collector PG asserts when VOUT reaches 86% of target - provides system-level power sequencing and fault detection. |
| Thermal Package | 10-lead 3mm × 3mm DFN with exposed GND pad (θJA = 45°C/W) - supports >1.5W dissipation in compact PCB layouts. |
Pinout & Package
LT3480IDD#PBF is housed in a thermally enhanced 10-lead (3mm × 3mm) plastic DFN package with exposed pad (Pin 11) soldered to PCB ground for low thermal resistance (θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (1) | Bias Diode Anode | Connects to boost Schottky anode; supplies bias current to internal regulator - must be bypassed with ≥1µF low-ESR capacitor if not tied to VOUT. |
| BOOST (2) | Boost Drive Node | Provides >VIN voltage to saturate internal NPN switch - requires external boost capacitor and Schottky diode. |
| SW (3) | Switch Output | Drives external inductor and catch diode - carries full switching current and high dv/dt; requires tight layout to minimize EMI. |
| VIN (4) | Main Input Supply | Supplies power to internal regulator and switch - must be locally bypassed with ≥4.7µF ceramic capacitor near pin. |
| RUN/SS (5) | Enable & Soft-Start Control | Logic-level shutdown input (0.2V low / 2.5V high); RC network here sets output voltage ramp rate during startup. |
| SYNC (6) | External Clock Input | Accepts 250kHz–2MHz external clock for synchronization - grounds for Burst Mode operation at light loads. |
| PG (7) | Power Good Output | Open-collector flag signaling VOUT ≥86% of regulation - requires external pull-up for MCU reset or status monitoring. |
| FB (8) | Feedback Input | Senses output via resistor divider; regulated to 0.790V - determines output voltage accuracy and loop stability. |
| VC (9) | Error Amplifier Output | Controls peak switch current; used for loop compensation with RC network to ground - critical for transient response tuning. |
| RT (10) | Oscillator Timing | Resistor-to-ground sets switching frequency (200kHz–2.4MHz) - value directly determines inductor size and input voltage range. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode | Eliminates external boost diode, reducing BOM count and board area while ensuring reliable switch saturation across temperature. |
| Low-Ripple Burst Mode | Maintains <15mV output ripple at light loads while achieving 70µA IQ - avoids audible noise and preserves signal integrity in sensitive analog circuits. |
| Programmable Switching Frequency | 200kHz–2.4MHz via single RT resistor - enables optimization for EMI compliance, component size, or high-VIN/VOUT ratio applications. |
| Overvoltage Lockout (OVL) | Disables switching above 38V (min 36V) - protects downstream circuitry during load dump or battery jump-start events in automotive systems. |
| Power Good Flag with Hysteresis | 12mV hysteresis ensures clean power sequencing; valid only when VIN > 3.6V and RUN/SS high - simplifies system-level health monitoring. |
Applications
| Automotive Battery Regulation | Industrial Distributed Power |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to 3.3V/5V for infotainment ECUs and ADAS sensors under cold-crank (4.5V) and load-dump (60V) conditions. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, ripple-controlled DC supply with OVL and PG signaling for safety-critical subsystems. Use Value: Withstands 60V transients without external TVS, delivers 2A at >90% efficiency across –40°C to 125°C, and enables deterministic power sequencing via PG. | Use Scenario: Point-of-load conversion in PLC backplanes and factory automation controllers where 24V rail powers FPGA I/O banks and ADC reference supplies. IC Role / Device Role / Timing Role: High-efficiency, low-noise buck regulator delivering stable sub-1% output voltage with minimal layout area in space-constrained DIN-rail modules. Use Value: 70µA Burst Mode IQ extends standby time; 0.790V reference enables accurate 1.2V/1.8V core rails; SYNC input allows EMI reduction via spread-spectrum clocking. |
| Portable Medical Instrumentation | Test & Measurement Equipment |
Use Scenario: Powering handheld ultrasound units and glucose meters from single-cell Li-ion (3.0–4.2V) or dual-cell packs (6–8.4V) with strict battery-life requirements. IC Role / Device Role / Timing Role: Main system regulator managing dynamic load steps from display backlight, RF transceivers, and precision analog front-ends. Use Value: 70µA IQ in Burst Mode extends runtime; soft-start prevents inrush into large capacitive loads; low 15mV ripple avoids interference with sensitive analog measurements. | Use Scenario: Generating clean 5V/±12V rails for oscilloscope front-ends and spectrum analyzer mixers where switching noise must not alias into measurement bandwidth. IC Role / Device Role / Timing Role: Low-noise, high-PSRR buck stage preceding LDO post-regulation - minimizing conducted EMI into analog signal chains. Use Value: Programmable 2.4MHz fSW allows use of tiny 1µH inductors; integrated boost diode eliminates reverse-recovery noise; PG flag validates rail readiness before acquisition triggers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8609SIS8#PBF | 42V input, 2.5A, 2MHz sync rectification, 2.5µA IQ; requires external bootstrap diode; different pinout. | Superior light-load efficiency and lower EMI due to Silent Switcher architecture; lacks integrated boost diode. | Choose LT8609S for ultra-low-noise applications requiring <2.5µA shutdown current and EMI-sensitive environments; redesign PCB for different pinout and external diode. |
| TPS54202DDCR | 28V input, 2A, 500kHz–2.2MHz, 2µA IQ, integrated high-side MOSFET; no boost diode; smaller 6-pin SOT-23 package. | Lower max input voltage (28V vs 36V); no OVL or PG flag; optimized for cost-sensitive consumer electronics. | Choose TPS54202 for space-constrained, non-automotive designs where 28V input suffices and PG/OVL are unnecessary; verify thermal performance at 2A in SOT-23. |
Compared with LT3480IDD#PBF, LT8609SIS8#PBF offers lower quiescent current and better EMI performance but requires external components and layout changes, while TPS54202DDCR reduces footprint and cost at the expense of input voltage range and protection features.
Availability
LT3480IDD#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed power, and portable medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3480IDD#PBF 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 LT3480 product line delivers robust, high-voltage buck regulation for harsh-environment applications including automotive electronics, industrial controls, and portable test equipment - emphasizing transient resilience, wide input range, and integrated protection.
FAQ
What is the maximum input voltage rating for LT3480IDD#PBF, and how does it behave above that threshold?
The LT3480IDD#PBF has an absolute maximum VIN rating of 60V for nonrepetitive transients up to 1 second, with continuous operation rated to 36V. Its overvoltage lockout circuit disables switching when VIN exceeds 38V (typical), allowing the device to safely sustain 60V input without damage while the output falls out of regulation. This behavior is critical for automotive load-dump protection and industrial surge immunity. The LT3480IDD#PBF resumes normal operation once VIN drops below the OVL threshold.
How does the LT3480IDD#PBF achieve 70µA quiescent current, and what design trade-offs does Burst Mode introduce?
The LT3480IDD#PBF achieves 70µA quiescent current through low-ripple Burst Mode operation, where control circuitry shuts down between switching bursts at light loads, reducing input current while maintaining output ripple below 15mV. This mode trades off slightly higher output voltage ripple and potential audible noise at very low loads for dramatic efficiency gains in standby. The LT3480IDD#PBF automatically enters Burst Mode below ~100mA load and exits seamlessly as load increases - no external enable required.
Can the LT3480IDD#PBF operate without an external boost diode and capacitor, and what is their function?
No - the LT3480IDD#PBF requires an external boost diode and capacitor connected between BD and BOOST pins. The boost capacitor charges to VIN + Vf during SW low-time, then applies this elevated voltage to the BOOST pin to fully saturate the internal bipolar NPN switch, minimizing conduction loss. The integrated Schottky diode on the BD pin serves only as the anode connection point; the external diode completes the charge path. Omitting these components causes switch saturation failure and thermal runaway. The LT3480IDD#PBF datasheet specifies Diodes Inc. PDS360 as a validated boost diode.
What is the role of the VC pin in LT3480IDD#PBF, and how is it used for loop compensation?
VC is the output of the internal error amplifier and directly controls peak switch current by setting the current-limit threshold for the PWM comparator. For stable operation, an RC compensation network (e.g., 10kΩ + 1nF) must be connected from VC to GND to shape the control loop's phase margin and transient response. Improper VC compensation causes oscillation or sluggish load-step recovery. The LT3480IDD#PBF's VC pin also serves as the soft-start clamp node - the RUN/SS voltage ramps VC during startup, preventing output overshoot. This dual function makes VC critical for both stability and sequencing.
Does LT3480IDD#PBF support synchronization to an external clock, and what are the timing requirements?
Yes - the LT3480IDD#PBF supports external clock synchronization via the SYNC pin (Pin 6), accepting frequencies from 250kHz to 2MHz. Clock edges must have rise/fall times faster than 1µs to ensure reliable edge detection and avoid jitter-induced instability. When synchronized, the LT3480IDD#PBF locks its internal oscillator to the external source, enabling EMI reduction through frequency alignment or spread-spectrum techniques. Grounding SYNC forces low-ripple Burst Mode operation, making it a functional mode-select pin rather than just a sync input.
LT3480IDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tube
- 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):
- 36V
- Voltage - Output (Min/Fixed):
- 0.79V
- Voltage - Output (Max):
- 20V
- Current - Output:
- 2A
- Frequency - Switching:
- 200kHz ~ 2.4MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3480IDD#PBF FAQ
1.How can I place an order for LT3480IDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3480IDD#PBF 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 LT3480IDD#PBF reliable?
The price and inventory of LT3480IDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3480IDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3480IDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3480IDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3480IDD#PBF?
LT3480IDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3480IDD#PBF 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 LT3480IDD#PBF?
For technical support, including LT3480IDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3480IDD#PBF requirements.
6.How does Aetrix verify that LT3480IDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3480IDD#PBF 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 LT3480IDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3480IDD#PBF?
All LT3480IDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3480IDD#PBF, 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 LT3480IDD#PBF part is unused and in its original packaging.
Return procedure for LT3480IDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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