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Analog Devices Inc. LTC3835IFE#TRPBF
- Part No.:
- LTC3835IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3835IFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,330
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Product details
Overview
LTC3835IFE#TRPBF from Analog Devices (formerly Linear Technology) is a high-performance, low-quiescent-current synchronous step-down switching regulator controller driving dual N-channel MOSFETs. It operates from 4V to 36V input, delivers 0.8V–10V output with ±1% accuracy, supports phase-lockable 140kHz–650kHz switching, and features OPTI-LOOP® compensation for optimized transient response in battery-powered telecom and automotive power systems.
For engineers reviewing the LTC3835IFE#TRPBF datasheet, LTC3835IFE#TRPBF pinout, LTC3835IFE#TRPBF application, or LTC3835IFE#TRPBF equivalent, key selection criteria include its 80µA no-load IQ, 99% duty cycle capability, integrated PGOOD monitor, EXTVCC-supported gate drive efficiency, and soft-start/tracking functionality for controlled power-up sequencing.
Technical Context
The LTC3835IFE#TRPBF implements a constant-frequency current-mode control architecture with an error amplifier (EA) output at ITH pin controlling peak inductor current via a differential current sense comparator (SENSE+/SENSE–). Its OPTI-LOOP® compensation allows stable loop design across wide output capacitance and ESR ranges without external type-II/III networks.
It integrates dual gate drivers (TG/BG) with 50ns rise/fall times, internal 5.25V/7.5V LDOs for INTVCC generation (selectable via EXTVCC), and a phase-locked loop (PLL) with 140kHz–650kHz lock range referenced to PLLIN/MODE and PLLLPF pins - enabling PolyPhase® synchronization and precise frequency tuning.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V - supports 12V/24V battery systems and wide industrial DC inputs. |
| Output Voltage Range | 0.8V to 10V - programmable via external resistor divider; 0.8V reference with ±1% accuracy over temperature. |
| No-Load Quiescent Current | 80µA - extends runtime in always-on battery applications such as IoT sensors and telematics. |
| Switching Frequency | 140kHz to 650kHz (phase-lockable) - balances efficiency vs. size; enables noise-sensitive or EMI-constrained designs. |
| Duty Cycle Max | 99.4% - enables ultra-low dropout operation near VIN ≈ VOUT, critical for high-efficiency 5V→3.3V or 12V→10V conversion. |
| PGOOD Threshold | ±10% on VFB - provides reliable power-good signaling for system enable sequencing and fault detection. |
| Shutdown IQ | 10µA - ensures minimal standby leakage when disabled via RUN pin. |
Pinout & Package
Package: 20-Lead Plastic TSSOP (FE package), exposed pad (Pin 21) tied to SGND for thermal and electrical integrity. qJA = 35°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CLKOUT (Pin 1) | Open-drain clock output | Drives daisy-chained controllers in PolyPhase® multi-phase systems; requires external pull-up. |
| PLLLPF (Pin 2) | PLL loop filter node | Connects RC network to set PLL bandwidth; floating/INTVCC/GND selects fixed frequencies (400/530/250kHz). |
| ITH (Pin 3) | Error amplifier output | Controls peak current limit; voltage sets trip point for SENSE+/- comparator in current-mode control. |
| TRACK/SS (Pin 4) | Soft-start & tracking input | Internal 1µA current source ramps voltage; regulates VFB to smaller of 0.8V or TRACK/SS voltage for controlled startup. |
| VFB (Pin 5) | Feedback input | Compares divided output voltage against 0.8V reference; determines regulation setpoint and load transient response. |
| SGND (Pin 6, Pad 21) | Small-signal ground | Must be isolated from PGND; exposed pad soldered to PCB for thermal performance and signal integrity. |
| PGND (Pin 7) | Power ground | Return path for bottom MOSFET source, Schottky cathode, and input capacitor negative terminal. |
| BG (Pin 8) | Bottom gate driver | Drives synchronous N-MOSFET source-to-ground; swing = 0V to INTVCC (5.25V/7.5V). |
| INTVCC (Pin 9) | Internal LDO output | Powers control circuitry and drivers; decoupled with ≥4.7µF low-ESR capacitor to PGND. |
| EXTVCC (Pin 10) | External VCC input | Enables higher-efficiency 7.5V LDO when >4.7V applied; bypasses VIN-fed LDO to reduce losses. |
| VIN (Pin 11) | Main input supply | Primary power source for controller and top gate driver bootstrap; requires local ceramic bypass to SGND. |
| SW (Pin 12) | Switch node | Connects to inductor and bootstrap capacitor; voltage swings from ~–0.3V (Schottky drop) to VIN. |
| TG (Pin 13) | Top gate driver | Floating driver output; swing = SW + (INTVCC – 0.5V); requires bootstrap diode/capacitor. |
| BOOST (Pin 14) | Bootstrap supply | Charged via external diode from INTVCC; supplies floating top driver; swings from INTVCC to VIN + INTVCC. |
| RUN (Pin 15) | Enable/disable control | Logic-level input; <0.7V disables controller and reduces IQ to 10µA; internal 0.5µA pull-up on release. |
| SENSE– (Pin 16) | Current sense (–) | Inverting input of differential current comparator; connects to low-side of RSENSE resistor. |
| SENSE+ (Pin 17) | Current sense (+) | Non-inverting input of differential current comparator; connects to high-side of RSENSE resistor. |
| PGOOD (Pin 18) | Power-good indicator | Open-drain output pulled low when VFB deviates >±10% from 0.8V; requires external pull-up. |
| PLLIN/MODE (Pin 19) | PLL sync / light-load mode | Accepts external clock for synchronization; also selects Burst Mode (GND), Pulse-Skipping (mid-voltage), or Continuous (INTVCC). |
| PHASMD (Pin 20) | Phase select input | Configures CLKOUT phase relationship (0° or 180°) for interleaved PolyPhase® operation. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Eliminates need for external compensation components; stabilizes loop across wide COUT/ESR variations without redesign. |
| Low 80µA No-Load IQ | Extends battery life in always-on systems by minimizing idle power loss while maintaining fast wake-up capability. |
| 99.4% Maximum Duty Cycle | Enables high-efficiency operation with minimal VIN–VOUT differential, reducing conduction losses in high-current 5V/3.3V rails. |
| Three Light-Load Operating Modes | Selectable via PLLIN/MODE: Burst Mode (highest efficiency), Pulse-Skipping (low ripple), or Forced Continuous (lowest noise). |
| Integrated PGOOD Monitor | Provides system-level power sequencing and fault indication without external comparators or logic. |
| EXTVCC-Powered INTVCC LDO | Allows gate drive power to be sourced from a secondary regulated rail, improving overall system efficiency and thermal distribution. |
Applications
| Telecom Power Supply | Automotive Infotainment |
|---|---|
Use Scenario: Generating stable 3.3V/5V rails from 12V vehicle battery in head units and ADAS modules. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-current CPU and memory power domains. Use Value: 80µA quiescent current prevents battery drain during vehicle sleep mode; 4V–36V input handles cold-crank and load-dump transients. | Use Scenario: Point-of-load conversion for FPGA, DSP, and display interfaces requiring tightly regulated low-noise outputs. IC Role / Device Role / Timing Role: High-accuracy voltage controller with PGOOD signaling for safe power sequencing and brown-out protection. Use Value: ±1% output accuracy and adjustable soft-start ensure reliable boot-up; OPTI-LOOP® maintains stability with polymer capacitors common in automotive designs. |
| Industrial Battery Backup | Distributed DC Power System |
Use Scenario: Secondary power rail in UPS or battery-backed PLCs where long standby life is critical. IC Role / Device Role / Timing Role: Low-IQ step-down controller converting 24V backup battery to 5V/3.3V system rails. Use Value: 10µA shutdown current minimizes self-discharge; TRACK/SS pin enables seamless switchover from AC to battery without output glitch. | Use Scenario: Multi-rail power management in 48V intermediate bus architectures for servers and telecom equipment. IC Role / Device Role / Timing Role: Phase-synchronizable controller enabling interleaved PolyPhase® operation for reduced input/output ripple. Use Value: CLKOUT and PHASMD pins allow precise timing alignment across multiple LTC3835IFE#TRPBF units, lowering EMI and improving thermal balance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3835EUFD#TRPBF | Same functional spec, but in 4mm × 5mm QFN (UFD) package with different pinout and thermal resistance (qJA = 37°C/W). | Preferred for space-constrained layouts; requires PCB rework due to non-pin-compatible footprint. | Select when board area is limited and thermal performance permits slightly higher junction rise. |
| LTC3835-1IFE#TRPBF | Omits CLKOUT, EXTVCC, and PGOOD functions; fixed 250kHz/530kHz operation only; no PLL or PolyPhase® support. | Suitable for cost-sensitive, single-phase, non-synchronized applications where those features are unused. | Choose only if CLKOUT, EXTVCC, and PGOOD are unnecessary - not a drop-in replacement. |
Compared with LTC3835EUFD#TRPBF and LTC3835-1IFE#TRPBF, the LTC3835IFE#TRPBF uniquely combines TSSOP packaging with full feature set - including phase-locked synchronization, EXTVCC efficiency optimization, and robust PGOOD monitoring - making it optimal for automotive and telecom designs requiring reliability, flexibility, and layout familiarity.
Availability
LTC3835IFE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, telecom power supplies, and industrial battery backup systems requiring stable component supply, extended temperature operation (–40°C to +85°C), and long-term lifecycle continuity.
Supply support for LTC3835IFE#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, documentation, and manufacturing continuity for all Linear ICs including the LTC3835 series.
The LTC3835IFE#TRPBF belongs to Linear's high-efficiency synchronous controller product line, designed specifically for demanding DC/DC conversion in battery-powered, automotive, and telecom infrastructure where low IQ, wide input range, and precise regulation are essential.
FAQ
What is the maximum supported switching frequency for the LTC3835IFE#TRPBF?
The LTC3835IFE#TRPBF supports a phase-lockable switching frequency range from 140kHz to 650kHz. When using the internal oscillator with PLLLPF pin tied to INTVCC, the nominal frequency is 530kHz; with PLLLPF floating, it is 400kHz. External synchronization guarantees lock between 140kHz and 650kHz per datasheet specifications.
Does the LTC3835IFE#TRPBF require an external current sense resistor?
Yes, the LTC3835IFE#TRPBF requires an external precision current sense resistor (RSENSE) connected between the power path and PGND. The SENSE+ and SENSE– pins measure the differential voltage across this resistor to implement current-mode control and foldback limiting. Typical values range from 1mΩ to 10mΩ depending on output current.
How does the EXTVCC pin improve efficiency in the LTC3835IFE#TRPBF?
The EXTVCC pin allows the LTC3835IFE#TRPBF to power its internal INTVCC LDO from an external regulated supply (e.g., a downstream converter output) instead of VIN. When EXTVCC exceeds 4.7V, the controller switches from the 5.25V VIN-fed LDO to a more efficient 7.5V LDO, reducing gate drive losses and overall system power dissipation - especially beneficial in multi-stage power architectures.
Can the LTC3835IFE#TRPBF operate in dropout mode, and what is its minimum dropout voltage?
Yes, the LTC3835IFE#TRPBF supports very low dropout operation with up to 99.4% duty cycle. Its minimum practical dropout is determined by the top MOSFET's RDS(on), gate drive capability, and bootstrap recharge time - not a fixed voltage. In practice, it can regulate with VIN as low as ~100mV above VOUT under light loads, enabled by the dropout detector that forces periodic top-FET off-time to refresh BOOST.
What are the valid configurations for light-load operation on the LTC3835IFE#TRPBF?
The LTC3835IFE#TRPBF supports three selectable light-load modes via the PLLIN/MODE pin: tie to SGND for Burst Mode® (highest efficiency, discontinuous), tie to INTVCC for forced continuous conduction (lowest noise, reversible current), or bias between 0.8V and INTVCC–0.5V for pulse-skipping (balanced ripple and efficiency). Each mode directly impacts output ripple, audio noise, and light-load efficiency.
LTC3835IFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 36V
- Frequency - Switching:
- 250kHz ~ 530kHz
- Duty Cycle (Max):
- 99.4%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Phase Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LTC3835IFE#TRPBF FAQ
1.How can I place an order for LTC3835IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3835IFE#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 LTC3835IFE#TRPBF reliable?
The price and inventory of LTC3835IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3835IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3835IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3835IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3835IFE#TRPBF?
LTC3835IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3835IFE#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 LTC3835IFE#TRPBF?
For technical support, including LTC3835IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3835IFE#TRPBF requirements.
6.How does Aetrix verify that LTC3835IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3835IFE#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 LTC3835IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3835IFE#TRPBF?
All LTC3835IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3835IFE#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 LTC3835IFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3835IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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