My Inquiry
My Account
Analog Devices Inc. LTC3835EUFD#PBF
- Part No.:
- LTC3835EUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC3835EUFD#PBF.pdf
- Description:
- IC REG CTRLR BUCK 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,554
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3835EUFD#PBF 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 up to 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 LTC3835EUFD#PBF datasheet, LTC3835EUFD#PBF pinout, LTC3835EUFD#PBF application, or LTC3835EUFD#PBF equivalent, key selection criteria include its 80µA no-load IQ, 0.8V precision reference, PGOOD monitoring, TRACK/SS soft-start/tracking capability, and support for Burst Mode®, pulse-skipping, or forced continuous operation at light loads.
Technical Context
The LTC3835EUFD#PBF implements a constant-frequency current-mode control architecture with an error amplifier (EA) outputting to the ITH pin to set peak inductor current. Its OPTI-LOOP® compensation network adapts loop stability across wide output capacitance and ESR ranges without external component changes.
It integrates dual gate drivers (TG/BG) with 50ns/40ns typical rise/fall times, internal LDOs powering INTVCC from VIN or EXTVCC (switchover at 4.7V), and a phase-locked loop (PLL) with guaranteed 140kHz–650kHz synchronization range via PLLIN/MODE and PLLLPF pins.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V - supports 12V/24V automotive, telecom, and multi-cell Li-ion battery inputs. |
| Output Voltage Range | 0.8V to 10V - programmable via external resistor divider; 0.8V ±1% reference enables precise regulation. |
| No-Load Quiescent Current | 80µA - extends runtime in always-on battery systems such as IoT sensors and portable medical devices. |
| Switching Frequency | 140kHz to 650kHz (phase-lockable) - balances efficiency vs. size; 400kHz typical default enables compact 3.3µH inductors. |
| Power Good Output | Open-drain PGOOD with ±10% trip threshold - provides reliable system-level power sequencing and fault indication. |
| Soft-Start / Tracking | TRACK/SS pin with 1µA internal pull-up - enables controlled ramp-up or voltage tracking of auxiliary rails during startup. |
| Shutdown Current | 10µA - ensures minimal leakage when disabled via RUN pin below 0.7V. |
Pinout & Package
Package: 20-pin (4mm × 5mm) plastic QFN (UFD), exposed thermal pad (Pin 21) connected to SGND. Requires soldering of exposed pad for thermal performance (θJA = 37°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CLKOUT (Pin 19) | Open-drain clock output | Provides synchronized clock signal for PolyPhase® multi-phase configurations or daisy-chained controllers. |
| PLLLPF (Pin 20) | PLL low-pass filter node | Accepts RC network to tune PLL bandwidth when synchronizing to external clock on PLLIN/MODE. |
| ITH (Pin 1) | Error amplifier output | Controls peak inductor current; voltage sets current limit and influences loop dynamics and transient response. |
| TRACK/SS (Pin 2) | Soft-start and tracking input | Regulates VFB to smaller of 0.8V or applied voltage; internal 1µA pull-up enables capacitor-based ramp timing. |
| VFB (Pin 3) | Feedback input | Compares divided output voltage against 0.8V reference; ±1% accuracy ensures tight regulation over line/load/temp. |
| SGND (Pins 4, 21) | Small-signal ground | Must be isolated from PGND; exposed pad (Pin 21) is SGND and critical for noise immunity and thermal conduction. |
| PGND (Pin 5) | Power ground | Return path for bottom MOSFET source, Schottky anode, and input capacitor - routed separately from SGND. |
| BG (Pin 6) | Bottom gate driver | Drives synchronous N-MOSFET source-to-ground; swing from 0V to INTVCC (5.25V or 7.5V). |
| INTVCC (Pin 7) | Internal LDO output | Supplies gate drivers and control circuitry; sourced from VIN (5.25V LDO) or EXTVCC (7.5V LDO) depending on voltage level. |
| EXTVCC (Pin 8) | External VCC input | Enables higher-efficiency biasing from secondary rail (e.g., regulated 5V or 8V); switchover at 4.7V with 0.2V hysteresis. |
| VIN (Pin 9) | Main input supply | Primary power source; bypassed to SGND with low-ESR capacitor to suppress high-frequency noise and ripple. |
| SW (Pin 10) | Switch node | Connects to inductor; voltage swings from ~–0.3V (Schottky drop) to VIN; critical for layout and EMI control. |
| TG (Pin 11) | Top gate driver | Floating driver output; swing equals INTVCC – 0.5V superimposed on SW node voltage. |
| BOOST (Pin 12) | Bootstrap supply | Charged via external diode/capacitor between BOOST and SW; supplies top driver floating bias. |
| RUN (Pin 13) | Enable control | Digital ON/OFF control; <0.7V disables controller and reduces IQ to 10µA; internal 0.5µA pull-up enables auto-start. |
| SENSE– (Pin 14) | Current sense negative | Differential input to current comparator; referenced to SENSE+ to detect RSENSE voltage drop. |
| SENSE+ (Pin 15) | Current sense positive | Differential input to current comparator; common-mode range up to 11V enables high-side sensing. |
| PGOOD (Pin 16) | Power good indicator | Open-drain output pulled low if VFB deviates >±10% from 0.8V; requires external pull-up for logic-level signaling. |
| PLLIN/MODE (Pin 17) | Sync input / light-load mode select | Accepts external clock for PLL sync; also selects Burst Mode® (GND), pulse-skipping (mid-voltage), or forced continuous (INTVCC). |
| PHASMD (Pin 18) | Phase select input | Configures CLKOUT phase relationship (0° or 180°) for interleaved multi-phase designs. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Minimizes required output capacitance and eliminates need for compensation component tuning across different COUT/ESR combinations. |
| Low 80µA No-Load IQ | Extends battery life in standby or intermittent-use applications without sacrificing fast wake-up response. |
| 99.4% Maximum Duty Cycle | Enables ultra-low dropout operation - supports VOUT close to VIN, e.g., 12V→11.9V conversion with minimal loss. |
| Current Foldback Limiting | Reduces MOSFET power dissipation during short-circuit by lowering peak current as duty cycle increases. |
| Selectably Light-Load Modes | Three user-selectable modes (Burst, pulse-skipping, forced continuous) allow trade-off between efficiency, ripple, and EMI per application needs. |
| Internal LDO Flexibility | Dual-input LDO (VIN or EXTVCC) improves system efficiency by enabling bias from regulated secondary rails instead of raw input. |
Applications
| Automotive Infotainment Power | Telecom Base Station Bias |
|---|---|
Use Scenario: Supplying 3.3V/5A to DSPs and FPGAs in head units with cold-crank (4.5V) and load-dump (36V) transients. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing input range, output accuracy, and sequencing with PGOOD. Use Value: 4V–36V input range withstands automotive transients; 80µA IQ preserves battery during ignition-off; TRACK/SS enables safe SoC core voltage ramp. | Use Scenario: Generating stable 5V/10A intermediate rail from –48V telecom supply using intermediate DC/DC stage. IC Role / Device Role / Timing Role: High-efficiency step-down controller driving discrete N-MOSFETs with precise current sensing and thermal robustness. Use Value: ±1% VOUT accuracy ensures downstream converter stability; phase-lockable frequency avoids beat frequencies in dense RF environments. |
| Industrial PLC I/O Module | Battery-Powered Test Equipment |
Use Scenario: Providing isolated 12V/2A auxiliary power for analog front-end and communication interfaces in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Main DC/DC controller with PGOOD monitoring, soft-start, and robust current foldback for field-replaceable modules. Use Value: EXTVCC option allows efficient bias from local 12V rail; 99.4% duty cycle supports brownout operation down to 12.1V input. | Use Scenario: Regulating 3.3V for microcontroller, ADC, and wireless transceiver in handheld calibration tools powered by 3S Li-ion (9–12.6V). IC Role / Device Role / Timing Role: Low-IQ buck controller enabling >100-hour standby with programmable soft-start and accurate voltage tracking. Use Value: 80µA IQ and selectable Burst Mode® maximize battery life; TRACK/SS pin enables seamless voltage ramp matching sensor excitation sequence. |
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 |
|---|---|---|---|
| LTC3833EUFD#PBF | Single-output, non-phase-lockable, 500kHz fixed frequency; no CLKOUT or PHASMD; lower IQ (55µA) but no PGOOD. | Lacks polyphase sync and power-good monitoring; suitable only for simpler, cost-sensitive single-rail designs. | Choose when phase synchronization and system-level sequencing are unnecessary and lowest possible IQ is prioritized. |
| MP2918GL-Z | Monolithic 6A buck converter (integrated MOSFETs); 4.5–18V input; 0.6–5.5V output; 30µA IQ; no EXTVCC or TRACK/SS. | Not a controller - integrates power stages; limited input range and output flexibility; no soft-start/tracking capability. | Choose only for space-constrained, low-power applications where discrete FETs are undesirable and input voltage is ≤18V. |
Compared with LTC3833EUFD#PBF and MP2918GL-Z, the LTC3835EUFD#PBF uniquely combines phase-lockable frequency, PGOOD, TRACK/SS, EXTVCC, and 4–36V input - making it the only choice for robust, scalable, multi-rail industrial and automotive power architectures requiring precise sequencing and wide input tolerance.
Availability
LTC3835EUFD#PBF is available at Aetrix Electronics and suitable for automotive infotainment, telecom base station bias, and industrial PLC I/O modules requiring stable component supply, long-term lifecycle assurance, and full temperature-grade traceability.
Supply support for LTC3835EUFD#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 full product support, documentation, and manufacturing continuity for all Linear ICs including the LTC series.
The LTC3835EUFD#PBF belongs to Linear's high-performance power controller family, designed specifically for demanding DC/DC conversion in automotive, industrial, and communications infrastructure where reliability, efficiency, and design flexibility are critical.
FAQ
What is the maximum supported switching frequency for the LTC3835EUFD#PBF?
The LTC3835EUFD#PBF supports a phase-lockable switching frequency range from 140kHz to 650kHz. Its nominal internal oscillator frequency is 400kHz (when PLLLPF is floating), with guaranteed lock range of 140kHz–650kHz when synchronized to an external clock on the PLLIN/MODE pin. This enables noise-sensitive applications to avoid interference bands while maintaining optimal efficiency and component size trade-offs.
Does the LTC3835EUFD#PBF require an external current sense resistor?
Yes, the LTC3835EUFD#PBF requires an external current sense resistor (RSENSE) connected between the SENSE– and SENSE+ pins. It uses differential sensing to monitor inductor current for peak-current-mode control. The maximum sense voltage threshold is 100mV (typical), and the controller supports adjustable current limiting via the ITH pin voltage and RSENSE value - enabling precise overcurrent protection and foldback behavior.
How does the EXTVCC pin improve efficiency in the LTC3835EUFD#PBF?
The EXTVCC pin on the LTC3835EUFD#PBF allows the internal INTVCC LDO to be powered from an external regulated rail (e.g., 5V or 8V) instead of the main VIN. When EXTVCC exceeds 4.7V, the device switches from the 5.25V VIN-powered LDO to a 7.5V EXTVCC-powered LDO, reducing power loss in the bias supply and improving overall system efficiency - especially beneficial when VIN is high (e.g., 24V or 36V) and a clean, lower-voltage rail is already available.
Can the LTC3835EUFD#PBF operate in dropout mode, and what is its minimum dropout voltage?
Yes, the LTC3835EUFD#PBF supports very low dropout operation with up to 99.4% maximum duty cycle. This enables regulation when VOUT is within ~0.1V of VIN (e.g., 12V input → 11.9V output). During dropout, the controller forces periodic off-time to recharge the BOOST capacitor, ensuring reliable top-FET gate drive even under extreme input-to-output differentials - critical for automotive cold-crank and industrial brownout conditions.
What are the three light-load operating modes supported by the LTC3835EUFD#PBF, and how are they selected?
The LTC3835EUFD#PBF supports Burst Mode®, pulse-skipping, and forced continuous conduction - selected via the PLLIN/MODE pin: tie to SGND (<0.7V) for Burst Mode® (highest efficiency, audible noise possible); tie to INTVCC for forced continuous (lowest ripple, reduced efficiency); tie to mid-voltage (0.9V–INTVCC–0.5V) for pulse-skipping (balanced efficiency/ripple/EMI). Each mode directly impacts quiescent current, output ripple, and EMI profile - allowing optimization per end-application requirements.
LTC3835EUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tube
- 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-QFN (4x5)
LTC3835EUFD#PBF FAQ
1.How can I place an order for LTC3835EUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3835EUFD#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 LTC3835EUFD#PBF reliable?
The price and inventory of LTC3835EUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3835EUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3835EUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3835EUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3835EUFD#PBF?
LTC3835EUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3835EUFD#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 LTC3835EUFD#PBF?
For technical support, including LTC3835EUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3835EUFD#PBF requirements.
6.How does Aetrix verify that LTC3835EUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3835EUFD#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 LTC3835EUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3835EUFD#PBF?
All LTC3835EUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3835EUFD#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 LTC3835EUFD#PBF part is unused and in its original packaging.
Return procedure for LTC3835EUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3835EUFD#PBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
