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Analog Devices Inc. LTC3835IFE#PBF
- Part No.:
- LTC3835IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3835IFE#PBF.pdf
- Description:
- IC REG CTRLR BUCK 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,962
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Product details
Overview
LTC3835IFE#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 adjustable output from 0.8V to 10V, features 80µA no-load IQ, ±1% output voltage accuracy, and supports phase-locked frequencies up to 650kHz. It is used in automotive power systems requiring stable, efficient DC/DC conversion with soft-start and power-good monitoring.
For engineers reviewing the LTC3835IFE#PBF datasheet, LTC3835IFE#PBF pinout, LTC3835IFE#PBF application, or LTC3835IFE#PBF equivalent, key selection criteria include its 20-pin TSSOP package with exposed thermal pad, OPTI-LOOP® compensation for wide capacitor/ESR tolerance, selectable light-load modes (Burst Mode®, pulse-skipping, continuous), and integrated PGOOD, TRACK/SS, and CLKOUT for multi-phase coordination.
Technical Context
The LTC3835IFE#PBF implements a constant-frequency current-mode control architecture with an error amplifier (EA) regulating VFB to 0.8V reference, where ITH voltage sets peak inductor current. Its OPTI-LOOP® compensation allows stable loop response across diverse output capacitors and ESR values without external compensation network redesign.
It integrates dual gate drivers (TG/BG) with precise timing control (70ns dead-time), internal 5.25V/7.5V LDOs for INTVCC (selectable via EXTVCC), and a phase-locked loop (PLL) with guaranteed 140–650kHz sync range. The device supports dropout operation up to 99% duty cycle and includes foldback current limiting, overvoltage protection, and reverse-current prevention during light loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 36V - supports 12V/24V automotive batteries and industrial DC rails without pre-regulation. |
| VOUT Range | 0.8V to 10V - programmable via external resistor divider; enables core logic, FPGA, and analog supply generation. |
| Quiescent Current | 80µA at no load - extends battery runtime in always-on systems like telematics and sensor nodes. |
| Output Accuracy | ±1% over line/load/temp - ensures reliable regulation for precision analog and digital loads. |
| Switching Frequency | 140kHz to 650kHz (phase-lockable) - balances efficiency vs. size; enables compact magnetics in space-constrained designs. |
| Duty Cycle Max | 99% - sustains regulation under near-dropout conditions (e.g., VIN = 5.5V → VOUT = 5V). |
| PGOOD Threshold | ±10% on VFB - provides robust power-rail monitoring with hysteresis for noise immunity. |
Pinout & Package
Package: 20-Lead Plastic TSSOP with exposed thermal pad (Pin 21 = SGND), rated for –40°C to +85°C operation. Exposed pad must be soldered to PCB for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CLKOUT (Pin 1) | Open-drain clock output | Synchronizes multiple controllers in PolyPhase® configurations; requires external pull-up. |
| PLLLPF (Pin 2) | PLL loop filter node | Connects RC network to set PLL bandwidth when synchronizing to external clock (140–650kHz). |
| ITH (Pin 3) | Error amplifier output / compensation node | Controls peak inductor current; interface for OPTI-LOOP® compensation network. |
| TRACK/SS (Pin 4) | Soft-start and tracking input | Internal 1µA current source ramps voltage; enables controlled startup or voltage tracking of another rail. |
| VFB (Pin 5) | Feedback input | Compares divided output voltage to 0.8V reference; high-impedance input (<50nA bias). |
| SGND (Pins 6 & 21) | Small-signal ground | Separate return path for feedback, error amp, and logic; exposed pad must be soldered to PCB plane. |
| PGND (Pin 7) | Power ground | High-current return for bottom MOSFET, Schottky cathode, and input capacitor negative terminal. |
| BG (Pin 8) | Bottom gate driver output | Drives synchronous N-MOSFET source; swing = 0V to INTVCC (5.25V or 7.5V). |
| INTVCC (Pin 9) | Internal LDO output | Powers control circuitry and gate drivers; requires ≥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-powered LDO. |
| VIN (Pin 11) | Main input supply | Primary power source for internal LDO (when EXTVCC inactive); requires local ceramic bypass. |
| SW (Pin 12) | Switch node | Connects to inductor; voltage swings from ~–0.3V (Schottky drop) to VIN. |
| TG (Pin 13) | Top gate driver output | Floating driver output; swing = SW + (INTVCC – 0.5V); drives high-side N-MOSFET gate. |
| BOOST (Pin 14) | Bootstrap supply | Charged via external diode/capacitor from INTVCC; supplies floating TG driver. |
| RUN (Pin 15) | Enable/shutdown control | Logic-level input; <0.7V disables controller, reducing IQ to 10µA. |
| SENSE– (Pin 16) | Current sense negative input | Low-side current sense node; referenced to PGND; accepts common-mode up to 11V. |
| SENSE+ (Pin 17) | Current sense positive input | High-side current sense node; differential pair with SENSE– sets current limit threshold. |
| PGOOD (Pin 18) | Power-good indicator | Open-drain output pulled low if VFB deviates >±10% from 0.8V; requires external pull-up. |
| PLLIN/MODE (Pin 19) | PLL sync input / light-load mode select | Accepts external clock (140–650kHz) or sets operating mode: GND = Burst Mode®, INTVCC = continuous, mid-voltage = pulse-skipping. |
| PHASMD (Pin 20) | Phase select input | Configures CLKOUT phase relationship (0° or 180°) for two-phase PolyPhase® operation. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Enables stable loop response across wide range of output capacitor types (ceramic, polymer, electrolytic) and ESR values without redesigning compensation network. |
| Selectably Optimized Light-Load Efficiency | Three user-selectable modes: Burst Mode® (80µA IQ), pulse-skipping (low ripple + moderate IQ), or forced continuous (lowest ripple, highest audio/EMI compatibility). |
| Integrated Power-Good Monitoring | PGOOD open-drain output asserts low when regulated output deviates >±10% from target, enabling system sequencing and fault detection without external comparators. |
| Robust Dropout Operation | 99% maximum duty cycle and dropout detector allow sustained regulation even when VIN approaches VOUT, with periodic top-FET blanking to recharge bootstrap capacitor. |
| Multi-Phase Coordination Support | CLKOUT and PHASMD pins enable daisy-chained or interleaved PolyPhase® operation with precise phase alignment and reduced input/output ripple. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Generating stable 3.3V/5V rails for microcontrollers, CAN transceivers, and display interfaces in head units and ADAS ECUs. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-efficiency, low-noise DC/DC conversion with soft-start and PGOOD sequencing. Use Value: 80µA quiescent current extends battery life during vehicle sleep mode; ±1% accuracy ensures reliable MCU operation across temperature. | Use Scenario: Providing isolated, tightly regulated 12V and 5V outputs for field I/O conditioning circuits in programmable logic controllers. IC Role / Device Role / Timing Role: High-input-voltage (up to 36V) step-down controller supporting wide industrial DC bus ranges and transient-heavy environments. Use Value: 4V–36V input range accommodates 24V nominal systems with brownout tolerance; current foldback protects MOSFETs during short-circuit faults. |
| Telecom Base Station Bias Supply | Portable Medical Diagnostic Equipment |
Use Scenario: Generating intermediate 5V/3.3V rails from 48V backplane for RF front-end biasing and digital signal processing modules. IC Role / Device Role / Timing Role: Phase-lockable controller enabling synchronized switching across multiple converter stages to minimize conducted EMI. Use Value: CLKOUT and PLLIN/MODE support multi-phase synchronization up to 650kHz, reducing input capacitor RMS current and EMI peaks. | Use Scenario: Powering low-power sensors, ADCs, and wireless transceivers in handheld ultrasound or glucose monitors with long battery life requirements. IC Role / Device Role / Timing Role: Low-IQ synchronous controller delivering regulated output with precise soft-start to prevent inrush-induced system reset. Use Value: TRACK/SS pin enables linear voltage ramp (via capacitor) or tracking of main system rail, ensuring safe power-up sequencing for sensitive analog front-ends. |
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 |
|---|---|---|---|
| LTC3833EFE#PBF | Lower max frequency (850kHz vs 650kHz), no CLKOUT or PHASMD, no PLL, fixed 0.8V ref only, no TRACK/SS | Lacks multi-phase coordination, soft-start/tracking, and external sync; suited for simpler single-rail converters | Select when phase synchronization, rail tracking, or ultra-low IQ are not required and cost optimization is critical. |
| MP2918GL-Z | Higher IQ (120µA), no PLL or CLKOUT, integrated MOSFET drivers only (no external FET control), 4.5–32V VIN | Monolithic design eliminates external MOSFETs but forfeits flexibility in FET selection and thermal management | Choose for space-constrained, lower-power applications where discrete FET control and thermal isolation are unnecessary. |
Compared with LTC3833EFE#PBF and MP2918GL-Z, the LTC3835IFE#PBF uniquely combines ultra-low 80µA quiescent current, full multi-phase coordination (CLKOUT/PHASMD/PLL), and flexible rail management (TRACK/SS, PGOOD, EXTVCC), making it optimal for high-reliability, battery-sensitive, and synchronized power systems.
Availability
LTC3835IFE#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and telecom base station bias supplies requiring stable component supply, extended temperature operation (–40°C to +85°C), and long-term lifecycle continuity.
Supply support for LTC3835IFE#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 qualification and long-term support.
The LTC3835 belongs to Linear's high-efficiency synchronous controller product line, designed specifically for demanding automotive, industrial, and telecom applications requiring low IQ, wide input range, and advanced system coordination features.
FAQ
What is the operating temperature range for the LTC3835IFE#PBF?
The LTC3835IFE#PBF is specified for operation from –40°C to +85°C ambient temperature. This industrial-grade rating is confirmed in the manufacturer's ordering information table and absolute maximum ratings section, and applies to both FE (TSSOP) and UFD (QFN) packages. The "I" grade designation explicitly guarantees full performance across this extended range.
How does the EXTVCC pin affect the LTC3835IFE#PBF's internal LDO operation?
The EXTVCC pin on the LTC3835IFE#PBF controls the source of the INTVCC supply: when EXTVCC is below 4.7V, the internal 5.25V LDO powers INTVCC from VIN; when EXTVCC exceeds 4.7V, the 7.5V LDO activates and powers INTVCC from EXTVCC instead. This allows higher-efficiency operation by using an existing regulated rail (e.g., a downstream converter output) to power the controller's gate drivers and logic, reducing overall system losses.
Can the LTC3835IFE#PBF be used without an external current sense resistor?
No, the LTC3835IFE#PBF requires an external current sense resistor (RSENSE) between the SENSE+ and SENSE– pins to implement current-mode control. The device does not support No-RSENSE™ operation. The sense resistor sets the current limit threshold (e.g., 100mV typical), and its value directly determines peak inductor current and foldback behavior. Omitting RSENSE disables current sensing and prevents proper regulation and protection.
What are the supported light-load operating modes of the LTC3835IFE#PBF and how are they selected?
Three light-load modes are supported on the LTC3835IFE#PBF and selected via the PLLIN/MODE pin: tying to SGND enables Burst Mode® (80µA IQ, discontinuous conduction); tying to INTVCC forces continuous conduction mode (lowest ripple, higher IQ); applying a voltage between 0.9V and INTVCC–0.5V selects pulse-skipping mode (moderate IQ, low ripple, no reverse current). These selections are explicitly defined in the Applications Information section of the datasheet.
Does the LTC3835IFE#PBF provide overvoltage protection for the output rail?
Yes, the LTC3835IFE#PBF includes output overvoltage protection (OVP) that triggers when the VFB voltage exceeds the regulated 0.8V reference by more than +10% (i.e., >0.88V). Upon detection, the controller immediately disables the top MOSFET (TG) and holds the bottom MOSFET (BG) on to clamp the output, preventing damage to downstream loads. This function is documented in the Electrical Characteristics table under "VPG - PGOOD Trip Level" and confirmed in the Functional Diagram and Operation sections.
LTC3835IFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width) 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-TSSOP-EP
LTC3835IFE#PBF FAQ
1.How can I place an order for LTC3835IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3835IFE#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 LTC3835IFE#PBF reliable?
The price and inventory of LTC3835IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3835IFE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3835IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3835IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3835IFE#PBF?
LTC3835IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3835IFE#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 LTC3835IFE#PBF?
For technical support, including LTC3835IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3835IFE#PBF requirements.
6.How does Aetrix verify that LTC3835IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3835IFE#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 LTC3835IFE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3835IFE#PBF?
All LTC3835IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3835IFE#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 LTC3835IFE#PBF part is unused and in its original packaging.
Return procedure for LTC3835IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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