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Analog Devices Inc. LTC3835EFE#TRPBF
- Part No.:
- LTC3835EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3835EFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,872
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Product details
Overview
LTC3835EFE#TRPBF from Analog Devices (formerly Linear Technology) is a high-performance, constant-frequency current-mode synchronous step-down controller driving dual N-channel MOSFETs. It operates from 4V to 36V input, delivers 0.8V–10V output with ±1% accuracy, features 80µA no-load quiescent current, and supports phase-locked synchronization up to 650kHz - ideal for battery-powered telecom and automotive DC/DC conversion.
For engineers reviewing the LTC3835EFE#TRPBF datasheet, LTC3835EFE#TRPBF pinout, LTC3835EFE#TRPBF application, or LTC3835EFE#TRPBF equivalent, key selection criteria include its OPTI-LOOP® compensation for wide-output-capacitance stability, TRACK/SS-controlled soft-start/tracking, PGOOD monitoring, and EXTVCC-enabled efficiency optimization in multi-rail systems.
Technical Context
The LTC3835EFE#TRPBF implements a peak-current-mode control architecture with internal 0.8V reference and transconductance error amplifier (gm = 1.55 mmho). Its ITH pin directly sets current-sense threshold via voltage-controlled offset between SENSE+ and SENSE−, enabling precise load-current regulation across duty cycles.
It integrates dual gate drivers (TG/BG) with 50ns/40ns typical rise/fall times, internal LDOs (5.25V from VIN or 7.5V from EXTVCC), and a configurable PLL with 140–650kHz lock range. The device supports three light-load modes - Burst Mode® (80µA IQ), pulse-skipping, or forced continuous - selected via PLLIN/MODE pin voltage level.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V - supports 12V/24V automotive, telecom, and wide-chemistry battery inputs. |
| Output Voltage Range | 0.8V to 10V - programmable via external resistor divider; ±1% accuracy ensures tight regulation at point-of-load. |
| No-Load Quiescent Current | 80µA - extends runtime in always-on battery systems without compromising transient response. |
| Switching Frequency | 140kHz to 650kHz - adjustable via PLLLPF or synchronizable externally; enables trade-off between efficiency and magnetics size. |
| Current Sense Threshold | 80mV to 115mV - scalable with ITH voltage; supports accurate current limiting and foldback during short-circuit events. |
| Power Good Output | Open-drain PGOOD - asserts low when VFB deviates >±10% from 0.8V setpoint; enables system sequencing and fault detection. |
| Shutdown Current | 10µA - achieved by pulling RUN pin <0.7V; minimizes standby power in sleep-mode applications. |
| Duty Cycle Max | 99.4% - enables very low dropout operation (e.g., 12V→11.8V), critical for high-VIN, low-VOUT conversion. |
Pinout & Package
Package: 20-lead plastic TSSOP (FE package) with exposed thermal pad (Pin 21 = SGND), rated for –40°C to +85°C operation. Exposed pad must be soldered to PCB for thermal performance and electrical grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CLKOUT (Pin 1) | Open-drain clock output | Provides synchronized timing signal for PolyPhase® multi-controller daisy-chaining; requires external pull-up. |
| PLLLPF (Pin 2) | PLL loop filter node | Connects R-C network to ground when synchronizing to external clock; selects fixed frequency (250/400/530kHz) when tied to GND/INTVCC/floating. |
| ITH (Pin 3) | Error amplifier output / compensation node | Sets current-sense trip point; used for loop compensation with external RC network; determines light-load behavior. |
| TRACK/SS (Pin 4) | Soft-start and tracking input | Internal 1µA current source ramps voltage to control output startup slope; enables output voltage tracking of another supply via resistor divider. |
| VFB (Pin 5) | Feedback input | Compares divided output voltage against 0.8V internal reference; high-impedance input (–50nA bias) minimizes divider loading. |
| SGND (Pins 6 & 21) | Small-signal ground | Separate return path for feedback, reference, and control circuits; exposed pad (Pin 21) must be soldered to PCB ground plane. |
| PGND (Pin 7) | Power ground | Return for bottom MOSFET source, Schottky anode, and input capacitor; routed separately from SGND to avoid noise coupling. |
| BG (Pin 8) | Bottom gate driver output | Drives synchronous N-MOSFET source-to-ground; swing = 0V to INTVCC (5.25V or 7.5V). |
| INTVCC (Pin 9) | Internal LDO output | Powers gate drivers and control logic; bypassed with ≥4.7µF low-ESR capacitor; sourced from VIN or EXTVCC depending on voltage level. |
| EXTVCC (Pin 10) | External LDO input | Enables higher-efficiency INTVCC sourcing from secondary rail (e.g., converter output); switchover at 4.7V with 0.2V hysteresis. |
| VIN (Pin 11) | Main input supply | Primary power source for controller and top-gate bootstrap; requires local ceramic bypass capacitor to SGND. |
| SW (Pin 12) | Switch node | Connects to inductor and MOSFET drains; voltage swings from –0.3V (Schottky drop) to VIN; critical for layout and EMI control. |
| TG (Pin 13) | Top gate driver output | Floating driver output referenced to SW; swing = SW to (SW + INTVCC − 0.5V); drives high-side N-MOSFET gate. |
| BOOST (Pin 14) | Bootstrap supply | Charged via external diode and capacitor between BOOST and SW; supplies floating top-driver bias; voltage = INTVCC to (VIN + INTVCC). |
| RUN (Pin 15) | Enable/shutdown control | Logic-level input; <0.7V disables controller and reduces IQ to 10µA; internal 0.5µA pull-up enables auto-start. |
| SENSE− (Pin 16) | Current sense negative input | Low-impedance node for differential current sensing across RSENSE; total bias current ≤ –660µA. |
| SENSE+ (Pin 17) | Current sense positive input | Paired with SENSE−; offset controlled by ITH voltage to set precise current limit threshold. |
| PGOOD (Pin 18) | Power-good indicator | Open-drain output pulled low when VFB is outside ±10% of 0.8V; requires external pull-up for system monitoring. |
| PLLIN/MODE (Pin 19) | PLL sync input / light-load mode select | Accepts external clock (140–650kHz) for synchronization; also selects Burst Mode® (<0.7V), pulse-skipping (0.9V–INTVCC−0.5V), or forced continuous (tied to INTVCC). |
| PHASMD (Pin 20) | Phase selector input | Configures CLKOUT phase relationship relative to TG edge; enables interleaved PolyPhase® operation with multiple controllers. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Allows stable loop response across wide range of output capacitance (e.g., 150µF polymer + 0.01µF ceramic) and ESR without redesigning compensation network. |
| Adjustable Light-Load Operation | Three selectable modes (Burst Mode®, pulse-skipping, forced continuous) optimize efficiency vs. ripple/noise trade-offs per application requirements. |
| Integrated Dual Gate Drivers | Delivers 3A peak current with fast transitions (TG: 50ns rise/90ns fall; BG: 40ns rise/80ns fall) to minimize switching losses in high-frequency designs. |
| EXTVCC-Powered INTVCC | Reduces power loss by sourcing gate drive from efficient secondary rail instead of main input, improving overall system efficiency in multi-output converters. |
| Output Overvoltage Protection | PGOOD monitors VFB and asserts fault within 10% deviation; combined with current foldback, provides robust protection against open-feedback or component failure. |
| 99.4% Maximum Duty Cycle | Supports ultra-low dropout operation (e.g., 12V → 11.8V), essential for post-regulation in high-input-voltage systems where minimal voltage headroom exists. |
Applications
| Automotive Infotainment Power Supply | Telecom Line Card DC/DC Converter |
|---|---|
Use Scenario: Providing clean, sequenced 3.3V/5V rails to DSPs, FPGAs, and interface ICs in vehicle head units under cold-crank (4.5V) and load-dump (36V) conditions. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-current POL conversion with TRACK/SS-based power-up sequencing and PGOOD-driven system enable. Use Value: 80µA quiescent current preserves battery life during vehicle sleep; 4V–36V input range handles automotive transients; ±1% VOUT accuracy ensures reliable digital logic operation. | Use Scenario: Generating isolated 12V and 3.3V outputs from –48V telecom supply using intermediate bus architecture with PolyPhase® interleaving. IC Role / Device Role / Timing Role: Phase-synchronized controller in multi-phase buck stage, using CLKOUT and PHASMD pins to coordinate switching across parallel channels. Use Value: PLL synchronization eliminates beat frequencies and reduces input/output ripple; EXTVCC allows INTVCC to be powered from intermediate 12V rail, cutting driver losses by ~40% vs. VIN sourcing. |
| Battery-Powered Medical Monitor | Distributed Industrial DC Power System |
Use Scenario: Regulating 5V and 3.3V from Li-ion (3.0–4.2V) or 2-cell LiFePO₄ (5.4–7.2V) battery packs in portable diagnostic devices requiring long shelf life. IC Role / Device Role / Timing Role: High-efficiency step-down controller operating in Burst Mode® to maintain sub-100µA system standby current while supporting rapid wake-up. Use Value: 10µA shutdown IQ and 80µA light-load IQ extend battery runtime; TRACK/SS enables controlled ramp-up to prevent inrush into capacitive loads like LCD bias supplies. | Use Scenario: Converting 24V or 48V factory bus to 5V/3.3V for PLC I/O modules, sensors, and communication interfaces in harsh industrial environments. IC Role / Device Role / Timing Role: Robust primary controller with current foldback limiting and overvoltage protection, interfacing with isolated feedback via optocoupler or digital isolator. Use Value: Wide 4V–36V input accommodates brownout and surge conditions; ±1% output accuracy ensures sensor ADC reference stability; PGOOD enables watchdog-triggered reset on rail fault. |
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#TRPBF | Lower max frequency (1MHz vs 650kHz), no PLL sync, no CLKOUT, no EXTVCC, 16-pin TSSOP | Lacks PolyPhase® support and advanced light-load modes; suited for cost-sensitive, single-phase, fixed-frequency designs | Select when phase synchronization, multi-rail efficiency optimization, or Burst Mode® are not required. |
| MP2918GL-Z | Monolithic 6A buck regulator (vs controller-only), 4.5–36V input, integrated MOSFETs, no TRACK/SS or PLL, 12-pin QFN | Eliminates external MOSFETs and gate drive complexity but sacrifices design flexibility and high-current scalability | Select for space-constrained, lower-power (<6A), simplified BOM applications where external FET control is unnecessary. |
Compared with LTC3833EFE#TRPBF and MP2918GL-Z, the LTC3835EFE#TRPBF uniquely combines phase-lockable frequency, EXTVCC efficiency enhancement, and three selectable light-load modes - making it optimal for high-reliability, multi-phase, and battery-sensitive systems demanding both precision and adaptability.
Availability
LTC3835EFE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, telecom line cards, battery-powered medical monitors, and distributed industrial DC power systems requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance over –40°C to +85°C.
Supply support for LTC3835EFE#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 LTC3835 belongs to Linear's high-performance power controller family, designed specifically for efficient, flexible, and robust synchronous buck conversion in demanding industrial, automotive, and communications applications.
FAQ
What is the minimum input voltage required for the LTC3835EFE#TRPBF to operate?
The LTC3835EFE#TRPBF has an undervoltage lockout (UVLO) threshold of 3.5V (typical) with hysteresis. It begins normal operation once VIN rises above 4V, and remains functional down to 4V under steady-state conditions. Below 3.5V, the controller disables and pulls TRACK/SS low to prevent unregulated startup.
How does the EXTVCC pin improve efficiency in the LTC3835EFE#TRPBF?
The EXTVCC pin allows the LTC3835EFE#TRPBF to power its internal gate drivers and logic from an external 4.7–10V supply instead of VIN. When EXTVCC > 4.7V, the device switches from its 5.25V VIN-sourced LDO to a more efficient 7.5V EXTVCC-sourced LDO, reducing power dissipation - especially beneficial when VIN is high (e.g., 24V or 36V) and INTVCC is used to drive large MOSFET gates.
Can the LTC3835EFE#TRPBF be used without an external current sense resistor?
No. The LTC3835EFE#TRPBF requires an external current sense resistor (RSENSE) between the SENSE− and SENSE+ pins to measure inductor current for peak-current-mode control. The device does not support No-RSENSE™ architecture; omitting RSENSE disables current limiting, foldback, and proper loop regulation.
What is the purpose of the PHASMD pin on the LTC3835EFE#TRPBF?
The PHASMD pin on the LTC3835EFE#TRPBF configures the phase relationship between the TG gate drive signal and the CLKOUT clock output. By applying logic levels (GND, INTVCC, or mid-rail), it sets CLKOUT phase offset (0°, 90°, 180°, or 270°) to enable precise interleaving in PolyPhase® multi-controller configurations - reducing input/output ripple and thermal stress.
Does the LTC3835EFE#TRPBF support output voltage tracking during startup?
Yes. The TRACK/SS pin on the LTC3835EFE#TRPBF enables precise output voltage tracking. By connecting a resistor divider from a master supply to TRACK/SS, the LTC3835EFE#TRPBF regulates VFB to match the divided voltage - allowing its output to ramp in sync with another rail, which is essential for FPGA, ASIC, or multi-core processor power sequencing.
LTC3835EFE#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
LTC3835EFE#TRPBF FAQ
1.How can I place an order for LTC3835EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3835EFE#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 LTC3835EFE#TRPBF reliable?
The price and inventory of LTC3835EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3835EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3835EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3835EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3835EFE#TRPBF?
LTC3835EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3835EFE#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 LTC3835EFE#TRPBF?
For technical support, including LTC3835EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3835EFE#TRPBF requirements.
6.How does Aetrix verify that LTC3835EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3835EFE#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 LTC3835EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3835EFE#TRPBF?
All LTC3835EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3835EFE#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 LTC3835EFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3835EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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