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Analog Devices Inc. LTC1435AIS#TRPBF
- Part No.:
- LTC1435AIS#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1435AIS#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,142
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Product details
Overview
LTC1435AIS#TRPBF from Analog Devices (formerly Linear Technology) is a synchronous step-down switching regulator controller driving external N-channel MOSFETs in fixed-frequency current-mode topology. It operates from 3.5V to 36V input, delivers output voltages from 1.19V to 9V, supports ≤300ns minimum on-time and 99% duty cycle for ultra-low dropout, and targets high-efficiency power conversion in portable battery-powered systems.
For engineers reviewing the LTC1435AIS#TRPBF datasheet, LTC1435AIS#TRPBF pinout, LTC1435AIS#TRPBF application, or LTC1435AIS#TRPBF equivalent, key selection criteria include its dual-N-MOSFET synchronous drive capability, programmable soft-start via external capacitor, secondary feedback control (SFB) for multi-output regulation, remote voltage sensing, and micropower shutdown with IQ < 25µA.
Technical Context
The LTC1435AIS#TRPBF implements constant-frequency current-mode control with an internal 1.19V reference and error amplifier output at ITH pin. Its peak-current sensing uses differential SENSE+ and SENSE− inputs with 150mV threshold, enabling precise overcurrent protection and load-matching response. The oscillator frequency is set externally via COSC pin (100pF yields ~125kHz), and burst mode operation is enabled by default for high light-load efficiency.
Secondary feedback (SFB) forces continuous conduction when pulled low-critical for auxiliary winding regulation-and disables burst mode to reduce EMI. INTVCC is internally regulated to 5.0V (±2%) and can be powered from EXTVCC ≥4.7V, allowing efficient bootstrapping from VOUT or auxiliary windings in isolated designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 36V - supports wide industrial and automotive battery inputs including 12V/24V rails and Li-ion stacks. |
| Output Voltage Range | 1.19V to 9V - set via external resistor divider on VOSENSE; 1.19V reference enables accurate low-VOUT regulation. |
| Max Duty Cycle | 99% - enables near-dropout operation (e.g., 24V→23.5V), extending runtime in battery systems under depletion. |
| Min On-Time | ≤300ns - permits high-frequency, low-duty-cycle conversion (e.g., 48V→3.3V at 500kHz) without pulse-skipping instability. |
| Shutdown Current | <25µA - ensures negligible battery drain during system sleep in portable instruments and PDAs. |
| Current Sense Threshold | 150mV - sets peak inductor current limit; used with RSENSE to define IMAX = 100mV/RSENSE for robust overcurrent protection. |
| Oscillator Frequency | 125kHz (typ, COSC=100pF) - adjustable from ~50kHz to 400kHz; lower frequencies improve efficiency at high VIN, higher frequencies reduce passive size. |
Pinout & Package
Package: 16-lead SSOP (Small Outline Package), 0.150" body width, JEDEC MS-013AC, RoHS-compliant, moisture sensitivity level 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COSC | Oscillator timing capacitor connection | External capacitor sets switching frequency; 100pF yields ~125kHz; critical for EMI and efficiency trade-off. |
| RUN/SS | Soft-start ramp and shutdown enable | Capacitor to ground controls startup slew rate (~0.5s/µF); <1.3V forces shutdown with IQ <25µA. |
| ITH | Error amplifier output / current comparator threshold | Voltage (0–2.5V) modulates peak current limit; compensation network connects here for loop stability. |
| SFB | Secondary winding feedback input | Pull low to force continuous mode; tie to INTVCC if unused; enables auxiliary output regulation in flyback-derived topologies. |
| VOSENSE | Main output voltage feedback input | Connects to resistive divider across VOUT; referenced to 1.19V internal bandgap for ±0.8% load regulation. |
| SENSE− / SENSE+ | Differential current sense inputs | Measure voltage across RSENSE; built-in offset enables accurate 150mV trip point for overcurrent protection. |
| TG / BG | Top/bottom gate drivers | High-current (2A peak) outputs driving external N-MOSFET gates; TG is floating, BG is ground-referenced. |
| INTVCC | Internal 5V regulator output | Powers internal logic and drivers; requires ≥2.2µF tantalum bypass; switchover to EXTVCC occurs at 4.7V. |
Key Features
| Feature | Design Value |
|---|---|
| Dual N-MOSFET synchronous drive | Enables >90% efficiency at 3A loads by replacing lossy Schottky diode with low-RDS(ON) bottom switch. |
| Programmable soft start | External CSS capacitor prevents inrush current and enables controlled power sequencing in multi-rail systems. |
| Remote output voltage sense | Separate VOSENSE and SGND pins eliminate IR drop errors in PCB traces, ensuring tight regulation at load point. |
| Burst Mode™ operation | Reduces quiescent current to <25µA at light loads while maintaining low output ripple and fast transient response. |
| Secondary feedback control (SFB) | Guarantees regulation of auxiliary outputs (e.g., bias rails) independent of main load, essential for multi-output DC/DC converters. |
Applications
| Portable Medical Instrumentation | Notebook & Ultrabook Power |
|---|---|
Use Scenario: Battery-powered handheld ultrasound or glucose meter requiring stable 3.3V/1.8V rails with minimal standby drain. IC Role / Device Role / Timing Role: Primary buck controller managing main system voltage from single-cell Li-ion (3.0–4.2V) or dual-cell pack (6–8.4V). Use Value: 99% duty cycle extends usable battery range; Burst Mode maintains <25µA IQ during idle periods between measurements. | Use Scenario: Core voltage regulation for Intel Core i-series CPUs in thin-and-light notebooks with thermal constraints. IC Role / Device Role / Timing Role: High-efficiency synchronous step-down controller delivering 1.0–1.35V at up to 3A with remote sensing. Use Value: ≤300ns min-on-time supports high VIN-to-VOUT ratios (e.g., 19V adapter → 1.2V core); low dropout preserves regulation during battery sag. |
| Industrial IoT Sensor Node | DC Power Distribution System |
Use Scenario: Remote wireless sensor node powered by 24V PoE or 12V field bus, needing isolated 5V and 3.3V supplies. IC Role / Device Role / Timing Role: Controller for primary non-isolated buck stage feeding isolated flyback or forward converter with SFB-driven auxiliary regulation. Use Value: SFB pin allows precise regulation of isolated bias rail without optocoupler; wide 3.5–36V input accommodates brownout conditions. | Use Scenario: Centralized 48V-to-12V/5V conversion in telecom shelf or server rack with strict efficiency and thermal requirements. IC Role / Device Role / Timing Role: High-current synchronous buck controller driving paralleled Si4412DY MOSFETs for 12V @ 10A output. Use Value: Dual N-MOSFET drive minimizes conduction losses; EXTVCC switchover from VOUT reduces driver supply current by >50% vs internal LDO. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8610EMSE#PBF | Integrated power MOSFETs (42V max VIN, 3.5A), Silent Switcher architecture, fixed 2MHz frequency. | Eliminates external FET layout complexity but lacks SFB pin and programmable frequency; not suitable for multi-output auxiliary regulation. | Select LT8610EMSE#PBF only when board space and EMI are prioritized over auxiliary rail control and frequency flexibility. |
| TPS54260DGQR | Integrated 60V buck regulator (2.5A), adjustable frequency (100kHz–2.5MHz), no SFB pin, no secondary feedback capability. | Offers wider VIN range and higher integration but cannot regulate auxiliary outputs via winding feedback; lacks Burst Mode for ultra-low IQ. | Choose TPS54260DGQR for cost-sensitive 60V-input applications where auxiliary regulation is handled separately. |
Compared with LT8610EMSE#PBF and TPS54260DGQR, the LTC1435AIS#TRPBF uniquely supports secondary winding feedback for multi-output isolation, offers user-programmable frequency via COSC, and delivers <25µA shutdown current-making it optimal for battery-critical and multi-rail industrial designs where external FET control is acceptable.
Availability
LTC1435AIS#TRPBF is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, and industrial IoT sensor nodes requiring stable component supply with guaranteed long-term availability and full traceability.
Supply support for LTC1435AIS#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 LTC portfolio.
The LTC1435AIS#TRPBF belongs to Linear's high-efficiency DC/DC controller family designed specifically for synchronous step-down conversion in battery-powered and industrial power systems demanding wide input range, low dropout, and multi-output regulation capability.
FAQ
What is the maximum input voltage rating for the LTC1435AIS#TRPBF?
The absolute maximum input voltage (VIN) for the LTC1435AIS#TRPBF is 36V. Continuous operation is specified from 3.5V to 30V, with transient tolerance up to 36V. Exceeding 36V risks permanent damage to internal circuitry, especially the gate drivers and INTVCC regulator. Always include input clamping or TVS protection when operating near this limit in 24V industrial or automotive environments.
Does the LTC1435AIS#TRPBF support remote voltage sensing, and how is it implemented?
Yes, the LTC1435AIS#TRPBF supports true remote voltage sensing via dedicated VOSENSE and SGND pins. VOSENSE connects directly to the load-side of the output filter, while SGND is routed separately from power ground to the (–) terminal of COUT. This eliminates PCB trace IR drop errors, enabling ±0.8% load regulation accuracy even with 100mΩ trace resistance-critical for precision analog or FPGA core rails.
How does the SFB (Secondary Feedback) pin function in the LTC1435AIS#TRPBF?
The SFB pin on the LTC1435AIS#TRPBF enables regulation of auxiliary outputs using a transformer secondary winding. When SFB is pulled below 1.19V, the controller forces continuous conduction mode and disables Burst Mode to maintain regulation under light loads on the auxiliary rail. If unused, SFB must be tied to INTVCC-not left floating-to prevent erratic operation or false triggering of continuous mode.
What is the purpose of the EXTVCC pin on the LTC1435AIS#TRPBF, and what happens if it is left unconnected?
The EXTVCC pin on the LTC1435AIS#TRPBF provides an alternative power source for the INTVCC regulator. If left open, the internal 5V LDO powers INTVCC, resulting in higher input supply current and up to 10% efficiency penalty at high VIN. Connecting EXTVCC to VOUT (≥4.7V) engages an internal switch, reducing driver supply current and improving overall efficiency-especially in 5V-output applications.
Can the LTC1435AIS#TRPBF operate in dropout mode, and what design considerations apply?
Yes, the LTC1435AIS#TRPBF supports 99% duty cycle operation for ultra-low dropout (e.g., 5.5V→5.4V). In dropout, the top MOSFET remains on continuously, and the dropout detector periodically forces brief off-cycles to recharge the bootstrap capacitor CB. To ensure reliable operation, select a low-ESR bootstrap capacitor (≥0.1µF ceramic) and verify that the bottom MOSFET's RDS(ON) and gate drive strength support sustained conduction without thermal runaway.
LTC1435AIS#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- 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):
- 3.5V ~ 30V
- Frequency - Switching:
- Up to 400kHz
- Duty Cycle (Max):
- 99%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
LTC1435AIS#TRPBF FAQ
1.How can I place an order for LTC1435AIS#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1435AIS#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 LTC1435AIS#TRPBF reliable?
The price and inventory of LTC1435AIS#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1435AIS#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1435AIS#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1435AIS#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1435AIS#TRPBF?
LTC1435AIS#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1435AIS#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 LTC1435AIS#TRPBF?
For technical support, including LTC1435AIS#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1435AIS#TRPBF requirements.
6.How does Aetrix verify that LTC1435AIS#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1435AIS#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 LTC1435AIS#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1435AIS#TRPBF?
All LTC1435AIS#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1435AIS#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 LTC1435AIS#TRPBF part is unused and in its original packaging.
Return procedure for LTC1435AIS#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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