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Analog Devices Inc. LTC1435CG#TRPBF
- Part No.:
- LTC1435CG#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1435CG#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,310
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Product details
Overview
LTC1435CG#TRPBF from Analog Devices (formerly Linear Technology) is a synchronous step-down switching regulator controller that drives external dual 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 up to 99% duty cycle for ultra-low dropout, and achieves >95% efficiency at 1A load with 3.3V output - ideal for battery-powered portable instrumentation.
For engineers reviewing the LTC1435CG#TRPBF datasheet, LTC1435CG#TRPBF pinout, LTC1435CG#TRPBF application, or LTC1435CG#TRPBF equivalent, key selection criteria include its programmable oscillator frequency (via COSC capacitor), secondary feedback control (SFB pin), logic-controlled micropower shutdown (<25µA IQ), remote voltage sensing, and soft-start programmability - all critical for high-efficiency DC/DC design in space-constrained, thermally sensitive systems.
Technical Context
The LTC1435CG#TRPBF implements a constant-frequency current-mode control architecture with peak inductor current regulation via the ITH pin and error amplifier feedback referenced to 1.19V. Its dual gate drivers (TG and BG) deliver fast transitions (50–150ns rise/fall) to external N-MOSFETs, supporting synchronous rectification without external diodes.
Burst Mode™ operation enables high light-load efficiency by disabling both drivers when inductor current reverses and ITH falls below 0.6V; continuous mode is enforced when SFB < 1.19V or SENSE+/- common-mode voltage drops below 1.4V. The internal 5V INTVCC regulator powers control circuitry and can be bypassed via EXTVCC ≥ 4.7V for improved system efficiency.
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, and 28V rails. |
| Output Voltage Range | 1.19V to 9V - set via external resistor divider on VOSENSE; 1.19V reference enables precise low-voltage regulation. |
| Max Duty Cycle | 99% - enables ultra-low dropout operation (e.g., VIN = 3.6V → VOUT = 3.3V), extending runtime in battery systems. |
| Shutdown Current | <25µA - ensures minimal quiescent drain during system sleep modes in portable devices. |
| Oscillator Frequency | 112–138 kHz (COSC = 100pF) - externally programmable for optimal trade-off between efficiency and EMI filtering. |
| Current Sense Threshold | 130–180 mV - sets peak inductor current limit; compatible with RSENSE = 0.005Ω–0.2Ω for 0.5A–20A output ranges. |
| Operating Temp Range | 0°C to 70°C - commercial-grade rating suitable for notebook, PDA, and industrial embedded applications. |
| Package | 16-lead SSOP (G package) - surface-mount, 5.3mm × 6.2mm footprint with 0.65mm pitch; thermal resistance θJA = 130°C/W. |
Pinout & Package
Package: 16-lead plastic SSOP (G package), RoHS-compliant, moisture-sensitive level 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COSC | Oscillator timing capacitor connection | Sets switching frequency; 100pF yields ~125kHz; charge/discharge current defines fOSC per datasheet formula. |
| RUN/SS | Soft-start ramp & shutdown enable | Internal 3µA current source charges CSS; voltage <1.3V forces shutdown; clamps ITH during startup. |
| ITH | Error amplifier output / current limit control | Voltage controls peak inductor current threshold; 0–2.5V range maps to full current range. |
| SFB | Secondary winding feedback input | Pull low to force continuous mode; tie to INTVCC if no secondary winding; enables multi-output regulation. |
| SGND | Small-signal ground reference | Must be routed separately from PGND to avoid noise coupling into feedback and sense paths. |
| VOSENSE | Main output voltage feedback input | Receives resistive divider signal; error amplifier compares to 1.19V reference for regulation. |
| SENSE– / SENSE+ | Differential current sense inputs | Measure voltage across RSENSE; built-in offset enables accurate current limiting without external amplifiers. |
| PGND | Power ground for bottom MOSFET source | Connects to CIN(–) and M2 source; separates high-current return from signal ground. |
| BG | Bottom N-MOSFET gate driver output | Swings from 0V to INTVCC (≈5V); drives synchronous rectifier with fast 50–150ns transitions. |
| INTVCC | Internal 5V regulator output | Powers control logic and drivers; requires ≥2.2µF tantalum bypass to PGND; max 15mA load. |
| VIN | Main input supply | 3.5–36V input; must be decoupled with low-ESR capacitors near pin; feeds internal LDO and oscillator. |
| SW | Switch node connection | Connects to inductor and top MOSFET drain; voltage swings from –0.3V (Schottky drop) to VIN. |
| BOOST | Bootstrap supply for top MOSFET driver | Accepts floating bootstrap capacitor CB; supplies TG driver with voltage referenced to SW node. |
| TG | Top N-MOSFET gate driver output | Floating driver output; voltage swing = INTVCC superimposed on SW node; drives high-side switch. |
| EXTVCC | External VCC input for INTVCC switch | Switches internal P-MOSFET to connect EXTVCC to INTVCC when >4.7V; improves efficiency vs internal LDO. |
Key Features
| Feature | Design Value |
|---|---|
| Dual N-MOSFET synchronous drive | Eliminates external Schottky loss; enables >95% efficiency at 3.3V/1A with proper MOSFET selection (e.g., Si4412DY). |
| Programmable fixed-frequency operation | External COSC capacitor allows optimization of switching frequency (100–400kHz) for EMI, size, and efficiency trade-offs. |
| 99% maximum duty cycle | Supports VIN–VOUT dropout as low as 0.1V - critical for maintaining regulation in Li-ion (3.0–4.2V) and lead-acid battery systems. |
| Secondary feedback control (SFB) | Enables independent regulation of auxiliary outputs using transformer secondaries - essential for isolated multi-rail supplies. |
| Logic-controlled micropower shutdown | IQ < 25µA in shutdown reduces standby power in always-on portable devices such as PDAs and wireless modems. |
| Remote output voltage sensing | Compensates for PCB trace IR drop; maintains ±0.5% load regulation accuracy even with 100mΩ interconnect resistance. |
Applications
| Portable Medical Instrumentation | Notebook & Ultrabook Power Rails |
|---|---|
Use Scenario: Powering precision analog front-ends and low-noise ADCs in handheld ECG or glucose meters with single-cell Li-ion input. IC Role / Device Role / Timing Role: Primary step-down controller regulating 3.3V and 1.8V rails from 3.6–4.2V battery; Burst Mode maintains efficiency at µA-level sensor bias currents. Use Value: 99% duty cycle sustains regulation down to 3.35V battery voltage; remote sensing ensures stable 0.1% reference accuracy under dynamic load. | Use Scenario: Generating core voltage (1.05V) and I/O rail (3.3V) in fanless ultrabooks using compact inductor solutions. IC Role / Device Role / Timing Role: Synchronous buck controller driving discrete N-MOSFETs; EXTVCC tied to 3.3V rail to reduce input current and improve full-load efficiency by ~8%. Use Value: Programmable soft-start prevents inrush into large output capacitance; SFB pin enables coordinated sequencing with companion regulators. |
| Industrial IoT Sensor Nodes | DC Power Distribution Systems |
Use Scenario: Converting 24V field bus to 5V/3.3V for LoRaWAN or NB-IoT modems operating in harsh ambient temperatures. IC Role / Device Role / Timing Role: High-input-voltage buck controller with 36V absolute max rating; operates continuously from –40°C to +70°C ambient. Use Value: Foldback current limiting protects against sustained short-circuit faults; low 260µA quiescent current extends battery life in energy-harvested nodes. | Use Scenario: Centralized 48V-to-12V conversion feeding multiple downstream point-of-load regulators in telecom base stations. IC Role / Device Role / Timing Role: Primary intermediate bus converter; uses secondary feedback (SFB) to regulate isolated 12V output while maintaining tight cross-regulation. Use Value: Dual gate drivers support high-current discrete FETs (e.g., 60A peak); 130°C/W θJA enables convection-cooled operation without heatsink. |
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#TRPBF | Integrated power MOSFETs (42V input, 3.5A); higher integration but fixed 3.5A current limit; no SFB pin. | Best for space-constrained designs needing integrated FETs; unsuitable for >3.5A or secondary-winding regulation. | Select LTC1435CG#TRPBF when discrete MOSFETs are required for >5A, high-efficiency optimization, or multi-output transformer-based designs. |
| TPS54260DGQR | Integrated 60V buck regulator (2.6A); includes internal compensation; no secondary feedback capability; lower IQ (14µA shutdown). | Preferred for cost-sensitive, medium-power applications without auxiliary output requirements. | Choose LTC1435CG#TRPBF when secondary feedback (SFB), 99% duty cycle, or external MOSFET flexibility is mandatory. |
Compared with LT8610EMSE#TRPBF and TPS54260DGQR, the LTC1435CG#TRPBF offers unique secondary feedback control and 99% duty cycle for ultra-low dropout - enabling reliable operation in battery systems where input voltage approaches output, and supporting transformer-coupled auxiliary rails not possible with integrated alternatives.
Availability
LTC1435CG#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, notebook power management, and industrial IoT sensor nodes requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC1435CG#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 the LTC portfolio.
The LTC1435CG#TRPBF belongs to Linear's high-efficiency synchronous buck controller family, designed specifically for discrete-FET DC/DC conversion in battery-powered and wide-input industrial systems where thermal performance, light-load efficiency, and multi-output regulation are critical.
FAQ
What is the maximum input voltage rating for the LTC1435CG#TRPBF?
The LTC1435CG#TRPBF has an absolute maximum input voltage rating of 36V on the VIN pin. 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 observe derating guidelines in high-temperature environments per the datasheet's thermal calculations.
Does the LTC1435CG#TRPBF support true synchronous rectification without external diodes?
Yes, the LTC1435CG#TRPBF supports full synchronous rectification using two external N-channel MOSFETs driven by its dedicated TG and BG pins. It does not require an external Schottky diode for freewheeling - though a small Schottky (e.g., MBRS140T3) is recommended across the bottom FET during dead-time to prevent body diode conduction and associated efficiency loss. This architecture enables >95% efficiency at typical loads.
How is the output voltage set on the LTC1435CG#TRPBF?
The output voltage of the LTC1435CG#TRPBF is set using an external resistor divider connected between VOUT, VOSENSE, and SGND. The internal 1.19V reference is compared to the divided feedback voltage; thus VOUT = 1.19V × (1 + R1/R2). Typical values like R1 = 32.4kΩ and R2 = 22.1kΩ yield 2.9V. Accuracy depends on resistor tolerance and temperature drift - precision metal-film resistors are recommended for <1% total error.
Can the LTC1435CG#TRPBF operate in dropout mode, and how is it implemented?
Yes, the LTC1435CG#TRPBF supports ultra-low dropout operation with up to 99% duty cycle. When VIN approaches VOUT, the controller enters dropout by holding the top MOSFET on continuously. A dropout detector monitors consecutive oscillator cycles with TG high and periodically inserts brief off-times to recharge the bootstrap capacitor (CB), preventing driver undervoltage. This preserves regulation down to VIN–VOUT ≈ 100mV.
What is the function of the SFB pin on the LTC1435CG#TRPBF, and how should it be used?
The SFB (Secondary Feedback) pin on the LTC1435CG#TRPBF enables regulation of auxiliary outputs via transformer secondary windings. When pulled below 1.19V, it forces continuous conduction mode and disables Burst Mode. For single-output designs without secondaries, tie SFB to INTVCC. For multi-output flyback or forward converters, connect SFB to a resistive divider from the secondary - ensuring tight cross-regulation even under unbalanced loading conditions.
LTC1435CG#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SSOP (0.209", 5.30mm 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
LTC1435CG#TRPBF FAQ
1.How can I place an order for LTC1435CG#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1435CG#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 LTC1435CG#TRPBF reliable?
The price and inventory of LTC1435CG#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1435CG#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1435CG#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1435CG#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1435CG#TRPBF?
LTC1435CG#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1435CG#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 LTC1435CG#TRPBF?
For technical support, including LTC1435CG#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1435CG#TRPBF requirements.
6.How does Aetrix verify that LTC1435CG#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1435CG#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 LTC1435CG#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1435CG#TRPBF?
All LTC1435CG#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1435CG#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 LTC1435CG#TRPBF part is unused and in its original packaging.
Return procedure for LTC1435CG#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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