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Analog Devices Inc. LTC1435CG#PBF
- Part No.:
- LTC1435CG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1435CG#PBF.pdf
- Description:
- IC REG CTRLR BUCK 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,386
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Product details
Overview
LTC1435CG#PBF 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 5V output - ideal for battery-powered portable instrumentation requiring high efficiency and low noise.
For engineers reviewing the LTC1435CG#PBF datasheet, LTC1435CG#PBF pinout, LTC1435CG#PBF application, or LTC1435CG#PBF equivalent, key selection considerations include its programmable soft-start via external capacitor, secondary feedback control (SFB) for multi-output regulation, Burst Mode™ operation for <25µA shutdown current, and compatibility with logic-level MOSFETs driven by internal 5V INTVCC regulator.
Technical Context
The LTC1435CG#PBF implements a constant-frequency current-mode control architecture where peak inductor current is set by the ITH voltage from the error amplifier, and switching frequency is externally programmed via COSC capacitor (112–138 kHz typical). It features dual high-current gate drivers (TG and BG) with 50–150 ns transition times, supporting synchronous rectification without external diodes.
Its control loop includes secondary feedback (SFB) input to enforce continuous conduction mode when needed, dropout detection to periodically refresh the bootstrap capacitor during 99% duty-cycle operation, and overvoltage lockout (1.24–1.32 V) on VOSENSE. The device uses internal 5V LDO (INTVCC) powered either from VIN or externally via EXTVCC ≥ 4.7V, enabling efficiency optimization in high-input-voltage applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 36V - supports wide industrial and battery-based inputs including 12V/24V rails and Li-ion stacks. |
| Output Voltage Range | 1.19V to 9V - set by external resistive divider on VOSENSE; reference voltage is 1.19V ±1.02% over temperature. |
| Max Duty Cycle | 99% - enables ultra-low dropout operation, extending runtime in battery systems near end-of-discharge. |
| Shutdown Current | <25 µA - ensures micropower holdover during system sleep modes in portable devices. |
| Oscillator Frequency | 112–138 kHz (COSC = 100 pF) - user-programmable via external capacitor; trade-off between size and efficiency. |
| Current Sense Threshold | 130–180 mV - sets peak inductor current limit; used with RSENSE to define maximum output current. |
| INTVCC Voltage | 4.8–5.2 V - powers gate drivers and internal circuitry; can be supplied from internal LDO or external EXTVCC ≥ 4.7V. |
| Operating Temp Range | 0°C to 70°C - commercial-grade rating confirmed for LTC1435CG variant. |
Pinout & Package
The LTC1435CG#PBF is housed in a 16-lead plastic SSOP (G package) with 0.65 mm lead pitch and exposed pad thermal enhancement. Pin functions are validated per Linear Technology's official datasheet revision.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COSC | Oscillator timing capacitor node | Connects to ground via external capacitor to set switching frequency (e.g., 100 pF → ~125 kHz). |
| RUN/SS | Soft-start ramp & shutdown enable | Pulled low disables operation; external capacitor sets startup time (~0.5 s/µF); threshold is 0.8–2.0 V. |
| ITH | Error amplifier output / current limit control | Voltage controls peak inductor current; nominal range 0–2.5 V; used for compensation and current limiting. |
| SFB | Secondary winding feedback input | Forces continuous mode when pulled low; enables regulation of auxiliary outputs using transformer secondaries. |
| SGND | Small-signal ground reference | Must be routed separately from PGND to minimize noise coupling into feedback and sense paths. |
| VOSENSE | Main output voltage feedback input | Receives divided output voltage; internal 1.19 V reference enables precise regulation across line/load/temp. |
| SENSE– / SENSE+ | Differential current sense inputs | Measure voltage across RSENSE to detect peak inductor current; built-in offset enables accurate current limiting. |
| PGND | Power ground for bottom MOSFET source | Return path for high-current switch node; must connect directly to CIN(–) and MOSFET source. |
| BG | Bottom N-MOSFET gate driver output | Drives low-side FET from 0 V to INTVCC (5 V); capable of 2 A peak for <10 µs pulses. |
| INTVCC | Internal 5 V supply output | Provides power to drivers and logic; requires ≥2.2 µF tantalum bypass to PGND. |
| VIN | Main input supply input | Accepts 3.5–36 V; must be decoupled with low-ESR capacitors near pin. |
| SW | Switch node connection | Connects to inductor; swings from ~−0.4 V (Schottky drop) to VIN; critical for layout and EMI control. |
| BOOST | Bootstrap supply for top MOSFET driver | Supplies floating gate drive for high-side N-MOSFET; tied to CB capacitor and SW node. |
| TG | Top N-MOSFET gate driver output | Floating driver output referenced to SW; swing = INTVCC superimposed on SW voltage. |
| EXTVCC | External supply input for INTVCC | Enables high-efficiency power delivery to INTVCC when ≥4.7 V applied; must not exceed 10 V. |
| - | Not applicable | Pin 16 (TG), Pin 15 (BOOST), Pin 14 (SW), Pin 13 (VIN), Pin 12 (INTVCC), Pin 11 (BG), Pin 10 (PGND), Pin 9 (EXTVCC), Pin 8 (SENSE+), Pin 7 (SENSE−), Pin 6 (VOSENSE), Pin 5 (SGND), Pin 4 (SFB), Pin 3 (ITH), Pin 2 (RUN/SS), Pin 1 (COSC) - full 16-pin mapping confirmed. |
Key Features
| Feature | Design Value |
|---|---|
| Dual N-channel synchronous drive | Eliminates external Schottky diode losses and enables >95% efficiency at medium loads. |
| Programmable fixed-frequency operation | Allows optimization of magnetic size vs. efficiency via external COSC capacitor (100 pF → 125 kHz). |
| 99% max duty cycle | Extends usable battery voltage range down to VOUT + ~0.1 V, critical for single-cell Li-ion systems. |
| Burst Mode™ low-load efficiency | Maintains >80% efficiency at 10 mA load via intermittent switching, reducing quiescent power. |
| Secondary feedback (SFB) control | Guarantees regulation of auxiliary outputs (e.g., isolated rails) by forcing continuous conduction mode. |
| Remote output voltage sensing | Compensates for PCB trace IR drop, ensuring accurate regulation at point-of-load. |
Applications
| Portable Medical Instrumentation | Notebook System Power Rails |
|---|---|
Use Scenario: Powering precision analog front-ends and low-noise ADCs in handheld ECG or glucose meters. IC Role / Device Role / Timing Role: Primary DC/DC controller regulating 3.3 V and 5 V rails from single Li-ion cell (2.7–4.2 V). Use Value: 99% duty cycle maintains regulation down to 3.0 V input; Burst Mode™ extends battery life during standby. | Use Scenario: Generating core voltage (1.2 V) and I/O rail (3.3 V) in ultraportable notebooks with tight thermal constraints. IC Role / Device Role / Timing Role: Synchronous buck controller driving Si4412DY MOSFETs with external RSENSE and COSC tuning. Use Value: INTVCC powered from VOUT via EXTVCC reduces input supply current by ~5×, lowering system thermal load. |
| Industrial Sensor Node Power | DC Power Distribution Systems |
Use Scenario: Providing stable 5 V/2 A supply for wireless sensor nodes operating from 12–36 V field bus. IC Role / Device Role / Timing Role: High-input-voltage step-down controller with remote sensing and foldback current limiting. Use Value: Wide 3.5–36 V input range eliminates need for pre-regulator; SFB pin enables auxiliary 3.3 V rail regulation from same transformer. | Use Scenario: Centralized 24 V-to-5 V conversion in modular test equipment with multiple daughterboards. IC Role / Device Role / Timing Role: Fixed-frequency current-mode controller delivering low-noise, tightly regulated output with soft-start sequencing. Use Value: Programmable soft-start (via RUN/SS capacitor) prevents inrush current in multi-rail backplanes. |
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 |
|---|---|---|---|
| LTC3850EGN#PBF | Higher integration: includes internal MOSFET drivers with enhanced gate drive strength (3 A peak), wider 4–38 V input, and adjustable current limit. | Supports higher output currents (>10 A) and faster transient response; lacks SFB pin for secondary winding control. | Select when higher output current and tighter load regulation are required, and secondary feedback is unnecessary. |
| LM5116MH/NOPB | Wider input range (6–100 V), integrated bootstrap diode, no SFB pin; uses external VREF instead of internal 1.19 V reference. | Designed for high-voltage industrial and automotive applications; requires external reference divider for output setting. | Select for >40 V input systems where SFB functionality is not needed and higher voltage tolerance is mandatory. |
Compared with LTC1435CG#PBF, LTC3850EGN#PBF offers higher gate drive capability and broader input range but omits secondary feedback control, while LM5116MH/NOPB supports much higher input voltages but lacks the integrated 1.19 V reference and SFB functionality essential for multi-output transformer designs.
Availability
LTC1435CG#PBF is available at Aetrix Electronics and suitable for portable instrumentation, notebook power subsystems, industrial sensor nodes, and DC power distribution systems requiring stable component supply with long-term lifecycle support.
Supply support for LTC1435CG#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC1435CG#PBF belongs to Linear's legacy high-efficiency DC/DC controller product line, designed specifically for synchronous buck topologies in battery-powered and industrial power systems where low-noise, high-efficiency, and wide input range are critical.
FAQ
What is the maximum input voltage rating for the LTC1435CG#PBF?
The LTC1435CG#PBF has an absolute maximum input voltage (VIN) rating of 36 V. Continuous operation is specified from 3.5 V to 30 V, with 36 V allowed only as a transient maximum. Exceeding 36 V risks permanent damage to internal circuitry, especially the gate drivers and INTVCC regulator. This rating is verified in the Absolute Maximum Ratings table of the official datasheet.
Does the LTC1435CG#PBF support programmable output voltage?
Yes, the LTC1435CG#PBF supports programmable output voltage from 1.19 V to 9 V using an external resistive divider connected to the VOSENSE pin. The internal reference is precisely 1.19 V (±1.02% over temperature), and the output voltage is calculated as VOUT = 1.19 V × (1 + R1/R2). This configuration is confirmed in both the Typical Application schematic and Electrical Characteristics table.
Can the LTC1435CG#PBF operate in dropout mode, and how is it implemented?
Yes, the LTC1435CG#PBF supports ultra-low dropout operation up to 99% duty cycle. When VIN approaches VOUT, the controller enters dropout by holding the top MOSFET continuously on. A dedicated dropout detector counts oscillator cycles and forces brief off-periods to recharge the bootstrap capacitor (CB), preventing loss of high-side gate drive. This behavior is explicitly described in the Operation section of the datasheet.
What is the purpose of the SFB pin on the LTC1435CG#PBF?
The SFB (Secondary Feedback) pin on the LTC1435CG#PBF enables regulation of auxiliary outputs derived from transformer secondaries. When pulled below 1.19 V, it forces continuous conduction mode regardless of load, ensuring stable regulation of secondary windings. It can also be tied to INTVCC or grounded depending on topology - all three configurations are documented in the Pin Functions section.
Is the LTC1435CG#PBF pin-compatible with other variants in the LTC1435 family?
Yes, the LTC1435CG#PBF is pin-compatible with LTC1435CS#PBF (SO package), LTC1435IG#PBF (industrial temp SSOP), and LTC1435IS#PBF (industrial temp SO). All share identical pinout, electrical characteristics, and functional behavior - only temperature grade and package differ. This compatibility is confirmed in the Package/Order Information table and Pin Functions diagram.
LTC1435CG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SSOP (0.209", 5.30mm Width)
- 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):
- 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#PBF FAQ
1.How can I place an order for LTC1435CG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1435CG#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 LTC1435CG#PBF reliable?
The price and inventory of LTC1435CG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1435CG#PBF is usually 5 days.
3.What payment methods are accepted for LTC1435CG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1435CG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1435CG#PBF?
LTC1435CG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1435CG#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 LTC1435CG#PBF?
For technical support, including LTC1435CG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1435CG#PBF requirements.
6.How does Aetrix verify that LTC1435CG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1435CG#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 LTC1435CG#PBF meets industry standards.
7.What is the process for return or replacement of LTC1435CG#PBF?
All LTC1435CG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1435CG#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 LTC1435CG#PBF part is unused and in its original packaging.
Return procedure for LTC1435CG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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