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Analog Devices Inc. LTC1735IS-1#PBF
- Part No.:
- LTC1735IS-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1735IS-1#PBF.pdf
- Description:
- IC REG CTRLR BUCK 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,870
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Product details
Overview
LTC1735IS-1#PBF from Analog Devices (formerly Linear Technology) is a synchronous step-down switching regulator controller optimized for CPU core power delivery in mobile computing systems. It features ±1% output voltage accuracy, 0.8V–7V programmable VOUT, 3.5V–36V input range, 99% maximum duty cycle for low-dropout operation, and OPTI-LOOP™ compensation for stable transient response across wide output capacitance/ESR variations.
For engineers reviewing the LTC1735IS-1#PBF datasheet, LTC1735IS-1#PBF pinout, LTC1735IS-1#PBF application, or LTC1735IS-1#PBF equivalent, this device is selected for Intel Mobile CPU-compliant dynamic voltage scaling, high-efficiency light-load performance via Burst Mode™, and robust protection including foldback current limiting, overvoltage crowbar, and latched short-circuit shutdown.
Technical Context
The LTC1735IS-1#PBF implements a constant-frequency, current-mode control architecture with dual N-channel MOSFET synchronous drive. Its error amplifier output (ITH pin) directly sets peak inductor current, while VOSENSE monitors feedback voltage against a 0.8V reference with ±7.5% power-good window compliance to Intel Mobile CPU Specifications.
It supports external frequency programming via COSC capacitor (265–335 kHz typical), synchronization to external clock via PGOOD pin (0.9fO–1.3fO), and programmable soft-start via RUN/SS capacitor. Protection includes internal foldback current limiting triggered below 0.6V VOSENSE, output overvoltage lockout at 0.84–0.88V, and latchoff short-circuit shutdown with defeat option.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Range | 0.8V to 7V - Programmable via external resistor divider; enables dynamic voltage scaling for SpeedStep-enabled processors. |
| Input Voltage Range | 3.5V to 36V - Supports wide-input industrial and notebook battery rails; UVLO threshold at 3.5V ensures safe startup. |
| Output Voltage Accuracy | ±1% - Tight regulation over temperature and line/load conditions ensures CPU core voltage compliance. |
| Max Duty Cycle | 99.4% - Enables ultra-low dropout operation near VIN ≈ VOUT, critical for battery-powered mobile systems. |
| Power Good Threshold | ±7.5% of set VOUT - Meets Intel Mobile CPU specification for reliable power sequencing and fault detection. |
| Quiescent Current (Shutdown) | <25µA - Micropower shutdown enables long battery standby in portable devices. |
| Oscillator Frequency | 265–335 kHz (COSC = 47pF) - Adjustable up to 500kHz; balances efficiency vs. component size for CPU VRMs. |
Pinout & Package
Package: 16-lead narrow SO (SO-16); RoHS-compliant, lead-free (Pb-free) finish per #PBF suffix.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COSC | Oscillator timing capacitor connection | Sets operating frequency; 47pF yields ~300kHz; supports synchronization when driven externally via PGOOD. |
| RUN/SS | Soft-start ramp & enable control | Capacitor-based soft-start (~1.25s/µF); <1.5V forces shutdown; discharge current enables short-circuit latchoff timer. |
| ITH | Error amplifier output / current limit control | Voltage (0–2.4V) sets peak inductor current; foldback reduces ITH below 0.6V VOSENSE to limit short-circuit current. |
| PGOOD | Open-drain power-good indicator & sync input | Pulled low when VOSENSE outside ±7.5%; tied to INTVCC enables Burst Mode™; driven externally enables oscillator sync. |
| SENSE– / SENSE+ | Differential current sense inputs | Monitor voltage across RSENSE; built-in offset sets trip threshold (75mV max) for accurate current limiting. |
| VOSENSE | Feedback voltage input | Receives divided output voltage; referenced to 0.8V internal bandgap; ±1% accuracy maintained over temp and line. |
| TG / BG | Top/bottom gate drivers | Drive external N-MOSFETs; TG is floating driver referenced to SW node; BG swings 0–INTVCC (5.2V). |
| VIN / PGND / SGND | Main input / power ground / signal ground | PGND carries high di/dt return path; SGND is star point for all small-signal components to minimize noise coupling. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP™ Compensation | Minimizes required output capacitance and relaxes ESR constraints-enables stable operation with ceramic capacitors alone. |
| Burst Mode™ Operation | Enables >85% efficiency at 10mA load (VIN=10V, VOUT=3.3V); eliminates audible noise and extends battery life in idle states. |
| Programmable Soft-Start | External CSS capacitor controls inrush current ramp time and provides short-circuit timeout function during startup. |
| Remote Output Voltage Sense | VOSENSE pin accepts Kelvin-sense connection to improve regulation accuracy under PCB trace resistance. |
| Logic-Controlled Shutdown | IQ < 25µA in shutdown; RUN/SS pin accepts logic-level control for system-level power sequencing. |
Applications
| Mobile CPU Core Power Supply | Intel SpeedStep®-Enabled Notebook VRM |
|---|---|
Use Scenario: Dynamic voltage/frequency scaling for Pentium® III processors in ultraportable notebooks. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing core voltage transitions between 1.35V and 1.60V. Use Value: ±7.5% PGOOD window and ±1% VOUT accuracy ensure compliance with Intel Mobile CPU specifications during rapid VSEL changes. |
Use Scenario: High-current (up to 12A) CPU core supply with thermal-aware load-line regulation. IC Role / Device Role / Timing Role: Current-mode controller with programmable RSENSE-based current limit and foldback protection. Use Value: Internal foldback current limiting reduces short-circuit stress on external MOSFETs and prevents thermal runaway during board faults. |
| Low-Power Wireless Modem Power | Industrial Embedded System DC/DC |
Use Scenario: Standby power rail for cellular baseband processors requiring micropower shutdown. IC Role / Device Role / Timing Role: Efficient light-load regulator using Burst Mode™ and <25µA shutdown IQ. Use Value: Burst Mode™ maintains >80% efficiency down to 1mA load, extending battery runtime without compromising transient response. |
Use Scenario: Wide-input (5–24V) 3.3V/5V system rail in ruggedized industrial controllers. IC Role / Device Role / Timing Role: Robust synchronous buck controller with 36V absolute max VIN and latched short-circuit shutdown. Use Value: Latched shutdown with RUN/SS defeat option allows controlled recovery after overcurrent events in unattended systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2315DJ-LF-Z | Integrated power stage (40V max VIN, 3A), fixed 500kHz fSW, no PGOOD sync capability | Lower current capacity; lacks programmable soft-start and remote sense; suited for space-constrained non-CPU apps | Select when board area is critical and full CPU compliance is not required. |
| TPS54620RGYR | 6V–18V VIN, integrated FETs, 2.5MHz fSW, PMBus interface, no Burst Mode™ | Higher switching frequency enables smaller magnetics; requires digital interface; no low-noise discontinuous mode | Select for compact designs needing telemetry and fast transient response, not ultra-low IQ. |
Compared with MP2315DJ-LF-Z and TPS54620RGYR, the LTC1735IS-1#PBF uniquely delivers Intel-compliant PGOOD timing, OPTI-LOOP™ adaptability to diverse output caps, and true low-noise Burst Mode™ operation-making it irreplaceable for legacy SpeedStep® CPU power where analog flexibility and specification fidelity are mandatory.
Availability
LTC1735IS-1#PBF is available at Aetrix Electronics and suitable for notebook computer power supplies, Intel SpeedStep®-enabled VRMs, and industrial embedded DC/DC converters requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for LTC1735IS-1#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; Linear pioneered high-performance analog ICs for precision power, signal conditioning, and timing applications.
The LTC1735IS-1#PBF belongs to Linear's CPU power controller family, designed specifically for mobile processor voltage regulation with dynamic scaling, tight accuracy, and robust fault protection.
FAQ
What is the maximum input voltage rating for the LTC1735IS-1#PBF?
The LTC1735IS-1#PBF has an absolute maximum input voltage (VIN) rating of 36V. Continuous operation is specified from 3.5V to 30V, with undervoltage lockout engaging below 3.5V. Exceeding 36V risks permanent damage to internal circuitry, especially the SW, BOOST, and TG pins which share this rating.
How does the LTC1735IS-1#PBF achieve ±1% output voltage accuracy?
The LTC1735IS-1#PBF achieves ±1% output voltage accuracy through a precision 0.8V internal bandgap reference, low-drift error amplifier, and tight tolerance on the VOSENSE feedback comparator threshold. This specification holds over the full operating temperature range (–40°C to 85°C) and across line/load variations as confirmed in the Electrical Characteristics table.
Can the LTC1735IS-1#PBF be synchronized to an external clock, and what are the limits?
Yes, the LTC1735IS-1#PBF can be synchronized to an external clock applied to the PGOOD pin. The internal oscillator locks to frequencies between 90% and 130% of its nominal free-running frequency (e.g., 270–390kHz for a 300kHz baseline). Clock high must exceed 1.3V for ≥0.3µs; low must be <0.3V for ≥0.3µs.
What protection features does the LTC1735IS-1#PBF include for short-circuit conditions?
The LTC1735IS-1#PBF includes foldback current limiting (activated when VOSENSE drops below 0.6V), output overvoltage crowbar (trip at 0.84–0.88V), and latched short-circuit shutdown with optional defeat via RUN/SS pin current injection. These operate independently of external MOSFET selection and require no additional components.
Is the LTC1735IS-1#PBF pin-compatible with other variants in the LTC1735 family?
Yes, the LTC1735IS-1#PBF shares identical pinout and package (16-lead SO) with LTC1735CS-1, LTC1735IGN-1, and LTC1735CGN-1. Differences are limited to temperature grade (–40°C to 85°C vs. 0°C to 85°C) and package type (SO vs. SSOP); electrical functionality and pin mapping are fully compatible.
LTC1735IS-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm 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:
- 300kHz
- Duty Cycle (Max):
- 99.4%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
LTC1735IS-1#PBF FAQ
1.How can I place an order for LTC1735IS-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1735IS-1#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 LTC1735IS-1#PBF reliable?
The price and inventory of LTC1735IS-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1735IS-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC1735IS-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1735IS-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1735IS-1#PBF?
LTC1735IS-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1735IS-1#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 LTC1735IS-1#PBF?
For technical support, including LTC1735IS-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1735IS-1#PBF requirements.
6.How does Aetrix verify that LTC1735IS-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1735IS-1#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 LTC1735IS-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC1735IS-1#PBF?
All LTC1735IS-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1735IS-1#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 LTC1735IS-1#PBF part is unused and in its original packaging.
Return procedure for LTC1735IS-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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