LTC1735 - High Efficiency Synchronous Step-Down Switching Regulator
Features
- Synchronizable/Programmable Fixed Frequency
- OPTI-LOOP™ Compensation Minimizes COUT
- ±1% Output Voltage Accuracy
- Dual N-Channel MOSFET Synchronous Drive
- Wide VIN Range: 4V to 36V Operation
- VOUT Range: 0.8V to 6V
- Internal Current Foldback
- Output Overvoltage Crowbar Protection
- Latched Short-Circuit Shutdown Timer with Defeat Option
- Very Low Dropout Operation: 99% Duty Cycle
- Forced Continuous Control Pin
- Optional Programmable Soft-Start
- Remote Output Voltage Sense
- Power Good Output (LTC1735F Only)
- Logic Controlled Micropower Shutdown: IQ < 25µA
- LTC1435 Pin Compatible with Minor Component Changes
- Available in 16-Lead Narrow SSOP, SO Packages and 20-Lead TSSOP Package (LTC1735F Only)
AEC-Q100 data available for specific packages
Typical Application
Description
The LTC1735 is a synchronous step-down switching regulator controller that drives external N-channel power MOSFETs using a fixed frequency architecture. Burst Mode operation provides high efficiency at low load currents. The precision 0.8V reference is compatible with future generation microprocessors. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values.
The operating frequency (synchronizable up to 500kHz) is set by an external capacitor allowing maximum flexibility in optimizing efficiency. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling Burst Mode operation when the main output is lightly loaded.
Protection features include internal foldback current limiting, output overvoltage crowbar and optional shortcircuit shutdown. Soft-start is provided by an external capacitor that can be used to properly sequence supplies. The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 4V to 30V (36V maximum).
| Features | |
| LTC1735 | - |
| LTC1735-1 | Power Good |
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC1735CF#PBF | TSSOP-20 | F | C | 05-08-1650 (F20) | Yes |
| LTC1735CF#TRPBF | TSSOP-20 | F | C | 05-08-1650 (F20) | Yes |
| LTC1735CGN#PBF | SSOP-16 | GN | C | 05-08-1641 (GN16) | Yes |
| LTC1735CGN#TRPBF | SSOP-16 | GN | C | 05-08-1641 (GN16) | Yes |
| LTC1735CS#PBF | SO-16 | S | C | 05-08-1610 (S16) | Yes |
| LTC1735CS#TRPBF | SO-16 | S | C | 05-08-1610 (S16) | Yes |
| LTC1735EGN#PBF | SSOP-16 | GN | E | 05-08-1641 (GN16) | Yes |
| LTC1735EGN#TRPBF | SSOP-16 | GN | E | 05-08-1641 (GN16) | Yes |
| LTC1735IF#PBF | TSSOP-20 | F | I | 05-08-1650 (F20) | Yes |
| LTC1735IF#TRPBF | TSSOP-20 | F | I | 05-08-1650 (F20) | Yes |
| LTC1735IGN#PBF | SSOP-16 | GN | I | 05-08-1641 (GN16) | Yes |
| LTC1735IGN#TRPBF | SSOP-16 | GN | I | 05-08-1641 (GN16) | Yes |
| LTC1735IS#PBF | SO-16 | S | I | 05-08-1610 (S16) | Yes |
| LTC1735IS#TRPBF | SO-16 | S | I | 05-08-1610 (S16) | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC1735CF#PBF | TSSOP-20 | C | $3.91 | $3.30 | Yes | |
| LTC1735CF#TRPBF | TSSOP-20 | C | $3.42 | Yes | ||
| LTC1735CGN#PBF | SSOP-16 | C | $3.80 | $3.25 | Yes | |
| LTC1735CGN#TRPBF | SSOP-16 | C | $3.31 | Yes | ||
| LTC1735CS#PBF | SO-16 | C | $3.65 | $3.10 | Yes | |
| LTC1735CS#TRPBF | SO-16 | C | $3.16 | Yes | ||
| LTC1735EGN#PBF | SSOP-16 | E | $4.25 | $3.60 | Yes | |
| LTC1735EGN#TRPBF | SSOP-16 | E | $3.66 | Yes | ||
| LTC1735IF#PBF | TSSOP-20 | I | $6.52 | $4.30 | Yes | |
| LTC1735IF#TRPBF | TSSOP-20 | I | $4.42 | Yes | ||
| LTC1735IGN#PBF | SSOP-16 | I | $5.05 | $4.25 | Yes | |
| LTC1735IGN#TRPBF | SSOP-16 | I | $4.31 | Yes | ||
| LTC1735IS#PBF | SO-16 | I | $4.90 | $4.05 | Yes | |
| LTC1735IS#TRPBF | SO-16 | I | $4.11 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC222A | LTC1735CS | 10A Synchronous Buck Regulator, Vin = 5.5V to 28V, Vout = 1.6V to 5V (thru-hole caps) | $125.00 | |
| DC247A | LTC1735CS | CPU Low Voltage High Current Supply, Vin = 6V to 26V, Vout = 1.6V @ 9A (thru-hole caps) | $125.00 | |
| Buy Now | |||
Designed for Automotive and Transportation Applications
AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC1735IGN#PBF | SSOP-16 | I | $5.05 | $4.25 | Yes | |
| LTC1735IGN#TRPBF | SSOP-16 | I | $4.31 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- Notebook and Palmtop Computers, PDAs
- Cellular Telephones and Wireless Modems
- DC Power Distribution Systems
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
Models for the following parts are available in LTspice:
LTC1735
LTC1735-1
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
