LTC3445 - I²C Controllable Buck Regulator with Two LDOs in a 4mm × 4mm QFN
Features
- Buck Regulator
- High Efficiency: Up to 93%
- 600mA Output Current (VCC1 = 3V, VOUT = 1.3V)
- Programmable Output Voltage: 0.85V to 1.55V
- 2.5V to 5.5V Input Voltage Range
- 1.5MHz Constant Frequency or Spread Spectrum Option
- Soft-Start
- LDOs
- Two LDO Regulators: 0.3V Dropout at 50mA
- PowerPath Controller
- Dynamically Regulates VCC BATT
- I2C
- Standard (100kHz) or Fast Mode (400kHz)
- 24-Lead (4mm × 4mm) QFN Package
Typical Application
Description
The LTC3445 contains a high efficiency monolithic synchronous current mode buck regulator, two LDO regulators, a PowerPath controller and an I2C interface.The buck regulator has a 6-bit programmable output range of 0.85V to 1.55V. Also, the buck regulator uses either a constant (1.5MHz) or a spread spectrum switching frequency. Using the spread spectrum option allows for a lower noise regulated output as well as low noise at the input. In addition, the regulated output voltage slew rate is programmable via the I2C interface.
The LTC3445 contains two LDO voltage regulators. The regulator output voltages are externally resistor programmable. Each LDO is capable of delivering up to 50mA.
The LTC3445 contains control circuitry (PowerPath) for automatic back-up battery selection. VBACKUP is typically a coin cell.
Typical supply current during operation is only 360µA and drops to 27µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3445 ideal for single Li-Ion battery-powered applications. Automatic Burst Mode® operation increases efficiency at light loads, further extending battery life.
Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, Spread Spectrum patent pending.
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 |
|---|---|---|---|---|---|
| LTC3445EUF#PBF | 4x4 QFN-24 | UF | E | 05-08-1697 | Yes |
| LTC3445EUF#TRPBF | 4x4 QFN-24 | UF | E | 05-08-1697 | 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 | |
|---|---|---|---|---|---|---|
| LTC3445EUF#PBF | 4x4 QFN-24 | E | $3.50 | $2.45 | Yes | |
| LTC3445EUF#TRPBF | 4x4 QFN-24 | E | $2.51 | 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 |
|---|---|---|---|
| DC698A | LTC3445EUF Demo Board | I2C-Controllable Buck Plus Dual LDO & PowerPath, 2.5V ≤ VIN ≤ 5.5V, Vout1 = 0.85 to 1.55 @ 0.6A, Vout2 = 1.3V @ 50mA, Vout3 = 1.1V @ 50mA | Contact Factory | |
| Buy Now | |||
Applications
- Intel’s Microprocessor Supply (PXA27X)
- Portable Instruments
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Design Tools
Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:
- LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
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- Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
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- And More!
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.
