LTC3445 - I²C Controllable Buck Regulator with Two LDOs in a 4mm × 4mm QFN

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.

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

Applications
  • Intel’s Microprocessor Supply (PXA27X)
  • Portable Instruments
Packaging
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC3445EUF#PBF4x4 QFN-24E$3.50$2.45
LTC3445EUF#TRPBF4x4 QFN-24E$2.51
Demo Boards
Part NumberDescriptionPrice
DC698ALTC3445EUF 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 @ 50mAContact Factory
Datasheet
Reliability Data
Press Release
Related Product
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LTC3445 Footprints and Symbols