QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 901 MICROPOWER SYNCHRONOUS BUCK-BOOST CONVERTER FOR CDMA AND HSDPA LTC3444 DESCRIPTION Demonstration circuit 901A features the LTC3444 and is a highly efficient, 1.5MHz fixed frequency buck-boost DC/DC converter. The input voltage can range from 3.1V to 5.0V and is suitable for Li-Ion or three-cell NiCd/NiMH battery applications while the output voltage can be set anywhere from 0.8V to 4.2V by injecting a 0.35V – 2.4V Control Signal. put voltages while component count is minimized. The board provides the fast transient response required to slew the RF power amplifier from standby to transmit and transmit to standby levels. Output overvoltage protection protects the RF power amplifier. Design files for this circuit board are available. Call the LTC factory. The DC901A has been optimized for use in 3G WCDMA applications. High efficiency is achieved at very low out- QUICK START PROCEDURE Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: 1. Start with Load set to 0A. 2. Set Power Supply 1 to 3.3V and Power Supply 2 to 1V. 3. The Load can be set from 0 – 400mA. Figure 1. Proper Measurement Equipment Setup 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 901 MICROPOWER SYNCHRONOUS BUCK-BOOST CONVERTER FOR CDMA AND HSDPA Demo Board Parameters: Parameter Condition Input Voltage Range Maximum Load Current Value 3.1V – 5.0V Vout = 0.8V – 4.2V 400mA VCONTROL Range 0.35V – 2.4V* Operating Frequency 1.5MHz * See Table 1 in LTC3444 Datasheet. 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 901 MICROPOWER SYNCHRONOUS BUCK-BOOST CONVERTER FOR CDMA AND HSDPA 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 901 MICROPOWER SYNCHRONOUS BUCK-BOOST CONVERTER FOR CDMA AND HSDPA 4