QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1053E through 1053H SYNCHRONOUS BOOST DC/DC CONVERTER LTC3526L/LTC3526LB/LTC3526L-2/LTC3526LB-2 DESCRIPTION Demonstration circuits1053A-E through 1053A- This demonstration circuit allows the user to H are high efficiency synchronous boost con- quickly evaluate the LTC3526L performance. verters capable of operating with an input volt- Individual jumpers are provided for selecting age range from 0.8V to 5.5V. The 2X2 mm DFN several regulated output voltages and a low thermally enhanced package with a 1MHz quiescent current shutdown. Terminals on the switching frequency (2MHz for -2 versions) and board allow easy hookup to an input supply and the 550mA internal switches provide a very tiny output load. solution. The LTC3526L family also features Design files for this circuit board are available. output disconnect and the input voltage can be Call the LTC factory. greater or less than the output voltage. LTC and Burst Mode are trademarks of Linear Technol- ogy Corporation Table 1. Typical Specifications (25C) Input Voltage Range V 0.8V to 5V IN 1.8V V V = 1V, I = 100mA 1.8V 2.5% OUT IN OUT 3.3V V V = 1.5V, I = 100mA 3.3V 2.5% OUT IN OUT 5V V V = 1.5V, I = 100mA 5.0V 2.5% OUT IN OUT Output Ripple Voltage (burst mode) V = 1.2V, V = 1.8V I = 1mA 45mV p-p IN OUT OUT Output Ripple Voltage (fixed frequency) V = 1.2V, V = 1.8V I = 100mA 10mV p-p IN OUT OUT Efficiency (1 MHz) V = 1.2V, V = 1.8V I = 50mA 85% IN OUT OUT Efficiency (1 MHz) V = 2.5V, V = 3.3V I = 50mA 92% IN OUT OUT Resistive Load - Input V Power V Supply + A A Figure 1. Demonstration Circuit Test Setup 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1053E through 1053H SYNCHRONOUS BOOST DC/DC CONVERTER Table 2. Demonstration Circuit Board Information Board LTC Part Number Part Frequency Inductor Mode Action Number Marking 1053A-A LTC3526EDC LCHW 1MHz 4.7H Burst Discontinued, use 1053A-E 1053A-B LTC3526BEDC LCNN 1MHz 4.7H No Burst Discontinued, use 1053A-F 1053A-C LTC3526EDC-2 LCNM 2MHz 2.2H Burst Discontinued, use 1053A-G 1053A-D LTC3526BEDC-2 LCNP 2MHz 2.2H No Burst Discontinued, use 1053A-H 1053A-E LTC3526LEDC LCSS 1MHz 4.7H Burst 1053A-F LTC3526LBEDC LCST 1MHz 4.7H No Burst 1053A-G LTC3526LEDC-2 LFFC 2MHz 2.2H Burst 1053A-H LTC3526LBEDC-2 LFFD 2MHz 2.2H No Burst QUICK START PROCEDURE There is one demonstration circuit board for board. At very low input voltages, voltage all four LTC3526L versions. The boards are drops in the power supply wire connections identified by the handwritten information on and Ammeter will result in the input voltage at the top of the pc board. the input terminals dropping below the mini- mum voltage required for operation. The boost converter can be evaluated using the setup shown in Figure 1. Select one of the The input voltage can exceed the output volt- three output voltages using jumpers JP1 age and still maintain regulation, although the through JP3. (With no jumpers installed, the load current is less and efficiency is lower. It output voltage is 5V.) Set jumper JP4 in the should be noted that under some load current ON position and connect voltmeters and am- conditions, the output voltage ripple could in- meters as shown on the test setup. Connect a crease as Vin approaches Vout. The increase will occur in a narrow range when Vin is be- power supply to the V and GND terminals IN tween 100 and 300mV below Vout. The ripple and a suitable load resistor between VOUT voltage in this range can be from 30mV to and GND. 100mV pp. Increasing output capacitance will With a light load (1k resistor) at the output, reduce this ripple. begin increasing the input power supply volt- Due to the high inductor current slew rate in 5V age. At approximately 750mV the output will output applications, the 2MHz LTC3526L-2 may rise to the selected regulated voltage. In- not enter burst mode for input voltages less than crease the input voltage to approximately 1.4V. For 5V applications requiring burst mode, 1.5V and increase the load current. Move out- the 1MHz LTC3526L is recommended. Refer to put voltage jumpers and verify output voltage. the Typical Performance Characteristics curves Note the excellent load regulation when going for the burst mode thresholds for different input from a light load current to a heavier load, but and output voltages. it is important to monitor the input voltage di- rectly at the input terminals of the circuit 2