QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1326A 1.5MHZ SYNCHRONOUS BOOST / SYNCHRONOUS BUCK CONVERTERS AND LDO LTC3100 DESCRIPTION Demonstration circuit 1326A consists of three Jumpers are also provided for selecting a total voltage regulators a synchronous boost, a syn- of nine output voltages and selecting BURST or chronous buck and a linear LDO. The high effi- PWM operation. The 16-pin 3X3 mm QFN ciency DC/DC converters feature 700mA thermally enhanced package combined with the high switching frequency provides a very tiny switches for the boost, 250mA for the buck and a 100mA rating for the LDO regulator. multi output solution. The LTC3100 boost con- verter also features output disconnect and the With a light load, the boost converter can input voltage can be greater or less than the startup with an input voltage as low as 700mV output voltage. Power Good terminals for the and once started, the input can go as low as boost and buck converters are also included. 500mV while maintaining a regulated output. Buck converter requires 1.8V minimum input. This demonstration circuit allows the user to quickly evaluate the LTC3100 performance. Separate input terminals are provided for each Jumpers make selecting different output volt- switch mode converter, and a jumper for paral- ages simple while terminals on the board allow leling the two converter inputs or powering the easy hookup to input supplies and output loads. buck from the output of the boost. The LDO regulator is always powered from the boost Design files for this circuit board are available. output. Call the LTC factory. Jumpers are included for separately shutting LTC and Burst Mode are trademarks of Linear Technol- ogy Corporation down the boost regulator or shutting down or sequencing the buck and LDO regulators. Table 1. Typical Specifications (25C) Conditions Limits Boost Converter Input Voltage Range V 0.68V to 5.5V IN Boost Converter, 1.8V V V = 1.2V, I = 100mA 1.8V 3% OUT IN OUT Boost Converter, 3.3V V V = 1.2V, I = 100mA 3.3V 3% OUT IN OUT Boost Converter, 5V V V = 1.2V, I = 100mA 5.0V 3% OUT IN OUT Boost Output Voltage Ripple (burst mode) V = 1.5V, V = 3.3V, I = 10mA 25mV p-p IN OUT OUT Boost Output Voltage Ripple (PWM) V = 1.5V, V = 5V, I = 100mA 10mV p-p IN OUT OUT Buck Converter, 1.2V V V = 2V, I = 100mA 1.2V 3% OUT IN OUT Buck Converter, 1.5V V V = 2V, I = 100mA 1.5V 3% OUT IN OUT Buck Converter, 1.8V V V = 2V, I = 100mA 1.8V 3% OUT IN OUT Buck Output Voltage Ripple (burst mode) V = 2V, V = 1.5V, I = 10mA 10mV p-p IN OUT OUT Buck Output Voltage Ripple (PWM) V = 2V, V = 1.5V, I = 100mA 5mV p-p IN OUT OUT LDO Regulator, 1.5V V V = 3.3V from V Boost, I = 50mA 1.5V 3% OUT IN OUT OUT LDO Regulator, 2.85V V V = 3.3V from V Boost, I = 50mA 2.85V 3% OUT IN OUT OUT LDO Regulator, 3V V V = 3.3V from V Boost, I = 50mA 3.0V 3% OUT IN OUT OUT 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1326A 1.5MHZ SYNCHRONOUS BOOST / SYNCHRONOUS BUCK CONVERTERS AND LDO Board Number LTC Part Number Part Marking 1326A LTC3100EUD LDJR Select BUCK Input BOOST Input PWM V or BURST Input Mode - Power Resistive Supply Loads 0 to 5V 1A + A A Select VOUT BOOST BOOST Boost V Converter ON/OFF Select Buck Select VOUT Input Power LDO A Select Buck ON/OFF or SEQ LDO V Reguator Select LDO ON/OFF or SEQ Select VOUT BUCK A V BUCK V V Converter GND Monitor Power Good Outputs Figure 1. Demonstration Circuit Test Setup QUICK START PROCEDURE The LTC3100 circuit can be evaluated using sufficient input voltage for the LDO regulator. the setup shown in Figure 1. Simply placing Enable each regulator by placing jumpers jumpers in various locations, attaching output JP2, JP3 and JP4 in the ON position. Select loads and measuring voltages can verify most the desired mode Using JP8 (PWM or of the features. It is recommended that the BURST). LTC3100 data sheet be nearby for a more Connect voltmeters and ammeters as shown complete explanation of the various features in the Figure 1 test setup. Connect a power and specifications. supply to the BUCK IN and GND terminals Place the BUCK INPUT jumper (JP1) in the and suitable load resistors on the three output PARALLEL position. Using jumpers JP5, and GND terminals. Avoid excessive wire JP6 and JP7, select the desired output volt- lengths between the input power supply and ages (with no jumpers installed, the output the demonstration board. Wire lengths greater voltage is set for the highest voltage). Note than 18 inches may require additional capaci- set the boost output voltage to 3.3V to provide tance near the input terminals. 2