QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 692 1.2MHZ HIGH CURRENT BOOST CONVERTER LTC3426ES6 DESCRIPTION Demonstration circuit 692 is a high efficiency 1.2MHz A switching frequency of 1.2MHz allows a tiny solu- boost DC/DC converter featuring the LTC3426ES6. tion footprint. Typical applications include local 3.3V The board is capable of supplying 400mA current or 5V supply, battery back-up, portable devices and from 1.8V to 4.2V input with a 5V output. It can de- white LED driver supply. liver 5V at 800mA from a 3.3V input. The converter Design files for this circuit board are available. Call has internal soft start and internal frequency compen- the LTC factory. sation features. The LTC3426 chip is in a low profile LTC is a trademark of Linear Technology Corporation (1mm) SOT-23 package and has very low shutdown current of about 0.5mA. Table 1. Performance Summary PARAMETER CONDITION VALUE Maximum Load Current, Min Vout = 5V, Vin = 1.8V 400mA Maximum Load Current, Min Vout = 5V, Vin = 3.3V 800mA Switching Frequency, Typ 1.2MHz Efficiency, Typ Vout = 5V, Vin = 3.3V, Iout = 800mA 87% Output Ripple, Typ Vout = 5V, V = 3.3V, I = 400mA (20MHz BW) 90mV IN OUT PP QUICK START PROCEDURE Demonstration circuit 692 is easy to set up to evalu- 3. Turn on the power at the input. ate the performance of the LTC3426. Refer to Figure 1 4. Check for the output voltage. Vout should be for proper measurement equipment setup and follow 5V0.2V. the procedure below: 5. Once the proper output voltage is established, ad- NOTE: When measuring the input or output voltage just the load within the operating range and ob- ripple, care must be taken to avoid a long ground lead serve the output voltage regulation, ripple voltage, on the oscilloscope probe. Measure the input or out- efficiency and other parameters. put voltage ripple by touching the probe tip directly NOTE: If there is no output, temporarily disconnect across the Vin or Vout and GND terminals. See the load to make sure that the load is not set too Figure 2 for proper scope probe technique. high. The available output current depends on the 1. Place the jumper in the following position: input voltage. The output diode is rated for 1A cur- JP1 On rent. 2. With power off, connect the input power supply (1.8V-4.2V) to Vin and GND. Connect the load to Vout and GND. Set initial load = 0A (no load). 1 GND VIN QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 692 1.2MHZ HIGH CURRENT BOOST CONVERTER Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2