QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 916 LOW NOISE REGULATED CHARGE PUMP IN 2X2 DFN LTC3204B-5 and LTC3204B-3.3 DESCRIPTION Demonstration circuit 916 is a low noise regulated space. No inductor and diode are needed. The circuit charge pump in 2X2 DFN. There are two assembly features constant frequency operation at any load. versions, DC916A-A and DC916A-B for featuring Built-in soft-start circuitry prevents excessive inrush LTC3204B-5 and LTC3204B-3.3 respectively. The current during start-up. Thermal shutdown and cur- DC916A-A produces a regulated 5V output from a rent-limit circuitry allow the parts to survive a con- 2.7V to 5.5V input. The guaranteed output load cur- tinuous output short circuit from V to GND. These OUT rent is 150mA for V between 3.1V and 5.5V, and circuits are particularly useful in applications that re- IN 65mA for V less than 3.1V. The DC916A-B produces quire low V ripple and extremely small size. IN OUT a regulated 3.3V output from a 1.8V to 4.5V input. Design files for this circuit board are available. Call The guaranteed output current is 50mA from V be- IN the LTC factory. tween 1.9V and 4.5V, and 40mA for V less than IN , LTC and LT are registered trademarks of Linear Technology Corporation. 1.9V. The circuit requires only three tiny 0603 surface mount capacitors and consumes minimal board PERFORMANCE SUMMARY PARAMETER CONDITION MIN TYP MAX DC916A-A (LTC3204B-5) 2.7V 5.5V Input Voltage Range DC916A-B (LTC3204B-3.3) 1.8V 4.5V DC916A-A (LTC3204B-5) 3.1V< V <5.5V, I <150mA 4.8V 5V 5.2V IN OUT Output Voltage V OUT 2.7V< V <5.5V, I <65mA IN OUT DC916A-B (LTC3204B-3.3) 1.9V< V <4.5V, I <50mA 3.168V 3.3V 3.432V IN OUT 1.8V< V <4.5V, I <40mA IN OUT Output Ripple V OUT V = 3.6V, I = 150mA (DC916A-A) 20mV 50mV IN OUT PP PP V = 2.4V, I = 50mA (DC916A-B) 10mV 20mV IN OUT PP PP Nominal Switching Frequency 1.2MHz Efficiency V = 3.0V, I = 100mA (DC916A-A) 81.2% IN OUT V = 1.8V, I = 20mA (DC916A-B) 90.2% IN OUT 1 GND VIN QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 916 LOW NOISE REGULATED CHARGE PUMP IN 2X2 DFN 3. Connect the load between V and GND terminals. OUT 4. Turn on the power at the input. QUICK START PROCEDURE NOTE: Make sure that the input voltage does not ex- Demonstration circuit 916 is easy to set up to evalu- ceed 5.5V for DC916A-A or 4.5V for DC916A-B. To ate the performance of the LTC3204B-5 and prevent input voltage overshoot when the circuit is LTC3204B-3.3. Refer to Figure 1 for proper meas- connected to a live supply, an aluminum electro- urement equipment setup and follow the procedure lytic capacitor can be added to bypass the V at IN below: the input terminals. See Linear Technology Applica- tion Note 88 for a complete discussion. NOTE: When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead 5. Check for the proper output voltages. V = 4.8V OUT on the oscilloscope probe. Measure the input or out- to 5.2V for DC916A-A, V = 3.168V to 3.432V for OUT put voltage ripple by touching the probe tip directly DC916A-B across the V or V and GND terminals. See IN OUT NOTE: If there is no output, temporarily disconnect Figure 2 for proper scope probe technique. the load to make sure that the load is not set too 1. Place jumpers in the following positions: high. JP1 ON 6. Once the proper output voltages are established, adjust the loads within the operating range and ob- 2. With power off, connect the input power supply to serve the output voltage regulation, ripple voltage, V and GND terminals. IN efficiency and other parameters. Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2