DEMO CIRCUIT 1672A QUICK START GUIDE LTC3816EUHF HIGH EFFICIENCY SINGLE PHASE BUCK CONVERTER FOR INTEL IMVP-6/IMVP-6.5 CPUs DESCRIPTION Demonstration circuit 1672A is a high efficiency, versatile power solutions for embedded computing, single phase, synchronous buck converter for Intel mobile computers, internet devices and navigation IMVP-6/IMVP-6.5 CPUs. It can supply 25A maxi- displays. The controller is available in 38-pin ther- mum load current at up to 1.5V output with 4.5V to mally enhanced eTSSOP and 5mm 7mm QFN 28V input range. The demo board features the packages. LTC3816EUHF controller. The LTC3816 is a sin- gle-phase synchronous buck controller in a con- The VRON pin (JP15) provides enable feature. To stant-frequency voltage mode architecture. The con- shut down the converter, one simple way is to force trollers leading edge modulation topology allows the VRON pin below 0.65V (JP15: OFF). Use JP19 extremely low output voltages and supports a phase- jumper to select pulse-skipping or forced continuous lockable switching frequency up to 550kHz. The mode operation. Switching frequency is pre-set at output voltage is programmed using a 7-bit VID about 400KHz, and it can be easily modified from code. The default VID jumpers (VID6 to VID0) are 150KHz to 550KHz. JP20~JP26 (VID0~VID7) are set to be 0110000 for 0.9V output. The LTC3816 used to set the output voltage based on the IMVP- features all of the IMVP-6/IMVP-6.5 requirements, 6/IMVP-6.5 VID code, as shown in table 2. JP1 and including start-up to a preset boot voltage, differen- JP18 are used to select either IMVP6 or IMVP6.5 tial remote output voltage sensing with programma- specification. For detailed information, please see ble active voltage positioning, Imon output current LTC3816 data sheet and Intel IMVP-6/IMVP-6.5 spe- reporting, power optimization during sleep state, and cification. slow slew rate sleep state exit. Fault protection fea- tures include input undervoltage lockout, cycle-by- Design files for this circuit board are available. Call cycle current limit, output overvoltage protection, the LTC factory. and power-good (PWRGD) and overtemperature flags. The LTC3816 supports wide input range (4.5V to 36V) with optional line feedforward compensation, temperature compensated inductor DCR or sense resistor output current monitoring. The LTC3816 can provide high efficiency, high power density and Table 1. Performance Summary (T = 25C) A PARAMETER CONDITION VALUE Input Voltage Range 4.5V to 28V Output Voltage, V V = 4.5-28V, I = 0A to 23A, VID6-0=0110000 0.9V 1.5% OUT IN OUT Maximum Output Current, I V = 4.5-28V, V = 1.5V 25A OUT IN OUTMAX Typical Efficiency V = 12V, V = 1.5V, I = 23A IN OUT OUT 86.7% Typical Switching Frequency 400kHz 1 LTC3816EUHF Table 2. IMVP-6/IMVP-6.5 VID Output Voltage Programming 2