QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 389 HIGH EFFICIENCY NOTEBOOK CPU POWER SUPPLY LTC3778 DESCRIPTION Demonstration circuit 389 is a step down controller featuring the LTC3778. It produces an output voltage suitable for Intel Mobile Tualatin, Low Voltage Tualatin and Ultra Low Voltage mobile processors. The LTC3778 is a synchronous step-down controller. It uses valley current control architecture to deliver low duty cycles. The maximum current supported by each version of the DC389 conforms to Intel IMVP-II Mobile Processor Core Voltage Design Guide REF. NO. OR-2980. Please contact Intel to obtain this restricted docu- ment. DC389 includes a dynamic load circuit for the convenience of the user. There are three versions of the board: * 389A-A: Mobile Tualatin, 23A max output * 389A-B: Low Voltage Tualatin, 15A max * 389A-C: Ultra Low Voltage Tualatin, 13A max Design files for this circuit board are available. Call the LTC factory. Table 1. Performance Summary PARAMETER CONDITION VALUE Minimum Input Voltage 7.5V Maximum Input Voltage 24 VOUT , IOUT See Tables 2,3,4 Typical Output Ripple VOUT VIN = 12V, IOUT =15A Nominal Switching Frequency 20mVP-P 300kHz QUICK START PROCEDURE Demonstration circuit 389 is easy to set up to evaluate the performance of the LTC3778. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: Table 2. Jumper Descriptions (See Figure 1) JUMPER DESCRIPTION JUMPER POSITION When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage ripple by touching the probe tip directly across the input or output and ground terminals. See Figure 2 for proper scope probe technique. 1. Set jumpers as shown in Figure 1. See also Table 2 for jumper descriptions. PURPOSE NUM BER 1-2 2-3 Dynamic Load JP1 Disabled Enabled VRON JP2 Enabled Disabled Deep Sleep JP3 Disabled Enabled a. VIN (Do not exceed 24V) Deeper Sleep JP4 Enabled Disabled b. 3.3V Performance Mode Performance Optimized Mode Battery Optimized Mode c. JP5 5V (Do not allow 5V to be ON without VIN ON) d. 12V. 2. With power off, connect the input power supply to VIN and GND. 3. Turn on the power in this sequence: 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 389 HIGH EFFICIENCY NOTEBOOK CPU POWER SUPPLY 4. Check for the proper output voltages. See Tables 3 5. Once the proper output voltage is established, ad- to 5 for expected output voltages. just the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. If there is no output, temporarily disconnect the load to make sure that the load is not set too high. See Figures 3 to 5 for expected performance. - + - + - + + + + + SCOPE OR VOLTMETER - - - + LOAD - - JUMPER POSITIONS 3 2 1 + - Figure 1. Proper Measurement Equipment Setup GND - VIN + Figure 2. Measuring Input or Output Ripple 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 389 HIGH EFFICIENCY NOTEBOOK CPU POWER SUPPLY 100 90 EFFICIENCY (%) 80 20mV/DIV 70 60 50 389A-A 40 389A-B 30 389A-C 20 10 0 0 10s/DIV 2s/DIV Figure 3. Step Load Response (389A-A, Performance Optimized Mode, VIN = 15V) Figure 4. Typical Output Ripple (389A-A, Performance Optimized Mode, IOUT = 15A, VIN = 15V) 5 10 15 20 25 LOAD CURRENT (A) Figure 5. Typical Performance Mode Efficiency curves for the 389A-A, 389A-B and 389A-C Table 3. Version A for Mobile Tualatin CPU MODE JP2 JP3 JP4 JP5 0A BOM* 1-2 1-2 2-3 2-3 1.115- 1.155 POM** 1-2 1-2 2-3 1-2 1.380- 1.420 POM** DEEP SLP 1-2 2-3 2-3 1-2 1.318- 1.358 BOM* DEEP SLP 1-2 2-3 2-3 2-3 1.064- 1.104 DEEPER SLP 1-2 2-3 1-2 2-3 0 .810- 0.870 3A 6A 8A 14A 23A 1.059- 1.099 1.288 - 1.328 1.286- 1.326 1.040- 1.080 0 .810 - 0.870 *Battery Optimized Mode **Performance Optimized Mode 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 389 HIGH EFFICIENCY NOTEBOOK CPU POWER SUPPLY Table 4. Version B for Low Voltage Tualatin CPU MODE JP2 JP3 JP4 JP5 0A BOM* 1-2 1-2 2-3 2-3 1.016- 1.056 POM** 1-2 1-2 2-3 1-2 1.130 - 1.170 POM** DEEP SLP 1-2 2-3 2-3 1-2 1.094- 1.134 BOM* DEEP SLP 1-2 2-3 2-3 2-3 0.996 - 1.036 DEEPER SLP 1-2 2-3 1-2 2-3 0 .810- 0.870 3A 5A 6A 10A 15A 0.976- 1.016 1.070 - 1.110 1.070- 1.110 0.976- 1.016 0.810- 0.870 *Battery Optimized Mode **Performance Optimized Mode Table 5. Version C for Ultra Low Voltage Tualatin CPU MODE JP2 JP3 JP4 JP5 0A BOM* 1-2 1-2 2-3 2-3 0.918- 0.958 POM** 1-2 1-2 2-3 1-2 1.080- 1.120 POM** DEEP SLP 1-2 2-3 2-3 1-2 1.048- 1.088 BOM* DEEP SLP 1-2 2-3 2-3 2-3 0.902- 0.942 DEEPER SLP 1-2 2-3 1-2 2-3 0 .810- 0.870 3A 4A 5A 8A 13A 0.886- 0.926 1.028- 1.068 1.028- 1.068 0.886- 0.926 0.810- 0.870 *Battery Optimized Mode **Performance Optimized Mode 4 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 389 HIGH EFFICIENCY NOTEBOOK CPU POWER SUPPLY 5