MAX77596EVKIT# Analog Devices

Evaluates: MAX77596 MAX77596 Evaluation Kit General Description Quick Start The MAX77596 evaluation kit (EV kit) demonstrates the Required Equipment MAX77596 synchronous step-down converter IC with MAX77596 EV kit integrated switches. The EV kit operates over a wide DC power supply capable of supplying 24V, 300mA input range of 3.5V to 24V and can support loads up to 300mA. The EV kit comes standard with the 3.3V fixed Variable load capable of sinking 300mA at 3.3V DC output voltage version of the IC. It can be easily modified Two voltmeters to evaluate the 5V fixed output version or the adjustable output voltage version. Procedure The EV kit is fully assembled and tested. Follow the steps The EV kit includes jumpers to enable or disable the below to verify board operation. Read all the steps before device, as well as to select either forced-PWM mode proceeding with step 1. (FPWM) or skip-mode operation. A RESETB test point is available to monitor the voltage quality of the converters 1) Verify that the IC is enabled by installing a shunt on output. pins 1-2 on jumper J1. 2) Verify that IC is operating in skip mode by installing a Features shunt on pins 2-3 on jumper J2. Evaluates Both Fixed-Output and Adjustable-Output 3) Set the DC power supply to 0V. Versions (3.3V Version Is Preinstalled) 4) Set the variable load to 0mA. 3.5V to 24V Input Voltage Range 5) Connect the positive and negative terminals of 300mA Maximum Load the power supply to the VIN and GND1 test pads, Demonstrates 1.1A Quiescent Current at 14V Input respectively. RESET Output Test Point 6) Connect terminals of the variable load to the VOUT Simple Two-Layer Board Serves as a Reference and GND2 test pads. Observe the positive and Design negative polarity requirements of the variable load, if there are any (VOUT is positive and GND2 is Proven PCB Layout negative). Fully Assembled and Tested 7) Attach a voltmeter across the VOUT and GND2 test pads. Ordering Information appears at end of data sheet. 8) Attach a voltmeter across the RESETB and GND2 test pads. 9) Ramp the DC power-supply voltage from 0 to 12V. 10) Verify that the voltmeter connected to VOUT measures approximately 3.3V. 11) Verify that the voltmeter connected to RESETB measures approximately 5V. 12) Enable the variable load and ramp the load current from 0mA to 300mA. 13) Repeat steps 10 and 11. 19-7752 Rev 1 3/16Evaluates: MAX77596 MAX77596 Evaluation Kit The feed-forward capacitor (C8) is already installed Detailed Description of Hardware for use with the external feedback resistors and the The MAX77596 EV kit is a fully assembled and tested adjustable version of the IC. C8 is not required for the circuit board to evaluate the performance of the MAX77596 fixed-output-voltage version. When evaluating other step-down converter IC. The EV kit operates over a 3.5V versions of the device, the inductor, input capacitors, and to 24V input voltage range, while consuming only 1.1A output capacitors might need to change. Refer to the of quiescent current at 14V and 0mA load (fixed-output IN Applications Information section in the MAX77596 IC data voltage version). sheet for more information. The EV kit can be configured to operate in forced-PWM mode (FPWM) or low-quiescent current skip mode using Enable Control jumper J2. The IC can be enabled or disabled using jump- The EV kit uses jumper J1 to control the enable (EN) er J1. The RESETB test point connects to the ICs RESET input. Connect EN to VIN (SUP) by shunting pins 1-2 to output, which monitors output-voltage quality. Refer to the enable the device. Connect EN to GND by shunting pins MAX77596 IC data sheet for more information on the IC. 2-3 to disable the device. Table 1 summarizes the opera- tion of J1. Configuring the Output Voltage (V ) OUT Mode Control The EV kit comes standard with the fixed 3.3V output version, but can easily be modified to evaluate the The EV kit uses jumper J2 to configure the IC in either adjustable-output version of the device or the 5V fixed forced-PWM (FPWM) mode or skip mode. Connect the version. MODE pin to BIAS by installing a shunt in positions 1-2 on J2 to enable FPWM mode. Connect MODE to GND To evaluate the 5V fixed output voltage version, replace by installing a shunt in positions 2-3 on J2 to enable skip U1 with the MAX77596ETBA+ and leave the rest of the mode. Table 2 summarizes the operation of J2. board unchanged. To evaluate the adjustable-output voltage version, replace RESET Output U1 with the MAX77596ETBC+ and remove the 0 The EV kit provides a RESETB test point to monitor resistor on R4. The output voltage of the adjustable the status of the RESET pin. RESET becomes high version can be set between 1V and 10V by populating impedance and is pulled to the BIAS voltage level through resistors R3 and R4. Choose R3 to be less than or equal resistor R1 after the regulator output increases above to 100k. Then calculate R4 for the desired V with OUT 92% of the nominal regulated voltage. RESET goes the following equation: low when the regulator output drops below 90% of the R4 = R3 x (V /V ) - 1 nominal regulated voltage. OUT FB where V = 1V. FB Table 1. Enable Control (J1) Table 2. Mode Control (J2) SHUNT SHUNT EN PIN VOUT MODE PIN MODE POSITION POSITION Connected to VIN 1-2 Enabled 1-2 Connected to BIAS Forced-PWM mode (SUP) Connected to GND 2-3 Disabled 2-3 Connected to GND Skip mode (PGND) Not Connected to an Enabled with logic-high Not Internally pulled down to Floating installed external source Disabled with logic-low installed GND, skip mode Maxim Integrated 2 www.maximintegrated.com