USERS MANUAL ISL8026xEVAL3Z UG033 Rev 1.00 Evaluation Board July 15, 2016 Description Key Features The ISL8026EVAL3Z and ISL8026AEVAL3Z are intended for use High efficiency synchronous buck regulator with up to 95% by customers with requirements for point-of-load applications efficiency sourcing from 2.5V to 5.5V. The ISL8026EVAL3Z and 1% reference accuracy over load/line/temperature ISL8026AEVAL3Z are used to demonstrate the performance of (-40C to +85C) the ISL8026 and ISL8026A, low quiescent high efficiency Start-up with prebiased output synchronous buck regulators. Internal soft-start - 1ms or adjustable The ISL8026 and ISL8026A are offered in a 3mmx3mm Soft-stop output discharge during disabled 16 Ld TQFN package with 1mm maximum height. The complete area that the converter occupies can be as small as Adjustable frequency from 500kHz to 4MHz - default at 1MHz 2 141.935mm . (2MHz for ISL8026A) External synchronization up to 4MHz Specifications Negative OC protection I V V OUT IN OUT PART (MAX) f RANGE RANGE RANGE PART SIZE SW References NUMBER (A) (MHz) (V) (V) (2mm) ISL8026, ISL8026A Datasheet ISL8026 Programmable 0.5 to 4 2.5 to 0.6 to 6 3x3 5.5 5.5 Ordering Information ISL8026A Programmable 1to4 PART NUMBER DESCRIPTION NOTES: ISL8026EVAL3Z Evaluation Board For ISL8026 1. The evaluation boards default configuration are V = 1.8V for OUT ISL8026EVAL3Z (f = 1MHz) and ISL8026AEVAL3Z (f =2MHz). ISL8026AEVAL3Z Evaluation Board For ISL8026A SW SW 2. V is 0.6V. REF ISL8026 VOUT GND PGND VIN VIN GND VIN PGND EPAD PGND/ PG SGND SYNC FB FIGURE 1. BLOCK DIAGRAM UG033 Rev 1.00 Page 1 of 13 July 15, 2016 EN VIN FS PHASE SS PHASE COMP PHASEISL8026xEVAL3Z FIGURE 3. ISL8026AEVAL3Z FIGURE 2. ISL8026EVAL3Z The ISL8026EVAL3Z and ISL8026AEVAL3Z outputs are preset to Recommended Equipment 1.8V for V , however, output voltages can be adjusted from OUT The following materials are recommended to perform testing: 0.6V to 5V. The output voltage programming resistor, R , will 1 depend on the desired output voltage of the regulator. The value 0V to 10V power supply with at least 10A source current for the feedback resistor is typically between 0 and 200k, as capability or 5V battery shown in Equation 1. Electronic loads capable of sinking current up to 7A VFB (EQ. 1) R = R --------------------------- 2 1 Digital Multimeters (DMMs) VO VFB 100MHz quad-trace oscilloscope If the output voltage desired is 0.6V, then R is left unpopulated 2 Signal generator and R is shorted. For faster response performance, add 10pF to 1 47pF in parallel to R . Check the Bode plot to insure optimum 1 performance. Quick Setup Guide 1. Ensure that the circuit is correctly connected to the supply and Frequency Control loads prior to applying any power. The ISL8026 and ISL8026A have an FS pin that controls the 2. Connect the bias supply to V , the plus terminal to V , P4 IN IN frequency of operation. Programmable frequency allows for and the negative return to PGND, P5. optimization between efficiency and external component size. 3. Connect the output load to V , the plus terminal to V , P3 Default switching frequency is 1MHz for ISL8026EVAL3Z and OUT OUT and the negative return to PGND, P7. 2MHz for ISL8026AEVAL3Z when FS is tied to V (R =0 and IN 11 R is open). By changing the value of R , the switching 4. Verify that the position is set to PWM for SW2. 12 12 frequency can be changed from 500kHz to 4MHz according to 5. Verify that the position is set to ON for SW1. Equation 2: 6. Turn on the power supply. 3 220 10 ------------------------------ (EQ. 2) 7. Verify that the output voltage is 1.8V for V . Rk = 14 OUT T f kHz OSC Operating Range When using R to adjust the operational frequency, this also 12 sets the external compensation mode. Please refer to the By default, the ISL8026EVAL3Z is configured for the operating ISL8026, ISL8026A datasheet for more details. conditions shown in the Quick Setup Guide. The board can also support a wider operating range. Modifying the operating conditions will change the performance results. UG033 Rev 1.00 Page 2 of 13 July 15, 2016