ISL21009-25 and ISL60002-30 Capacitive Load Drive Capability ® Technical Brief Introduction This report describes the capacitive load drive capability of the ISL21009-25 and ISL60002-30 voltage references. ISL21009-25 is a 2.500V reference and is specified to operate in a supply range of 3.5V to 16.5V, and comes in an 8 Ld SOIC package. ISL60002-30 is a 3.000V reference specified to operate in the range of 3.2V to 5.5V. It is available in a 3 Ld SOT package. June 10, 2008 TB475.0 • ISL60002-30 was tested under the following COUT conditions and a ±500µA load: a) No Load b) nF c) 10nF||1µF d) 100nF||10µF • Both the references were tested for capacitive load drive capability at room temperature and 5.0VIN. All the capacitors used were of surface mount X7R/X5R ceramic chip type. The DUT was placed in an appropriate socket mounted on a milled copper board. The ±7mA and ±500µA loads were generated by means of a voltage pulse through a suitable through-hole resistor. • ISL21009-25 was tested under the following COUT conditions and a ±7mA load: a) No Load The supply voltage was provided by an Agilent 3631A. The aforementioned pulse was generated using HP3245A, and the DUT output was probed using a TDS744A oscilloscope. Test Conditions Figures 1 thru 12 shows the bench test results for ISL21009-25 as a function of varying load capacitors, and Figures 13 thru 16 for ISL60002-30. The board schematic for this test setup is outlined in Figures 21 and 22. b) nF c) 10nF||1µF d) 100nF||10µF Bench Test Results for ISL21009-25 FIGURE 1. NO CAPACITIVE LOAD, VIN = 5.0V, I_LOAD = ±7mA 1 FIGURE 2. NO CAPACITIVE LOAD, VIN = 5.0V, I_LOAD = ±7mA CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2008. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Technical Brief 475 Bench Test Results for ISL21009-25 (Continued) FIGURE 3. COUT = 1nF, VIN = 5.0V, I_LOAD = ±7mA FIGURE 4. COUT = 1nF, VIN = 5.0V, I_LOAD = ±7mA FIGURE 5. COUT = 10nF, VIN = 5.0V, I_LOAD = ±7mA FIGURE 6. COUT = 10nF, VIN = 5.0V, I_LOAD = ±7mA FIGURE 7. COUT = 100nF, VIN = 5.0V, I_LOAD = ±7mA FIGURE 8. COUT = 100nF, VIN = 5.0V, I_LOAD = ±7mA 2 TB475.0 June 10, 2008 Technical Brief 475 Bench Test Results for ISL21009-25 (Continued) FIGURE 9. COUT = 1µF, VIN = 5.0V, I_LOAD = ±7mA FIGURE 10. COUT = 1µF, VIN = 5.0V, I_LOAD = ±7mA FIGURE 11. COUT = 10µF, VIN = 5.0V, I_LOAD = ±7mA FIGURE 12. COUT = 10µF, VIN = 5.0V, I_LOAD = ±7mA 3 TB475.0 June 10, 2008 Technical Brief 475 Bench Test Results for ISL60002-30 FIGURE 13. COUT = 0, VIN = 5.0V, FREQ = 100Hz, I_LOAD = ±500µA FIGURE 14. COUT = 100nF, VIN = 5.0V, FREQ = 100Hz, I_LOAD = ±500µA FIGURE 15. COUT = 100nF||1µF, VIN = 5.0V, FREQ = 100Hz, I_LOAD = ±500µA FIGURE 16. COUT = 100nF||10µF, VIN = 5.0V, FREQ = 100Hz, I_LOAD = ±500µA Bench Test at -40°C and +125°C FIGURE 17. ISL21009-25 COUT = 10µF, VIN = 5.0V, I_LOAD = ±500µA, -40°C 4 FIGURE 18. ISL21009-25 COUT = 10µF, VIN = 5.0V, I_LOAD = ±500µA, +125°C TB475.0 June 10, 2008 Technical Brief 475 Bench Test at -40°C and +125°C (Continued) FIGURE 19. ISL60002-30 COUT = 100nF||1µF, VIN = 5.0V, I_LOAD = ±500µA, -40°C FIGURE 20. ISL60002-30 COUT = 100nF||1µF, VIN = 5.0V, I_LOAD = ±500µA, +125°C Board Schematics 5.0 VIN ISL60002-30 CAP XxR CAP X7R 1206 100nF RESISTOR I_LOAD FIGURE 21. ISL60002-30 DUT TEST SETUP 5.0VIN ISL21009-25 CAP XxR RESISTOR I_LOAD FIGURE 22. ISL21009-25 DUT TEST SETUP 5 TB475.0 June 10, 2008 Technical Brief 475 Test Observation and Conclusion Based on the bench testing of randomly picked units from available production material, the outputs of the ISL21009-25 and ISL60002-30 did not display a tendency to oscillate under varying COUT conditions. The ISL21009-25 COUT varied from no load to 10µF, and COUT conditions of ISL60002-30 were no load, 100nF, 100nF||1µF, and 100nF||10µF. As seen in the plots above, by varying output capacitors of surface mount XxR ceramic chip type, the ISL21009-25 and ISL60002-30 are not expected to oscillate. Contact Information Intersil Corporation 1001 Murphy Ranch Rd. Milpitas, CA 95035 U.S.A. Applications Manager: Jim Pflasterer [email protected] Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that the Application Note or Technical Brief is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com 6 TB475.0 June 10, 2008