Si3402-A-GM to Si3402-B-GM EVB Modifications Version 0.4 The Si3402-B-GM device requires component value changes from those used with the Si3402-A-GM evaluation board (EVB) reference design. Table 1 below is a summary of the required modifications. Following Table 1 are two reference schematic excerpts showing the locations of the modified component values for both the isolated (flyback) and non-isolated (buck) topologies. Table 1. Si3402-B-GM EVB modifications versus the Si3402-A-GM EVB Item Modification description M1 Detect resistor value change Application design effect The former 25.5kΩ detect resistor must be replaced by 24.3kΩ 1% M2 Classification resistor value change The following 1% resistors must be used: Class0: 681.00 or higher (It is optional to place this resistor) Class1: 140.0 Class2: 75.0 Class3: 48.7 Class4: 33.2 M3* ISO EVB DCDC 3.3V changes Flyback M4 M5 M6 ISO EVB DCDC 5V changes Flyback ISO EVB DCDC 12V changes Flyback DCDC reference voltage change (Buck case only) C8, R9 & C23 are not need—Do not populate them. C9=10nF, C21=33nF, R12=475 Ω & R8=1.1k Ω Replace D2 (DFLT15A) with DFLT30A * See Revision Notes C8, R9 & C23 are not need—Do not populate them. C9=3.3nF, C21=15nF, R12=0 & R8=0 (place zero Ω resistors) Replace D2 (DFLT15A) with DFLT30A C8, R9 & C23 are not need—Do not populate them. C9=10nF, C21=15nF, R12=0, R8=0 (place zero Ω resistor) R7=3k Replace D2 (DFLT15A) with DFLT30A Now 1.35V instead of previous 1.23V. Thus, R5 changes from 2.87kΩ 1% to 3.24kΩ 1%. R6 (1%) is modified according to this table: SILICON LABS CONFIDENTIAL Vout Target 3.3 5 9 12 M7 M8 M9 BUCK EVB DCDC 3.3V compensation network changes BUCK EVB DCDC 5V compensation network changes BUCK EVB DCDC 12V compensation network changes R5 kΩ 3.24 3.24 3.24 3.24 R6 kΩ 4.64 8.66 18.2 25.5 Vref 1.35 1.35 1.35 1.35 Vout Measured 3.37 4.96 8.93 11.98 C19, C20 & C9 are not need—Do not populate them. R8 can be populated with a 0Ω resistor (creating a short between pins 3 and 4) or left unpopulated, since the ISOSSFT function is now internal (see datasheet). C7=1nF, R7=47kΩ ±20%. C19, C20, R8 & C9 are not need—Do not populate them. R8 can be populated with a 0Ω resistor (creating a short between pins 3 and 4) or left unpopulated, since the ISOSSFT function is now internal (see datasheet). C7=1nF, R7=47kΩ ±20%. C19, C20, R8 & C9 are not need—Do not populate them. R8 can be populated with a 0Ω resistor (creating a short between pins 3 and 4) or left unpopulated, since the ISOSSFT function is now internal (see datasheet). C7=1nF, R7=47kΩ ±20%. SILICON LABS CONFIDENTIAL Si3402ISO (Flyback, Isolated) EVB Reference Design – 5V See M2 24.3kΩ DFLT30A 0Ω 15nF 3.3nF 0Ω SILICON LABS CONFIDENTIAL Si3402 (Buck, Non-Isolated) EVB Reference Design - 5V See M2 24.3kΩ See M6 1nF 47kΩ See M7-M9 SILICON LABS CONFIDENTIAL Revision Notes 26 August 2015: Added B5 indicating the Si3402-B-EN1 samples should be run only at room temperature Clarified Buck (Non-Isolated) case R7 to standard value 47kΩ and relaxed to 20% tolerance 28 October 2015: Previous version silicon errata resolved Several components in the change list updated Document renamed “Si3402-B RevA3 Change List_<YYYYMMDD>” 24 November 2015: M2 and M6 components updated Aligns with production Si3402-B-GM silicon 08 December 2015: (Version 0.3) Changed title of doc and name of file Clarified M7-M9 changes with regard to R8 21 March 2016: (Version 0.4) Updated M3, the 3.3V Isolated Flyback case. o Explanation: 3.3V Flyback compensation was updated to address a small overshoot condition under no-load conditions (3.66V is allowed, the overshoot was 3.73V). The problem is fixed with revised compensation with a resulting overshoot of about 3.5V. o If a no-load condition is unlikely, the customer may keep the original M3 change recommendation: C8, R9 & C23 are not need—Do not populate them C9=3.3nF, C21=15nF, R12=0 & R8=0 (place zero Ω resistors) Replace D2 (DFLT15A) with DFLT30A SILICON LABS CONFIDENTIAL