MIC2130/1 Evaluation Board High Voltage Synchronous Buck Controller IC with Low EMI Option General Description This MIC2130/1 evaluation board is a high voltage input PWM synchronous buck converter. The schematic is shown in Figure 1. The MIC2130/1 is a voltage mode controller with a fast hysteretic control loop (FHyCL) employed during fast line and load transients. The MIC2130/1 has an internal transconductance error amplifier, gate drivers, current limit, enable and under voltage lock out and soft start circuitry. The internal gate drivers are designed to drive high current MOSFETs. The evaluation board output voltage is selected by a jumper for pre-selected voltage divider network, 1.8V, 3.3V, 5V or leaving the jumper open for 0.7 V. The maximum current limit is set at 9A. The input voltage is 8V to 40V. The MIC2130 family of control ICs implements fixed frequency PWM control. The MIC2130/1-1 parts run at 150kHz and the MIC2130/1-4 parts run at 400kHz. The MIC2131 is the fully functional version of the family and implements a new feature to minimize EMI. The MIC2131 dithers the switching frequency ±12% to produce a spread spectrum thereby lowering the EMI peaks. This function is critical for systems that need to be compliant with EMI standards throughout the world. The MIC2131 also allows the user to program a higher current limit for a short duration. The under voltage lockout is used to prevent operation below 8V. The input of the converter can be 8V to 40V and the output can be from 0.7V to 0.85*VIN but the output caps are rated at 6.3V. For higher output voltages the output caps have to be replaced with higher voltage ratings. Table 1 provides a summary of the specifications. The evaluation board schematic is shown in Figure 1 and the parts list is shown in the Bill of Materials section. Requirements 1. Voltage source capable of supplying 50 Watts 2. Load: a resistive or a electronic load 3. Scope 4. Voltage meter Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN terminal may damage the device. The maximum input voltage is limited to 40V. The power MOSFETS are rated for 40V Max. Getting Started 1. Connect an external supply to the VIN. Apply desired input voltage to the VIN (J1) and ground J2 terminals of the evaluation board, paying careful attention to polarity and supply voltage (8≤VIN≤40V). 2. Ensure that the supply voltage is monitored at the VIN terminal. The power lead resistance can reduce the voltage supplied to the input. 3. Connect a resistive or electronic load to the output J3 and J4. 4. Monitor the Switch node with a scope to monitor the switch waveform RSET – Current Limit Sensing The MIC2130/31 features output current limit sensing. Current limit is set by an external resistor by the following equation: R10 is the current limit resistor R10 = RDSON*IL/200µA Where, IL is the peak inductor current that will trigger the current limit, RDSON is that of the MOSFET (9.5m Ω/2 for 2 Si7484 in parallel). Default setting for the evaluation board is R10 = 316Ω with the current limit set at 9A. HCL (MIC2131 only) The high current limit (HCL) is a function of the MIC2131 only. It allows for twice the output load current (for a time T determined by the HCL cap) before the current limit comparator trips. During the time T, the current sense current source (200µA nominal) is increased to 400µA. T = CHCL * 2/13µ = CHCL * 153.85 *1e3 Where, CHCL is the cap at the HCL pin. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com August 2008 M9999-082608-D Micrel, Inc. MIC2130/1 Evaluation Board Frequency Dithering The MIC2131 has an additional useful feature. The switching frequency is dithered ±12% in order to spread the frequency spectrum over a wider range to lower the EMI noise peaks generated by the switching components. A pseudo random generator is used to generate the dithering which reduces the EMI noise peaks. MIN VIN 8V Output Voltage 0.7 TYP 40V 1.8V, 3.3V, 5V 0 9A Power Out 0 50W Efficiency 96% Description 150kHz 400kHz Line Regulation Evaluation board with the MIC2130-1YTSE (150kHz) device Evaluation board with the MIC2131-1YTSE (150kHz with dither) device MIC2131 EV 50mV Switching Frequency Ordering Information MIC2130 EV 0.85*VIN Output Current Output Ripple Part Number MAX <1% Line Transients <1% Load Regulation <1% Load Transients <1% Ambient Temperature –40°C +25°C +85°C Over-current HCL* 18A Dither Frequency* ±12% *MIC2131 Only *Output Cap change required for higher than 5V out Table 1. Design Specifications +VIN J1 VIN +8V to 40V C22 1µF/6V R3 49.9k 8 6 1 2 3 14 R8 Q2 SI7848DP 4 R11 13 CS R9 1 2 3 LSD C8 0.1µF Q3 SI7848DP 4 11 R10 16 Q4 SI7848DP 4 1 2 3 C7 0.15µF SW SS PROBE-CONT Probe1 CDEP147NP-3R5NC TP1 B340A D2 J3 +VO R18 2 R19 Open C16 100pF C19 330µF/6.3V C20 330µF C21 10µF/6.3V C13 0.1µF J4 GND C18 Open C17 Open R12 Open 5 4 6 JP1 R14 3.92k 3.3V 5 R13 9.31k 1.8V 2 AGND FB 3 7 Install R20 for the MIC2130 Install C23 for the MIC2131 AGND2/HCL 1 3 L1 7.3µH PGND C23 1µF R16 14.7k 12 R20 0 1 15 MIC2130/31YTSE 4 C15 10µF/50V Q1 SI7848DP 4 8 7 6 5 R6 5.1k C6 Open BS HSD COMP 10 8 7 6 5 C12 100pF EN/UVLO VDD +VIN C11 0.1µF/25V C10 10µF/6V 8 7 6 5 AVDD PGOOD 1 2 R2 R4 10k SD103BWS D1 VDD R7 10k 9 C5 0.1µF/25V R1 10 C4 10µF/50V 2 3 C9 0.1µF VDD +VIN C3 10µF/50V 8 7 6 5 C2 220µF/50V 1 2 3 C1 220µF/50V VIN J2 GND R15 2.37k 5V C14 Open R5 R17 Open Figure 1. Schematic Diagram August 2008 2 M9999-082608-D Micrel, Inc. MIC2130/1 Evaluation Board 98 Efficiency VOUT = 3.3V @ +25°C 8V 96 12V 94 92 10V 20V 90 88 86 84 82 80 30V 24V 40V 4 5 6 7 OUTPUT CURRENT (A) Figure 2. Typical Characteristics Figure 4. Functional Characteristic (IOUT = 2A) Figure 3. Functional Characteristics ( IOUT = 10A) August 2008 3 M9999-082608-D Micrel, Inc. MIC2130/1 Evaluation Board Bill of Materials Item C1, C2 C3, C4, C15 C5, C8, C9, C11, C13 C6 C7 C10, C12 C12, C16 C14 C17, C18 C19, C20 C22 C23 D1 D2 L1 Q1, Q2, Q3, Q4 R1 R2, R5 R3 R4, R7 R6 R8, R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 U1 Part Number PCE4324CT-ND GRM32ER71H106 GRM42-2X7R106K50 Manufacturer DigiKey(1) Description 220µF/50V, Aluminum Electrolytic Qty 2 Murata(2) 4.7µF/50V, Ceramic Capacitor 3 VJ0603Y104KXAAT Vishay Vitramon(3) GRM188R71E104KA01D Murata(2) 0.1µF/ 50V, Ceramic Capacitor 5 VJ0603A470KXAAT GRM188R71A154KA01D VJ0603Y154KXJCW1BC CM21X5R106M06AT GRM21BR60J106M C2012X5R0J106M VJ0603A101KXXAT VJ0603YxxxKXXAT VJ0603YxxxKXXAT 54D337X06R3D2T TPSD337M06R30100 GRM188R61A105KA01D VJ0603Y105KXQAT SD103BWS SS34L B340A CDEP-147NP-7R3MC-73 Si7848DP-T1-E3 IRF7842 CRCW080510R0FRT1 CRCW060310R0FRT1 CRCW06034992FRT1 CRCW06031002FRT1 CRCW06033161FRT1 CRCW06030000FRT1 CRCW06033160FRT1 CRCW08054R02FRT1 CRCW06031001FRT1 CRCW06039311FRT1 CRCW06032371FRT1 CRCW06031001FRT1 CRCW06031472FRT1 CRCW0603xxxxFRT1 CRCW06032R00FRT1 CRCW0603xxxxFRT1 CRCW06030000FRT1 MIC2130-1YTSE Or MIC2131-1YTSE Vishay Vitramon(3) Murata(2) Vishay Vitramon(3) AVX(4) Murata(2) TDK(5) Vishay Vitramon(3) Vishay Vitramon(3) Vishay Vitramon(3) Vishay Dale(3) AVX(4) Murata(2) Vishay(3) Vishay(3) Vishay(3) Diodes, Inc.(6) Sumida(7) Vishay Siliconix(3) (8) International Rectifier (3) Vishay Dale Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) Vishay Dale(3) 47pF/50V, X7R (Open Location) 0 0.15µF/6.3V, Ceramic Capacitor 1 10µF/6.3V, Ceramic Capacitor 2 100pF/25V, Ceramic Capacitor Open Open 2 1 2 330µF/6.3V, Tantalum Capacitor 2 1µF/10V, Ceramic Capacitor 1µF/10V, Ceramic Capacitor 200mW, Small Diode 1 1 1 3A/40V Schottky Diode 1 7.3µH/14.6A, Inductor 1 40V, N-Channel MOSFET 4 10Ω, 0805, 1% 10Ω, 0603, 1%. 49.9K, 0603, 1% 10K, 0603, 1% 3.16K, 0603, 1% 0Ω, 0603, 1% 316Ω, 0603, 1% 4.02Ω, 0805, 1% Open 9.31K, 0603, 1% 3.92K, 0603, 1% 2.37K, 0603, 1% 14.7K, 0603, 1% Open 2Ω, 0603, 1% Open MIC2130 ONLY, otherwise install C23 1 2 1 2 1 2 1 1 1 1 1 1 1 1 1 1 1 Micrel, Inc.(9) High Voltage Synchronous Buck Control IC 1 August 2008 4 M9999-082608-D Micrel, Inc. MIC2130/1 Evaluation Board Notes: 1. DigiKey: www.digikey.com 2. Murata: www.murata.com 3. Vishay: www.vishay.com 4. AVX: www.avx.com 5. TDK: www.tdk.com 6. Diodes, Inc.: www.diodes.com 7. Sumida: www.sumida.com 8. International Rectifier: www.irf.com 9. Micrel, Inc: www.micrel.com August 2008 5 M9999-082608-D Micrel, Inc. MIC2130/1 Evaluation Board PCB Layout Recommendations Top Layer Bottom Layer August 2008 6 M9999-082608-D Micrel, Inc. MIC2130/1 Evaluation Board MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2007 Micrel, Incorporated. August 2008 7 M9999-082608-D