MIC4782 Evaluation Board Dual 2A Buck Regulator General Description The Micrel MIC4782 is a high efficiency dual PWM buck (step-down) regulator that provides up to 2A of output current for each channel. The MIC4782 operates at 1.8MHz and has proprietary internal compensation that allows a closed loop bandwidth of over 200kHz. The low on resistance internal P-Channel MOSFET of the MIC4782 allows efficiencies up to 92%, reduces external component count and eliminates the need for an expensive external current sense resistor. The MIC4782 operates from a 3.0V to 6.0V input and its output is adjustable down to 0.6V. The devices can operate with a maximum duty cycle of 100% for use in low-dropout applications. placed between the load and the VOUT1/VOUT2 terminal. Ensure the output voltage is monitored at the VOUT1/VOUT2 terminal. The default VOUT1 is set to 1.8V and the default VOUT2 is set to 1.2V. This can be adjusted by changing the feedback resistors. See “Output Voltage.” 3. Enable the MIC4782. The enable pins are connected to pull up resistors. Both outputs of the MIC4782 turn on when VIN exceeds the UVLO threshold at the VIN pin. Each output of the MIC4782 may be turned off by shorting the enable pin to ground or bringing the enable pin below the enable threshold. An external connection on the board provides easy access to the enable pin. Output Voltage Requirements The MIC4782 evaluation board requires an input power source that is able to deliver greater than 3.0V at over 4A. The output load can either be an active or passive load. The output voltages on the MIC4782 evaluation board are adjustable. The output voltage is controlled by the feedback resistors (R11 and R12 for VOUT1, R21 and R22 for VOUT2) and can be calculated as follows: VOUT1 = VREF × (1 + Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN terminal may damage the device. In addition, the maximum operating voltage of the MIC4782 evaluation board is 6.0V. Exceeding 6.5V on the input could damage the device. VOUT2 = VREF × (1 + R21 ) R22 where VREF = 0.6V. The evaluation board is preset at 1.8V for VOUT1 and 1.2V for VOUT2, but can easily be modified by removing R12 or R22 and replacing them with the value that yields the desired output voltage. Getting Started 1. Connect an external supply to VIN terminal. Apply desired input voltage to the VIN and ground terminals of the evaluation board, paying careful attention to polarity and supply voltage (3.0V<VIN<6.0V). An ammeter may be placed between the input supply and the VIN terminal to the evaluation board. Ensure the supply voltage is monitored at the VIN terminal. The ammeter and/or power lead resistance can reduce the voltage supplied to the input. 2. Connect the load to the VOUT1/VOUT2 and ground terminals. The load can be either passive (resistive) or active (as in an electronic load). An ammeter can be R11 ) R12 R12 = R11× VREF VOUT1 − VREF R22 = R21× VREF VOUT2 − VREF For VREF = 0.6V, this reduces to: R12 = R11× 0.6 V VOUT1 − 0.6 V R22 = R21× 0.6 V VOUT2 − 0.6 V MLF is a registered trademark of Amkor Technology. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2009 1 M9999-122209-A Micrel, Inc. MIC4782 Evaluation Board Ordering Information Part Number MIC4782YML MIC4782YML EV Description Package IC 16-Pin MLF® EPAD Evaluation Board 16-Pin MLF® EPAD MLF is a registered trademark of Amkor Technology. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2009 2 M9999-122209-A Micrel, Inc. MIC4782 Evaluation Board Bill of Materials Item Part Number Manufacturer Description Qty C11,C12 C21,C22 0805ZD106MAT2A AVX(1) 10µF, Ceramic Capacitor, X5R, 0805, 10V 6 C15,C25 C13*,C23* VJ0603A681KXXCW Vishay(2) 680pF, Ceramic Capacitor, NP0, 0603, 25V 2 C14,C24 VJ0603A820KXXCW Vishay 82pF, Ceramic Capacitor, NP0, 0603, 25V 2 VJ0603Y104KXXAT Vishay 0.1µF, Ceramic, Capacitor, X7R, 0603, 25V 5 SS2P3L Vishay SSA23L Vishay 2A Schottky, 30V 2 C16,C26,C7 C18,C28 D1,D2 B230A L1,L2 IHLP2525AH-01 1R0 RLF7030-1R0 N HCP0703-1R0 Diodes (3) Vishay TDK 1µH Inductor, 17.5mΩ 6.86mm(L) x 6.47mm(W) x 1.8mm(H) (4) COOPER CRCW060310K0FKXX R12,R22 CRCW06033K16FKXX 3.16kΩ,1%, 0603 For 2.5VOUT CRCW06034K99FKXX 4.99kΩ, 1%, 0603 For 1.8 VOUT Vishay 2 1µH Inductor, 10mΩ 7.3mm(L) x 7.0mm(W) x 3.0mm(H) R11,R21 CRCW06036K65FKXX Vishay 1µH Inductor, 8.8mΩ 7.3mm(L) x 6.8mm(W) x 3.2mm(H) (5) 10kΩ, 1%, 0603, resistor 2 6.65kΩ, 1%, 0603 For 1.5 VOUT CRCW060310K0FKXX 10kΩ, 1%, 0603 For 1.2 VOUT CRCW060315K0FKXX 15kΩ, 1%, 0603 For 1.0 VOUT 2 * only for ultra-low noise applications. MLF is a registered trademark of Amkor Technology. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2009 3 M9999-122209-A Micrel, Inc. MIC4782 Evaluation Board Item Part Number R13*, R23* CRCW06032R70FKXX Vishay 2.7Ω, 1%, 0603, resistor 2 R14, R24 CRCW060349K9FKXX Vishay 49.9kΩ, 1%, 0603, resistor 2 R5 CRCW060310R0FKXX Vishay 10Ω, 1%, 0603, resistor 1 Dual, 2A, 1.8MHz, Integrated Switch Buck Regulator 1 U1 MIC4782YML Manufacturer (6) Micrel, Inc. Description Qty Notes: 1. AVX: www.avx.com 2. Vishay: www.vishay.com 3. Diodes: www.diodes.com 4. TDK: www.tdk.com 5. Cooper: www.cooperbussmann.com 6. Micrel, Inc: www.micrel.com * only for ultra-low noise applications. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2009 4 M9999-120209-A Micrel, Inc. MIC4782 Evaluation Board Printed Circuit Board Layouts Figure 1a. Top Layer Figure 1b. Bottom Layer MLF is a registered trademark of Amkor Technology. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2009 5 M9999-122209-A Micrel, Inc. MIC4782 Evaluation Board Figure 1c. Mid-Layer 1 (GND Plane) Figure 1d. Mid-Layer 2 Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2009 6 M9999-120209-A Micrel, Inc. MIC4782 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. © 2009 Micrel, Incorporated. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2009 7 M9999-120209-A