MIC49300 Evaluation Board 3.0A Low Voltage LDO Regulator with Dual Input Voltages General Description Features The MIC49300 voltage regulator provides highbandwidth, low-dropout, and high current drive for powering core voltages of low-power microprocessors. The MIC49300 uses separate supplies for VIN and VBIAS allowing for very low output impedance and very fast transient response. The main input supply of the MIC49300 is separate from the bias input supply, thus allowing for ultra-low input voltages on the main supply rail. The main input supply operates between 1.4V to 6.5V and the bias supply requires between 3V to 6.5V for proper operation. Main Input voltage range: 1.4V to 6.5V Bias Input voltage range: 3V to 6.5V Maximum load current: 3.0A Adjustable output voltage down to 0.9V Stable with 1µF ceramic capacitor Power S-Pak package MIC49300BR +VIN VOUT +VIN C1 10µF VBIAS VOUT R1 BIAS ADJ C3 10µF C2 1µF GND R2 GND GND Pin Description Pin Number Part Name Pin Function 1 Adj Adjustable regulator feedback input. Connect to resistor voltage divider 2 Vbias Input Bias Voltage for powering all circuitry on the regulator with the exception of the output power device 3 GND Ground (TAB is connected to ground on S-Pak) 4 VIN Input voltage which supplies current to the output power device 5 VOUT Regulator Output Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax 1 (408) 474-1000 • http://www.micrel.com M9999-030405 (408) 955-1690 March 2005 Micrel, Inc. MIC49300 Evaluation Board GND TAB is also used for ground Adjustable Regulator Design The MIC49300 adjustable version allows the output voltage to be set between 0.9V and 5V. The ADJ pin voltage is 0.9V on the adjustable versions. Once a suitable VOUT voltage is determined values for R1 and R2 can be calculated. The only requirement is that R1 should not exceed 1kΩ. VIN VIN provides the high current to the collector of the pass transistor of the regulator. The minimum input voltage for the MIC49300 is 1.4V. The suggested bypass capacitor value for VIN on the demo board is a 100µF ceramic capacitor. R1 = R2 x (Vout/0.9 – 1) VBIAS The VBIAS input voltage must be 1.6V above the output voltage with a minimum VBIAS input voltage of 3V. Small ceramic capacitors from VBIAS to group help reduce high frequency noise from being injected into the control circuitry from the bias rail and are good design practice. A 4.7µF capacitor should be sufficient. VOUT The MIC49300 does not require a minimum load to maintain output voltage regulation. The suggested bypass capacitor value for VOUT on the demo board is a 10µF ceramic capacitor. An output capacitance is required on the MIC49300 to maintain stability. Bill of Material MIC49300 Evaluation Board Ref Des C1 C2 C3 C4 J1-J5 R1,R2 U1 Part Number C3225X5R0J107K C2012Y5V1A475M C3225Y5V0J106K Description 100µF, 6.3V X5R Ceramic Capacitor 4.7µF, 10V Y5V Ceramic Capacitor 10µF, 6.3V Y5V Ceramic Capacitor 2551-2-00-01-00-00-07-0 Turret pins CRCW08051001FRT1 1k, 1%, 1/10W, 0805 MIC49300BR SPAK – 5 Pins Manufacturer Qty TDK 1 TDK 1 TDK 1 1 MillMax 5 Vishay 2 Micrel 1 Notes: 1. Mill Max: www.millmax.com 2. TDK: www.tdk.com 3. Vishay: www.vishay.com 4. Micrel Semiconductor: www.micrel.com March 2005 2 M9999-030405 (408) 955-1690 Micrel, Inc. MIC49300 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 This 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. © 2005 Micrel Incorporated March 2005 3 M9999-030405 (408) 955-1690