MIC49200 Evaluation Board 2.0A Low Voltage LDO Regulator General Description The demonstration board can be used to evaluate the MIC49200. The MIC49200, a 2 amp, ultra-high speed, low dropout linear regulator, utilizes a split supply input to regulate low output voltages. It is offered in a low profile S-pack. The MIC49200 is also offered in fixed and adjustable outputs. Fixed output versions add enable pin functionality, allowing it to be placed in a zero-current off mode state. The adjustable version allows for the use of a resistor divider network to adjust for the desired output voltage. The evaluation board accommodates the adjustable version. Requirements The MIC49200 requires two power supplies; one to provide a minimum of 2A to the VIN and the other to provide VBIAS current. Although typical VBIAS current is 40mA, in dropout conditions VBIAS currents can reach as high as 270mA. The VBIAS supply should be able to supply a minimum of 300mA. The VBIAS should be able to deliver a minimum of 3V or 2.1V greater than VOUT, whichever is greater. In cases where the VIN voltage satisfies the minimum VBIAS voltage, one supply can be used. Circuit Description The MIC49200 ultra-high speed regulator is easy to use. It is extremely tolerable to a wide range and types of output capacitors. Although there is no minimum output capacitor requirement for the MIC49200, a minimum 1µF capacitor is recommended. The evaluation board has a 10µF ceramic on the VIN pin. Although this is much larger than required for the device, this was designed to allow for the long inductive test leads that will be attached to the evaluation board. The output can be selected by using the evaluation board jumper. The available output options on the evaluation board are 1.0V, 1.2V, 1.5V and 1.8V. Also, a 0.9V output can be obtained by removing the jumper altogether. Any of the 4 bottom feedback resistors can be substituted to obtain a different output voltage. The equation to set the output is as follows: ⎛ R1 ⎞ VOUT = VREF ⎜ + 1⎟ ⎝ R2 ⎠ VREF = 0.9 R1 on the evaluation board is set to 1KΩ. Due to the high bandwidth of the MIC49200, larger values of R1 and the parasitic capacitance of the feedback pin introduce an additional pole. For R1 values greater than 1KΩ, a small feed forward capacitor across R1 will be required to maintain stability. Since R1 on the evaluation board is set to 1K, the formula for adjusting the output to the desired level is as follows: ⎛V ⎞ R2 = ⎜⎜ REF − VREF ⎟⎟ × R1 ⎝ VOUT ⎠ ⎛ 0.9V ⎞ R2 = ⎜⎜ − 0.9V ⎟⎟ × 1kΩ ⎝ VOUT ⎠ An input capacitor is required when the power supply is more than 4” away from the device. All evaluation boards include an input capacitor within 1” of the device. This is the minimum recommended distance from the device that the capacitor should be placed. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com February 2006 M9999-021306 (408) 955-1690 Micrel MIC49200 Evaluation Board MIC49200WR Circuit Bill of Materials MIC49200WR Evaluation Board Item C1, C2, C3 Part Number GRM40X5R105K10 Manufacturer TDK (1) Description 10µF, 6.3V capacitor (2) J1 – J5 2551200010000070 Millmax JP1, JP2 S201204ND Sullins(3) R1, R5 CRCW06031001FRT1 Vishay(4) CRCW06038871FRT1 Vihsay (4) 8.87K, 1%, 1/16W, 0603 resistor Vishay (4) 2.87K, 1%, 1/16W, 0603 resistor Vishay (4) 1.5K, 1%, 1/16W, 0603 resistor Vishay (4) R2 R3 R4 R6 U1 CRCW06032871FRT1 CRCW06031501FRT1 CRCW06031002FRT1 MIC49200WR Qty. 1K, 1%, 1/16W, 0603 resistor 10K, 1%, 1/16W, 0603 resistor (5) Micrel, Inc. 2A, Low Voltage LDO with Dual Input Notes: 1. TDK: www.tdk.com 2. Millmax: www.mill-max.com 3. Sullins: www.sullinselectronics.com 4. Vishay: www.vishay.com 5. Micrel, Inc.: www.micrel.com 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. © 2006 Micrel, Incorporated. February 2006 2 M9999-021306 (408) 955-1690