MIC5337 Evaluation Board 300mA Low IQ Ultra Low Dropout LDO with Auto Discharge General Description The MIC5337 is a low quiescent current, low dropout regulator with an internal auto discharge feature designed for optimal performance in a small space. The auto discharge circuit switches in a 300Ω load when the regulator is disabled to discharge the output capacitor. The MIC5337 is capable of sourcing 300mA of output current while only consuming 24µA of operating current. This high performance LDO offers fast transient response and good PSRR. The MIC5337 is an ideal solution for battery operated applications due to extremely low dropout voltage of 180mV at 300mA. The MIC5337 can also be put into a zero-off-mode current state, drawing virtually no current when disabled. An input capacitor may be required when the power supply is more than 4-inches away from the device. The evaluation board includes an input capacitor of 10µF to compensate for long inductive test leads. Requirements The MIC5337 evaluation board requires an input power supply that is able to deliver at least 400mA at a voltage within the range of 2.3V to 5.5V. The output load can be either active or passive. 2. Enable/Disable the MIC5337. The evaluation board is set up for “Default Enable” with a 10k pull up resistor on enable pin (EN) to VIN. To disable the output, simply jumper the EN terminal (J5) to the GND terminal (J2).The enable pin must be either pulled high or low. Removing the pull up resistor and leaving the pin floating will cause the regulator to operate in an indeterminate state. 3. Connect the load to the VOUT terminal (J3) and ground terminal (J4). The load can be either a passive (resistor) or active (electronic load). Be sure to monitor the output voltage at the VOUT (J3) terminal. Ordering Information Part Number Description MIC5337-2.8YMT EV 300mA Low IQ , Low dropout LDO VOUT = 2.8V Evaluation Board MIC5337-1.8YMT EV 300mA Low IQ , Low dropout LDO VOUT = 1.8V Evaluation Board Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN terminal may damage the device. Getting Started 1. Connect an external supply to VIN. Apply the desired input voltage to the VIN (J1) and ground terminal (J2) of the evaluation board, paying careful attention to polarity and supply voltage (2.3V ≤ VIN ≤ 5.5V). An ammeter may be placed between the input supply and the VIN terminal of the evaluation board. Ensure that the supply voltage is monitored at the VIN terminal. The ammeter and/or power lead resistance can reduce the voltage supplied to the input. MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. 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 2008 M9999-120508-A Micrel, Inc. MIC5337 Evaluation Board Evaluation Board Schematic U1 MIC5337-xxYMT J1 VIN J5 EN 1 C1 10µF/6.3V VIN VOUT R1 10k 3 EN GND J3 VOUT 4 2 C2 1µF/6.3V J4 GND J2 GND Bill of Materials Item C1 Part Number C1608X5R0J106Z Manufacturer Description TDK (1) Capacitor, 10µF Ceramic, 6.3V, X5R, Size 0603 TDK (1) Qty 1 C2 C1608X5R0J105K Capacitor, 1µF Ceramic, 6.3V, X5R, Size 0603 1 R1 CRCW06031002FKEYE3 Vishay(2) Resistor, 10kΩ, 1%, 1/16W, Size 0603 1 U1 MIC5337-XXYMT Micrel(3) 300mA Low IQ LDO with Auto Discharge 1.2mmx1.6mm Thin MLF® 1 Notes: 1. TDK: www.tdk.com 2. Vishay: www.vishay.com 3. Micrel, Inc.: www.micrel.com December 2008 2 M9999-120508-A Micrel, Inc. MIC5337 Evaluation Board PCB Layout Recommendations Top Layer Bottom Layer December 2008 3 M9999-120508-A Micrel, Inc. MIC5337 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. © 2008 Micrel, Incorporated. December 2008 4 M9999-120508-A