MIC5308-1.8YMT-EV

MIC5308 Evaluation Board Low VIN/VOUT 150mA High PSRR ULDO™ with Ultra-Low IQ 3. Enable/Disable the MIC5308. The evaluation board is provided with 10k pull up resistors on enable pin (EN) to VIN. To disable an output, simply jumper the EN terminal (J6) to the GND terminal (J3).The enable pin must be either pulled high or low. Removing the pull up resistors and leaving the pins floating will cause the regulators to operate in an indeterminate state. General Description The MIC5308 is a high performance, µCap low dropout regulator, offering ultra-low operating current while maintaining very fast transient response. The MIC5308 can source up to 150mA of output current and can regulate down from a low input supply voltage to increase system efficiency. Ideal for battery operated applications; the MIC5308 offers extremely low dropout voltage 45mV typically @ 150mA, and low ground current at all load conditions (typically 23µA). The MIC5308 can also be put into a zero-off-mode current state, drawing virtually no current when disabled. 4. Connect the loads to the VOUT terminal (J4) and ground terminal (J5). The load can be either a passive (resistor) or active (electronic load). Be sure to monitor the output voltage at the VOUT (J4) terminals. The evaluation board has a 1uF capacitor connected from VOUT (J4) to GND (J5). Requirements The MIC5308 evaluation board requires two power supplies. The first supply must be able to provide a minimum of 150mA with a voltage range of 1.6V to 5.5V to the VIN. Although typical VBIAS current is 15µA in dropout conditions, VBIAS current can reach as high as a few mA. The VBIAS supply should be able to deliver a minimum of 100mA with a voltage range of 2.5V to 5.5V. The output load can be either an active or passive load. 5. Bypass/Adjust Pin. The evaluation board provides 10nF capacitor connected from Bypass pin to GND to reduce the output voltage noise. The capacitor bypasses the internal reference. The bypass capacitor can be increased, further reducing noise and improving PSRR. Turn-on time increases slightly with respect to bypass capacitance. A unique, quick-start circuit allows the MIC5308 to drive a large capacitor on the bypass pin without significantly slowing turn-on time. The evaluation board also provides the footprint to place feedback resistor for adjustable output versions. The resistor values can be calculated by: 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 VBIAS. Apply a desired voltage to VBIAS (J1) and ground terminal (J3), paying careful attention to polarity and supply voltage (2.5V ≤ VBIAS ≤ 5.5V). An ammeter may be placed between the Bias supply and VBIAS terminal to the evaluation board. The evaluation board has a 1µF capacitor connected from VBIAS (J1) pin to GND (J3). 2. Connect an external supply to VIN. Apply desired input voltage to the VIN (J2) and ground terminal (J3) of the evaluation board, paying careful attention to polarity and supply voltage (1.6V ≤ VIN ≤ VBIAS). An ammeter may be placed between the input supply and the VIN terminal to the evaluation board. Ammeter and/or power lead resistance can reduce the voltage supplied to the input. Ensure that the supply voltage is monitored at the VIN terminal. There is 1µF capacitor connected from VIN (J2) to GND (J3). ⎞ ⎛V R1 = R 2 × ⎜⎜ OUT − 1⎟⎟ ⎠ ⎝ 0.775 Recommended Feedback Resistors VOUT R1 R2 1.2V 5.49kΩ 10kΩ 1.5V 9.31kΩ 10kΩ 1.8V 13.3kΩ 10kΩ 2.8V 26.1kΩ 10kΩ Ordering Information Part Number Description MIC5308-XXYMT EV Evaluation board with the 150mA ULDO™ device ULDO is a trademark of Micrel, Inc. 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 May 2008 M9999-050908-A Micrel, Inc. MIC5308 Evaluation Board Evaluation Board Schematic U1 MIC5308-xxYMT VBIAS J1 VBIAS 1 VBIAS VOUT VOUT J4 VOUT 4 R1 TBD C1 1µF/6.3V J2 VIN 3 R3 10k J6 EN BYP/ADJ VIN 5 C3 10nF/10V EN GND C2 1µF/6.3V 6 R2 TBD C4 1µF/6.3V 2 J5 GND J3 GND Bill of Materials Item C1, C2, C4 Part Number C1608X5R0J105K Manufacturer (1) TDK Capacitor, 1µF Ceramic, 6.3V, X5R, Size 0603 3 Capacitor, 10nF Ceramic, 10V, X7R, Size 0603 1 (2) Resistor, 10kΩ, 1%, 1/16W, Size 0603 1 VJ0603Y103KXXAT Vishay R3 CRCW06031002FKEYE3 Vishay MIC5308-XXYMT Micrel Qty (2) C3 U1 Description (3) ® ULDO, 150mA, 1.6mm x 1.6mm Thin MLF 1 Notes: 1. TDK: www.tdk.com 2. Vishay: www.vishay.com 3. Micrel, Inc.: www.micrel.com May 2008 2 M9999-050908-A Micrel, Inc. MIC5308 Evaluation Board PCB Layout Recommendations Top Layer Bottom Layer May 2008 3 M9999-050908-A Micrel, Inc. MIC5308 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. May 2008 4 M9999-050908-A