MIC39150/39300/39500 Micrel MIC39150/39300/39500 Evaluation Board 1.5A Low-Voltage Low-Dropout Regulator General Description Circuit Description This evaluation board can be used to evaluate several of Micrel’s new, low voltage, high current, low-dropout linear voltage regulators. The MIC39150/1 is a 1.5A output current LDO regulator. The MIC39300/1 and MIC39500/1 are capable of sourcing 3A and 5A, respectively. The board has two layouts, one on the topside and one on the backside to accommodate a three-terminal device and a five-terminal device. The three-terminal devices, the MIC39150, MIC39300 and MIC39500 are fixed output voltage regulators with output voltages of 2.5V or 1.8V. The five-terminal devices are the MIC39151, MIC39301 and the MIC39501. The five-terminal devices are fixed voltage devices that include an active-high enable pin to turn-on and shutdown the regulator, as well as an out-of-regulation indicator. This one board can easily be used to evaluate any one of these parts. The MIC39XXX regulators are simple to implement, requiring only an output capacitor for proper operation. An input cap is required when the power supply is greater than 4” away from the device. All evaluation boards include an input capacitor within 1” of the device. This is the recommended maximum distance away from the device that a capacitor should be placed. A minimum of 10µF of output capacitance is required for the MIC39150, while the MIC39300 and MIC39500 require 47µF. Using large values of capacitance at the input and output will help to improve transient response. Table 1 shows the bill of materials for the different part numbers. The five-terminal circuit implements an error flag and an enable function. The enable function allows the user to put the device into a zero-current off state when the regulator is not required. The error flag function is a voltage monitor that indicates when the output falls out of regulation for any reason. The error flag output is an open-collector output, which is active-low, and requires a pull-up resistor for proper operation. Boards assembled with the five-terminal device have a 47kΩ pull-up resistor from FLG to the input voltage. All of the devices require a minimum load of 10mA. A resistor is included on the board to provide a minimum load of 10mA. The resistor value is different depending on the voltage option of the device. Requirements The evaluation board requires a power supply capable of supplying a minimum of 1.5A of output current for the MIC39150, 3A for the MIC39300 and at least 5A of current for the MIC39500. The maximum voltage of that power supply should be at least 5V. These parts are intended for 3.3V to 2.5V and 3.3V or 2.5V to 1.8V conversion. A high voltage power supply should not be needed. Note: For systems that require a higher input voltage, the MIC39XXX family is capable of input voltages up to 16V. Input capacitors used on the evaluation board for the MIC39300 and MIC39500 may only be rated to 10V. Operation at or above 10V is not recommended with these capacitors. Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com August 2000 1 MIC39150/39300/39500 MIC39150/39300/39500 Micrel MIC39XXX-X.XBM IN OUT VIN J1 C1B C2B VOUT J3 R2B GND J2 GND J4 GND Figure 1. Bottom-Side Schematic, 3-Terminal Regulator MIC39XXX-X.XBM IN OUT VIN J1 C1 VOUT J3 R2 C2 R1 VEN J5 EN GND J2 GND FLG FLAG J4 J6 GND Figure 2. Top-Side Schematic, 5-Terminal Regulator MIC39150/39300/39500 2 August 2000 MIC39150/39300/39500 Micrel Bill of Materials Item Part Number C1B TPSC106M025R0500 C2B TPSC106M025R0500 R2B Manufacturer Description AVX Qty. 10µF, 25V, Tantalum 1 AVX 10µF, 25V, Tantalum 1 AVX 240Ω (2.5V) or 180Ω (1.8V) 5% 1/8W, size 0805 1 LDO Regulator 1 U1B MIC39150-x.xBU Micrel C1B TPSC476M0100350 AVX 47µF, 10V, Tantalum 1 C2B TPSC476M0100350 AVX 47µF, 10V, Tantalum 1 240Ω (2.5V) or 180Ω (1.8V) 5% 1/8W, size 0805 1 LDO Regulator 1 R2B U1B MIC39300-x.xBU Micrel C1B TPSC476M0100350 AVX 47µF, 10V, Tantalum 1 C2B TPSC476M0100350 AVX 47µF, 10V, Tantalum 1 R2B 240Ω (2.5V) or 180Ω (1.8V) 5% 1/8W, size 0805 1 LDO Regulator 1 AVX 10µF, 25V, Tantalum 1 AVX 10µF, 25V, Tantalum 1 R1 47Ω 5% 1/8W, size 0805 (placed on reverse side of board) 1 R2 240Ω (2.5V) or 180Ω (1.8V) 5% 1/8W, size 0805 1 LDO Regulator 1 U1B MIC39500-x.xBU C1 TPSC106M0250500 C2 TPSC106M0250500 Micrel U1B MIC39151-x.xBU Micrel C1 TPSC476M0100350 AVX 47µF, 10V, Tantalum 1 C2 TPSC476M0100350 AVX 47µF, 10V, Tantalum 1 R1 47Ω 5% 1/8W, size 0805, (placed on reverse side of board) 1 R2 240Ω (2.5V) or 180Ω (1.8V) 5% 1/8W, size 0805 1 LDO Regulator 1 U1B MIC39301-x.xBU C1 TPSC476M0100350 AVX 47µF, 10V, Tantalum 1 C2 TPSC476M0100350 AVX 47µF, 10V, Tantalum 1 R1 47Ω 5% 1/8W, size 0805, (placed on reverse side of board) 1 R2 240Ω (2.5V) or 180Ω (1.8V) 5% 1/8W, size 0805 1 LDO Regulator 1 U1B August 2000 MIC39501-x.xBU Micrel Micrel 3 MIC39150/39300/39500 MIC39150/39300/39500 Micrel MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2000 Micrel Incorporated MIC39150/39300/39500 4 August 2000