MAQ5280 Evaluation Board 25mA, 120V, Low I , High PSRR LDO Q Automotive General Description The MAQ5280 is a high performance, linear regulator, offering a very low noise output with a very wide input voltage operating range, from 4.5V to 120V DC input 2. Enabling the MAQ5280. The MAQ5280 has an voltage. enable pin EN for enable/disable functionality. Ideal for high input voltage applications such as EN: A logic high will turn on the linear regulator automotive and telecom, the MAQ5280 offers 2% initial and a logic low will shut down the linear regulator accuracy, extremely high power supply rejection ratio reducing the quiescent current to less than (PSRR > 80dB) and low ground current (typically 31A). 0.02A (typical). The MAQ5280 can also be put into a zero-off-mode current state, drawing minuscule amount of current when Output Voltage disabled. The output voltage on the MAQ5280 evaluation board is The MAQ5280 has a very wide input voltage range, with adjustable. The output voltage is controlled by the DC rated from 24V to +120V. This wide input range feedback resistors (R1 and R2) and can be calculated as covers the automotive load dump range and the follows: MAQ5280 is optimized for line transient response, making R1 it ideal for harsh environment applications. V = V + 1 OUT REF R2 Requirements V = 1.219V REF The MAQ5280 evaluation board requires an input power The evaluation board is initially adjusted to 5V, but can source that is able to deliver greater than 0.1A at easily be modified by removing R1 and replacing it with +120VDC. the value that yields the desired output voltage. Precautions V OUT The evaluation board does not have reverse polarity R1 = R2 1 V protection. Applying a negative voltage lower than 24V to REF the V (J1) terminal may damage the device. IN Ensure the output voltage selected does not exceed 5V. The MAQ5280 evaluation board is tailored for a 4.5V to 120V input voltage range. The input voltage range should Ordering Information not exceed 120VDC on the input. Getting Started Part Number Description 1. Connect an external supply to the V . Apply IN MAQ5280YME EV Evaluation board for the desired input voltage to the V (J1) and ground IN MAQ5280QYME device (J2) terminals of the evaluation board, paying careful attention to polarity and supply voltage (4.5V V 120V). An ammeter may be placed IN between the input supply and the V terminal to IN the evaluation board. Ensure that the supply voltage is monitored at the V terminal. The IN ammeter and/or power lead resistance can reduce the voltage supplied to the input. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MAQ5280 Evaluation Board Evaluation Board Schematic Bill of Materials Item Part Number Manufacturer Description Qty. (1) NMC-P1210X7R184K200TRPLPF NIC 0.18F, 200V, 1210, X7R Ceramic Capacitor (2) C1 1 C1812C184K2RAC Kemet 0.18F, 200V, 1812, X7R Ceramic Capacitor (3) VJ1812Y184KXC Vishay (4) C1608X5R1A225K TDK (5) C2 0603C225MAT AVX 2.2F, 6.3V, 0603, X5R Ceramic Capacitor 1 (6) GRM188R60J225KE19D Murata (4) C1608X5R0J105K TDK (3) C3 VJ0603G105KXYPW1BC Vishay 0.1F, 6.3V, 0603, X5R Ceramic Capacitor 1 (6) GRM188R60J105KA01D Murata (4) R1 CRCW060315R4FKEYE3 Vishay Dale 15.4k, 0603, 1%, 1/16W Resistor 1 (4) R2 CRCW06034R87FKEYE3 Vishay Dale 4.87k, 0603, 1%, 1/16W Resistor 1 (7) U1 MAQ5280YME Micrel, Inc. 25mA, 120V, Low I , High PSRR LDO 1 Q Notes: 1. NIC: www.niccomp.com 2. Kemet: www.kemet.com 3. Vishay: www.vishay.com 4. TDK: www.tdk.com 5. AVX: www.avx.com 6. Murata: www.murata.com 7. Micrel, Inc.: www.micrel.com M9999-091708-A September 2008 2