MICROCHIP MIC9131YM

The MIC9131 is a current-mode PWM controller that efficiently converts –48V telecom voltages to logic levels. The MIC9131 features a high voltage start-up circuit that allows the device to be connected to input voltages as high as 180V. The high input voltage capability protects the MIC9131 from line transients that are common in telecom systems. The start-up circuitry also saves valuable board space and simplifies designs by integrating several external components. The MIC9131 is capable of high speed operation. Typically the MIC9131 can control a sub-25ns pulse width on the gate out pin. Its internal oscillator can operate over 2.5MHz, with even higher frequencies available through synchronisation. The high speed operation of the MIC9131 is made safe by the very fast, 34ns response from current sense to output, minimizing power dissipation in a fault condition. The MIC9131 allows for the designs of high efficiency power supplies. It can achieve efficiencies over 90% at high output currents. Its low 1.3mA quiescent current allows high efficiency even at light loads. The MIC9131 has a maximum duty cycle of 75%. For designs requiring a maximum duty cycle of 50%, refer to the MIC9130. The MIC9131 is available in a 16-pin SOP and 16-pin QSOP package options. The junction temperature range is from -40°C to +125°C.

• Input voltages up to 180V
• Internal oscillator capable of > 2.5MHz operation
• Accurate 75% maximum duty cycle
• Synchronisation capability to 6MHz
• Current sense delay of 34ns
• Minimum pulse width of <25ns
• 90% efficiency
• 1.3mA quiescent current
• 1μA shutdown current
• Soft-start
• Resistor programmable current sense threshold
• Selectable soft-start retry
• 4Ω sink, 12Ω source output driver
• Programmable under-voltage lockout
• Constant-frequency PWM current-mode control
• 16-pin SOIC and 16-pin QSOP

• Telecom power supplies
• Line cards
• ISDN network terminators
• Micro- and pico-cell base stations
• Low power (<100W) dc-dc converters
• DSL line cards