The PX3511A and PX3511B are high-frequency MOSFET drivers specifically designed to drive an up-and-down power N-channel MOSFET in a synchronous rectified buck converter topology. These drivers are combined with the ISL6595 digital multiphase Buck PWM controller and n-channel mosfet to form a complete core voltage regulator solution for advanced microprocessors.
The PX3511A drives the upper grid up to 12V, while the lower grid can be driven independently in the 5V to 12V range. The PX3511B drives the upper and lower doors in the 5V to 12V range. This drive voltage provides the flexibility necessary to optimize applications involving trade-offs between grid charge and conduction loss. Adaptive zero-through-protection is integrated to prevent the upper and lower MOSFeTs from conducting at the same time and minimize dead zone time.
These products add overvoltage protection to operate before the VCC exceeds its on-off threshold, at which the PHASE node connects to the gate of the low-side MOSFET (LGATE). The output voltage of the converter is then limited by the threshold of the lower side MOSFEts, which provides some protection for the microprocessor if the upper mosFEts short out during initial startup.
These drivers also feature a three-state PWM input that works in conjunction with Intersil's polyphase PWM controller to prevent negative transients of the output voltage when the output is turned off. This feature eliminates Schottky diodes, which are used in some systems to protect loads from reverse output voltage events.
Pinouts
Block Diagram
Time diagram
Features
● Dual MOSFET driver for synchronous rectifier bridge
● Optimum efficiency for adjustable grid voltages (5V to 12V)
● 36V internal guide Schottky diode
● Prevent bootstrap capacitor overcharging
● Support high switching frequency (up to 2MHz)
- 3A Sinking current capacity
- Fast rise/fall time and low propagation delay
● Three-state PWM I/O stage stops
● Three-state PWM input lag
● Power sequencing requirement
● Pre-Por overvoltage protection
● VCC undervoltage protection
● Expandable bottom copper pad enhances heat sink
● Dual-plane lead-free (DFN) package
- Close to chip size package footprint; Improved printed circuit boards High efficiency, thinner profile
● Lead-free annealed (RoHS compliant)
Applications
● Core regulator for Intel and AMD microprocessors
● High current DC/DC converter
● High frequency and high efficiency VRDS and VRDS
