Simplified Block Diagram
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- Demonstrates PCIe ExpressModule Hot-Swap and DC-DC Design
- 1.2V at 2.5A
- 2.5V at 1.25A
- 3.3V at 1.25A
- X8E PCIe ExpressModule Form Factor
- Demonstrates Inrush Current Control and Lossless Current Sensing
- Demonstrates Output Overcurrent/Short-Circuit Protection
- Configurable PWM and Hot-Swap UVLO
- Configurable for Several Startup Tracking/Sequencing Modes
- Power Board Assembly Eases Bench Evaluation
- Surface-Mount Components
- Fully Assembled and Tested
- Base Stations
- Blade Servers
- General 12V-Input PWM Controllers with Hot-Swap
- PCIe® ExpressModule™
- Work Stations
The MAX5950 EV kit demonstrates the MAX5950 IC's hot-swap inrush current control capabilities as well as the MAX5950 and MAX5951 ICs' hiccup-mode output short-circuit protection during normal operation. The MAX5950 controls an external n-channel MOSFET for inrush control during hot swapping. The EV kit can operate over an 8V to 16V input range, however, it is configured for 12V input operation by default. The MAX5950 EV kit also includes connections for the PCIe bus 3.3V auxiliary supply.
Additionally, the MAX5950 and MAX5951 PWM DC-DC step-down controllers' lossless current sensing, digital soft-start, startup synchronization, thermal shutdown, and hiccup-mode output short-circuit current-limit features can be evaluated using the EV kit. The VOUT1 circuit can also be reconfigured to evaluate an alternate current-sense method using a resistor for the DC-DC converter. The hot-swap and PWM undervoltage lockouts (UVLO) can easily be reconfigured for other set points. The MAX5950 EV kit can be reconfigured for various startup tracking/sequencing modes such as ratiometric-tracking, startup sequencing, PGOOD sequencing. The EV kit is configured for PGOOD sequencing by default.
To ease bench evaluation of the MAX5950 EV kit, a MAX5950PB power board assembly is included with the EV kit. The power board features bulk holdup capacitance for the 12V and 3.3V auxiliary power rails providing power to a single X8E PCIe connector. The power board includes switches, HC logic, and LEDs to simulate hot swapping a MAX5950 EV kit into a server's backplane utilizing an X8E PCIe connector.
The MAX5950 EV kit is not optimized for size, but is designed for ease of lab evaluation. See Appendix A, which shows a compact reference design with the same output voltages and currents. The reference design is configured for PGOOD sequencing.