Maxim Offers Drop-In Power-Supply Sequencers/Monitors To Provide Reverse Sequencing
Maxim Integrated Products introduced the MAX16050/MAX16051, drop-in power-supply supervisors. The MAX16050/MAX16051 are said to let customers safely power up and power down their system(s) without the need for programming and/or elaborate board modifications. The devices sequence up and sequence down as many as five power supplies, while also monitoring undervoltage and overvoltage conditions.
With the additional capability of reverse sequencing, the company claims that customers can now power down their system safely with no extra effort, cost, or loss of board space. The main applications for MAX16050/MAX16051 are servers/storage, networking, and telecom systems.
The MAX16050 device’s sequencing engine allows the sequence order to be changed without altering the signal routing to the power supplies. Furthermore, this configurable sequencing order is accomplished without adding bulky discrete components and/or making elaborate layout changes to the board.
The MAX16050 exchanges the 5th sequencing/monitoring channel, found in the MAX16051, for three 3-state pins used to configure the sequencing order of the four remaining channels in any one of 24 possible combinations. Users thus have full control of the sequence up/down order and can change the order on-the-fly. The ability to utilize a pin-selectable sequencing order is said to be unique to the MAX16050.
The MAX16050/MAX16051’s 85mA pulldown circuitry enables a fast discharge of output capacitance. Furthermore, integrated comparators ensure that the supply voltages are below 250mV before powering down the next channel in the reverse sequence, regardless of how fast the system power is cycled. This pulldown circuitry is said to increase reliability in complex systems. External resistor-divider networks set the 1.5% accurate undervoltage and overvoltage thresholds. In the event of an overvoltage condition, an independent output signals the system controller. This additional control is said to protect the system, reduces damage to expensive system components, and ultimately reduces repair costs.
Users can configure the devices’ outputs either to: 1) enable point-of-load dc-dc converters; or 2) fully enhance the gate of series-pass FETs. An integrated charge pump enables this flexibility. The charge pump functions as a pullup voltage for FETs, otherwise the open-drain outputs are pulled up to the supply voltage for enabling dc-dc converters. Consequently, users have the versatility of operating with mixed mode by driving both dc-dc converters and series-pass FET simultaneously in their system. Multiple MAX16050/MAX16051’s can be daisy-chained to sequence and reverse sequence across multiple devices. This scalability requires no programming and is said to be easy to implement.
The MAX16050/MAX16051 have a wide 2.7V to 13.2V operating voltage range, which allows operation directly from an intermediate bus voltage. The devices are fully specified over the -40 to +85°C extended temperature range. The MAX16050/MAX16051 are offered in a small 28-pin, 4 x 4mm QFN package.
