The Intersil ISL6123, ISL6124, ISL6125, ISL6126, ISL6127, ISL6128 and ISL6130 are integrated four channel controlled-on/controlled-off power-supply sequencers with supply monitoring, fault protection and a "sequence completed" signal (RESET). For larger systems, more than four supplies can be sequenced by simply connecting a wire between SYSRESET pins of cascaded IC's. The ISL6125 uses four open-drain outputs to control the on/off sequencing of four supplies, while the other sequencers use a patented, micropower 7x charge pump to drive four external low-cost NFET switch gates above the supply rail by 5.3V. These IC's can be biased from any supply 5V down to 1.5V. Individual product descriptions follow.

The four channel ISL6123 (ENABLE input), ISL6124 (ENABLE input) and ISL6125 ICs offer the designer 4 rail control when it is required that all four rails are in minimal compliance prior to turn on and that compliance must be maintained during operation. The ISL6123 and ISL6130 have a low power standby mode when disabled, suitable for battery powered applications.

The ISL6125 operates like the ISL6124 but instead of charge pump driven gate drive outputs it has open drain logic outputs for direct interface to other circuitry.

In contrast to the majority, for both the ISL6126 and ISL6130 each of the four channels operates independently so that the various GATEs will turn on once its individually associated input voltage requirements are met.

The ISL6127 is a pre-programmed A-B-C-D turn-on and D-C-B-A turn-off sequenced IC. Once all inputs are in compliance and ENABLE is asserted, the sequencing starts and each subsequent GATE will turn-on after the previous one completes turning-on.

The ISL6128 has two groups of two channels each with its independent I/O and is ideal for voltage sequencing into redundant capability loads as all four inputs need to be satisfied prior to turn on but a single group fault is ignored by the other group.

External resistors provide flexible voltage threshold programming of monitored rail voltages. Delay and sequencing are provided by external capacitors for both ramp-up and ramp-down.

Additional I/O is provided indicating and driving RESET state in various configurations.

For volume applications, other programmable options and features can be had. Contact the factory with your needs.

• Enables arbitrary turn-on and turn-off sequencing of up to four power supplies (0.7V to 5V)
• Operates from 1.5V to 5V supply voltage
• Supplies V_DD +5.3V of charge pumped gate drive
• Adjustable voltage slew rate for each rail
• Multiple sequencers can be daisy-chained to sequence an infinite number of independent supplies
• Glitch immunity
• Undervoltage lockout for each supply
• 1μA Sleep State (ISL6123, ISL6130)
• Active high (ISL6123, ISL6130) or low (ISL6124, ISL6125, ISL6126, ISL6127, ISL6128) ENABLE input
• Open drain version available (ISL6125)
• Voltage Determined Sequence (ISL6126, ISL6130)
• Pre-programmed Sequence available (ISL6127)
• Dual channel groupings (ISL6128)
• QFN package
• Pb-free available (RoHS compliant)

• Graphics cards
• FPGA/ASIC/microprocessor/PowerPC supply sequencing
• Network routers
• Telecommunications systems