SMH4804 Datasheet, PDF (19/41 Pages) Summit Microelectronics, Inc. – -48V Programmable Hot Swap Sequencing Power Controller

SMH4804
Timing Diagram
SMH4804 Power-On Waveforms - Ref to -48V
Tektronix TDS3054: Time/Horizontal division = 40mS
Ch 1 (2V/Div) = 3.3V DC-DC converter output (Yellow trace)
Ch 2 (50V/Div) = PG#2 output (Blue trace) - Note 1
Ch 3 (50V/Div) = Switched 48V supply voltage (Purple trace)
Ch 4 (2A/Div) = Inrush input current (Green)
Note 1 – After initial hot swap conditions are met, he PG# outputs first drop to –43V
until ready to sequence the DC-DC converter. When ready to sequence, the PG#
outputs then drop an additional 5V to enable the converters.
SMH4804 Sequencing waveforms - Ref to GND
Four DC/DC converters sequenced on at 160ms intervals
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Ch 1 (1V/Div) = 5.0V DC-DC converter output (Yellow trace)
Ch 2 (1V/Div) = 3.3V DC-DC converter output (Yellow trace)
Ch 3 (1V/Div) = 2.5V DC-DC converter output (Yellow trace)
Ch 4 (1V/Div) = 1.8V DC-DC converter output (Yellow trace)
SMH4804 with 0.1uF and 0.01uF Soft-Start Capacitors
Tektronix TDS3054: Time/Horizontal division = 40mS
Ch 1 (50V/Div) = MOSFET Drain (Yellow trace)
Ch 2 (5V/Div) = SMH4804 UV pin (Blue trace)
Ch 3 (10V/Div) = MOSFET Gate (Purple trace)
Ch 4 (2A/Div) = -48V Inrush input current (Green)
SMH4804 with 1uF and 0.1uF Soft-Start Capacitors
Tektronix TDS3054: Time/Horizontal division = 200mS
Ch 1 (50V/Div) = MOSFET Drain (Yellow trace)
Ch 2 (5V/Div) = SMH4804 UV pin (Blue trace)
Ch 3 (10V/Div) = MOSFET Gate (Purple trace)
Ch 4 (2A/Div) = -48V Inrush input current (Green)
Summit Microelectronics
2050 3.7 10/30/02
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