ISL6536 Datasheet, PDF (4/6 Pages) Intersil Corporation – Four Channel Supervisory IC

ISL6536
ISL6536 Description and Operation
The ISL6536 is a four channel supervisory IC designed to
monitor multiple voltages greater than 0.7V. This IC is
suitable for both microprocessors or industrial system
applications.
Upon VDD bias power up the PGOOD output is held low with
VDD as low as 0V. Once biased to 2.6V and enabled the IC
continuously monitors from one to four voltages
independently through external resistor dividers comparing
each VMON pin voltage to an internal 0.63V reference.
Once all VMON input voltages rise above 0.63V the PGOOD
(power good) output signal is released and is pulled high via
an external pull resistor to indicate that the power conditions
have been met. The PGOOD output is an open-drain to
allow ORing of the signals and interfacing to a wide range of
logic levels.
Once any VMON input falls below 0.63V the PGOOD output
is pulled low, the VMON inputs are designed to reject fast
transients (30µs).
If less than four voltages are being monitored, connect the
unused VMON pins to VDD.
The PGOOD pin has an internal 20kΩ pull-up to VDD
making an external pull-up resistor unnecessary.
Figure 1 illustrates the operational timing diagram.
4/5 EN/VMON INPUTS HIGH
VTH
LAST EN/VMON INPUT
T_FIL
<T_FIL
PGOOD OUTPUT
FIGURE 1. ISL6536 OPERATIONAL TIMING DIAGRAM
Typical Performance Curves
0.6
0.5
VMON<VMON_{_L2H}
0.4
0.3
0.2
0.1
VMON>VMON_{_L2H}
0
2.6
3.0
3.33
3.66
4.0
VDD BIAS VOLTAGE (V)
FIGURE 2. VDD CURRENT vs. VDD VOLTAGE
0.645
0.642
0.639
0.636
0.633
0.630
0.627
2.6
3.3
3.5
3.7
3.9
VDD BIAS VOLTAGE (V)
FIGURE 3. VMON THRESHOLD vs. VDD VOLTAGE
4
FN9114.2
December 28, 2004