MAX16047A Datasheet, PDF (54/61 Pages) Maxim Integrated Products – 12-Channel/8-Channel EEPROM-Programmable System Managers with Nonvolatile Fault Registers

12-Channel/8-Channel EEPROM-Programmable
System Managers with Nonvolatile Fault Registers
V_IN
V_CC
C
MAX16047A
MAX16049A
If more than six series-pass MOSFETs are required for
an application, additional series-pass p-channel
MOSFETS may be connected to outputs configured as
active-low open drain (Figure 17). Connect a pullup
resistor from the gate to the source of the MOSFET, and
ensure the absolute maximum ratings of the
MAX16047A/MAX16049A are not exceeded.
GND
Figure 15. Power Circuit for Shutdown During Fault Conditions
Driving High-Side MOSFET Switches
The MAX16047A/MAX16049A use external n-channel
MOSFET switches for voltage tracking applications. To
configure the part for closed-loop voltage tracking using
series-pass MOSFETs, configure up to four of the pro-
grammable outputs (EN_OUT1–EN_OUT4) of the
MAX16047A/MAX16049A as closed-loop tracking out-
puts and configure up to four of the GPIOs as sense-
return inputs (INS1–INS4). Connect the EN_OUT_ output
to the gate of an n-channel MOSFET, connect the source
of the MOSFET to the INS_ feedback input, and monitor
the drain side of the MOSFET with the corresponding
MON_ input (see Figure 16). Both the input and the out-
put must be assigned to the same slot (see the
Closed–Loop Tracking section). Configure the power-up
and power-down slew rates in the configuration regis-
ters. To provide additional control over power-down,
enable the internal 100Ω pulldown resistors on the INS_
connections.
Up to six of the programmable outputs (EN_OUT1–
EN_OUT6) of the MAX16047A/MAX16049A may be con-
figured as charge-pump outputs. In this case, they can
drive the gates of series-pass n-channel MOSFETS with-
out closed-loop tracking functionality. When configured
in this way, these outputs act as simple power switches
to turn on the voltage supply rails. Approximate the slew
rate, SR, using the following formula:
( ) ^{SR =}
I_CP
C_GATE + C_EXT
V_IN
MON_
ADC MUX
LOGIC
REFERENCE
RAMP
V_OUT
EN_OUT_ INS_
GATE
DRIVE
V_{TH_PG}
100Ω
Figure 16. Closed-Loop Tracking
V_IN
S
D
V_OUT
R
G
MON_
EN_OUT_
MAX16047A
MAX16049A
where I_CP is the 6µA (typ) charge-pump source cur-
rent, C_GATE is the gate capacitance of the MOSFET,
and C_EXT is the capacitance connected from the gate
to ground. Power-down is not well controlled due to the
absence of the 100Ω pulldowns.
Figure 17. Connection for a p-Channel Series-Pass MOSFET
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