MAX5039 MAXIM [Maxim Integrated Products], MAX5039 Datasheet - Page 9

• Manufacturer Part Number: MAX5039
• Description: Voltage-Tracking Controllers for PowerPC, DSPs, and ASICs
• Manufacturer: MAXIM [Maxim Integrated Products]

and off the CORE and I/O power supplies. The
MAX5039/MAX5040 monitor and compare the CORE
and I/O voltages as follows.
When the I/O voltage is greater than or equal to the
CORE voltage, MAX5039/MAX5040 regulate the exter-
nal N-channel MOSFET as a linear regulator by control-
ling NDRV. The linear regulator regulates the CORE
voltage to the value set by the external resistor-divider
connected from CORE to CORE_FB and GND (see
Figures 9 and 10). If the CORE_FB voltage is far less
than its regulation point, V
high to V
through the external MOSFET. If the CORE_FB voltage
Figure 5. System Power-Up/Power-Down, Fault Startup
(CORE Supply Fails to Turn On)
Figure 7. System Turn-On/Turn-Off Under UVLO Control
(V
CORE
Rising Before V
CC
, effectively shorting CORE and I/O together
(CORE SUPPLY FAILS TO TURN ON)
POK
SYSTEM TURN-ON/TURN-OFF
(V
NDRV
SYSTEM FAULT STARTUP
CORE
POK
UNDER UVLO CONTROL
_______________________________________________________________________________________
NDRV
UVLO
I/O
CORE
SDO
RISING BEFORE V
)
SDO
4ms/div
5ms/div
C_REF
I/O
CORE
V
CC
I/O
(800mV), NDRV drives
I/O
)
Voltage-Tracking Controllers for
V
5V/div
NDRV
5V/div
SDO
5V/div
POK
5V/div
I/O
AND CORE
2V/div
CC
UVLO
5V/div
SDO
5V/div
POK
5V/div
NDRV
5V/div
I/O
AND CORE
1V/div
PowerPC, DSPs, and ASICs
equals V
CORE_FB voltage is higher than V
ulator goes into standby mode and pulls NDRV low,
turning off the external N-channel MOSFET.
When the I/O voltage is lower than the CORE voltage by
V
channel MOSFET on by driving NDRV high to V
Whenever SDO is high, the MAX5039/MAX5040 track the
time that NDRV is in regulation mode or driven high. If
NDRV is in regulation mode or driven high for longer than
t
Figure 6. System Turn-On/Turn-Off Under UVLO Control
(V I/O Rising Before V CORE )
Figure 8. Short-Circuit Response (CORE Shorted to GND)
FAULT
TH
(90mV), the MAX5039/MAX5040 turn the external N-
(15ms), a fault occurs and SDO is pulled low.
C_REF
POK
, NDRV goes into regulation mode. If the
SYSTEM TURN-ON/TURN-OFF
NDRV
(V
(CORE SHORTENED TO GND)
SHORT-CIRCUIT RESPONSE
I/O
UNDER UVLO CONTROL
CORE
RISING BEFORE V
UVLO
I/O
SDO
NDRV
POK
2ms/div
I/O
2ms/div
CORE
CORE
SDO
C_REF
)
, the linear reg-
UVLO
5V/div
SDO
5V/div
POK
5V/div
NDRV
5V/div
I/O
AND CORE
1V/div
NDRV
5V/div
SDO
5V/div
POK
5V/div
I/O
AND CORE
1V/div
CC
.
9