MAX5040EUB+ Maxim Integrated Products, MAX5040EUB+ Datasheet - Page 13

• Manufacturer Part Number: MAX5040EUB+
• Description: IC CNTRLR VOLT TRACK 10-UMAX
• Manufacturer: Maxim Integrated Products

Specifications of MAX5040EUB+

• Applications: Processor
• Current - Supply: 1.3mA
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 11. Circuit Prolongs V
Condition
power supplies startup delay and/or soft-start timing,
which are specific to each of the power supplies,
CORE and I/O outputs may not rise at the same time or
at the same rate. Output loading and capacitance fur-
ther separate the two output’s rise time. The
MAX5039/MAX5040 help the system to overcome these
differences and keeps CORE and I/O voltages tracking
together by controlling NDRV, dynamically driving
NDRV high, low, or in regulation mode, depending on
the CORE and I/O voltage condition.
After the power-up period is over, CORE and I/O output
voltages settle to their respective regulated values. The
linear regulator formed by MAX5039/MAX5040 and the
external MOSFET is turned off. During normal opera-
tion, the linear regulator goes into a standby mode and
NDRV is driven low.
The resistor-divider from CORE to CORE_FB to GND
must be set so that the linear regulator regulation voltage
is less than the CORE power-supply regulation voltage.
See the Programming the CORE Voltage section.
During normal operation, the MAX5039/MAX5040 con-
stantly monitor the CORE, I/O, and CORE_FB voltages.
NDRV responds as needed, according to the condi-
tions described in the NDRV section.
The MAX5039/MAX5040 continue to provide tracking
for the CORE and I/O output voltages during power-
down/brownout or shutdown.
During shutdown (UVLO is pulled below V
pulled low, disabling the CORE and I/O power supplies
together. The CORE and I/O output voltages start to fall.
Power-Down/Brownout or Shutdown
V
IN
______________________________________________________________________________________
C
HD
CC
10µF
After a Brownout/Power-Down
V
UVLO
Normal Operation
CC
Voltage-Tracking Controllers for
MAX5039
MAX5040
UVCC
), SDO is
PowerPC, DSPs, and ASICs
Without voltage tracking, depending on the output capac-
itance and loading, CORE and I/O voltages may not fall at
the same rate. Similar to the power-up condition, the
MAX5039/MAX5040 keep CORE and I/O voltages track-
ing together by controlling NDRV, dynamically driving
NDRV high, low, or in regulation mode, depending on the
CORE and I/O voltage condition.
During power-down/brownout, V
UVLO voltage is also dropping. When the UVLO voltage
falls below V
CORE and I/O power supplies. Similar to the shutdown
condition, the MAX5039/MAX5040 keep CORE and I/O
voltages together. It is important that V
operating voltage range in order to keep the MAX5039/
MAX5040 operating to provide tracking until the output
voltages have discharged to a safe level. Figure 11 illus-
trates a method to prolong V
down/brownout condition. The bleeder circuitry is
helpful in this power-down/brownout condition because
the bleeder helps speed up the discharge process.
While SDO is high, the MAX5039/MAX5040 keep track of
the time NDRV is driven high or in regulation mode. In a
typical system during power-up, power-down/
brownout, and normal operation, the time NDRV is driven
high or in regulation mode should last for only a few mil-
liseconds. If this time exceeds t
an abnormal condition, a fault is generated. During a
fault condition, SDO is driven low and NDRV continues
its operation as described in the NDRV section.
A fault condition is latched. To clear a fault, toggle V
and/or UVLO to unlatch and restart the system.
If any of the outputs are shorted to ground, NDRV is dri-
ven high to keep the CORE and I/O voltages tracking
each other. The current through the external MOSFET is
limited by the current limit provided by the external
power supply. If the short-circuit condition lasts more
than t
(which turns off the CORE and I/O power supplies), and
NDRV continues its operation as described in the
NDRV section.
The external N-channel MOSFET connected between
CORE and I/O power supplies is expected to turn on
briefly during power-up and power-down/brownout
conditions. During normal operation, this MOSFET is
turned off. In general, only a small size MOSFET is
needed. A MOSFET capable of carrying 1/4th to 1/8th
FAULT
, a fault is generated, SDO is driven low
UVCC
Applications Information
Output Short-Circuit Condition
N-Channel MOSFET Selection
, SDO is pulled low, disabling the
FAULT
CC
FAULT Condition
CC
is dropping and the
(15ms), indicating
CC
after a power-
remains in its
CC
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