MAX5909EEE Maxim Integrated Products, MAX5909EEE Datasheet - Page 19

• Manufacturer Part Number: MAX5909EEE
• Description: Hot Swap & Power Distribution
• Manufacturer: Maxim Integrated Products

Specifications of MAX5909EEE

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Figure 9. VariableSpeed/BiLevel Response
Figure 10. Operating with an External Gate Capacitor
OUTC is high impedance when V
1.236V.
Using the MAX5904–MAX5909 on the backplane allows
multiple cards with different input capacitance to be
inserted into the same slot even if the card does not
Low-Voltage, Dual Hot-Swap Controllers/Power
110µs
260ns
3ms
*
OPTIONAL COMPONENTS (SEE THE ON COMPARATOR SECTION).
*
Using the MAX5904–MAX5909 on the
R
V
PULLUP
IN
V
SC,TH
SENSE VOLTAGE (V
*
______________________________________________________________________________________
PGOOD
ON
COMPARATOR
IN
SLOW
R
SENSE
IN
MAX5906
MAX5907
MAX5908
MAX5909
- V
GND
SENSE
SENSE
(4 x V
)
V
INC+
FC,TH
SC,TH
GATE
)
COMPARATOR
is greater than
Backplane
FAST
V
OUT
C
C
GATE
BOARD
have on-board hot-swap protection. The startup period
can be triggered if IN is connected to ON through a
trace on the card (Figure 13).
The voltage at IN1 or IN2 must be above the UVLO dur-
ing inrush and fault conditions. When a short-circuit
condition occurs on the board, the fast comparator
trips causing the external MOSFET gates to be dis-
charged at 3mA. The main system power supply must
be able to sustain a temporary fault current, without
dropping below the UVLO threshold of 2.4V, until the
external MOSFET is completely off. If the main system
power
MAX5904–MAX5909 will force the device to restart
once the supply has recovered. The MOSFET is turned
off in a very short time resulting in a high di/dt. The
backplane delivering the power to the external card
must have low inductance to minimize voltage tran-
sients caused by this high di/dt.
During normal operation, the external MOSFETs dissi-
pate little power. The MOSFET R
MOSFET is fully enhanced. The power dissipated in
normal operation is P
power dissipation occurs during the turn-on and turn-
off transients when the MOSFETs are in their linear
regions. Take into consideration the worst-case sce-
nario of a continuous short-circuit fault, consider these
two cases:
1) The single turn-on with the device latched after a
2) The continuous automatic retry after a fault
MOSFET manufacturers typically include the package
thermal resistance from junction to ambient (R
thermal resistance from junction to case (R
determine the startup time and the retry duty cycle (d =
t
mal resistance with the following equation:
where I
To take full tracking advantage of the switch response
time to an output fault condition, it is important to keep
all traces as short as possible and to maximize the
high-current trace dimensions to reduce the effect of
undesirable parasitic inductance. Place the MAX5904–
START
fault (MAX5905/MAX5907/MAX5909)
(MAX5904/MAX5906/MAX5908)
START
/ t
supply
RETRY
MOSFET Thermal Considerations
= V
Z
). Calculate the required transient ther-
θ
SU,TH
JA MAX
collapses
(
D
/ R
= I
)
≤
SENSE
Layout Considerations
Sequencers
LOAD
V
T
IN
JMAX
×
2
DS(ON)
I
below
START
Input Transients
x R
−
T
A
DS(ON)
is low when the
UVLO,
. The most
θJC
θJA
) which
) and
the
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