MAX5954LEVKIT Maxim Integrated, MAX5954LEVKIT Datasheet - Page 6

• Manufacturer Part Number: MAX5954LEVKIT
• Description: Power Management IC Development Tools Evaluation Kit/Evaluation System for the MAX5954L/MAX5954A
• Manufacturer: Maxim Integrated
• Series: MAX5954r

The MAX5954L EV kit features two slide switches to
reset a latched fault at the channel. The respective
switch resets the MAX5954L and unlatches faults when
toggled from on to off. See Table 2 for resetting the
channel. Refer to the MAX5954L data sheet for addi-
tional functions of the MAX5954L ON pin.
The MAX5954L fault timeout period is configured for a
default value of 10ms and can be reconfigured to a
new timeout period by installing surface-mount resistor
R10. The MAX5954L POR timeout period is configured
for a default value of 160ms, however a new POR time-
out period can be reconfigured by installing surface-
mount resistor R11. Refer to the MAX5954L data sheet
Applications Information section for selecting the val-
ues of resistors R10 or R11.
When adjusting the t
adequate startup time, t
startup time for a given output is the greater of either
as described in the Detailed Description of Hardware
section. Refer to the MAX5954 data sheet for more
information on selecting R
The PCI Express slot can be forced to turn on regard-
less of the MAX5954L logic status inputs. To force the
channel on, install surface-mount resistor R12. A typical
value is less than 1kΩ.
The MAX5954L EV kit can evaluate other current-limit
configurations for the 12V and 3.3V main outputs.
Resistor R1 sets the 12V current limit and R15 sets the
3.3V current limit. The 3.3V-auxiliary current limit is
fixed at 470mA (typ) and is not reconfigurable. Refer to
the MAX5954L IC data sheet for information on select-
ing other current-limit resistors.
The MAX5954L EV kit can be used to evaluate the
MAX5954A. Replace U1 with the MAX5954A that can
be ordered by contacting the factory.
6
Evaluating Other MAX5954L Hot-Plug Controllers
_______________________________________________________________________________________
Control Methods, Other Configurations,
or
PWRGD threshold voltage input voltage
MAX5954L Evaluation Kit/Evaluation System
total gate capaci
output load capaci
thresholdvoltage
Fault Timeout and POR Periods
FAULT
5
5
TIM
µ
SU
µ
A
tan
A
timeout, be sure to allow
. The minimum required
and R
ce PWRGD
+
and I/O Expander
tan
×
PORADJ
ce
Forced On Inputs
Current Limiting
Fault Resetting
.
×
The MAX5954L EV kit features a MAX7313 I/O
expander (U2) and PC board pads for connecting to an
SMBus system (SDA and SCL signals). The I/O
expander interfaces with the PRES-DET, FAULT, ON,
and OUT signals of the MAX5954L. A 9-pin header, J2,
is provided to enable easy access to each signal
through a ribbon cable or scope probe. Green and yel-
low LEDs (D3, D4) are also provided for user applica-
tions such as status indication. Jumper JU2 (MRL) is
provided to mimic a PCI Express mechanical retention
locking (MRL) signal. Surface-mount resistors R20–R25
configure the MAX7313 SMBus address, which is set to
0x40 by default.
If the MAX7313 I/O expander is used to control the
MAX5954L ON/AUXON signals and read back the vari-
ous other signals, jumpers JU3 and JU4 must be
reconfigured or U2 may be destroyed when switching
logic states. See Table 3 below for configuring jumpers
JU3 and JU4. Pads are provided on the EV kit’s PC
board for interfacing with a user’s system SMBus VDD,
SDA, SCL, and GND signals if the CMAXQUSB inter-
face board is not used.
If a user’s SMBus system is not available, a Windows-
based computer can be interfaced with the EV kit by
connecting the CMAXQUSB interface board to connec-
tor J4. The CMAXQUSB interface board enables the
computer to interface with the EV kit’s SMBus signals.
The interface board and GUI software provides the
user with the capability of controlling and monitoring
the MAX5954L IC using the MAX7313 I/O expander.
Table 3. MAX5954L Channel ON Signals
Configuration
JUMPER
JU4
JU3
JU4
JU3
MAX7313 Input/Output Expander and SMBus
LOCATION
SHUNT
1 and 2
1 and 2
2 and 3
2 and 3
ON controlled by
SW3
AUXON
controlled by SW4
ON controlled by
U2, MAX7313
with SMBus
AUXON
controlled by U2,
MAX7313 with
SMBus
MAX5954L PIN
CONNECTION
Local switch
control
Local switch
control
SMBus or
computer
control
SMBus or
computer
control
OPERATION
EV KIT
Interface