General Description
The MAX8533 evaluation kit (EV kit) is a fully assembled
and tested surface-mount circuit board demonstrating
the MAX8533 to be a versatile, single-port, 12V,
Infiniband™ (IB)-compliant hot-swap controller. The
MAX8533 integrates several features that allow for reli-
able insertion and removal of the circuit card as well as
real-time fault protection of abnormal occurrences. The
MAX8533 allows for an adjustable soft-start ramp during
turn-on of the input voltage while providing overcurrent
protection. It also provides accurate and consistent cur-
rent-regulated outputs for a programmable period of time
to latchoff and soft-start in the presence of overcurrent
(OC) conditions. Additionally, it provides a second level
of severe overcurrent (SOC) protection by responding to
a dead short in 100ns.
The MAX8533 EV kit incorporates a power-good (POK)
open-drain output that can easily be pulled up to the
input voltage or to another logic level using a jumper.
Two enable inputs, EN (logic enable) and LPEN (local
power enable), provide flexible sequencing.
The MAX8533 EV kit comes with an edge-card connector
backplane board that is used to verify the hot-swap
function.
Features
♦12V Hot-Swap Controller for 25W or 50W
Applications
♦Programmable Overcurrent Protection
♦EN and LPEN Inputs for Flexible Sequencing
♦Power-Good Output
♦Adjustable Turn-On Ramp
♦16V Absolute Maximum Rating
♦Soft-Start Overcurrent Protection During Turn-On
♦Undervoltage Lockout
♦Timed Current-Regulation Period (Optional)
♦100ns IC Response Time to Output Dead Short
♦Adjustable Overvoltage Protection
♦Fully Assembled and Tested
Evaluates: MAX8533
MAX8533 Evaluation Kit
________________________________________________________________ Maxim Integrated Products 1
19-3085; Rev 0; 12/03
Component List
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Ordering Information
PART TEMP RANGE IC PACKAGE
MAX8533EVKIT 0°C to +70°C 10 µMAX
DESIGNATION QTY DESCRIPTION
C1 1
470µF, 25V aluminum electrolytic
capacitor
Sanyo 25MV470HC
C2 1
0.1µF ±10%, 25V X5R ceramic
capacitor (0603)
Taiyo Yuden TMK107BJ104KA
C3 1
0.01µF ±10%, 50V X7R ceramic
capacitor (0603)
TDK C1608X7R1H103K
C4 1 Not installed
C5 1
0.22µF ±10%, 10V X5R ceramic
capacitor (0603)
TDK C1608X5R1A224K
C6 1
10µF ±20%, 16V X7R ceramic
capacitor (1812)
TDK C4532X7R1C106M
C7 1 100µF ±20%, 16V tantalum capacitor
Kemet T495D107M016AS
DESIGNATION QTY DESCRIPTION
J1 1 6-dual-position card-edge connector
Sullins EZM06DRXH
JU1 1 3-pin header
Sullins PTC36SAAN
N1 1 N-channel MOSFET 30V, VGS = 20V
Vishay/Siliconix SI4842DY
R1, R2 2
20mΩ ±1%, 0.5W current-sense
resistors
Vishay/Dale LRF1206-01-R020-F
R3 1 20Ω ±5% resistor (0603)
R4 1 3.09kΩ ±1% resistor (0603)
R5 1 4.99kΩ ±1% resistor (0603)
R6 1 31.6kΩ ± 1% resistor (0603)
R7 1 100kΩ ±5% resistor (0603)
TP1, TP2, TP3 3 1-pin headers
Sullins PTC36SAAN
U1 1 MAX8533EUB
None 1 MAX8533 EV kit PC board
None 1 MAX8533 backplane PC board
InfiniBand is a trademark of InfiniBand Trade Association.
Evaluates: MAX8533
Recommended Equipment
Before you begin, you need the following equipment:
•0 to +14V, 7A, variable-output power supply
•Dummy load capable of sinking 6A–7A
•Two digital multimeters (DMMs)
Quick Start
The MAX8533 EV kit is fully assembled and tested.
Follow these steps to verify board operation. Do not
turn on the power supply until all connections are
completed:
1) Remove the MAX8533 EV kit from the backplane
board.
2) Preset a power supply to zero and turn off the
power supply.
3) Connect the positive lead of PS1 to the VIN pad on
the backplane board. Connect the negative lead
of the power supply to the GND connection on the
backplane board.
4) Connect the EN pad on the backplane board to
the GND pad. This enables the MAX8533.
5) Connect the positive input of one DMM (VVOUT) to
the OUT pad on the MAX8533 EV kit board.
Connect the negative input of the DMM to the
GND pad on the MAX8533 EV kit board to mea-
sure the output voltage.
6) Connect the positive input of the second DMM to
the POK pad on the MAX8533 EV kit board.
Connect the negative input of the DMM to the
GND pad on the MAX8533 EV kit board to mea-
sure the power-good signal (VPOK).
7) Verify JU1 is shorted between positions 1 and 2.
8) Turn on the power supply.
9) Plug the MAX8533 EV kit into the socket on the
backplane board.
10) Set the power supply to +10V. Verify that the POK
(VPOK) voltage and the VVOUT voltage read +10V.
11) Sweep the power-supply voltage from +10V to
+14V. Verify that VVOUT and VPOK track the power
supply over the entire input range.
12) Increase the power supply to +15V. Verify that
VOUT and VPOK drop to zero due to overvoltage
protection.
13) Set the power supply to +12V.
14) Pull the MAX8533 EV kit board out of the socket
and plug it back in to reset the fault.
15) Verify that VVOUT is +12V.
16) Connect the 6A load between the VVOUT and GND
pads on the MAX8533 EV kit board.
17) Verify that the output voltage equals VVIN minus
the voltage drop across the MOSFET and current-
sense resistors, which is ~(VIN – 90mV).
18) Increase the load to 6A. Verify that VOUT drops to
zero due to overcurrent protection.
19) Remove the load.
20) Verify that VVOUT remains at zero.
21) Pull the MAX8533 EV kit board out of the socket
and plug it back in to reset the fault.
22) Verify that VVOUT is 12V.
23) Short OUT to GND. Verify that VOUT drops to zero
and remains at zero after the short is removed.
24) Pull the MAX8533 EV kit board out of the socket
and plug it back in to reset the fault.
25) Verify that VVOUT is +12V.
MAX8533 Evaluation Kit
2 _______________________________________________________________________________________
SUPPLIER COMPONENT PHONE WEBSITE
Kemet Capacitors 864-963-6300 www.kemet.com
Panasonic Resistors 714-373-7366 www.maco.panasonic.co.jp
Sanyo Capacitors 619-661-6835 www.sanyo.com
Taiyo Yuden Capacitors 408-573-4150 www.t-yuden.com
TDK Capacitors 888-835-6646 www.component.tdk.com
Vishay/Dale Current-Sense Resistors 402-563-6866 www.vishay.com
Vishay/Siliconix MOSFET 402-563-6866 www.vishay.com
Component Suppliers
Note: Please indicate that you are using the MAX8533 when contacting these suppliers.
Detailed Description
50W/25W Operation
The MAX8533 EV kit is assembled for 50W application
with the overcurrent protection set at 6.2A. Remove R2
to use the MAX8533 EV kit in a 25W application. This
changes the overcurrent protection to 3.1A.
POK Output
The MAX8533 EV kit has a POK open-drain output that
becomes high impedance when the output has
reached 90% of its final value. The POK output can be
pulled up to the input voltage or to the user’s digital
logic level (VDLL) using JU1.
LPEN/EN
LPEN and EN are used to enable the MAX8533. Drive EN
high or LPEN low to disable the MAX8533. Drive EN low
and LPEN high or leave floating to enable the MAX8533.
Soft-Start
The output for the MAX8533 increases to VVIN with a
controlled soft-start ramp to limit inrush current. C2 is
used to control the MOSFET turn-on ramp rate. Refer to
the Setting the Turn-On Ramp Rate section in the
MAX8533 data sheet for more details.
Overcurrent Protection
The MAX8533 utilizes two schemes for overcurrent pro-
tection. The first scheme employs a programmable time-
out that counts down once an overcurrent condition is
sensed. During this time, the gate of the MOSFET is reg-
ulated to limit the current to the output. Once the time-
out occurs, if the overcurrent condition still exists, the
MOSFET is latched off. The current limit and timeout are
programmable using R4 and C3, respectively. Refer to
the Current-Limit and Overload Protection section of the
MAX8533 data sheet for more details on setting the cur-
rent limit.
The second scheme senses severe overload and short-
circuit conditions. The MOSFET is latched off immedi-
ately when these conditions occur. Refer to the Current-
Limit and Overload Protection section of the MAX8533
data sheet for more details.
Fault Condition Reset
After entering a latched-off fault condition, reset the
MAX8533 by toggling EN, LPEN, or the input power.
The fault condition is also reset by removing the board
from the backplane and then plugging it back in.
Startup into Load
The MAX8533 is intended to be used in a circuit where
no load is applied until the POK signal is enabled. In an
application where the load is applied during the output-
voltage ramp-up, the RDS(ON) of the MOSFET is higher
and the power dissipated by the MOSFET is larger.
Repeated, rapid hot swaps into a load can create suffi-
cient heat to exceed the power-dissipation limits of the
package, causing failure of the MOSFET.
Jumper Settings
Evaluates: MAX8533
MAX8533 Evaluation Kit
_______________________________________________________________________________________ 3
JU1
POSITION POK FUNCTION
1 and 2 Connected
to VIN Connects R7 to the input voltage
2 and 3 Connected
to VDLL
Connects R7 to the user’s digital
logic level connected to the DLL
input
Table 1. JU1 (POK Pullup Voltage)
Evaluates: MAX8533
MAX8533 Evaluation Kit
4 _______________________________________________________________________________________
R4
3.09kΩ
1%
R2
20mΩ
0.5W 1%
R1
20mΩ
0.5W 1%
N1
SI4842DY
R3
20Ω
C2
0.1µF
213 7
IN ISET GATE OUT
OVP
POKGND
EN
LPEN
CTIM
85
6
10
9
4
MAX8533
U1
R6
31.6kΩ
1%
R5
4.99kΩ
1%
C4
OPEN
C5
0.22µF
VIN
C3
0.01µF
GND JU1
123
VIN
DLL
POK
TP2
VOUT
GND
TP3
TP1
C1
470µF
C6
10µF
C7
100µF
VIN
EN
LPEN
GND
BACKPLANE MAX8533 EV KIT
J1
R7
100kΩ
Figure 1. MAX8533 EV Kit Schematic
Evaluates: MAX8533
MAX8533 Evaluation Kit
_______________________________________________________________________________________ 5
Figure 2. MAX8533 EV Kit Component Placement Guide—Top
Silkscreen
Figure 3. MAX8533 EV Kit PC Board Layout—Component Side
Figure 4. MAX8533 EV Kit PC Board Layout—Solder Side Figure 5. MAX8533 EV Kit Component Placement Guide—
Bottom Silkscreen
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
6_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Evaluates: MAX8533
MAX8533 Evaluation Kit
Figure 6. MAX8533 Backplane Component Placement Guide—
Top Silkscreen
Figure 7. MAX8533 Backplane PC Board Layout—
Component Side
Figure 8. MAX8533 Backplane PC Board Layout—Solder Side
