19-3840; Rev 0; 10/05
MAX8632 Evaluation Kit
General Description
The MAX8632 evaluation kit (EV kit) is designed to evalu-
ate the MAX8632 DDR power-supply solution for note-
books, desktops, and graphics cards. The EV kit board
produces VDDQ at the output of the synchronous PWM
buck, VTT at the output of the sourcing/sinking LDO linear
regulator, and VTTR at the output of the reference buffer.
The VDDQ output is preset to 1.8V and sources up to
10A. The VTT output is always VDDQ / 2 and can
source/sink up to 3A of peak current and 1.5A of continu-
ous current. The VTTR output is also always VDDQ /2
and can source/sink up to 10mA.
The MAX8632 EV kit was conveniently designed with
jumpers to select the OVP/UVP, TON,
SKIP, STBY,
and
SHDN
modes. The board’s default settings enable OVP
(overvoltage protection), 300kHz switching frequency,
low-noise PWM mode, VDDQ, VTT, and VTTR.
The VIN input accepts voltages from 7V to 20.5V and
VDD requires a 5V bias supply.
♦
VDDQ Preset to 1.8V/10A
♦
VTT 0.9V Source/Sink 1.5A Continuous/3A Peak
♦
VTTR 0.9V Source/Sink 10mA
♦
V
IN
Range: 7V to 20.5V
♦
Optimized Switching Frequency: 300kHz
♦
Overvoltage/Undervoltage Protection
♦
Independent Shutdown and Standby Controls
♦
Power OK
Features
Evaluates: MAX8632
Ordering Information
PART
MAX8632EVKIT
TEMP RANGE
0°C to +70°C
IC PACKAGE
28 Thin QFN 5mm x 5mm
Component List
DESIGNATION QTY
C1
1
DESCRIPTION
0.1µF ±10%, 16V X7R (0603) ceramic
capacitor
Taiyo Yuden EMK107BJ104MA
10µF ±10%, 6.3V X5R (0805) ceramic
capacitors
Kemet C0805C106K9PAC
Taiyo Yuden JMK212BJ106MG
1µF ±10%, 10V X5R (0603) ceramic
capacitors
TDK C1608X5R1A105K
4.7µF ±20%, 6.3V (0805) X5R ceramic
capacitor
TDK C2012X5R0J475M
0.22µF ±20%, 16V X7R (0603)
ceramic capacitors
TDK C1608X7R1C224M
10µF ±20%, 25V X5R (1210) ceramic
capacitors
Taiyo Yuden TMK325BJ106MM
TDK C3225X5R1E106M
DESIGNATION QTY
DESCRIPTION
4700pF ±10%, 50V X7R (0603)
ceramic capacitor
Kemet C0603C472K5RAC or
equivalent
150µF, 4V, 18mΩ POS capacitors
Sanyo 4TPE150MI
Schottky diode, 30V, 100mA (SOD-323)
Central CMDSH-3
3-pin headers, 0.1in center
36-pin header, 0.1in center
Sullins PTC36SAAN or equivalent
Digi-key S1012-36-ND
1.4µH, 15.5A, 2.8mΩ power inductor
Sumida CEP125-1R4MC-U
30V, 12mΩ (SO-8) n-channel MOSFET
International Rectifier IRF7821
30V, 4mΩ (SO-8) n-channel MOSFET
International Rectifier IRF7832
C9
1
C2, C4A,
C4B
3
C11, C12
D1
2
1
C3, C6
2
JU1–JU4, JU6
5
C5
1
L1
Q1
Q2
1
1
1
C7, C10
2
C8A, C8B, C8C
3
________________________________________________________________
Maxim Integrated Products
1
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.
MAX8632 Evaluation Kit
Evaluates: MAX8632
Component List (continued)
DESIGNATION QTY
R1
R2, R3, R4
R5
R13
R18
U1
1
3
1
1
1
1
DESCRIPTION
10Ω ±5% (0603) resistor
100kΩ ±5% (0603) resistors
36.5kΩ ±1% (0603) resistor
20Ω ±5% (0603) resistor
0Ω ±5% (0603) resistor
Integrated DDR power supply
(28-pin, 5mm x 5mm, Thin QFN)
MAX8632ETI+
Shunts
Sullins STC02SYAN
Digi-key S9000-ND or equivalent
3) Ensure a shunt is placed across pins 1-2 of jumper
JU3 to enable low-noise PWM mode.
4) Ensure a shunt is placed across pins 2-3 of jumper
JU4 to disable the VDDQ buck output.
5) Ensure a shunt is placed across pins 2-3 of jumper
JU6 to set the board in normal operation mode.
6) Connect the 5VDC power supply across the VDD
pad and the GND pad nearest VIN.
7) Connect the 12VDC power supply across the VIN
pad and the corresponding GND pad.
8) Turn on both of the power supplies.
9) Set JU4 (1-2). This turns VDDQ on.
10)Using one of the DVMs, verify that the VDDQ voltage
between the VDDQ and PGND pads is 1.8V (±2%).
11)Using the other DVM, verify that the VTT voltage
between the VTT and PGND pads is 0.9V (±2%).
—
5
Component Suppliers
SUPPLIER
Central
Semiconductor
International
Rectifier
Kemet
Sanyo USA
Sumida
Taiyo Yuden
TDK
PHONE
WEBSITE
631-435-1110 www.centralsemi.com
310-322-3331 www.irf.com
864-963-6300 www.kemet.com
619-661-6835 www.sanyo.com
847-545-6700 www.sumida.com
800-348-2496 www.t-yuden.com
847-803-6100 www.component.tdk.com
Detailed Description
Jumper Selection
Table 1. Overvoltage/Undervoltage
Control Input (OVP/UVP)
JUMPER
JU2
JU2
JU2
JU2
SHUNT
POSITION
1-2
1-3
1-4*
Open
DESCRIPTION
Disable OVP and UVP.
Enable UVP. Disable OVP.
Enable OVP and UVP.
Enable OVP. Disable UVP.
Note:
Indicate that you are using the MAX8632 when contact-
ing these component suppliers.
*Default
position.
Note:
Refer to the MAX8632 data sheet for additional informa-
tion on OVP/UVP.
Recommended Equipment
• 5VDC power supply (500mA rated)
• 7VDC to 20.5VDC power supply (5A rated)
• Two digital voltmeters (DVM)
Setting the Buck Regulator Output
Voltage (VDDQ)
The output voltage of the buck regulator is preset to
1.8V on the MAX8632 EV kit for DDR memory applica-
tions. To pin-strap the output voltage to 2.5V, follow the
steps below:
1) Remove R18.
2) Solder the 0Ω resistor from step 1 in the R9 location.
Refer to the MAX8632 data sheet to change the external
components for optimum performance.
Quick Start
The MAX8632 EV kit is fully assembled and tested. Follow
these steps to verify board operation.
Do not turn on the
power supplies until all connections are completed.
1) Ensure a shunt is placed across pins 1-4 of jumper
JU2 to enable OVP and UVP.
2) Ensure jumper JU1 is open to set the switching fre-
quency to approximately 300kHz.
2
_______________________________________________________________________________________
MAX8632 Evaluation Kit
Evaluates: MAX8632
Table 2. On-Time Selection Input (TON)
JUMPER
JU1
JU1
JU1
JU1
SHUNT
POSITION
1-2
1-3
1-4
Open*
DESCRIPTION
600kHz switching frequency
450kHz switching frequency
200kHz switching frequency
300kHz switching frequency
Table 4. Shutdown Control Input (SHDN)
JUMPER
JU4
JU4
SHUNT
POSITION
1-2
2-3*
DESCRIPTION
The VDDQ buck output is enabled.
The VDDQ buck output is shut
down.
*Default
position.
Note:
Refer to the MAX8632 data sheet for additional informa-
tion on
SHDN
.
*Default
position.
Note:
Refer to the MAX8632 data sheet for additional informa-
tion on TON.
Table 3. Pulse-Skipping Control Input
(SKIP)
JUMPER
JU3
JU3
SHUNT
POSITION
1-2*
2-3
DESCRIPTION
Low-noise PWM mode.
Pulse-skipping mode.
Table 5. Standby Control Input (STBY)
JUMPER
JU6
JU6
SHUNT
POSITION
2-3
1-2*
DESCRIPTION
The VTT output is shut down.
Normal operation.
*Default
position.
Note:
Refer to the MAX8632 data sheet for additional informa-
tion on
STBY
.
*Default
position.
Note:
Refer to the MAX8632 data sheet for additional informa-
tion on
SKIP
.
_______________________________________________________________________________________
3
Evaluates: MAX8632
JP1
VTTI
C1
0.1µF
VDD
1
2
JU3
3
17
C3
1µF
26
J10
PGND
R1
10Ω
VDD
J12
R10
SHORT
D1
CMDSH-3
Q1
C5
4.7µF
C7 IRF7821
0.22µF
C8A–C8C
3 x 10µF
25V L1
1.4µH
C13
OPEN
VDD
4.5V TO 5.5V
U1
PGND2
V
DD
BST
DH
24
GND
LX
DL
5
POK1
PGND1
VDD
POK2
SHDN
3
4
1 JU1
1
VDD
2
OVP/UVP
STBY
JU2 4
1
3
7
2
REF
3 REF
C10
0.22µF
R4
100kΩ
4
ILIM
SS
OUT
TPO
R14
SHORT
28
R19
OPEN
VDD
TAB
29
16
R5
36.5kΩ
C9
4700pF
8
FB
15
1
2
3 JU6
TON
VDD
J5
STBY
2
JU4
27
1
2
J7
SHDN
23
C15
OPEN
21
R11
SHORT
Q2
IRF7832
R12
OPEN
19
18
20
22
VIN
7V TO 20.5V
J11
13
R17
SHORT
9
VTTS
AV
DD
12
VTT
C4B
10µF
11
C4A
10µF
R16
OPEN
V
IN
VTTI
REFIN
SKIP
14
25
C2
10µF
R13
20Ω
MAX8632 Evaluation Kit
4
C16
OPEN
Figure 1. MAX8632 EV Kit Schematic
MAX8632
10
VTTR
C6
1µF
J9
VDDQ
1.8V AT 10A
J8
PGND
C12
150µF
4V
C11
150µF
4V
R2
100kΩ
R3
100kΩ
6
VDD
REF
R18
0Ω
VDD
R9
OPEN
R8
OPEN
VTT
0.9V AT 3A
J1
J13
GND
VTTR
0.9V AT 10mA
J2
J14
GND
J3
POK1
VDD
J15
POK2
REF
3
VDD
R7
OPEN
R6
OPEN
_______________________________________________________________________________________
C14
OPEN
MAX8632 Evaluation Kit
MAX8632 Evaluation Kit
Evaluates: MAX8632
Figure 2. MAX8632 EV Kit Component Placement Guide—Component Side
_______________________________________________________________________________________
5
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