MAX1637 Evaluation Kit
General Description
The MAX1637 evaluation kit (EV kit) contains two sepa-
rate switching-regulator circuits. The first circuit converts
high-voltage battery power into a low-voltage supply rail
for next-generation notebook CPU cores. Its output is
fixed at 1.7V and delivers up to 7A output current with
greater than 87% efficiency. The second circuit gener-
ates a low-voltage supply for general-purpose use. Its
output is fixed at 2.5V and delivers up to 3A output cur-
rent. The battery range for both circuits is 4.5V to 22V,
and both require a separate 5V input voltage to power the
MAX1637. Output voltages can be adjusted by changing
the feedback resistor values.
The MAX1637 EV kit has excellent dynamic response to
correct for fast output transients. This EV kit is a fully
assembled and tested circuit board.
____________________________Features
o
4.5V to 22V Battery Voltage Range
o
4.5V to 5.5V Input Voltage Range (IC Power)
o
Output Voltage:
Fixed 1.7V, 7A (Circuit 1)
Fixed 2.5V, 3A (Circuit 2)
o
Circuit 1 Efficiency = 90%
(V
IN
= 7V, V
OUT
= 1.7V @ I
OUT
= 3A)
o
Circuit 2 Efficiency = 91%
(V
IN
= 7V, V
OUT
= 2.5V @ I
OUT
= 3A)
o
3µA Max IC Shutdown Current
o
Fast MOSFETs for Low Switching Losses
o
Tight PC Board Layout for Low Switching Losses
o
300kHz Switching Frequency
o
Surface-Mount Construction
o
Fully Assembled and Tested
Evaluates: MAX1637
Ordering Information
PART
MAX1637EVKIT
TEMP. RANGE
0°C to +70°C
IC PACKAGE
16 QSOP
Component List
DESIGNATION
C1, C2, C3,
C4, C22
QTY
5
DESCRIPTION
10µF, 25V ceramic capacitors
Tokin C34Y5U1E106Z or
United Chemi-Con/Marcon
THCR50E1E106ZT
470µF, 6.3V, 30mΩ, low-ESR
tantalum capacitors
Kemet T510X477M006
470µF, 4V, 55mΩ, low-ESR
tantalum capacitors
Sprague 594D477X0004R2T
0.1µF ceramic capacitors
1500pF ceramic capacitors
1µF ceramic capacitors
4.7µF, 16V tantalum capacitors
Sprague 595D475X0016A2B
Not installed
0.01µF ceramic capacitors
2A Schottky diode
SGS-Thomson STPS2L25U or
Nihon EC20QS03L
1A Schottky diode
International Rectifier 10BQ040 or
Motorola MBRS130LT3
N3
1
N2
1
N1
1
DESIGNATION
D2, D3
QTY
2
DESCRIPTION
Schottky diodes
Central Semiconductor CMPSH-3
2.2µH power inductor
Panasonic P1F2R0HL,
Coiltronics UP4B-2R2, or
Coilcraft DO5022P-222HC
10µH power inductor
Sumida CDRH125-100,
Coiltronics UP2B-100, or
Coilcraft DO3316P-103
N-channel MOSFET
Fairchild FDS6612 or FDS9412,
International Rectifier IRF7803, or
Siliconix Si9804DY
N-channel MOSFET
Fairchild FDS6680 or
Siliconix Si4420DY
N-channel MOSFET
International Rectifier IRF7403 or
Siliconix Si4412DY
N-channel MOSFET
International Rectifier IRF7413,
Fairchild NDS8410A, or
Siliconix Si4410DY
L1
1
C5, C6, C7,
C20
OR
C5, C6, C7,
C8, C20
C9, C10, C17, C19
C11, C16
C12, C15
C13, C18
C14, C21,
C23, C24
C25, C26
D1
4
5
4
2
2
2
0
2
1
L2
1
D4
1
N4
1
Component List continued on next page.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
MAX1637 Evaluation Kit
Evaluates: MAX1637
Component List (continued)
DESIGNATION
R1
R2
R3
R4–R9
R10, R11
R12
R13
R14
U1, U2
JU1–JU6
None
None
QTY
1
1
1
6
2
1
1
1
2
6
1
1
DESCRIPTION
0.010Ω, 1%, 1W resistor
Dale WSL-2512-R010F
56.2kΩ, 0.1% resistor
Dale TNPW-1206 series
100kΩ, 0.1% resistor
Dale TNPW-1206 series
1MΩ, 5% resistors
20Ω, 5% resistors
0.020Ω, 1%, 0.5W resistor
Dale WSL-2010-R020-F or
IRC LR2010-R020-F
130kΩ, 1% resistor
100kΩ, 1% resistor
MAX1637EEE
2-pin headers
MAX1637 PC board
MAX1637 data sheet
SUPPLIER
AVX
Central
Semiconductor
Coilcraft
Dale-Vishay
Fairchild
International
Rectifier
IRC
Kemet
Motorola
Panasonic
Sanyo
SGS-Thomson
Siliconix
Sprague
Sumida
Taiyo Yuden
Tokin
Vishay/Vitramon
Component Suppliers
PHONE
(803) 946-0690
(516) 435-1110
(708) 639-6400
(402) 564-3131
(408) 721-2181
(310) 322-3331
(512) 992-7900
(408) 986-0424
(602) 303-5454
(714) 373-7939
(619) 661-6835
(617) 259-0300
(408) 988-8000
(603) 224-1961
(847) 956-0666
(408) 573-4150
(408) 432-8020
(203) 268-6261
FAX
(803) 626-3123
(516) 435-1824
(708) 639-1469
(402) 563-6418
(408)721-1635
(310) 322-3332
(512) 992-3377
(408) 986-1442
(602) 994-6430
(714) 373-7183
(619) 661-1055
(617) 259-9442
(408) 970-3950
(603) 224-1430
(847) 956-0702
(408) 573-4159
(408) 434-0375
(203) 452-5670
Quick Start
The MAX1637 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.
Note:
Please indicate that you are using the MAX1637 when
contacting these component suppliers.
2.5V Output (3A Configuration)
1) Connect a +7V to +22V supply voltage to the VBATT
pad. Connect a +4.5V to +5.5V supply voltage to
the VBIAS pad. Connect the grounds to the GND
pads.
2) Connect a voltmeter and load, if any, to the VOUT
pad.
3) Turn on the VBATT power supply to the board
first.
4) Turn on the VBIAS power supply. Verify that the out-
put voltage is 2.5V.
5) For other output voltages, refer to the
Setting the
Output Voltage
section in the MAX1637 data sheet
for instructions on selecting feedback resistors
R13 and R14.
1.7V Output (7A Configuration)
1) Connect a +4.5V to +22V supply voltage to the
VBATT pad. Connect a separate +4.5V to +5.5V
supply voltage to the VBIAS pad. Connect the
grounds to the GND pads.
2) Connect a voltmeter and load, if any, to the VOUT
pad.
3) Turn on the VBATT power supply to the board
first.
4) Turn on the VBIAS power supply. Verify that the out-
put voltage is 1.7V.
5) For other output voltages, refer to the
Setting the
Output Voltage
section in the MAX1637 data sheet
for instructions on selecting feedback resistors R2
and R3.
2
_______________________________________________________________________________________
MAX1637 Evaluation Kit
Evaluates: MAX1637
Table 1. Jumpers JU1 and JU2 Functions
SHUNT
LOCATION
OFF
SKIP
PIN
Connected
to GND
Connected
to V
BIAS
OPERATIONAL MODE
Idle mode, pulse-skipping
operation for highest light-
load efficiency
Low-noise mode,
fixed frequency PWM
operation.
Table 3. Jumpers JU5 and JU6 Functions
SHUNT
LOCATION
OFF
ON
SHDN
PIN
MAX1637 OUTPUT
Connected to V
BIAS
MAX1637 enabled
Connected to GND
Shutdown mode,
V
OUT
= 0V
ON
Jumper Selection
The 2-pin headers JU1 and JU2 select the mode of
operation. Table 1 lists the selectable jumper options.
The 2-pin headers JU3 and JU4 select the operating
frequency. Table 2 lists the selectable jumper options.
The EV kit’s components are selected for 300kHz oper-
ation. Component values might need to be changed if
200kHz operation is selected (refer to the
Design
Procedure
section in the MAX1637 data sheet).
Synchronize the oscillator to an external clock signal by
driving the SYNC pad with a pulse train of 5V amplitude
in the 240kHz to 340kHz frequency range. The 2-pin
headers JU5 and JU6 select the shutdown mode.
Table 3 lists the selectable jumper options.
Table 2. Jumpers JU3 and JU4 Functions
SHUNT
LOCATION
OFF
ON
SYNC
PIN
Connected to V
BIAS
Connected to GND
FREQUENCY (kHz)
300
200
Detailed Description
Both switching regulators require a bias supply voltage
(VBIAS) to power the IC and provide gate-drive current.
VBIAS must be in the range of 4.5V to 5.5V due to the
MOSFETs selected, although the MAX1637 itself oper-
ates over a wider range (3.15V to 5.5V). The +5V
VBIAS supply must be capable of sourcing at least
20mA. Actual VBIAS current draw is:
I
BIAS
= (Q
G1
+ Q
G2
) x f + I
CC
where Q
G1
, Q
G2
is the total gate charge of the
MOSFETs at V
GS
= VBIAS, and I
CC
is the current
drawn by the MAX1637 V
CC
input.
Battery power must be applied prior to VBIAS power
due to the output undervoltage lockout built into the
MAX1637. If VBIAS is applied first, the circuit begins
switching and attempts to bring up the output voltage.
Since battery power is not present, the 20ms UVLO
timer expires and the PWM is latched off until VBIAS or
SHDN
is cycled.
_______________________________________________________________________________________
3
Evaluates: MAX1637
MAX1637 Evaluation Kit
4
V
CC
VCC
C9
0.1µF
9
V
GG
BST
5, 6, 7, 8
DH
5
REF
14
N1
1, 2, 3
5, 6, 7, 8
11
4
N2
1, 2, 3
D1
12
1
2
3
4
C11
1500pF
L1
2.2µH
15
C10
0.1µF
R1
0.010Ω
1%
4
13
D2
CMPSH-3
C1
10µF
25V
C2
10µF
25V
C3
10µF
25V
10
V
CC
6
SHDN
C26
0.01µF
R10
20Ω
C13
4.7µF
16V
VBATT
4.5V TO 22V
C4
10µF
25V
VBIAS
4.5V TO 5.5V
Figure 1. MAX1637 EV Kit Schematic (1.7V, 7A)
U1
MAX1637
DL
PGND
CSH
16
SKIP
FB
7
SYNC
CC
CSL
2
JU3
1
8
GND
LX
C12
1µF
VBIAS
2
JU2
1
C5
470µF
6.3V
C6
470µF
6.3V
C7
470µF
6.3V
VOUT
1.7V
C8
OPEN
SENSE
R2
56.2k
0.1%
C14
OPEN
R3
100k
0.1%
CUT TRACE FOR
REMOTE SENSING
R6
1M
ON/OFF
JU5
REF
R4
1M
SKIP
R5
1M
VBIAS
_______________________________________________________________________________________
SYNC
VBIAS
4.5V TO 5.5V
VCC
R11
20Ω
C17
0.1µF
9
V
CC
V
GG
BST
5, 6, 7, 8
DH
5
REF
14
N3
1, 2, 3
5, 6, 7, 8
11
4
N4
D4
1, 2, 3
12
1
2
3
4
C16
1500pF
L2
10µH
15
C19
0.1µF
R12
0.020Ω
1%
4
C22
10µF
25V
13
C23
OPEN
6
SHDN
C25
0.01µF
D3
CMPSH-3
10
C18
4.7µF
16V
Figure 2. MAX1637 EV Kit Schematic (2.5V, 3A)
R7
1M
VBATT
4.5V TO 22V
ON/OFF
JU6
REF
U2
MAX1637
DL
PGND
CSH
LX
VOUT
2.5V
C15
1µF
VBIAS
GND
2
16
SKIP
SYNC
FB
CC
CSL
7
R9
1M
2
JU4
1
JU1
1
8
R8
1M
C20
470µF
6.3V
C24
OPEN
SENSE
SKIP
SYNC
R13
130k
1%
VBIAS
C21
OPEN
R14
100k
1%
Evaluates: MAX1637
_______________________________________________________________________________________
CUT TRACE FOR
REMOTE SENSING
MAX1637 Evaluation Kit
5
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