19-1740; Rev 3; 11/04
MAX1748 Evaluation Kit
General Description
The MAX1748 evaluation kit (EV kit) is a fully assembled
and tested surface-mount circuit board that contains a
boost switching regulator and two charge-pump volt-
age-regulator circuits. The boost switching circuit is
configured for a +10V output that provides up to 200mA
of current from a supply voltage of +2.7V to +5.5V.
The positive charge-pump circuit is configured for a
+15V output that provides >20mA of current. The nega-
tive charge-pump circuit is configured for a -5V output
and provides >20mA of current. Power for either or
both charge-pump inputs can be provided from the
+2.7VDC to +5.5VDC source or from the boost switch-
ing-regulator output.
The MAX1748 EV kit demonstrates low-quiescent cur-
rent and high efficiency (over 86%) for maximum bat-
tery life. Operation at 1MHz allows the use of tiny sur-
face-mount components. The MAX1748 TSSOP pack-
age (1.1mm max) with low-profile external components
allows this circuit to be less than 1.2mm high. The
MAX1748 EV kit can also be used to evaluate the
MAX1779 IC.
Features
♦
+2.7V to +5.5V Input Range (as Configured)
♦
Output Voltages
+10V Output at 200mA (Boost Switching)
+15V Output >20mA (Positive Charge-Pump
Regulator)
-5V Output >20mA (Negative Charge-Pump
Regulator)
♦
Outputs Are Adjustable with Resistors
♦
♦
♦
♦
>85% Efficiency
Internal MOSFET Switches
0.1µA (typ) IC Shutdown Current
1MHz Boost Switching Frequency,
500kHz Charge-Pump Switching Frequency
♦
Low Profile
♦
Evaluates MAX1779 (Component Replacement
Required)
♦
Surface-Mount Components
♦
Fully Assembled and Tested
Evaluates: MAX1748/MAX1779
Ordering Information
PART
MAX1748EVKIT
TEMP RANGE
0°C to +70°C
IC PACKAGE
16 TSSOP
Component List
DESIGNATION
C1, C16, C17,
C18, C21
QTY
5
DESCRIPTION
3.3µF, 10V X7R ceramic capacitors
(1210)
Taiyo Yuden LMK325BJ335KD
0.1µF, 16V X7R ceramic capacitors
(0603)
Taiyo Yuden EMK107BJ104MA
Not installed (R)
Sprague 592D336X0016R2T
recommended
1µF, 16V X7R ceramic capacitors
(1206)
Murata GRM319R71C105K
470pF, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H47IJ
0.22µF, 10V X7R ceramic
capacitor (0603)
Taiyo Yuden LMK107BJ224KA
DESIGNATION
C10–C13
C14
QTY
0
1
DESCRIPTION
Not installed (0805)
0.15µF, 25V X7R ceramic
capacitor (1206)
Taiyo Yuden TMK316BJ154MD
Not installed, ceramic capacitors
(0603)
1.0A, 30V Schottky diode (S-flat)
Toshiba CRS02 or Nihon EP10QY03
200mA, 25V Schottky diodes
(SOT23)
Fairchild BAT54S
Not installed (SOT23)
6.8µH inductor
Coilcraft LPO2506IB-682
348kΩ ±1% resistor (0805)
549kΩ ±1% resistor (0805)
49.9kΩ ±1% resistors (0805)
200kΩ ±1% resistor (0805)
C2, C4, C5, C6,
C22, C23
6
C19, C20
D1
0
1
C3
0
D2, D3
D4, D5
L1
R1
R3
R2, R4, R6
R5
2
0
1
1
1
3
1
C7, C15, C24
3
C8
1
C9
1
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX1748 Evaluation Kit
Evaluates: MAX1748/MAX1779
Component List (continued)
DESIGNATION
R7
R8, R9
U1
JU1, JU4, JU5
None
None
None
None
QTY
0
2
1
3
3
1
1
1
DESCRIPTION
Not installed (0805)
1MΩ ±5% resistors (0805)
MAX1748EUE (16-pin TSSOP)
3-pin headers
Shunts (JU1, JU4, JU5)
MAX1748 PC board
MAX1748 data sheet
MAX1748 EV kit data sheet
Component Suppliers
SUPPLIER
Coilcraft
Fairchild
Murata
Sprague
Sumida
Taiyo Yuden
Toshiba
PHONE
847-639-6400
408-822-2000
814-237-1431
603-224-1961
708-956-0666
408-573-4150
949-455-2000
FAX
847-639-1469
408-822-2102
814-238-0490
603-224-1430
708-956-0702
408-573-4159
949-859-3963
Note:
Please indicate that you are using the MAX1748/MAX1779
when contacting these component suppliers.
Quick Start
The MAX1748 EV kit is fully assembled and tested.
Perform the following steps to verify board operation for
a +10V output.
Do not turn on the power supply until
all connections are completed:
1) Connect a +2.7VDC to +5.5VDC power supply to
the PIN pad. Connect the supply ground to the
GND pad.
2) Connect a voltmeter to the V1 pad.
3) Verify that shunts JU1 (SHDN) are across pins
1 and 2 and that shunts JU4 (SUPP) and JU5
(SUPN) are across pins 2 and 3.
4) Turn on the power supply and verify that the main
output (V1) is +10V.
5) Verify that the negative charge-pump regulator out-
put (VN) is -5V.
6) Verify that the positive charge-pump regulator out-
put (VP) is +15V.
For instructions on selecting the feedback resistors for
other output voltages, see the
Output Voltage Selection
section. The input voltage range is +2.7V to +5.5V
when selecting the output voltage.
The boost switching-regulator output voltage can be
adjusted from +2.7V to +13V with resistors. The positive
charge-pump regulator’s output can be adjusted up to
+25V, and the negative regulator can be adjusted to
-15V with resistors.
The MAX1748 EV kit charge-pump circuits feature PC
board pads for a positive voltage tripling and negative
voltage doubling output circuits. The MAX1748 EV kit
can evaluate the MAX1779 IC after replacing several
components. See the
Evaluating the MAX1779
section.
Jumper Selection
Shutdown Mode
The MAX1748 EV kit features a shutdown mode that
reduces the MAX1748 quiescent current, preserving
battery life. The 3-pin jumper (JU1) selects the shut-
down mode for the MAX1748. Table 1 lists the selec-
table jumper options.
Positive Charge-Pump Regulator Feedback
In the MAX1748 EV kit, jumper JU2 selects which posi-
tive charge pump will be regulated: VP, a voltage dou-
bler, or VPA, a voltage tripler. Table 2 lists the positive
charge-pump regulator jumper options.
Negative Charge-Pump Regulator Feedback
In the MAX1748 EV kit, jumper JU3 selects which nega-
tive charge pump will be regulated: VN or VNA, a volt-
age doubler. Table 3 lists the negative regulator jumper
options.
Positive Voltage Source
The MAX1748 EV kit features an option to choose which
voltage source feeds the positive charge-pump regula-
tor circuit. Jumper JU4 selects the input voltage source
for the MAX1748’s SUPP pin. Table 4 lists the options.
Detailed Description
The MAX1748 EV kit contains a boost switching regula-
tor and two regulating charge pumps. The EV kit oper-
ates from a +2.7V to +5.5V input voltage range. The
boost switching regulator provides up to 200mA with a
+10V output.
The positive charge-pump regulator generates a +15V
output and can provide >20mA of current. The negative
charge-pump regulator generates -5V output and can
provide >20mA of current. Jumper options allow either
charge pump to be fed power from PIN or V1.
2
_______________________________________________________________________________________
MAX1748 Evaluation Kit
Table 1. Jumper JU1 Functions
SHUNT LOCATION
1-2
2-3
SHDN
PIN
Connected
to PIN
Connected
to GND
MAX1748 OUTPUT
MAX1748 enabled,
V1 = +10V
Shutdown mode,
V1 = P
IN
- V
DIODE
the
Output Voltage Selection
section in the MAX1748
data sheet for instructions on selecting the resistors. See
Table 4 for the jumper selection of input voltage ranges.
Check that the capacitor voltage rating is adequate for
the configuration.
Evaluates: MAX1748/MAX1779
Positive Tripler Charge-Pump
Output Voltages
The MAX1748 EV kit features a positive charge-pump
voltage tripler circuit. Three components (C10, C11, D4)
must be installed and jumper JU2 modified to utilize the
tripler circuit. Capacitors C10 and C11 should be 0.1µF
(Taiyo Yuden, UMK212BJ104MG recommended) with a
voltage rating equal to or greater than the expected out-
put voltage at VPA. Lower cost diodes with higher for-
ward voltage drops can be used for D4, if enough volt-
age headroom is available. The shorted PC trace across
pinholes 1 and 2 must be cut open and a jumper wire
installed in pinholes 2 and 3 at jumper JU2.
Note:
VPA
will now be the regulated output.
To generate a different voltage, select proper voltage-
divider resistors (R3, R4) while taking into consideration
input voltages and jumper settings. Refer to the
Output
Voltage Selection
section in the MAX1748 data sheet for
instructions on selecting the resistors. See Table 4 for
jumper selection of input voltage ranges.
Table 2. Jumper JU2 Functions
SHUNT LOCATION
1-2
(PC trace shorts 1-2)
2-3
(cut open trace across
1-2 , short across 2-3)
R3
Connected
to VP
Connected
to VPA
OPERATING MODE
Regulate VP, doubler
output voltage
Regulate VPA, tripler
output voltage
Table 3. Jumper JU3 Functions
SHUNT LOCATION
1-2
(PC trace shorts 1-2)
2, 3
(cut open trace across
1-2, short across 2-3)
R5
Connected
to VN
Connected
to VNA
OPERATING MODE
Regulate VN, -5V
output voltage
Regulate VNA,
negative doubler
output voltage
Negative Charge-Pump Output Voltages
Negative Voltage Source
The MAX1748 EV kit features an option to choose which
voltage source feeds the negative charge-pump regula-
tor circuit. Jumper JU5 selects the input voltage source
for the MAX1748’s SUPN pin. Table 5 lists the options.
The MAX1748 EV kit’s negative charge-pump regulator
output is set to -5V by feedback resistors (R5, R6). To
generate different voltages, select different external volt-
age-divider resistors (R5, R6) while taking into consider-
ation input voltages and jumper settings. Refer to the
Output Voltage Selection
section in the MAX1748 data
sheet for instructions on selecting the resistors. See
Table 5 for the jumper selection of input voltage ranges.
Output Voltage Selection
Boost Switching-Regulator
Output Voltages
The MAX1748 EV kit’s boost switching-regulator output
is set to +10V by feedback resistors (R1, R2). To gener-
ate output voltages other than +10V (+2.7V to +13V),
select different external voltage-divider resistors (R1,
R2). The ceramic capacitors (C17, C18, C20) are rated
to +10V. To set the voltage >+10V, use higher-voltage-
rated capacitors. Refer to the
Output Voltage Selection
section in the MAX1748 data sheet for instructions on
selecting the resistors. The input voltage range will be
+2.7V to V
PIN
when selecting other output voltages.
Negative Doubler Charge-Pump
Output Voltages
The MAX1748 EV kit features a negative charge-pump
voltage doubler circuit. Three components (C12, C13,
D5) must be installed and jumper JU3 modified to utilize
the doubler circuit. Capacitors C12 and C13 should be
0.1µF (Taiyo Yuden UMK212BJ104MG recommended)
with a voltage rating equal to or greater than the expect-
ed output voltage at VNA. Lower cost diodes with higher
forward voltage drops can be used for D5 if enough volt-
age headroom is available. The shorted PC trace across
pinholes 1 and 2 must be cut open and a jumper wire
installed in pinholes 2 and 3 at jumper JU3.
To generate a different negative output voltage, select
different external voltage-divider resistors (R5, R6) while
taking into consideration input voltages and jumper set-
tings. Refer to the
Output Voltage Selection
section in
the MAX1748 data sheet for instructions on selecting the
3
Positive Charge-Pump Output Voltages
The MAX1748 EV kit’s positive charge-pump regulator
output is set to +15V by feedback resistors (R3, R4). To
generate output voltages other than +15V, select differ-
ent external voltage-divider resistors (R3, R4). Refer to
_______________________________________________________________________________________
MAX1748 Evaluation Kit
Evaluates: MAX1748/MAX1779
Table 4. Jumper JU4 Functions
SHUNT LOCATION
1-2
SUPP PIN
Connected
to PIN
Connected
to V1
OPERATING MODE
PIN voltage source
feeds positive
charge-pump input
Boost converter (V1)
feeds positive
charge-pump input
resistors. See Table 5 for jumper selection of input volt-
age ranges.
Evaluating the MAX1779
MAX1779 Reconfiguration
The MAX1748 EV kit can be reconfigured to evaluate
the MAX1779EUE. Replace the components listed in
Table 6. The boost switching regulator output (V1)
+5.1V and provides up to 50mA to 100mA of current,
depending on the inductor value and output capaci-
tance chosen. The positive and negative charge-pump
outputs provide +9V (VP) and -4V (VN) at their outputs.
Table 6 below lists the components that must be
replaced to evaluate a MAX1779.
2-3
Table 5. Jumper JU5 Functions
SHUNT LOCATION
1-2
SUPN PIN
Connected
to PIN
Connected
to V1
OPERATING MODE
PIN voltage source
feeds negative
charge-pump input
Boost converter (V1)
feeds negative
charge-pump input
2-3
Table 6. Component List
DESCRIPTION
PART
C4, C6
C8
C18
C19
C21, C17
QTY
2
1
0
1
2
V
OUT
= 5.1V, V
IN
= 3.0V,
I
OUT
= 50MA (MAX)
0.22µF, 16V X7R ceramic capacitors (0603)
0.0022µF, 10V X5R ceramic capacitor (0603)
Open
220pF, 10V X5R ceramic capacitor (0603)
4.7µF, 6.3V X7R ceramic
capacitors (1210)
10µH, 0.3A inductor
Coilcraft LPO2506IB-103 or
Sumida CMD4D08-100 recommended
154kΩ
±1%
resistor (0805)
309kΩ
±1%
resistor (0805)
158kΩ
±1%
resistor (0805)
10kΩ
±5%
resistor (0805)
MAX1779EUE (16-pin TSSOP)
V
OUT
= 5.1V, V
IN
= 3.0V,
I
OUT
= 100MA (MAX)
0.22µF, 16V X7R ceramic capacitors (0603)
0.0022µF, 10V X5R ceramic capacitor (0603)
Open
470pF, 10V X5R ceramic capacitor (0603)
10µF, 6.3V X7R ceramic capacitors
(1210)
33µH, 0.3A inductor
Sumida CMD4D08-330 or
Coilcraft LPO2506IB-333 recommended
154kΩ
±1%
resistor (0805)
309kΩ
±1%
resistor (0805)
158kΩ
±1%
resistor (0805)
24kΩ
±5%
resistor (0805)
MAX1779EUE (16-pin TSSOP)
L1
R1
R3
R5
R7
U1
1
1
1
1
1
1
4
_______________________________________________________________________________________
Figure 1. MAX1748 EV Kit Schematic
V1
L1
6.8μH
D1
V1
+10V
C21
3.3μF
GND
C1
3.3μF
TIN
LX
U1
D4 OPEN
2
3
L
1
V1
2
3
10
DRVN
DRVP
12
V1
R
3
C4
0.1μF
7
5
R4
49.9kΩ
9
JU1
R8
1MΩ
R9
1MΩ
SHDN
PIN
RDY
1
RDY
R3
549kΩ
D2
L
1
C22
0.1μF
JU2
V1
C5
0.1μF
C23
0.1μF
C24
1μF
VP
+15V
R
C11
OPEN
C10
OPEN
MAX1748
FB
R7
OPEN
C19
OPEN
PIN
1
2
JU4
14
C15
1μF
R2
49.9kΩ
2
C20
OPEN
TPA
INTG
PGND
11
SUPN
SUPP
13
C14
0.15μF
GND
16
3
3
PIN
C12
OPEN
JU5
V1
3
C8
470pF
C16
3.3μF
C2
0.1μF
4
15
R1
348kΩ
VPA
C17
3.3μF
C18
3.3μF
C3
OPEN
VPA
C6
0.1μF
8
FBN
REF
GND
FBP
R5
200kΩ
6
R6
49.9kΩ
PIN
1
2
3
C9
0.22μF
JU3
3
1
2
1
2
3
GND
VPA
PIN
+2.7V TO +5.5V
PIN
VNA
VNA
D5
OPEN
1
L
C13
OPEN
2
R
GND
2
R
VN
-5V
1
L
D3
C7
1μF
VNA
Evaluates: MAX1748/MAX1779
_______________________________________________________________________________________
UNLESS OTHERWISE NOTED, ALL RESISTORS ARE (0805) 1%.
MAX1748 Evaluation Kit
5
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