19-1987; Rev 0; 3/01
MAX1802 Evaluation Kit
for Digital Still Cameras
General Description
The MAX1802 evaluation kit (EV kit) accepts +3.3V to
+11V battery voltages and provides all of the output volt-
ages required in digital still cameras (DSC). This EV kit
consists of the MAX1802 multi-output master converter
and the MAX1801 slave step-up converter.
The MAX1802 EV kit provides 10 separate output volt-
ages. The MAX1802 provides one main system step-
down converter (+3.3V/1A), one DSP core step-down
(+1.8V/400mA), one step-up converter for the backlight
(+7V/100mA), three flyback outputs for the CCD, and
three flyback outputs for the LCD. In addition, the
MAX1801 provides one general-purpose step-up con-
verter (+12V/100mA).
The MAX1802 EV kit’s outputs are adjustable and are
suitable for applications running from 4-cell alkaline,
NiCd, or NiMH batteries, or from lithium ion (Li+) batter-
ies (1 or 2 cell).
Features
o
10 Outputs
2 Synchronous Rectified Step-Down Converters
2 Step-Up Converters
6 Flyback Outputs
o
+3.3V to +11V Input Voltage Range
o
All Converters Synchronized to Single Oscillator
o
100kHz to 1MHz Switching Frequency
(set to 400kHz)
o
Independent Shutdown of Each Converter
o
Short-Circuit Protected Flyback Outputs
o
Soft-Start on Each Output
o
Fully Assembled and Tested
Evaluates: MAX1802
Component Suppliers
SUPPLIER
AVX
Central Semiconductor
Fairchild Semiconductor
Motorola
Sumida
Taiyo Yuden
TDK
PHONE
803-946-0690
631-435-1110
408-721-2181
602-303-5454
847-956-0666
408-573-4150
847-803-6100
FAX
803-626-3123
631-435-1824
408-721-1635
602-994-6430
847-956-0702
408-573-4159
847-803-6296
PART
MAX1802EVKIT
Ordering Information
TEMP. RANGE
0°C to +70°C
IC PACKAGE
32 TQFP
Note:
Please indicate that you are using the MAX1802 when
contacting these component suppliers.
Component List
DESIGNATION
C1
C2, C5, C6, C25
C3, C24
C4, C7, C8, C9
C10
C11
C12
C13, C17
C14
QTY
1
4
2
4
1
1
1
2
1
DESCRIPTION
100pF ceramic capacitor (0603)
0.1µF ceramic capacitors (0603)
10µF, 16V ceramic capacitors (1812)
TDK C4532X7R1C106M
1000pF ceramic capacitors (0603)
4.7nF ceramic capacitor (0603)
470pF ceramic capacitor (0603)
4.7µF, 16V ceramic capacitor (1206)
TDK C3216X5R1C475M
1µF, 10V ceramic capacitors (0805)
TDK C2012X5R1A105M
10µF, 10V ceramic capacitor (1206)
TDK C3216X5R1A106M
C18–C23
C26
6
1
C16
1
DESIGNATION
C15
QTY
1
DESCRIPTION
100µF, 10V tantalum capacitor
(D case)
AVX TPSD107M010R0100
22µF, 16V ceramic capacitor (1812)
TDK C4532X5R1C226M
1µF, 25V ceramic capacitors (1206)
TDK C3216X7R1E105M
10µF, 16V ceramic capacitor (1210)
TDK C3225X5R1C106M
P-N junction diodes (SOT323)
Central Semiconductor
CMSD-4448
Schottky diodes (SOT323)
Central Semiconductor CMSSH-3
D1, D4, D6
3
D2, D3, D5
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.
MAX1802 Evaluation Kit for
Digital Still Cameras
Evaluates: MAX1802
Component List (continued)
DESIGNATION
D7, D8
D9
JU1–JU6
JU7–JU12
L1
L2, L4
L3
Q1, Q2, Q3, Q5
Q4
Q6
R1
R2
R3, R19, R20,
R22, R24, R28
R4, R13, R14,
R15
R5, R6, R26,
R27, R30, R31
R7
R8–R12
R16
R17
R18
R21
R23
R25, R29
R32, R33, R37,
R38, R41, R42
R34, R35, R39, R40
R36
QTY
2
1
6
6
1
2
1
4
1
1
1
1
6
4
6
1
5
1
1
1
1
1
2
6
4
1
DESCRIPTION
Schottky diodes (SOD123)
Motorola MBR0520L or
Fairchild Semiconductor MBR0520L
Schottky diode (S-FLAT)
Toshiba CRS05 (not installed)
3-pin headers
2-pin headers
4.7µH inductor
Sumida CR43-4R7
10µH inductors
Sumida CDRH6D28-100
3.3µH inductor
Sumida CR43-3R3
N-channel MOSFETs (SuperSOT-3)
Fairchild Semiconductor FDN337N
P-channel MOSFET (SO-8)
Vishay/Siliconix SI9803DY
N-channel MOSFET (SuperSOT-3)
Fairchild Semiconductor FDN359AN
40.2kΩ
±1%
resistor (0603)
866kΩ
±1%
resistor (0603)
100kΩ
±1%
resistors (0603)
10kΩ
±5%
resistors (0402)
Open (0402), not installed
Short (0603), not installed,
shorted in the PC board layout
Open (0603), not installed
33kΩ
±5%
resistor (0603)
91kΩ
±5%
resistor (0603)
464kΩ
±1%
resistor (0603)
44.2kΩ
±1%
resistor (0603)
165kΩ
±1%
resistor (0603)
301kΩ
±1%
resistors (0603)
3kΩ
±5%
resistors (1206)
200Ω
±5%
resistors (1206)
750Ω
±5%
resistor (1206)
DESIGNATION
T1
QTY
1
DESCRIPTION
Sumida transformer
CLQ72-type package
Sample number: 6333-T334
Sumida transformer
CLQ72-type package
Sample number: 6333-T333
MAX1802EHJ (32-pin TQFP)
MAX1801EKA (8-pin SOT23)
Shunts
T2
U1
U2
None
1
1
1
12
Recommended Equipment
•
•
+3.3V to +11V battery or power supply
Digital voltmeter (DVM)
Quick Start
1) Make sure jumpers JU1–JU6 are connected in the
ON position. This ensures all converters will turn on
at power-up.
2) Before loading any output, check the output voltage
and output current capability shown in Table 1.
3) Make sure jumpers JU7–JU12 are connected if no
external loads are attached to the OUT1A, OUT1B,
OUT1C, OUT2A, OUT2B, and OUT2C outputs.
4) Attach a +3.3V to +7V battery or power supply to
IN.
5) Using the DVM, measure the voltage at MAIN,
CORE, OUT1_, OUT2_, OUT3, and OUT4.
Detailed Description
MAIN Output
The main output (MAIN) powers the core supply of the
MAX1802. MAIN must be regulated before any of the
other outputs function.
To enable MAIN, place jumper JU4 to the ON position.
Apply +3.3V to +11V between IN and GND. The voltage
between MAIN and GND should be approximately +3.3V.
If IN is less than +3.3V, MAIN will not be regulated.
CORE Output
The core output (CORE) is powered from MAIN and reg-
ulated at +1.8V using a synchronous-rectified step-down
converter. Drawing more than 200mA out of CORE
reduces the current capability at MAIN.
To enable CORE, place jumper JU5 to the ON position.
2
_______________________________________________________________________________________
MAX1802 Evaluation Kit for
Digital Still Cameras
Table 1. Output Voltage and Current
Capability
LABEL
MAIN
CORE
OUT1A
OUT1B
OUT1C
OUT2A
OUT2B
OUT2C
OUT3
OUT4
VOLTAGE/CURRENT
+3.3V at 1A
+1.8V at 400mA
+13.5V at 10mA
+5V at 50mA
-9V at 10mA
+13.5V at 10mA
+5V at 50mA
-19.0V at 10mA
+7V at 100mA
+12V at 100mA
To enable OUT2_, place jumper JU2 to the ON posi-
tion. To disable OUT2_, place jumper JU2 to the OFF
position. To enable and disable the output voltages
using an external signal, see the
Logic Control of the
Output Voltages
section.
If a different set of output voltages is required, see the
Setting the Flyback Circuit Voltages
section.
Evaluates: MAX1802
OUT3
The voltage at OUT3 is typical of that required by a
CCFL backlight inverter. To enable OUT3, place jumper
JU3 to the ON position. Place the external load
between OUT3 and GND. To change the output voltage
of OUT3, see the
Setting the Step-Up Output Voltage
section. OUT3 is configured for a 7V output. For input
voltages greater than 7V, the output will approximately
track the input.
OUT3 can be configured to drive a white LED backlight
instead of a CCFL backlight.
OUT1_ (Flyback Outputs)
The voltages at OUT1_ are typical of CCD bias voltages.
The output voltages are +13.5V/10mA, +5V/50mA, and
-9V/10mA. These voltages are generated through a cus-
tom flyback transformer. OUT1B (+5V) is used to regu-
late the flyback circuit. The other output voltages
(+13.5V and -9V) are controlled by the turns-ratio of the
flyback transformer. If the +13.5V and -9V outputs are
not loaded at the fixed 10mA load, then the output volt-
age will change from the nominal loaded output voltage.
Loads are included on the MAX1802 EV kit by shorting
jumpers JU7 through JU12. If external loads are used,
remove these jumpers to disable the built-in loads.
To enable OUT1_, place jumper JU6 to the ON position.
To disable OUT1_, place jumper JU6 to the OFF posi-
tion. To enable and disable the output voltages using an
external signal, see the
Logic Control of the Output
Voltages
section.
If a different set of output voltages is required, see the
Setting the Flyback Circuit Voltages
section.
OUT4
The voltage at OUT4 is a general-purpose +12V output
that can supply up to 100mA. To enable OUT4, place
jumper JU1 to the ON position. Place the external load
between OUT4 and GND. To change the output voltage
of OUT4, see
Setting the Step-Up Output Voltage
sec-
tion.
Customizing the MAX1802 EV Kit
Setting the Main Output Voltage
MAIN is set by a voltage-divider, which drops the out-
put voltage to the +1.25V feedback threshold voltage.
To change the 3.3V setting of MAIN, change the resis-
tor-divider ratio by changing R23. Use:
R23 = 80kΩ/V x (V
OUT
- 1.248V)
The MAIN output voltage may be set to any voltage
between +2.7V and +5.5V. For additional information,
refer to the MAX1802 IC data sheet.
OUT2_ (Flyback Outputs)
The voltages at OUT2_ are typical of LCD bias volt-
ages. The output voltages are +13.5V/10mA,
+5V/50mA, and -19V/10mA. These voltages are gener-
ated through a custom flyback transformer. OUT2B
(+5V) is used to regulate the flyback circuit. The other
output voltages (+13.5V and -19V) are controlled by the
turns-ratio of the flyback transformer. If the +13.5V and
-19V outputs are not loaded at the fixed 10mA load,
then the output voltage will change from the nominal
loaded output voltage. Loads are included on the
MAX1802 EV kit by shorting jumpers JU7 through
JU12. If external loads are used, disable the built-in
loads by removing these jumpers.
Setting the Core Output Voltage
CORE is set by a voltage-divider, which drops the out-
put voltage to the +1.25V feedback threshold voltage.
To change the +1.8V setting of CORE, change the
resistor-divider ratio by changing R21. Use:
R21 = 80kΩ/V x (V
CORE
- 1.248V)
CORE may be set to any voltage between +1.25V and
+5.5V but must remain less than the voltage at MAIN.
The MAX1802 EV kit is configured so that MAIN powers
the CORE input.
_______________________________________________________________________________________
3
MAX1802 Evaluation Kit for
Digital Still Cameras
Evaluates: MAX1802
Setting the Flyback Circuit Voltages
(OUT1_ and OUT2_)
A flyback circuit generates OUT1_ and OUT2_. This
allows multiple positive or negative voltages to be gen-
erated by a single converter and allows the voltages to
drop to 0 when the converter is disabled. The trans-
former must be designed for a given set of output voltages.
On the flyback circuits, only a single output voltage is
directly regulated by the MAX1802. All other voltages
are controlled by the transformer’s turns-ratio. If another
set of output voltages is required, a transformer with a
different secondary turns-ratio must be used. Consult
the transformer manufacturer for details. Typically, the
highest power, positive voltage output of the flyback
transformer is fed back to the controller. To change the
regulated output voltage, use a different resistor in the
voltage-divider. Table 2 lists the resistors used for each
output. Leave the resistors off (open) for unregulated
outputs.
For a given output voltage, if the bottom resistor is
100kΩ, then the top resistor value is:
R__ = 80kΩ/V x (V
OUT
- 1.248V)
Setting the Switching Frequency
All of the switching regulators are synchronized to a
single oscillator frequency. The oscillator capacitor
(C1) is charged through R1 and discharged internally
by the MAX1802. The MAX1802 EV kit operates at
400kHz, with MAIN set to 3.3V. Change resistor R1 or
capacitor C1 if a different MAIN voltage is used or
another frequency is desired. Refer to the MAX1802 IC
data sheet for the correct values to use for R1 and C1.
Logic Control of the Output Voltages
Each controller may be independently turned off or on
using jumpers (JU1–JU6) or with logic voltages. To
control an output using an external logic signal, remove
the ON and OFF jumper for that output and place the
control signal on the corresponding ON_ pad. To
enable MAIN, drive the ON pad greater than +1.8V. To
enable CORE or OUT1, drive the corresponding ON_
pad greater than +1.6V. To enable OUT2, OUT3, or
OUT4 with the default maximum duty cycle, drive the
corresponding ON_ pad to greater than or equal to the
reference voltage. If a resistor-divider is used for duty
cycle adjustment (R5, R6, R9, R10, R11, and R12), use
an open-drain driver on the corresponding ON_ pad.
See the
Setting the Maximum Duty Cycle
section for
additional information. To disable each output individu-
ally, drive the voltage at the corresponding ON_ pad
less than +0.3V.
Note that the voltages at OUT3 and OUT4 will drop
slightly below the battery voltage when off, due to the
DC current path through the inductor and output rectifi-
er. For the step-up outputs, a switch may be added
between the output voltage and the load to disconnect
them while the output is disabled.
Setting the Step-Up Output Voltage
(OUT3 and OUT4)
The output voltage of the step-up circuit voltages
(OUT3 and OUT4) may be set to any voltage above
+1.25V. Note that if the battery voltage is greater than
the step-up regulation voltage, the output voltage will
rise above the regulation voltage. To set the output volt-
age, choose the voltage-divider resistors. For OUT3,
choose:
R18 = 80kΩ/V x (V
OUT3
- 1.248V)
For OUT4, choose:
R2 = 80kΩ/V x (V
OUT3
- 1.248V)
Setting the Maximum Duty Cycle
DCON1, DCON2, and DCON3 set the maximum duty
cycle for controllers 1, 2, and 3, respectively. A resistor-
divider from REF to DCON_ sets the corresponding
maximum duty cycle up to 90%. The MAX1802 EV kit
has DCON_ shorted to REF, producing a default duty
cycle of 76%. Refer to the MAX1802 IC data sheet for
additional information.
Table 2. Flyback Converter Feedback
Resistors
OUTPUT
OUT_A
OUT_B
OUT_C
OUT1_
R30
R29
R31
OUT2_
R26
R25
R27
4
_______________________________________________________________________________________
+2.7V TO +7.0V
R32
3kΩ
JU7
C23
1.0µF
OUT1A
OUT1B
GND
JU8
OUT1C R34
200Ω
JU9
R36
750Ω
R28
100kΩ
1%
OUT2A
1
1
JU11
OUT2C
R41
3kΩ
R42
3kΩ
24
VL
FB2
13
ON1
VDDC 27
COMP1
COMP2
13 2
COMP3
DHM
56
LXM 7
DLM
PGNDM
20 DL3
LXC
30
28
C13
1.0µF
FBC
22
FB3 GND PGND VL
32 25
26
9
L4
10µH
C14
10µF
8
2
1
Q6
3
7 8
L2
10µH
1
D9
2
MAIN
Q4
COMPM
COMPC
6
4
C16
22µF
C17
1.0µF
R23
165kΩ
1%
FBM 1
ON1
1
2
3 JU6
14
17
21
R16
33kΩ
2
R17
91kΩ
29
IN
C26
10µF
C11
470pF
D7
1
1
Q1
2
3
C12
4.7µF
2
L1
4.7µH
C10
4.7nF
ONC
16
R24
100kΩ
1%
R39
200Ω
R40
200Ω
D5
3
OUT2B
R37
3kΩ
R38
3kΩ
D4
1
C20
1.0µF
JU10
R35
200Ω
R29
301kΩ
1%
R30
OPEN
R33
3kΩ
IN
IN
GND
OUT4
IN
1
C24
10µF
10
OSC
VDDM
5
3
1
R31
OPEN
D3
4
VH
12
DL1
5
4
31 REF
11
DCON1
DCON2
DCON3
FB1
T2
XF MR–CLQ72
IN
8
1
7
6
5
3
R27
OPEN JU12
D6
1
15
18
23
VL
6
C22
1.0µF
C21
1.0µF
7
1
3
D2
T1
XF MR–CLQ72
8 1 1 D1 3
D8
L3
3.3µH
2
C3
10µF
REF
OSC
R1
40.2kΩ
1%
VL
2
8
R2
866kΩ
1%
1
Q5
3
DL
U2
IN
7
C2
0.1µF
Figure 1. MAX1802 EV Kit Schematic
R11
OPEN
R9
OPEN
R7
SHORT
R8
OPEN
R10
OPEN
C6
0.1µF
C25
O.1µF 1
2 Q2
3
6
R3
100kΩ
1%
FB
MAX1801
OSC 1
R4
10kΩ
C1
100pF
5
C4
1000pF
COMP
REF 3
C5
0.1µF
VL
4 DCON
GND 2
ON4
JU1
1
2
3
R5
OPEN
R6
OPEN
R12
OPEN
U1
MAX1802
4
DL2
3
3
ONM
19
2
1
Q3
ON2
VL
1
2
3 JU2
C19
1.0µF
C18
1.0µF
ON3
IN
1
2
3 JU3
VL
1
2
3 JU5
R26
OPEN
R25
301kΩ
1%
ONM
1
2
3 JU4
ONC
R13
10kΩ
C7
1000pF
R14
10kΩ
C8
1000pF
R15
10kΩ
R22
100kΩ
1%
C9
1000pF
C15
100µF
10V
CORE
GND
OUT3
GND
R18
464kΩ
1%
Evaluates: MAX1802
_______________________________________________________________________________________
R21
44.2kΩ
1%
R20
100kΩ
1%
R19
100kΩ
1%
MAX1802 Evaluation Kit for
Digital Still Cameras
5
单片机
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
