19-2810; Rev 1; 8/05
MAX1565 Evaluation Kit
General Description
The MAX1565 evaluation kit (EV kit) is a fully assembled
and tested circuit board that accepts 1.5V to 3.6V input
voltages and provides all the output voltages required
for a typical digital still camera. The outputs consist of
the main step-up output (3.35V), a step-down output
(1.5V), a general-purpose 5V output, two outputs for
charge-coupled device (CCD) and LCD bias, and an
optional general-purpose output using the MAX1801
slave controller.
♦
♦
♦
♦
♦
♦
♦
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Features
95% Efficiency
1.5V to 3.6V Input Voltage Range
Main Step-Up Output: 3.35V or Adjustable
Step-Down Output: 1.5V or Adjustable
5V General-Purpose Output
CCD and LCD Bias Outputs (+15V/-7.5V)
Power-Regulated Output for White LED
Backlighting
Optional General-Purpose Output Using the
MAX1801 Slave Controller
1µA Shutdown Mode
Internal Soft-Start Control
Overload Protection for All Outputs
Fully Assembled and Tested
Evaluates: MAX1565
Component List
DESIGNATION QTY
DESCRIPTION
6800pF, 25V X7R ceramic capacitor
(0402)
Murata GRP155R71E682K or
equivalent
3300pF, 50V X7R ceramic capacitor
(0402)
Murata GRP155R71H332K or
equivalent
0.01µF, 25V X7R ceramic capacitor
(0402)
Murata GRP155R71E103K or
equivalent
1000pF, 50V X7R ceramic capacitors
(0402)
Murata GRP155R71H102K or
equivalent
10µF, 10V X5R ceramic capacitors
(1210)
Taiyo Yuden LMK325BJ106MN or
equivalent
1µF, 25V X7R ceramic capacitors
(1206)
TDK C3216X7R1E105K or equivalent
10µF, 6.3V X5R ceramic capacitors
(0805)
Panasonic ECJ2FB0J106M or
Taiyo Yuden JMK212BJ106MG
47µF, 6.3V X5R ceramic capacitor
(1812)
Taiyo Yuden JMK432BJ476MM
0.1µF, 16V X7R ceramic capacitor
(0603)
Taiyo Yuden EMK107BJ104MA or
equivalent
C1
1
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♦
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Ordering Information
PART
MAX1565EVKIT
TEMP RANGE
-40°C to +85°C
IC PACKAGE
32 Thin QFN 5mm
✕
5mm
C2
1
Quick Start
Follow the steps below to verify operation of the
MAX1565 EV kit.
Do not turn on the power supply until
all connections are completed:
1) Connect a series LED array or install surface-mount
white LEDs in D7–D10. When connecting an LED
array, connect the anode to LEDOUT+ and connect
the cathode to LEDOUT-.
2) Preset the power supply to between 1.5V and 3.6V.
3) Turn off the power supply.
4) Connect the power-supply positive lead to IN.
5) Connect the power-supply ground lead to GND.
6) Connect loads from outputs OUTSD, OUT1, OUT3A,
and OUT3B to GND. See Table 1 for maximum load
currents.
7) To enable the main step-up output, verify that JU1
has pins 2 and 3 shorted.
8) Verify that JU2–JU8 have pins 1 and 2 shorted.
9) Turn on the power supply.
10) Use a voltmeter to verify the OUTSU voltage (3.35V).
11) Connect a load, if desired, from OUTSU to GND.
See Table 1 for maximum load currents.
12) To verify other outputs, move JU2–JU5 to short pins
2 and 3. Use a voltmeter to verify output voltages.
1
C3
1
C4, C5
2
C6A, C6B
2
C7, C8
2
C9, C10, C17,
C18, C19
5
C11
1
C12
1
________________________________________________________________
Maxim Integrated Products
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.
MAX1565 Evaluation Kit
Evaluates: MAX1565
Component List (continued)
DESIGNATION QTY
C13
1
DESCRIPTION
1µF, 35V X5R ceramic capacitor
(1206)
Taiyo Yuden GMK316BJ105ML
100pF, 50V C0G ceramic capacitor
(0402)
Murata GRM36C0G101K050AD
or equivalent
1000pF ceramic capacitor (0402),
not installed
Not installed (0805)
500mA Schottky diodes (SOD-123)
Central CMHSH5-2L or
International Rectifier MBR0520
60V, 1A Schottky diode
(SOD-123F)
Central CMMSH1-60
40V, 500mA Schottky diode
(SOD-123)
Central CMHSH5-4
Not installed (SOD-123)
Not installed, surface-mount LEDs
3-pin headers
Not installed, PC board short
3.3µH inductor
Sumida CDRH6D38-3R3
4.2µH inductor
Sumida CDRH5D28-4R2
2µH inductor
TOKO A918CY-2R0M
1.4µH inductor
Sumida CDR43-1R4 or
TOKO A918CY-1R5M
Not installed
N-channel MOSFET (6-pin SOT)
Fairchild FDC637AN or
International Rectifier IRLMS2002
N-channel MOSFETs (SOT23)
Fairchild FDN337N
Not installed (SOT23)
46.4kΩ
±1%
resistor (0603)
26.1kΩ
±1%
resistor (0603)
8.2kΩ
±5%
resistor (0603)
10kΩ
±5%
resistors (0603)
Not installed, PC board shorts (0603)
DESIGNATION QTY
R7, R11, R13,
R17, R18
R8
R9
R14
R15
R16
R19
R20
T1
0
1
1
1
1
0
1
1
1
DESCRIPTION
Not installed (0603)
1MΩ
±1%
resistor (0603)
90.9kΩ
±1%
resistor (0603)
51kΩ
±5%
resistor (0603)
2.2kΩ
±5%
resistor (0603)
10kΩ
±5%
resistor (0603),
not installed
36.5kΩ
±1%
resistor (0603)
33Ω
±5%
resistor (0603)
Transformer
Sumida CLQ72 type, sample number
6333-T507
MAX1565ETJ
(32-pin thin QFN 5mm x 5mm)
Not installed (8-pin SOT23), MAX1801
Shunts
MAX1565ETJ EV kit PC board
C14
1
C15
C16
D1, D3, D5
0
0
3
D2
1
U1
U2
—
—
1
0
8
1
D4
D6
D7–D10
JU1–JU8
JU9
L1
L2
L3
1
0
0
8
0
1
1
1
Table 1. Output Voltages and Maximum
Currents
OUTPUT
OUTSU
OUTSD
OUT1
LEDOUT+ to LEDOUT-
OUT3A
OUT3B
VOLTAGE
(V)
3.35
1.5
5
16 (Note 2)
15
-7.5 (Note 3)
MAXIMUM
CURRENT
(mA)
500 (Note 1)
350
500
15
20
30
L4
L5
N1
1
0
1
Note 1:
If both OUTSU and OUTSD are operating, subtract half
the OUTSD load current from the maximum load capability of
OUTSU.
Note 2:
With four white LEDs connected in series from LEDOUT+
to LEDOUT-, this output is regulated to approximately 60mW per
LED. With typical white LEDs, this is approximately 16V at 15mA.
With an open circuit, LEDOUT+ is approximately 30V.
Note 3:
Only the 15V output is fed back to the controller regula-
tion point. A small preload (at least 5mA) is needed for the -7.5V
output to be in regulation.
N2, N3
N4
R1
R2
R3
R4, R5
R6, R10, R12
2
0
1
1
1
2
0
2
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MAX1565 Evaluation Kit
Detailed Description
Main Step-Up Output (OUTSU)
The main output (OUTSU) powers the internal circuitry
of the MAX1565 and must reach its regulation voltage
before any other output turns on. To enable OUTSU,
short pins 2 and 3 of JU1. When JU1 pins 1 and 2 are
shorted, all outputs shut down and the IC is in low-cur-
rent shutdown mode.
When pins 1 and 2 of JU8 are shorted, OUTSU is pre-
set to 3.35V. If a different output voltage is desired, see
the
Adjusting the Main Step-Up Output Voltage
section.
Evaluates: MAX1565
Table 2. Jumper Functions
JUMPER
JU1
JU2
JU3
JU4
JU5
JU6
JU7
JU8
PINS 1 AND 2
All outputs are shut down
OUTSD shut down
OUT1 shut down
LEDOUT shut down
OUT1 set to 5V
OUTSD set to 1.5V
OUTSU set to 3.35V
PINS 2 AND 3
OUTSU enabled
OUTSD enabled
OUT1 enabled
LEDOUT enabled
OUT1 adjustable
OUTSD adjustable
OUTSU adjustable
OUT3A/OUT3B shut down OUT3A/OUT3B enabled
Step-Down Output (OUTSD)
The step-down output (OUTSD) is preset to 1.5V. To
enable OUTSD, short pins 2 and 3 of JU2. To shut
down OUTSD, short pins 1 and 2 of JU2. For the preset
1.5V output, short pins 1 and 2 of JU7. To adjust the
output voltage, see the
Adjusting the Step-Down
Output Voltage
section.
load of 5mA (min) is required on OUT3B to maintain
regulation at -7.5V. To enable OUT3A/OUT3B, short
pins 2 and 3 of JU5. To turn off these outputs, short
pins 1 and 2 of JU5.
Step-Down OK (SDOK)
The step-down OK output (SDOK) is an active-low,
open-drain output that is low until the step-down con-
verter has completed soft-start. For more details on
SDOK, refer to the MAX1565 data sheet.
Customizing the MAX1565
Evaluation Kit
Optional Step-Up Controller (OUT4)
A MAX1801 step-up slave controller can be used with
the MAX1565 EV kit to generate an additional output. To
use this feature, install a MAX1801 in U2 on the solder
side of the PC board. Contact Maxim for free samples of
the MAX1801. Also install components N4, D6, L5, C15,
C16, R16, R17, and R18. Refer to the MAX1801 data
sheet for information on selecting these components.
OUT1
OUT1 is a regulated 5V output. To enable OUT1, connect
pins 2 and 3 of JU3. If an output voltage other than 5V is
desired, see the
Adjusting the OUT1 Voltage
section.
LED Outputs (LEDOUT+, LEDOUT-)
LEDOUT+ and LEDOUT- are designed to drive a series
array of white LEDs for backlighting. Connect an array
consisting of two to six white LEDs in series to these
outputs. The anode side connects to LEDOUT+ and the
cathode side connects to LEDOUT-. Alternately, indi-
vidual surface-mount white LEDs can be installed in
D7–D10. If only two or three LEDs are connected, short
the pads of the remaining unpopulated LEDs. With four
white LEDs installed, the LED power is regulated to
approximately 60mW each. To enable the LED output,
short pins 2 and 3 of JU4. To turn off the LED output,
short pins 1 and 2 of JU4. To adjust the LED bright-
ness, see the
Adjusting the LED Brightness
section.
Adjusting the Main Step-Up
Output Voltage
The main step-up output (OUTSU) can be adjusted
from 2.7V to 5.5V using the following procedure:
1) Short pins 2 and 3 of JU8.
2) Cut the PC board trace that shorts the pads of R12
(located on the solder side of the PC board).
3) Select a value for R13 between 10kΩ and 100kΩ.
4) Solve for R12:
⎛
V
⎞
R12
=
R13
× ⎜
OUTSU
- 1
⎟
⎝
1.25
⎠
5) Install R12 and R13.
CCD Outputs (OUT3A, OUT3B)
OUT3A and OUT3B provide the voltages necessary for
CCD bias. OUT3A is +15V, and OUT3B is -7.5V. These
voltages are generated using a flyback transformer.
The output voltage at OUT3A is regulated, while the
voltage at OUT3B is controlled by the turns ratio of the
transformer. If OUT3B is not loaded while OUT3A is
loaded at 20mA or more, OUT3B is then -10V (typ). A
Adjusting the Step-Down Output Voltage
The step-down output voltage (OUTSD) can be set
from 1.25V to V
OUTSU
using the following procedure:
1) Short pins 2 and 3 of JU7.
2) Cut the PC board trace that shorts the pads of R10
(located on the solder side of the PC board).
3
_______________________________________________________________________________________
MAX1565 Evaluation Kit
Evaluates: MAX1565
3) Select a value for R11 between 10kΩ and 100kΩ.
4) Solve for R10:
⎛
V
⎞
R10
=
R11
× ⎜
OUTSD
- 1
⎟
⎝
1.25
⎠
5) Install R10 and R11.
5) Choose a value for R15. The MAX1565 EV kit has a
2.2kΩ resistor installed for R15. In most cases, it is
not necessary to change R15.
6) Calculate the value for R14:
R14
=
n
×
V
FMIN
×
R15
1.25 - I
LED(MAX)
×
R20
Adjusting the OUT1 Voltage
OUT1 can be set to any voltage above 1.25V. Note that
OUT1 rises above its regulation voltage if the input volt-
age is greater than what OUT1 is set to. Use the follow-
ing procedure to set V
OUT1
:
1) Short pins 2 and 3 of JU6.
2) Cut the PC board trace that shorts the pads of R6
(located on the solder side of the PC board).
3) Select a value for R7 between 10kΩ and 100kΩ.
4) Solve for R6:
⎛
V
⎞
R6
=
R7
× ⎜
OUT1
- 1
⎟
⎝
1.25
⎠
5) Install R6 and R7.
(
)
7) Find the open-circuit voltage of the circuit. To pre-
vent damage to the EV kit when the LEDs are not
installed, make sure this voltage is less than 30V:
⎛
R14
⎞
V
OPENCIRCUIT
=
1.25
× ⎜
+
1
⎟
⎝
R15
⎠
8) Install the new resistors.
Constant-Current Regulation
The MAX1565 EV kit can be configured to regulate the
current through the LEDs. Note that this connection does
not include the overvoltage protection provided by the
constant-power design. Two to six LEDs must be con-
nected from LEDOUT+ to LEDOUT-. Use the following
procedure to configure the EV kit for constant-current
regulation:
1) Remove R14.
2) Short the pads of R15.
3) Calculate the value for R20:
R20
=
1.25
I
LED
Adjusting the LED Brightness
Constant Power Regulation
The MAX1565 EV kit uses a three-resistor feedback
connection that regulates the LEDs at a nearly constant
power. This configuration also protects the circuit by
limiting the voltage at LEDOUT+ in case of an open cir-
cuit. Use the following procedure to set the LED power:
1) Select the desired power per LED (P
LED
) and the
number of LEDs to be used (n), between two and six.
2) Determine the minimum and maximum LED forward-
voltage drop (V
FMIN
and V
FMAX
) at the desired
power. Refer to the LED data sheet for this informa-
tion. For typical white LEDs, these are approximately
V
FMIN
= 3V and V
FMAX
= 4V.
3) Find the minimum and maximum LED current, assum-
ing a constant power of P
LED
:
I
LED(MIN)
= P
LED
/ V
FMAX
I
LED(MAX)
= P
LED
/ V
FMIN
4) Calculate the value for R20:
R20
=
1.25
I
LED(MAX)
+ I
LED(MIN)
4) Replace R20 with the new value resistor.
Adjusting the CCD Output Voltages
A custom flyback transformer is used to generate out-
puts OUT3A and OUT3B. To change these outputs,
replace T1 with a transformer designed for the new out-
put voltages. OUT3A is regulated, while OUT3B
depends on the turns ratio of the transformer. To set a
new regulation voltage for OUT3A, use the following
procedure:
1) Select a value for R9 between 10kΩ and 100kΩ.
2) Solve for R8:
⎛
V
⎞
R8
=
R9
× ⎜
OUT3A
- 1
⎟
⎝
1.25
⎠
3) Replace R8 and R9.
4
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MAX1565 Evaluation Kit
Table 3. Component Suppliers
SUPPLIER
Central
Semiconductor
Fairchild
Semiconductor
International Rectifier
Kamaya
Murata
Panasonic
Sumida
Taiyo Yuden
TDK
TOKO
PHONE
WEBSITE
631-435-1110 www.centralsemi.com
—
www.fairchildsemi.com
Changing the Switching Frequency
The switching frequency of the MAX1565 is adjustable.
Typically, frequencies from 400kHz to 500kHz provide
a good compromise between efficiency and compo-
nent size. To change the frequency, replace C14 and
R19. Refer to the MAX1565 data sheet for information
on selecting values for these components.
Evaluates: MAX1565
310-322-3331 www.irf.com
260-489-1533 www.kamaya.com
814-237-1431 www.murata.com
714-373-7939 www.panasonic.com
847-956-0666 www.sumida.com
408-573-4150 www.t-yuden.com
847-803-6100 www.component.tdk.com
847-297-0070 www.toko.com
Note:
Indicate that you are using the MAX1565 when contact-
ing these component suppliers.
IN
C17
10µF
C18
10µF
L3
2µH
C3
OUT1
+5V
D1
C4
C5
C6A
10µF
C6B
10µF
N1
R6
SHORT
C1
C2
R3
R4
R5
R1
R2
1
31
24
15
7
29
R7
OPEN
2
16
MAIN
JU8
3
2
1
MAIN
JU7
3
2
1
MAIN
JU6
3
2
1
MAIN
JU1
3
2
1
MAIN
JU2
3
2
1
MAIN
JU3
3
2
1
MAIN
JU4
3
2
1
JU5
11
10
9
ON1
ON2
ON3
PGND
3
PGND
20
EP
JU9
C12
0.1µF
REF
C14
100pF
OSC
OSC
REF
GND
19
13
30
R19
36.5kΩ
17
18
12
6
21
27
25
28
32
4
8
5
26
22
23
14
IN
SDOK
C11
47µF
D5
R12
SHORT
OUTSU
+3.35V
500mA
C19
10µF
MAIN
R11
OPEN
DL2
FB2
L2
4.2µH
C9
10µF
C10
10µF
OUTSD
+1.5V
R10
350mA
SHORT
IN
T1
L1
3.3µH
1
7
4
D3
8
D2
C7
1µF
C8
1µF
R8
1MΩ
OUT3A
+15V
20mA
OUT3B
-7.5V
30mA
COMP1
COMP2
COMP3
COMPSU
COMPSD
DL1
FB1
FBSELSU
FBSELSD
FBSEL1
ONSU
ONSD
LXSU
DL3
FB3
DL2
N3
6
R9
90.9kΩ
U1
MAX1565
FB2
LXSD
FBSD
INSD
OUTSU
OUTSU
SDOK
FBSU
MAIN
3
2
1
R13
OPEN
Figure 1. MAX1565 EV Kit Schematic (Sheet 1 of 2)
_______________________________________________________________________________________
5
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