19-1214; Rev 1; 1/98
MAX1620 Evaluation Kit
General Description
The MAX1620 evaluation kit (EV kit) converts a +1.8V to
+12V battery voltage to a +12.5V to +23.5V LCD back-
plane bias voltage for currents up to 20mA. Both the
MAX1620 and MAX1621 include a 5-bit DAC, allowing
digital software control of the bias voltage. The
MAX1620 uses up/down digital signaling to adjust the
DAC, and the MAX1621 uses the System Management
Bus (SMBus鈩? 2-wire serial interface.
The MAX1620 EV kit is a fully assembled and tested sur-
face-mount circuit board. It can also be used to evaluate
the MAX1621.
o
+1.8V to +12V Battery Input Voltage
o
+12.5V to +23.5V Adjustable Output
o
20mA Output
o
32-Level Internal DAC
o
10碌A(chǔ) Shutdown Current
o
Surface-Mount Components
o
Fully Assembled and Tested
Features
Evaluates: MAX1620/MAX1621
Ordering Information
PART
MAX1620EVKIT
TEMP. RANGE
0擄C to +70擄C
BOARD TYPE
Surface Mount
Component List
DESIGNATION
C1, C6
C2, C3
C5
D1
D4
L1
N1
Q1
R1
R2, R8, R9, R10
R3, R4
R5
R6, R7
R11
U1
JU3
None
JU8
None
QTY
2
2
1
1
1
1
1
1
1
4
2
1
2
1
1
1
1
1
1
DESCRIPTION
22碌F, 35V tantalum capacitors
AVX TPSE226M035R0300 or
Sprague 593D226X0035E2T
0.1碌F ceramic capacitors
100pF ceramic capacitor
Schottky diode Motorola MBR0540T1
Schottky diode
Central Semiconductor CMPSH-3
100碌H inductor Sumida CD54-101
N-channel MOSFET Motorola
MMFT3055VL
2N2907A transistor Central
Semiconductor CMPT2907A
82k鈩? 5% resistor
100k鈩? 5% resistors
300k鈩? 5% resistors
2.2M鈩? 5% resistor
56k鈩? 5% resistors
10k鈩? 5% resistor
MAX1620EEE (QSOP-16)
3-pin header
Shunt (JU3)
2-pin header
MAX1620/MAX1621 PC board
Note: To evaluate the MAX1621, request a free MAX1621EEE
sample with the MAX1620 EV kit.
Component Suppliers
SUPPLIER*
AVX
Central
Semiconductor
Coilcraft
Coiltronics
Dale-Vishay
Motorola
Sprague
Sumida
Vishay/Vitramon
PHONE
803-946-0690
516-435-1110
847-639-6400
561-241-7876
402-564-3131
602-303-5454
603-224-1961
847-956-0666
203-268-6261
FAX
803-626-3123
516-435-1824
847-639-1469
561-241-9339
402-563-6418
602-994-6430
603-224-1430
847-956-0702
203-452-5670
*
Please indicate that you are using the MAX1620 EV kit when
contacting these component suppliers.
Quick Start
The MAX1620 EV kit is fully assembled and tested.
Follow these steps to verify board operation.
Do not
turn on the power supply until all connections are
completed.
1) Connect a +1.8V to +12V power supply to the
VBATT pad and a +3V to +5.5V supply to the VIN
pad. Connect ground to the GND pad.
2) Connect a voltmeter and load, if any, to the VOUT
pad.
3) Verify the JU3 shunt is across pins 1 and 2 (positive
output).
4) Turn on the power supply and verify that the output
voltage is typically +17.8V.
5) For other output voltages, refer to the
Output Adjustment
section in the MAX1620/MAX1621 data sheet for
instructions on selecting the feedback resistors.
1
None
1
MAX1620/MAX1621 data sheet
Additional components for negative output (included in
1
Shunt
the EV kit) but not installed:
C4
1
1碌F ceramic capacitor
C7
D2, D3
1
2
22碌F, 35V tantalum capacitor
AVX TPSE226M035R0300 or
Sprague 593D226X0035E2T
Schottky diodes Motorola MBR0540T1
SMBus is a trademark of Intel Corp.
________________________________________________________________
Maxim Integrated Products
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Maxim
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