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19-1985; Rev 1; 1/02
MAX1800 Evaluation Kit
General Description
The MAX1800 evaluation kit (EV kit) accepts 1.8V to 5.5V battery voltages and provides all of the output voltages required in digital still cameras (DSC). The EV kit consists of the MAX1800 multi-output master converter and the MAX1801 slave step-up converter. The EV kit provides 10 separate output voltages. The MAX1800 provides one main-system step-up converter (3.3V/400mA), one linear regulator for the DSP core (1.8V/200mA), one step-up converter for the backlight (7V/100mA), three flyback outputs for the CCD (14.3V/10mA, 5V/50mA, -8.15V/10mA), and three flyback outputs for the LCD (13.85V/10mA, 5V/50mA, -16.23V/10mA). In addition, the MAX1801 provides one step-up converter for the motor (5V/500mA). The EV kit's outputs are adjustable and are suitable for applications running from 2- or 3-cell alkaline, NiCd, or NiMH batteries or from a single lithium-on (Li+) battery.
Features
o 10 Outputs One Synchronous Rectified Step-Up Converter Two Step-Up Converters One Low-Dropout Linear Regulator Output Six Flyback Outputs o 1.8V to 5.5V Input Voltage Range o All Converters Synchronized to Single Oscillator o 100kHz to 1MHz Switching Frequency o Main Power-OK Output o Independent Shutdown of Each Converter o Short-Circuit-Protected Flyback Outputs o Soft-Start on Each Output o Fully Assembled and Tested
Evaluates: MAX1800/MAX1801
Ordering Information
PART MAX1800EVKIT TEMP RANGE 0C to +70C IC PACKAGE 32 TQFP, 8 SOT23
Component List
DESIGNATION C1, C22 QTY 2 DESCRIPTION 10F, 10V ceramic capacitors (1210) TDK C3225X5R1A106M 100pF, ceramic capacitor (0603) 0.1F ceramic capacitors (0603) 4.7F, 10V ceramic capacitors (1206) TDK C3216X5R1A475M or Taiyo Yuden LMK316BJ475ML 1000pF ceramic capacitors (0603) 1F, 25V ceramic capacitors (1206) TDK C3216X7R1E105KT 4.7F, 6.3V ceramic capacitor (0805) TDK C2012X5R0J475K DESIGNATION C17 QTY 1 DESCRIPTION 220F, 10V, 100m low-ESR (E case) AVX TPSE227M010R0100 47F, 6.3V, 100m low-ESR (C case) Sanyo 6TPA47M 0.01F ceramic capacitor (0603) PN junction diodes (SOT323) Central Semiconductor CMSD-4448 Schottky diodes (SOT323) Central Semiconductor CMSSH-3 Schottky diodes (SOD-123) Motorola MBR0520L or Fairchild Semiconductor MBR0520L Schottky diode (CASE 403A03 SMB) Motorola MBRS130LT3
C2 C3, C15, C21
1 3
C19
1
C24
1
C4, C18
2
D1, D4, D6
3
C5-C8, C20
5
D2, D3, D5, D9
4
C9-C14
6
D7, D8
2
C16
1
D10
1
________________________________________________________________ Maxim Integrated Products
1
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MAX1800 Evaluation Kit Evaluates: MAX1800/MAX1801
Component List (continued)
DESIGNATION JU1-JU6 JU7- JU12 L1 L2 QTY 6 6 1 1 DESCRIPTION 3-pin headers 2-pin headers 1.4H inductor Sumida CR43-1R4 10H inductor Sumida CDRH6D38-100 0.5H inductor Sumida CR43 Type Sample 4757-T019 N-channel MOSFETs Fairchild Semiconductor FDN337N P-channel MOSFET Fairchild Semiconductor NDS336P 200 5% resistors (1206) 40.2k 1% resistor (0603) Shorted in the PC board layout (0402) (not installed) U1 U2 None 1 1 12 DESIGNATION R7, R8, R9, R27 R11, R16, R24 R18 R20 R21 R23 R35, R36, R40, R41, R44, R45 R39 R46 T1 QTY 4 3 1 1 1 1 6 1 1 1 DESCRIPTION 10k 5% resistors (0402) 301k 1% resistors (0603) 44.2k 1% resistor (0603) 4.7 5% resistor (0402) 165k 1% resistor (0603) 1M 5% resistor (0402) 3k 5% resistors (1206) 750 5% resistor (1206) 100k 5% resistor (0402) Transformer Sumida "Sample Number": 6333-T330 Transformer Sumida "Sample Number": 6333-T329 MAX1800EHJ (32-pin TQFP) MAX1801EKA (8-pin SOT23) Shunts
L3
1
Q1, Q2, Q3, Q5
4
Q4 R37, R38, R42, R43 R1 R2, R29, R31, R33
1
T2
1
4 1 4
R3, R12-R15, R26, R28, R30, R32, R34 R4 R5, R10, R17, R19, R22, R25 R6
graph in the Typical Operating Characteristics in the MAX1800 data sheet before loading MAIN.
10 1 6 1 Open, not installed (0402) 464k 1% resistor (0603) 100k 1% resistors (0603) 200k 5% resistor (0402)
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 1.8V to 5.5V battery or power supply to IN. 5) Using the DVM, measure the voltage at MAIN, LDO, OUT1_, OUT2_, OUT3 and OUT4.
Detailed Description Quick Start
Recommended Equipment
* 1.8V to 5.5V battery or power supply * Digital voltmeter (DVM) The main output (MAIN) powers the MAX1800's internal circuitry. MAIN must be regulated before any of the other outputs function. To enable MAIN, place jumper JU2 in the 1-2 position. Apply 1.8V to 5.5V between IN and GND. The voltage between MAIN and GND should be approximately 3.3V if IN is <3.3V. Because the IC is powered from MAIN, the IC does not work at maximum efficiency until MAIN is in regulation. Thus, at low battery voltages and heavy loads, MAIN may not have sufficient power to start. The output current capability shown in Table 1 is valid for input voltages down to 1.8V. The circuit operates for
Connections and Setup
1) Make sure jumpers JU1-JU6 are connected in the 12 (ON) position. This ensures that 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. See the Startup Input Voltage vs. MAIN Output Current
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MAX1800 Evaluation Kit
Table 1. Output Voltage and Current Capability
LABEL MAIN LDO OUT1A OUT1B OUT1C OUT2A OUT2B OUT2C OUT3 OUT4 VOLTAGE/CURRENT 3.3V at 400mA 1.8V at 200mA 14.3V at 10mA 5V at 50mA -8.15V at 10mA 13.85V at 10mA 5V at 50mA -16.23V at 10mA 7V at 100mA 5V at 500mA
3 (OFF) position. To enable/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 (OUT1_ and OUT2_) section.
Evaluates: MAX1800/MAX1801
OUT2_ (Flyback Outputs)
The voltages at OUT2_ are typical of LCD bias voltages. The output voltages are 13.85V/10mA, 5V/50mA, and -16.23V/10mA. These voltages are generated through a custom flyback transformer. OUT2B (5V) is used to regulate the flyback circuit. The other output voltages (13.85V and -16.23V) are controlled by the turns-ratio of the flyback transformer. If the 13.85V and -16.23V 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 MAX1800 EV kit by shorting jumpers JU7 through JU12. If external loads are used, disable the built-in loads by removing these jumpers. To enable OUT2_, place jumper JU5 to the 1-2 (ON) position. To disable OUT2_, place jumper JU5 to the 23 (OFF) position. To enable/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 (OUT1_ and OUT2_) section.
input voltages below 1.8V but with reduced output current capability. Refer to the MAX1800 data sheet for the minimum allowable input voltage for the part to start at a given load. When the MAIN output is in regulation, the MAIN_OK output will be pulled up to the MAIN output voltage. If the MAIN_OK output is low (near ground), MAIN is not in regulation.
LDO Output
The LDO output is linearly regulated from MAIN to 1.8V. Note that the load current on LDO is produced from MAIN. Drawing more than 200mA out of LDO reduces the current capability at MAIN. To enable LDO, place jumper JU3 in the 1-2 (ON) position.
OUT3
The voltage at OUT3 is typical of that required by a CCFL backlight inverter. To enable OUT3, place jumper JU6 to the 1-2 (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 (OUT3 and OUT4) section. 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 14.3V/10mA, 5V/50mA, and -8.15V/10mA. These voltages are generated through a custom flyback transformer. OUT1B (5V) is used to regulate the flyback circuit. The other output voltages (14.3V and -8.15V) are controlled by the turnsratio of the flyback transformer. If the 14.3V and -8.15V 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 MAX1800 EV kit by shorting jumpers JU7 through JU12. If external loads are used, disable the built-in loads by removing these jumpers. To enable OUT1_, place jumper JU4 to the 1-2 (ON) position. To disable OUT1_, place jumper JU4 to the 2-
OUT4
The voltage at OUT4 is a general-purpose 5V output that can be used for powering a small motor or other peripheral circuitry and can supply up to 500mA. To enable OUT4, place jumper JU1 to the 1-2 (ON) position. Place the external load between OUT4 and GND. To change the output voltage of OUT4, see the Setting the Step-Up Output Voltage (OUT3 and OUT4) section.
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MAX1800 Evaluation Kit Evaluates: MAX1800/MAX1801
Customizing the MAX1800 EV Kit
Setting the Main Output Voltage
MAIN is set by a voltage divider, which drops the output voltage to the 1.25V feedback threshold voltage. To change the 3.3V setting of MAIN, change the resistor divider ratio by changing R21. Use: R21 = 80k / V ( VMAIN - 1.25V ) The MAIN output voltage may be set to any voltage between 2.7V and 5.5V. For additional information, see the MAX1800 data sheet. 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, the resistor value (Table 2) is: R = 80k / V ( VOUT - 1.25V )
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 voltage, choose the voltage divider resistors. For OUT3, choose: R4 = 80k / V ( VOUT3 - 1.25V ) For OUT4, choose: R24 = 80k / V ( VOUT4 - 1.25V )
Setting the LDO Output Voltage
The LDO output voltage is set by a voltage divider, which drops the output voltage to the 1.25V feedback threshold voltage. To change the 1.8V setting of LDO, change the resistor divider ratio by changing R18. Use: R18 = 80k / V ( VLDO - 1.25V ) The LDO output voltage may be set to any voltage between 1.25V and 5.5V but must remain less than the voltage at MAIN when powered from MAIN. The MAX1800 EV kit is configured so that MAIN powers the LDO input; however, opening up the short across R33 and shorting R34 will allow LDO to be powered from IN.
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 EV kit has DCON_ shorted to REF, producing a default duty cycle of 84%. See the MAX1800 data sheet for additional information.
Setting the Flyback Circuit Voltages (OUT1_ and OUT2_)
A flyback circuit generates OUT1_ and OUT2_. This allows multiple, positive, or negative voltages to be generated by a single converter and allows the voltages to drop to 0V when the converter is disabled. The transformer must be designed for a given set of output voltages. On the flyback circuits, only a single output voltage is used to regulate all the voltages. All other voltages are controlled by the turns-ratio of the transformer. If another set of output voltages is required, a transformer with a different secondary turns-ratio must be used. Consult
Setting the Switching Frequency
All of the switching regulators are synchronized to a single oscillator frequency. The oscillator capacitor (C2) is charged through R1 and discharged internally by the MAX1800. The EV kit is designed to operate at 440kHz with MAIN set to 3.3V. If a different MAIN voltage is used, or if a different oscillator frequency is desired, change resistor R1 or capacitor C2. Consult the MAX1800 data sheet for the correct values to use for R1 and C2.
Logic Control of the Output Voltages
Table 2. Flyback Converter Feedback Resistors
OUTPUT OUT_A OUT_B OUT_C OUT1_ R13 R11 R12 OUT2_ R14 R16 R15
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/OFF jumper for that output, and place the control signal on the corresponding ON_ pad. To enable the output, make sure that the voltage of the control signal at the corresponding ON_ pad is >1.6V. To disable it, make sure the voltage at the corresponding ON_ pad is <0.3V.
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_______________________________________________________________________________________
MAX1800 Evaluation Kit
Also, note that the voltages at MAIN, OUT3, and OUT4 will drop slightly below the battery voltage when OFF, due to the DC current path through the inductor and output rectifier. 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.
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
Evaluates: MAX1800/MAX1801
High Input Voltage Operation
The MAIN output is designed to operate with an input voltage above or below the output regulation voltage. Since MAIN is a step-up converter, when the input voltage is above the regulation voltage, the output will be nearly that of the input voltage. If the input battery voltage ranges above and below the regulation voltage, follow the MAIN output with the LDO output to form a step-up/step-down regulator. In this case, when the battery voltage is low, the step-up converter raises the battery voltage to the regulation voltage. When the battery voltage is above the regulation voltage, the LDO regulator controls the output voltage. For high input voltages, if the power is applied abruptly, the MAIN output capacitor charges quickly, causing the L2 inductor current to rise above the 2A current limit. To prevent damage to the MAX1800, diode D10 is used to charge main output capacitor C17, preventing excessive current in the inductor. Components R46, C24, and D9 delay turn-on of the MAIN converter when power is applied. This prevents damage to the switches caused by switching with excessive inductor current at turn-on. If the MAX1800 is used exclusively with low input voltage, components R46, C24, D9, and D10 may be omitted.
Note: Please indicate that you are using the MAX1800/ MAX1801 when contacting these suppliers.
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Evaluates: MAX1800/MAX1801
MAX1800 Evaluation Kit
Figure 1. MAX1800 EV Kit Schematic
MAIN MAIN JU7 C9 1F IN 16 OSC 14 C3 R31 0.1F SHORT R29 SHORT 5 DCON1 DCON2 DCON3 T2 XFMR-CLQ72 8 7 6 5 D6 R15 OPEN FB2 ONM A0 A1 27 ONA R18 44.2k 1% 25 Q4 1 2 3 MAIN ON1 3 ON1 MAIN 1 2 9 ON2 MAIN ON3 JU6 3 ROYM GND 15 PGND 1 PGND 19 23 GND 1 2 FBM 31 ON3 17 3 3 ON2 JU5 1 JU4 2 28 C15 0.1F LDO C16 4.7F GND R34 OPEN R33 SHORT IN 10 IN 24 R17 100k 1% JU12 R44 3k C13 1F C14 1F OUT2C R45 3k JU11 R42 200 R43 200 R16 301k 1% D5 D4 1 4 DL2 8 Q3 C12 1F DL3 R12 OPEN R39 750 R10 100k 1% OUT2A Q2 JU9 12 25 FB1 4 D3 R3 OPEN R30 OPEN R2 SHORT 2 L1 1.4H R26 OPEN C1 10F REF 4 5 C11 1F 20 LX LX 21 DL1 2 OUT1C R37 200 R11 301k 1% R38 200 L2 10H R13 OPEN JU8 OUT1B GND OUT1A R36 3k 7 C21 0.1F 1 C2 100pF 3 R1 40.2k 1% T1 XFMR-CLQ72 D1 8 17 D2 C22 10F 6 C10 1F R35 3k IN
6
U2 MAX1801 OSC
REF GND
IN
IN
GND
L3 0.5H
OUT4
D8
Q5
R24 301k 1%
C19 47F 6.3V
8
DL
6
FB
R25 100k 1%
R27 10k
5 COMP
C20 1000pF
MAIN
4
OCON
ON4 JU1 1
R28 OPEN
U1 MAX1800
GND C4 4.7F 32 30 FB3 18 COMPM 5 COMP1 R7 10k 11 COMP2 COMP3 R8 10k 29 R9 10k C8 1000pF C7 1000pF MAIN_ON C24 0.01F JU2 3 1 2 Q1 D7 R4 464k 1% R5 100k 1% IN MAIN D9 C5 R6 1000pF 200k C6 1000pF
2 3 R32 OPEN
OUT3
JU10
OUT2B R40 3k R41 3k R14 OPEN
R46 100k
LDO_ON JU3
POUT 7 22 POUT OUT 13
R19 100k 1% R20 4.7 C18 4.7F R21 165k 1% R22 100k 1%
MAIN
D10 MAIN R23 1M C17 220F 10V MAIN_OK
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MAX1800 Evaluation Kit Evaluates: MAX1800/MAX1801
1.0"
1.0"
Figure 2. MAX1800 EV Kit Component Placement Guide-- Component Side
Figure 3. MAX1800 EV Kit PC Board Layout--Component Side
1.0"
1.0"
Figure 4. MAX1800 EV Kit PC Board Layout--Inner Layer 2 (AGND)
Figure 5. MAX1800 EV Kit PC Board Layout--Inner Layer 3 (VCC)
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MAX1800 Evaluation Kit Evaluates: MAX1800/MAX1801
1.0"
Figure 6. MAX1800 EV Kit PC Board Layout--Solder Side
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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