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MAX828, MAX829 Switched Capacitor Voltage Converter
The MAX828 and MAX829 are CMOS charge pump voltage inverters that are designed for operation over an input voltage range of 1.15 V to 5.5 V with an output current capability in excess of 50 mA. The operating current consumption is only 68 mA for the MAX828 and 118 mA for the MAX829. The devices contain an internal oscillator that operates at 12 kHz for the MAX828 and 35 kHz for the MAX829. The oscillator drives four low resistance MOSFET switches, yielding a low output resistance of 26 W and a voltage conversion efficiency of 99.9%. These devices require only two external capacitors, 10 mF for the MAX828 and 3.3 mF for the MAX829, for a complete inverter making it an ideal solution for numerous battery powered and board level applications. The MAX828 and MAX829 are available in the space saving Thin SOT-23-5 package.
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MARKING DIAGRAM
5 5 1 THIN SOT-23-5 CASE 483 1 xxx = Device Code MAX828 = EAA MAX829 = EAB Y = Year W = Work Week xxxYW
* * * * * * * * * * * * * * *
Pb-Free Packages are Available Operating Voltage Range of 1.15 V to 5.5 V Output Current Capability in Excess of 50 mA Low Current Consumption of 68 mA (MAX828) or 118 mA (MAX829) Operation at 12 kHz (MAX828) or 35 kHz (MAX829) Low Output Resistance of 26 W Space Saving Thin SOT-23-5 Package
PIN CONFIGURATION
Vout Vin C- 1 2 3 4 GND 5 C+
Typical Applications
LCD Panel Bias Cellular Telephones Pagers Personal Digital Assistants Electronic Games Digital Cameras Camcorders Hand-Held Instruments
-Vout
Thin SOT-23-5*
(Top View)
ORDERING INFORMATION
Device MAX828EUK MAX828EUKG Package Thin SOT-23-5 Thin SOT-23-5 (Pb-Free) Thin SOT-23-5 Thin SOT-23-5 (Pb-Free) Shipping 3000 Tape/Reel 3000 Tape/Reel
MAX829EUK 1 Vin 2 3 4 5 MAX829EUKG
3000 Tape/Reel 3000 Tape/Reel
For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D.
This device contains 77 active transistors.
Figure 1. Typical Application
(c) Semiconductor Components Industries, LLC, 2004
1
July, 2004 - Rev. 3
Publication Order Number: MAX828/D
MAX828, MAX829
MAXIMUM RATINGS*
Rating Input Voltage Range (Vin to GND) Symbol Vin Value -0.3 to 6.0 -6.0 to 0.3 100 Unit V V
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Output Voltage Range (Vout to GND) Output Current (Note 1) Vout Iout tSC TJ mA Output Short Circuit Duration (Vout to GND, Note 1) Operating Junction Temperature Indefinite 150 256 313 sec C Power Dissipation and Thermal Characteristics Thermal Resistance, Junction to Air Maximum Power Dissipation @ TA = 70C Storage Temperature RqJA PD Tstg C/W mW C -55 to 150 Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected. *ESD Ratings ESD Machine Model Protection up to 200 V, Class B ESD Human Body Model Protection up to 2000 V, Class 2
ELECTRICAL CHARACTERISTICS (Vin = 5.0 V for MAX828 C1 = C2 = 10 mF, for MAX829 C1 = C2 = 3.3 mF, TA = -40C to 85C, typical
values shown are for TA = 25C unless otherwise noted. See Figure 20 for test setup.) Characteristic Operating Supply Voltage Range (RL = 10 k) Supply Current Device Operating (RL = R) TA = 25C MAX828 MAX829 TA = 85C MAX828 MAX829 Oscillator Frequency TA = 25C MAX828 MAX829 TA = -40C to 85C MAX828 MAX829 Output Resistance (Iout = 25 mA, Note 2) MAX828 MAX829 Voltage Conversion Efficiency (RL = R) Power Conversion Efficiency (RL = 1.0 k) Symbol Vin Iin - - - - fOSC 8.4 24.5 6.0 19 Rout - - VEFF PEFF 99 - 26 26 99.9 96 50 50 - - % % 12 35 - - 15.6 45.6 21 54 W 68 118 73 128 90 200 100 200 kHz Min 1.5 to 5.5 Typ 1.15 to 6.0 Max - Unit V mA
1. Maximum Package power dissipation limits must be observed to ensure that the maximum junction temperature is not exceeded. TJ + TA ) (PD RqJA) 2. Capacitors C1 and C2 contribution is approximately 20% of the total output resistance.
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MAX828, MAX829
100 Rout, OUTPUT RESISTANCE (W) Figure 20 Test Setup 90 80 70 60 50 40 30 20 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 TA = 25C
100 Rout, OUTPUT RESISTANCE (W) Figure 20 Test Setup 90 80 70 60 50 40 30 20 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 TA = 25C
Vin, SUPPLY VOLTAGE (V)
Vin, SUPPLY VOLTAGE (V)
Figure 2. Output Resistance vs. Supply Voltage MAX828
90 Rout, OUTPUT RESISTANCE (W) Figure 20 Test Setup 80 70 60 50 40 30 20 -50 Vin = 5.0 V -25 0 25 50 75 100 Vin = 3.3 V Vin = 2.0 V Vin = 1.5 V 100 Rout, OUTPUT RESISTANCE (W)
Figure 3. Output Resistance vs. Supply Voltage MAX829
Figure 20 Test Setup 90 80 70 60 50 40 Vin = 3.3 V 30 20 -50 -25 0 25 50 75 100 Vin = 5.0 V Vin = 2.0 V Vin = 1.5 V
TA, AMBIENT TEMPERATURE (C)
TA, AMBIENT TEMPERATURE (C)
Figure 4. Output Resistance vs. Ambient Temperature MAX828
35 Figure 20 Test Setup Iout, OUTPUT CURRENT (mA) 30 25 20 15 10 5 0 0 10 20 30 40 50 C1, C2, C3, CAPACITANCE (mF) Vin = 1.9 V Vout = -1.5 V Vin = 4.75 V Vout = -4.0 V Vin = 3.15 V Vout = -2.5 V TA = 25C Iout, OUTPUT CURRENT (mA) 30 25 20 15 10 5 0 0 35
Figure 5. Output Resistance vs. Ambient Temperature MAX829
Figure 20 Test Setup Vin = 4.75 V Vout = -4.0 V Vin = 3.15 V Vout = -2.5 V
TA = 25C
Vin = 1.9 V Vout = -1.5 V 10 20 30 40 50
C1, C2, C3, CAPACITANCE (mF)
Figure 6. Output Current vs. Capacitance MAX828
Figure 7. Output Current vs. Capacitance MAX829
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MAX828, MAX829
Vout, OUTPUT VOLTAGE RIPPLE (mVpp)
400 350 300 250 200 150 100 50 0 0
Vout, OUTPUT VOLTAGE RIPPLE (mVpp)
Figure 20 Test Setup Vin = 4.75 V Vout = -4.0 V Vin = 3.15 V Vout = -2.5 V Vin = 1.9 V Vout = -1.5 V
TA = 25C
350 300 250 200 150 100 50 0 0
Figure 20 Test Setup
TA = 25C
Vin = 4.75 V Vout = -4.0 V
Vin = 3.15 V Vout = -2.5 V Vin = 1.9 V Vout = -1.5 V
10
20
30
40
50
10
20
30
40
50
C1, C2, C3, CAPACITANCE (mF)
C1, C2, C3, CAPACITANCE (mF)
Figure 8. Output Voltage Ripple vs. Capacitance MAX828
90 Figure 20 Test Setup Iin, SUPPLY CURRENT (mA) 80 70 TA = 85C 60 50 40 30 20 1.5 TA = -40C TA = 25C RL = Iin, SUPPLY CURRENT (mA) 130
Figure 9. Output Voltage Ripple vs. Capacitance MAX829
Figure 20 Test Setup 120 110 100 90 80 70 60 50 TA = -40C TA = 25C TA = 85C RL =
2.0
2.5
3.0
3.5
4.0
4.5
5.0
40 1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Vin, SUPPLY VOLTAGE (V)
Vin, SUPPLY VOLTAGE (V)
Figure 10. Supply Current vs. Supply Voltage MAX828
fOSC, OSCILLATOR FREQUENCY (kHz) fOSC, OSCILLATOR FREQUENCY (kHz) 13.0 Figure 20 Test Setup 12.5 Vin = 5.0 V 12.0 11.5 11.0 Vin = 1.5 V 10.5 10.0 -50 Vin = 3.3 V 40
Figure 11. Supply Current vs. Supply Voltage MAX829
Figure 20 Test Setup 39 38 37 36 35 34 33 32 -50 -25 0 25 50 75 100 Vin = 5.0 V Vin = 1.5 V Vin = 3.3 V
-25
0
25
50
75
100
TA, AMBIENT TEMPERATURE (C)
TA, AMBIENT TEMPERATURE (C)
Figure 12. Oscillator Frequency vs. Ambient Temperature MAX828
Figure 13. Oscillator Frequency vs. Ambient Temperature MAX829
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MAX828, MAX829
0 Figure 20 Test Setup Vout, OUTPUT VOLTAGE (V) -1.0 -2.0 -3.0 -4.0 -5.0 -6.0 0 Vin = 5.0 V Vin = 3.3 V Vin = 2.0 V TA = 25C Vout, OUTPUT VOLTAGE (V)
0 Figure 20 Test Setup -1.0 -2.0 -3.0 -4.0 -5.0 -6.0 0 Vin = 5.0 V Vin = 3.3 V Vin = 2.0 V TA = 25C
10
20
30
40
50
10
20
30
40
50
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 14. Output Voltage vs. Output Current MAX828
, POWER CONVERSION EFFICIENCY (%) 100 Figure 20 Test Setup 90 80 70 60 50 40 0 Vin = 1.5 V Vin = 2.0 V TA = 25C 10 20 30 40 50 Vin = 3.3 V Vin = 5.0 V , POWER CONVERSION EFFICIENCY (%) 100
Figure 15. Output Voltage vs. Output Current MAX829
Figure 20 Test Setup 90 80 70 60 50 40 0 Vin = 1.5 V Vin = 2.0 V TA = 25C 10 20 30 40 50 Vin = 3.3 V Vin = 5.0 V
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
OUTPUT VOLTAGE RIPPLE & NOISE = 10 mV/Div. AC COUPLED
Figure 20 Test Setup
Vin = 3.3 V Iout = 5.0 mA TA = 25C
OUTPUT VOLTAGE RIPPLE & NOISE = 10 mV/Div. AC COUPLED
Figure 16. Power Conversion Efficiency vs. Output Current MAX828
Figure 17. Power Conversion Efficiency vs. Output Current MAX829
Figure 20 Test Setup
Vin = 3.3 V Iout = 5.0 mA TA = 25C
TIME = 25 ms/div
TIME = 10 ms/div
Figure 18. Output Voltage Ripple and Noise MAX828
Figure 19. Output Voltage Ripple and Noise MAX829
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MAX828, MAX829
-Vout RL
Charge Pump Efficiency
1 OSC Vin 2 C3 3
6
C +2
+ C1 4
+
MAX828: C1 = C2 = C3 = 10 mF MAX829: C1 = C2 = C3 = 3.3 mF
Figure 20. Test Setup/Voltage Inverter
The overall power efficiency of the charge pump is affected by four factors: 1. Losses from power consumed by the internal oscillator, switch drive, etc. (which vary with input voltage, temperature and oscillator frequency). 2. I2R losses due to the on-resistance of the MOSFET switches on-board the charge pump. 3. Charge pump capacitor losses due to Equivalent Series Resistance (ESR). 4. Losses that occur during charge transfer from the commutation capacitor to the output capacitor when a voltage difference between the two capacitors exists. Most of the conversion losses are due to factors 2, 3 and 4. These losses are given by Equation 1.
P + I out 2 LOSS(2,3,4) 1 (f OSC )C1 ) 8R SWITCH R out ^ I out 2 ) 4ESR C1 ) ESR C2 (eq. 1)
DETAILED OPERATING DESCRIPTION The MAX828/829 charge pump converters inverts the voltage applied to the Vin pin. Conversion consists of a two-phase operation (Figure 21). During the first phase, switches S2 and S4 are open and S1 and S3 are closed. During this time, C1 charges to the voltage on Vin and load current is supplied from C2. During the second phase, S2 and S4 are closed, and S1 and S3 are open. This action connects C1 across C2, restoring charge to C2.
S1 Vin C1 S2
The 1/(fOSC)(C1) term in Equation 1 is the effective output resistance of an ideal switched capacitor circuit (Figures 22 and 23). The losses due to charge transfer above are also shown in Equation 2. The output voltage ripple is given by Equation 3.
PLOSS + [ 0.5C 1 (Vin 2 * Vout 2) ) 0.5C2 (VRIPPLE 2 * 2VoutVRIPPLE)] fOSC (eq. 2) V + I out (f OSC )(C 2) ) 2(I out)(ESR ) C2
C2 S3 S4 -Vout From Osc
RIPPLE
(eq. 3)
f Vin RL Vout
C1
C2
Figure 21. Ideal Switched Capacitor Charge Pump
APPLICATIONS INFORMATION
Output Voltage Considerations
Figure 22. Ideal Switched Capacitor Model
REQUIV Vin R + 1 C1 RL Vout
The MAX828/829 performs voltage conversion but does not provide regulation. The output voltage will drop in a linear manner with respect to load current. The value of this equivalent output resistance is approximately 26 W nominal at 25C and Vin = 5.0 V. Vout is approximately -5.0 V at light loads, and drops according to the equation below:
VDROP + Iout Rout Vout + * (Vin * VDROP)
EQUIV
f
C2
Figure 23. Equivalent Output Resistance
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MAX828, MAX829
Capacitor Selection Voltage Inverter
In order to maintain the lowest output resistance and output ripple voltage, it is recommended that low ESR capacitors be used. Additionally, larger values of C1 will lower the output resistance and larger values of C2 will reduce output voltage ripple. (See Equation 3). Table 1 shows various values of C1, C2 and C3 with the corresponding output resistance values at 25C. Table 2 shows the output voltage ripple for various values of C1, C2 and C3. The data in Tables 1 and 2 was measured not calculated.
Table 1. Output Resistance vs. Capacitance (C1 = C2 = C3), Vin = 4.75 V and Vout = -4.0 V
C1 = C2 = C3 (mF) 0.7 1.4 3.3 7.3 10 24 50 MAX828 Rout (W) 127.2 67.7 36 26.7 25.9 24.3 24 MAX829 Rout (W) 55.7 36.8 26.0 24.9 25.1 25.2 24
The most common application for a charge pump is the voltage inverter (Figure 20). This application uses two or three external capacitors. The capacitors C1 (pump capacitor) and C2 (output capacitor) are required. The input bypass capacitor C3, may be necessary depending on the application. The output is equal to -Vin plus any voltage drops due to loading. Refer to Tables 1 and 2 for capacitor selection. The test setup used for the majority of the characterization is shown in Figure 20.
Layout Considerations
As with any switching power supply circuit, good layout practice is recommended. Mount components as close together as possible to minimize stray inductance and capacitance. Also use a large ground plane to minimize noise leakage into other circuitry.
Capacitor Resources
Selecting the proper type of capacitor can reduce switching loss. Low ESR capacitors are recommended. The MAX828 and MAX829 were characterized using the capacitors listed in Table 3. This list identifies low ESR capacitors for the voltage inverter application.
Table 3. Capacitor Types
Manufacturer/Contact Part Types/Series TPS
Table 2. Output Voltage Ripple vs. Capacitance (C1 = C2 = C3), Vin = 4.75 V and Vout = -4.0 V
C1 = C2 = C3 (mF) 0.7 1.4 3.3 7.3 10 24 50 MAX828 Ripple (mV) 377.5 360.5 262 155 126 55.1 36.6 MAX829 Ripple (mV) 320 234 121 62.1 51.25 25.2 27.85
AVX 843-448-9411 www.avxcorp.com Cornell Dubilier 508-996-8561 ll d bili www.cornell-dubilier.com Sanyo/Os-con 619-661-6835 id / ht www.sanyovideo.com/oscon.htm Vishay 603-224-1961 ih www.vishay.com
ESRD
SN SVP 593D 594
-Vout
1 + OSC 2
5
Input Supply Bypassing
The input voltage, Vin should be capacitively bypassed to reduce AC impedance and minimize noise effects due to the switching internals in the device. If the device is loaded from Vout to GND, it is recommended that a large value capacitor (at least equal to C1) be connected from Vin to GND. If the device is loaded from Vin to Vout a small (0.7 mF) capacitor between the pins is sufficient.
Vin
+
+
3
4
MAX828: Capacitors = 10 mF MAX829: Capacitors = 3.3 mF
Figure 24. Voltage Inverter
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MAX828, MAX829
The MAX828 / 829 primary function is a voltage inverter. The device will convert 5.0 V into -5.0 V with light loads. Two capacitors are required for the inverter to function. A third capacitor, the input bypass capacitor, may be required depending on the power source for the inverter. The performance for this device is illustrated below.
0.0 TA = 25C Vout, OUTPUT VOLTAGE (V) -1.0 -2.0 Vin = 3.3 V -3.0 -4.0 -5.0 -6.0 0 10 20 30 40 50 Iout, OUTPUT CURRENT (mA) Vin = 5.0 V Vout, OUTPUT VOLTAGE (V) -1.0 -2.0 Vin = 3.3 V -3.0 -4.0 -5.0 -6.0 0 10 20 30 40 50 Iout, OUTPUT CURRENT (mA) Vin = 5.0 V 0.0 TA = 25C
Figure 25. Voltage Inverter Load Regulation Output Voltage vs. Output Current MAX828
Figure 26. Voltage Inverter Load Regulation Output Voltage vs. Output Current MAX829
-Vout
1 + Vin + 2 OSC
5 +
1 OSC 2
5
3 +
4
3 +
4
MAX828 Capacitors = 10 mF MAX829 Capacitors = 3.3 mF
Figure 27. Cascade Devices for Increased Negative Output Voltage
Two or more devices can be cascaded for increased output voltage. Under light load conditions, the output voltage is approximately equal to -Vin times the number of stages. The converter output resistance increases dramatically with each additional stage. This is due to a reduction of input voltage to each successive stage as the converter output is loaded. Note that the ground connection for each successive stage must connect to the negative output of the previous stage. The performance characteristics for a converter consisting of two cascaded devices are shown below.
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MAX828, MAX829
-1.0 Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) -2.0 -3.0 -4.0 -5.0 -6.0 -7.0 -8.0 -9.0 -10.0 0 10 20 30 40 Iout, OUTPUT CURRENT (mA) B A -1.0 -2.0 -3.0 -4.0 -5.0 -6.0 -7.0 -8.0 -9.0 -10.0 0 10 20 30 40 Iout, OUTPUT CURRENT (mA) D C
Figure 28. Cascade Load Regulation, Output Voltage vs. Output Current MAX828
Figure 29. Cascade Load Regulation, Output Voltage vs. Output Current MAX829
Curve A B C D
Vin (V) 3.0 5.0 3.0 5.0
Rout (W) 173 141 179 147
1 OSC Vin 2
5 -Vout + + +
+
+
3
4 MAX828: Capacitors = 10 mF MAX829: Capacitors = 3.3 mF
Figure 30. Negative Output Voltage Doubler
A single device can be used to construct a negative voltage doubler. The output voltage is approximately equal to -2Vin minus the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below. Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower loss MBRA120E Schottky diodes.
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MAX828, MAX829
0.0 Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) -2.0 A -4.0 B -6.0 C
-2.0 A -4.0 B -6.0 D -8.0 TA = 25C 0 10 20 30 40 C
-8.0 D TA = 25C 0 10 20 30 40
-10.0 Iout, OUTPUT CURRENT (mA)
-10.0 Iout, OUTPUT CURRENT (mA)
Figure 31. Doubler Load Regulation, Output Voltage vs. Output Current MAX828
Figure 32. Doubler Load Regulation, Output Voltage vs. Output Current MAX829
Curve A B C D
Vin (V) 3.0 3.0 5.0 5.0
Diodes 1N4148 MBRA120E 1N4148 MBRA120E
MAX828 Rout (W) 122 114 96 91
MAX829 Rout (W) 118 106 90 87
1 OSC Vin 2
5 -Vout + + + + +
+
+
3
4 MAX828: Capacitors = 10 mF MAX829: Capacitors = 3.3 mF
Figure 33. Negative Output Voltage Tripler
A single device can be used to construct a negative voltage tripler. The output voltage is approximately equal to -3Vin minus the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below. Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower loss MBRA120E Schottky diodes.
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MAX828, MAX829
0.0 Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) -2.0 A -4.0 -6.0 -8.0 D -10.0 -12.0 TA = 25C -14.0 0 10 20 30 40 Iout, OUTPUT CURRENT (mA) -14.0 0 10 20 30 40 Iout, OUTPUT CURRENT (mA) C B 0.0 -2.0 A -4.0 -6.0 B -8.0 C
-10.0 -12.0 D TA = 25C
Figure 34. Tripler Load Regulation, Output Voltage vs. Output Current MAX828
Figure 35. Tripler Load Regulation, Output Voltage vs. Output Current MAX829
Curve A B C D
Vin (V) 3.0 3.0 5.0 5.0
Diodes 1N4148 MBRA120E 1N4148 MBRA120E
MAX828 Rout (W) 259 251 209 192
MAX829 Rout (W) 246 237 198 185
1 OSC
5 +
Vin
+
2
+
Vout
3
4
MAX828: Capacitors = 10 mF MAX829: Capacitors = 3.3 mF
Figure 36. Positive Output Voltage Doubler
A single device can be used to construct a positive voltage doubler. The output voltage is approximately equal to 2Vin minus the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below. Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower loss MBRA120E Schottky diodes.
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MAX828, MAX829
10.0 D Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) 8.0 C 6.0 B 8.0 C 6.0 B 4.0 A TA = 25C 2.0 0 10 20 30 40 0 10 20 30 40 Iout, OUTPUT CURRENT (mA) Iout, OUTPUT CURRENT (mA) 10.0 D
4.0 A TA = 25C 2.0
Figure 37. Doubler Load Regulation, Output Voltage vs. Output Current MAX828
Figure 38. Doubler Load Regulation, Output Voltage vs. Output Current MAX829
Curve A B C D
Vin (V) 3.0 3.0 5.0 5.0
Diodes 1N4148 MBRA120E 1N4148 MBRA120E
MAX828 Rout (W) 32.5 27.1 26.0 21.2
MAX829 Rout (W) 32.2 25.7 25.1 19.0
1 OSC
5 + + + + Vout
Vin
+
2
3
4 MAX828: Capacitors = 10 mF MAX829: Capacitors = 3.3 mF
Figure 39. Positive Output Voltage Tripler
A single device can be used to construct a positive voltage tripler. The output voltage is approximately equal to 3Vin minus the forward voltage drop of each external diode. The performance characteristics for the above converter are shown below. Note that curves A and C show the circuit performance with economical 1N4148 diodes, while curves B and D are with lower loss MBRA120E Schottky diodes.
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MAX828, MAX829
14.0 D Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) 12.0 10.0 C 8.0 B 6.0 4.0 TA = 25C 2.0 0 10 20 30 40 Iout, OUTPUT CURRENT (mA) A 2.0 0 10 20 30 40 Iout, OUTPUT CURRENT (mA) 12.0 10.0 C 8.0 B 6.0 4.0 TA = 25C A 14.0 D
Figure 40. Tripler Load Regulation, Output Voltage vs. Output Current MAX828
Figure 41. Tripler Load Regulation, Output Voltage vs. Output Current MAX829
Curve A B C D
Vin (V) 3.0 3.0 5.0 5.0
Diodes 1N4148 MBRA120E 1N4148 MBRA120E
MAX828 Rout (W) 110 96.5 84.5 78.2
MAX829 Rout (W) 111 96.7 87.3 77.1
-Vout + 1 OSC Vin 2 2 5 1 OSC 5
+
3
4
3
4
+ MAX828 Capacitors = 10 mF MAX829 Capacitors = 3.3 mF
+
Figure 42. Paralleling Devices for Increased Negative Output Current
An increase in converter output current capability with a reduction in output resistance can be obtained by paralleling two or more devices. The output current capability is approximately equal to the number of devices paralleled. A single shared output capacitor is sufficient for proper operation but each device does require it's own pump capacitor. Note that the output ripple frequency will be complex since the oscillators are not synchronized. The output resistance is approximately equal to the output resistance of one device divided by the total number of devices paralleled. The performance characteristics for a converter consisting of two paralleled devices is shown below.
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MAX828, MAX829
-1.0 TA = 25C Vout, OUTPUT VOLTAGE (V) -2.0 B Vout, OUTPUT VOLTAGE (V) -2.0 -1.0 TA = 25C
D
-3.0
-3.0
-4.0
A
-4.0
C
-5.0 0 20 40 60 80 100 Iout, OUTPUT CURRENT (mA)
-5.0 0 20 40 60 80 100 Iout, OUTPUT CURRENT (mA)
Figure 43. Parallel Load Regulation, Output Voltage vs. Output Current MAX828
Figure 44. Parallel Load Regulation, Output Voltage vs. Output Current MAX829
Curve A B C D
Vin (V) 5.0 3.0 5.0 3.0
Rout (W) 13.3 17.3 14.4 17.3
Q2 1 OSC Vin 2 C3 3 4 5 Q1
C1 + + C2 -Vout
+
C1 = C2 = 470 mF C3 = 220 mF Q1 = PZT751 Q2 = PZT651
-Vout = Vin -VBE(Q1) - VBE(Q2) -2 VF
Figure 45. External Switch for Increased Negative Output Current
The output current capability of the MAX828 and MAX829 can be extended beyond 600 mA with the addition of two external switch transistors and two Schottky diodes. The output voltage is approximately equal to -Vin minus the sum of the base emitter drops of both transistors and the forward voltage of both diodes. The performance characteristics for the converter are shown below. Note that the output resistance is reduced to 0.9 and 1.0 ohms for the 828 and 829 respectively.
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MAX828, MAX829
-2.2 Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) -2.0 -2.2 -2.4 -2.6 -2.8 -3.0 -3.2 Vin = 5.0 V Rout = 1.0 W TA = 25C 0 0.1 0.2 0.3 0.4 0.5 0.6
-2.4
-2.6
-2.8 Vin = 5.0 V Rout = 0.9 W TA = 25C 0 0.1 0.2 0.3 0.4 0.5 0.6
-3.0
-3.2
Iout, OUTPUT CURRENT (A)
Iout, OUTPUT CURRENT (A)
Figure 46. Current Boosted Load Regulation, Output Voltage vs. Output Current MAX828
Figure 47. Current Boosted Load Regulation, Output Voltage vs. Output Current MAX829
50 Q2 1 OSC Vin 2 C3 3 4 Capacitors = 220 mF Q1 = PZT751 Q2 = PZT651 5 50 Q1 + + + C2 C1 Vout
Figure 48. Positive Output Voltage Doubler with High Current Capability
The MAX828/829 can be configured to produce a positive output voltage doubler with current capability in excess of 500 mA. This is accomplished with the addition of two external switch transistors and two Schottky diodes. The output voltage is approximately equal to 2Vin minus the sum of the base emitter drops of both transistors and the forward voltage of both diodes. The performance characteristics for the converter are shown below. Note that the output resistance is reduced to 1.8 W.
8.8 Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) Vin = 5.0 V Rout = 1.8 W TA = 25C 9.0 Vin = 5.0 V Rout = 1.8 W TA = 25C
8.4
8.6
8.0
8.2
7.6
7.8
7.2
7.4
6.8
0
0.1
0.2
0.3
0.4
0.5
0.6
7.0
0
0.1
0.2
0.3
0.4
0.5
0.6
Iout, OUTPUT CURRENT (mA)
Iout, OUTPUT CURRENT (mA)
Figure 49. Positive Doubler with Current Boosted Load Regulation, Output Voltage vs. Output Current, MAX828
Figure 50. Positive Doubler with Current Boosted Load Regulation, Output Voltage vs. Output Current, MAX829
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MAX828, MAX829
-Vout
1 OSC Vin 2
5
+ MAX828: Capacitors = 10 mF MAX829: Capacitors = 3.3 mF + +
+
3
4
+
+Vout
Figure 51. A Positive Doubler, with a Negative Inverter
All of the previously shown converter circuits have only single outputs. Applications requiring multiple outputs can be constructed by incorporating combinations of the former circuits. The converter shown above combines Figures 24 and 36 to form a negative output inverter with a positive output doubler. Different combinations of load regulation are shown below. In Figures 52 and 53 the positive doubler has a constant Iout = 15 mA while the negative inverter has the variable load. In Figures 54 and 55 the negative inverter has the constant Iout = 15 mA and the positive doubler has the variable load.
9.5 Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) Positive Doubler Iout = 15 mA 9.5 Positive Doubler Iout = 15 mA
9.0
9.0
8.5
8.5
-4.0 Negative Inverter -4.5 Negative Inverter Rout = 28.8 W TA = 25C 0 10 20 30
-4.0 Negative Inverter -4.5 Negative Inverter Rout = 28 W TA = 25C 0 10 20 30 Iout, NEGATIVE INVERTER OUTPUT CURRENT (mA)
-5.0
-5.0
Iout, NEGATIVE INVERTER OUTPUT CURRENT (mA)
Figure 52. Negative Inverter Load Regulation, Output Voltage vs. Output Current, MAX828
Figure 53. Negative Inverter Load Regulation, Output Voltage vs. Output Current, MAX829
9.5 Vout, OUTPUT VOLTAGE (V) Vout, OUTPUT VOLTAGE (V) Positive Doubler Rout = 21.4 W
9.5 Positive Doubler Rout = 20 W
9.0
9.0
8.5
8.5
-4.0 Negative Inverter -4.5 Negative Inverter Iout = 15 mA TA = 25C -5.0 0 10 20 30 Iout, POSITIVE DOUBLER OUTPUT CURRENT (mA)
-4.0 Negative Inverter -4.5 Negative Inverter Iout = 15 mA TA = 25C -5.0 0 10 20 30 Iout, POSITIVE DOUBLER OUTPUT CURRENT (mA)
Figure 54. Positive Doubler Load Regulation, Output Voltage vs. Output Current, MAX828 http://onsemi.com
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Figure 55. Positive Doubler Load Regulation, Output Voltage vs. Output Current, MAX829
MAX828, MAX829
+ Vin
IC1
C1
C2 -Vout
GND
C3 0.5
+
+
GND
Inverter Size = 0.5 in x 0.2 in Area = 0.10 in2, 64.5 mm2
Figure 56. Inverter Circuit Board Layout, Top View Copper Side
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MAX828, MAX829
PACKAGE DIMENSIONS
THIN SOT-23-5 PLASTIC PACKAGE CASE 483-01 ISSUE A
NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. MAXIMUM LEAD THICKNESS INCLUDES LEAD FINISH THICKNESS. MINIMUM LEAD THICKNESS IS THE MINIMUM THICKNESS OF BASE MATERIAL. DIM A B C D G H J K L M S MILLIMETERS MIN MAX 2.90 3.10 1.30 1.70 0.90 1.10 0.25 0.50 0.85 1.00 0.013 0.100 0.10 0.26 0.20 0.60 1.25 1.55 0_ 10 _ 2.50 3.00 INCHES MIN MAX 0.1142 0.1220 0.0512 0.0669 0.0354 0.0433 0.0098 0.0197 0.0335 0.0413 0.0005 0.0040 0.0040 0.0102 0.0079 0.0236 0.0493 0.0610 0_ 10 _ 0.0985 0.1181
D
5 1 2 4 3
S
B
L G A J C 0.05 (0.002) H K M
SOLDERING FOOTPRINT*
1.9 0.074
0.95 0.037
2.4 0.094 1.0 0.039 0.7 0.028
SCALE 10:1
mm inches
*For additional information on our Pb-Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. "Typical" parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including "Typicals" must be validated for each customer application by customer's technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
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MAX828/D

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