MAX829EUK-T ,Switched-Capacitor Voltage InvertersELECTRICAL CHARACTERISTICS(V = +5V, C1 = C2 = 10µF (MAX828), C1 = C2 = 3.3µF (MAX829), T = 0°C to + ..
MAX829SNTR ,Switched Capacitor Voltage Converters3MAX828 MAX829VCapacitor SelectioninC3 +In order to maintain the lowest output resistance and 3.3 * ..
MAX830CWE ,5V/3.3V/3V/Adjustable-Output / 1A / Step-Down / PWM / Switch-Mode DC-DC RegulatorsELECTRICAL CHARACTERISTICS(V = 25V, T = T to T , unless otherwise noted. Typical values are at T = ..
MAX833CWE ,5V/3.3V/3V/Adjustable-Output / 1A / Step-Down / PWM / Switch-Mode DC-DC RegulatorsFeatures' Input Range: Up to 30VThe MAX830/MAX831/MAX832/MAX833 are monolithic,bipolar, pulse-width ..
MAX834EUK+T ,Micropower, Latching Voltage Monitors in SOT23-5ELECTRICAL CHARACTERISTICS(V = +2.5V to +11V, T = T to T , unless otherwise noted. Typical values a ..
MAX834EUK-T ,Micropower / Latching Voltage Monitors in SOT23-5Applications ______________Ordering InformationPrecision Battery MonitorTEMP. PIN- SOTPARTLoad Swit ..
MB81C81A-35 ,CMOS 256K-BIT HIGH-SPEED SRAMMay 1990 00
Edition1.0 FUJITSU
M38 1 C8 1A-25/-35
CMOS 256K-BI T HIGH-SPEED SRAM
256K Words ..
MB81F643242C-10FN ,4 x 512K x 32 bit synchronous dynamic RAMFUJITSU SEMICONDUCTORADVANCED INFO. AE0.1EDATA SHEETMEMORYCMOS4 · 512 K · 32 BITSYNCHRONOUS DYNAMIC ..
MB81F643242C-10FN ,4 x 512K x 32 bit synchronous dynamic RAMfeatures a fully synchronous operation referenced to a positive edge clock whereby all operations a ..
MB81N643289-60FN ,8 x 256K x 32 bit double data rate FCRAMapplications where large memory density and high effective bandwidth arerequired and where a simple ..
MB8264A-10 , MOS 65536-BIT DYNAMIC RANDOM ACCESS MEMORY
MB8264A-10 , MOS 65536-BIT DYNAMIC RANDOM ACCESS MEMORY
MAX828EUK+-MAX828EUK+T-MAX828EUK-T-MAX829EUK+T-MAX829EUK-T
Switched-Capacitor Voltage Inverters
General DescriptionThe ultra-small MAX828/MAX829 monolithic, CMOS
charge-pump inverters accept input voltages ranging
from +1.5V to +5.5V. The MAX828 operates at 12kHz,
and the MAX829 operates at 35kHz. Their high efficiency
(greater than 90% over most of the load-current range)
and low operating current (60µA for the MAX828) make
these devices ideal for both battery-powered and board-
level voltage-conversion applications.
The MAX828/MAX829 combine low quiescent current
and high efficiency. Oscillator control circuitry and four
power MOSFET switches are included on-chip.
Applications include generating a -5V supply from a +5V
logic supply to power analog circuitry. Both parts come
in a 5-pin SOT23-5 package and can deliver 25mA with
a voltage drop of 500mV.
For a similar device with logic-controlled shutdown,
refer to the MAX1719/MAX1720/MAX1721. For applica-
tions requiring more power, the MAX860 delivers up to
50mA with a voltage drop of 600mV, in a space-saving
µMAX package.
ApplicationsSmall LCD Panels
Cell Phones
Medical Instruments
Handy-Terminals, PDAs
Battery-Operated Equipment
Features5-Pin SOT23-5 Package 95% Voltage Conversion EfficiencyInverts Input Supply Voltage60µA Quiescent Current (MAX828)+1.5V to +5.5V Input Voltage Range Requires Only Two Capacitors25mA Output Current
MAX828/MAX829
Switched-Capacitor Voltage InvertersTOP VIEW
GNDC1-
C1+OUT
SOT23-55
MAX828
MAX82924
Pin Configuration
NEGATIVE VOLTAGE CONVERTERC1+
C1-
OUT
GND
INPUT
SUPPLY
VOLTAGE
NEGATIVE
OUTPUT
VOLTAGE
MAX828
MAX829
ypical Operating Circuit19-0495; Rev 3; 9/99
PART
MAX828EUK-40°C to +85°C
TEMP. RANGEPIN-
PACKAGE5 SOT23-5
Ordering Information
MAX829EUK-40°C to +85°C5 SOT23-5
SOT
TOP MARKAABI
AABJ
MAX828/MAX829
Switched-Capacitor Voltage Inverters
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VIN= +5V, C1 = C2 = 10µF (MAX828), C1 = C2 = 3.3µF (MAX829), TA= 0°C to +85°C, unless otherwise noted. Typical values
are at TA= +25°C.)
ELECTRICAL CHARACTERISTICS(VIN= +5V, C1 = C2 = 10µF (MAX828), C1 = C2 = 3.3µF (MAX829), TA= -40°C to +85°C, unless otherwise noted. Typical values
are at TA= +25°C.) (Note 2)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note 1:Capacitor contribution is approximately 20% of the output impedance [ESR + 1 / (pump frequency x capacitance)].
Note 2:All -40°C to +85°C specifications above are guaranteed by design.
IN to GND.................................................................+6.0V, -0.3V
OUT to GND.............................................................-6.0V, +0.3V
OUT Output Current ...........................................................50mA
OUT Short-Circuit to GND ............................................Indefinite
Continuous Power Dissipation (TA= +70°C)
SOT23-5 (derate 7.1mW/°C above +70°C)...................571mW
Operating Temperature Range
MAX828EUK/MAX829EUK...............................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10s).................................+300°C
MAX829
MAX828
RLOAD= ∞
RLOAD= 1kΩ, TA= +25°C
MAX829
RLOAD= 10kΩ
RLOAD= 10kΩ
MAX828
CONDITIONS15026090Supply Current9599.9Voltage Conversion Efficiency94Power Efficiency
kHz24.53545.5Oscillator Frequency
1.251.0V1.5Minimum Supply Voltage5.5Maximum Supply Voltage
UNITSMINTYPMAXPARAMETER= +25°C= 0°C to + 85°C
IOUT= 5mATA= 0°C to + 85°C= +25°CΩ65Output Resistance2050
MAX829
MAX828
IOUT= 5mA
MAX829
RLOAD= 10kΩ
MAX828
CONDITIONS325
115Supply Current65Output Resistance
kHz1954.3Oscillator Frequency1.55.5Supply Voltage Range
UNITSMINTYPMAXPARAMETER= +25°C= +25°C
MAX828/MAX829
Switched-Capacitor Voltage InvertersOUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
MAX828/829-01
SUPPLY VOLTAGE (V)
OUTPUT RESISTANCE (
MAX829
MAX828
OUTPUT RESISTANCE
vs. TEMPERATUREMAX828/829-02
TEMPERATURE (°C)
OUTPUT RESISTANCE (
VIN = 3.3V
VIN = 5.0V
VIN = 1.5V
MAX828
OUTPUT CURRENT vs. CAPACITANCE
MAX828/829-03
CAPACITANCE (μF)
OUTPUT CURRENT (mA)25304550
VIN = 3.15V, VOUT = -2.5V
VIN = 1.9V, VOUT = -1.5V
VIN = 4.75V, VOUT = -4.0V52025
MAX829
OUTPUT CURRENT vs. CAPACITANCEMAX828/829-04
CAPACITANCE (μF)
OUTPUT CURRENT (mA)1030
VIN = 3.15V, V- = -2.5V
VIN = 1.9V, V- = -1.5V
VIN = 4.75V, V- = -4.0V
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX828/829-07
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
MAX829
MAX828
MAX828
OUTPUT VOLTAGE RIPPLE
vs. CAPACITANCE
MAX828/829-05
CAPACITANCE (μF)
OUTPUT VOLTAGE RIPPLE (mVp-p)1030
VIN = 4.75V, VOUT = -4.0V
VIN = 3.15V, VOUT = -2.5V
VIN = 1.9V, VOUT = -1.5V
MAX829
OUTPUT VOLTAGE RIPPLE
vs. CAPACITANCE
MAX828/829-06
CAPACITANCE (μF)
OUTPUT VOLTAGE RIPPLE (mVp-p)1030
VIN = 4.75V, VOUT = -4.0V
VIN = 3.15V, VOUT = -2.5V
VIN = 1.9V, VOUT = -1.5V
MAX828
PUMP FREQUENCY vs. TEMPERATURE
MAX828/829-08
TEMPERATURE (°C)
PUMP FREQUENCY (kHz)4080
VIN = 3.3V
VIN = 5.0V
VIN = 1.5V
__________________________________________Typical Operating Characteristics(Circuit of Figure 1, VIN= +5V, C1 = C2 = C3, TA= +25°C, unless otherwise noted.)
MAX829
PUMP FREQUENCY vs. TEMPERATUREMAX828/829-9
TEMPERATURE (°C)
PUMP FREQUENCY (kHz)
VIN = 3.3V
VIN = 5.0V
VIN = 1.5V
-40-20060204080
_____________________Pin Description
MAX828/MAX829
Switched-Capacitor Voltage Inverters
Typical Operating Characteristics (continued)(Circuit of Figure 1, VIN= +5V, C1 = C2 = C3, TA= +25°C, unless otherwise noted.)
OUTPUT VOLTAGE
vs. OUTPUT CURRENT
-0.5MAX828/829-10
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)3025455040
VIN = 3.3V
VIN = 5.0V
VIN = 2.0V
EFFICIENCY vs. OUTPUT CURRENT
MAX828/829-11
OUTPUT CURRENT (mA)
EFFICIENCY (15302545405035
VIN = 2.0VVIN = 3.3V
VIN = 5.0V
VOUT
20mV/div
MAX828
OUTPUT NOISE AND RIPPLEMAX828/829-12
VIN = 3.3V, VOUT = -3.2V, IOUT = 5mA, AC COUPLED
20μs/div
Flying Capacitor’s Positive TerminalC1+5
GroundGND4
Flying Capacitor’s Negative TerminalC1-3
PINPositive Power-Supply InputIN2
Inverting Charge-Pump OutputOUT1
FUNCTIONNAME
VOLTAGE INVERTEROUT
C1+
VIN
3.3μF*
*10μF
(MAX828)
3.3μF*
3.3μF*14
VOUT
GNDC1-
MAX828
MAX829
Figure 1. Test Circuit
VOUT
20mV/div
MAX829
OUTPUT NOISE AND RIPPLEMAX828/829-13
VIN = 3.3V, VOUT = -3.2V, IOUT = 5mA, AC COUPLED
10μs/div
_______________Detailed DescriptionThe MAX828/MAX829 capacitive charge pumps invert the
voltage applied to their input. For highest performance,
use low equivalent series resistance (ESR) capacitors.
During the first half-cycle, switches S2 and S4 open,
switches S1 and S3 close, and capacitor C1 charges to
the voltage at IN (Figure 2). During the second half-
cycle, S1 and S3 open, S2 and S4 close, and C1 is level
shifted downward by VINvolts. This connects C1 in par-
allel with the reservoir capacitor C2. If the voltage across
C2 is smaller than the voltage across C1, then charge
flows from C1 to C2 until the voltage across C2 reaches -
VIN. The actual voltage at the output is more positive
than -VIN, since switches S1–S4 have resistance and the
load drains charge from C2.
Charge-Pump OutputThe MAX828/MAX829 are not voltage regulators: the
charge pump’s output source resistance is approxi-
mately 20Ωat room temperature (with VIN= +5V), and
VOUTapproaches -5V when lightly loaded. VOUTwill
droop toward GND as load current increases. The
droop of the negative supply (VDROOP-) equals the cur-
rent draw from OUT (IOUT) times the negative convert-
er’s source resistance (RS-):
VDROOP-= IOUTx RS-
The negative output voltage will be:
VOUT= -(VIN- VDROOP-)
Efficiency ConsiderationsThe efficiency of the MAX828/MAX829 is dominated by
its quiescent supply current (IQ) at low output current
and by its output impedance (ROUT) at higher output
current; it is given by:
where the output impedance is roughly approximated
by:
The first term is the effective resistance of an ideal
switched-capacitor circuit (Figures 3a and 3b), and
RSWis the sum of the charge pump’s internal switch
resistances (typically 8Ωto 9Ωat VIN= +5V). The typical
output impedance is more accurately determined from
the Typical Operating Characteristics.
Applications Information
Capacitor SelectionTo maintain the lowest output resistance, use capacitors
with low ESR (Table 1). The charge-pump output resis-
tance is a function of C1’s and C2’s ESR. Therefore,
minimizing the charge-pump capacitor’s ESR minimizes
the total output resistance.1 x C12R4ESRESROUT
OSCC1C2≅()+++I1I x R
OUT
OUTQ
OUTOUTη≅+−
MAX828/MAX829
Switched-Capacitor Voltage InvertersS4
VOUT = -(VIN)
Figure 2. Ideal Voltage InverterRL
VOUT
Figure 3a. Switched-Capacitor Model
REQUIV =
REQUIV
VOUT
f × C1C2
Figure 3b. Equivalent Circuit
MAX828/MAX829
Switched-Capacitor Voltage Inverters
Flying Capacitor (C1)Increasing the flying capacitor’s size reduces the output
resistance. Small C1 values increase the output resis-
tance. Above a certain point, increasing C1’s capaci-
tance has a negligible effect, because the output
resistance becomes dominated by the internal switch
resistance and capacitor ESR.
Output Capacitor (C2)Increasing the output capacitor’s size reduces the output
ripple voltage. Decreasing its ESR reduces both output
resistance and ripple. Smaller capacitance values can
be used with light loads if higher output ripple can be
tolerated. Use the following equation to calculate the
peak-to-peak ripple:
Input Bypass CapacitorBypass the incoming supply to reduce its AC impedance
and the impact of the MAX828/MAX829’s switching noise.
The recommended bypassing depends on the circuit
configuration and on where the load is connected.
When the inverter is loaded from OUT to GND, current
from the supply switches between 2 x IOUTand zero.
Therefore, use a large bypass capacitor (e.g., equal to
the value of C1) if the supply has a high AC impedance.
When the inverter is loaded from IN to OUT, the circuit
draws 2 x IOUTconstantly, except for short switching
spikes. A 0.1µF bypass capacitor is sufficient.
Voltage InverterThe most common application for these devices is a
charge-pump voltage inverter (Figure 1). This application
requires only two external components—capacitors C1
and C2—plus a bypass capacitor, if necessary. Refer to
the Capacitor Selection section for suggested capacitor
types and values.
Cascading DevicesTwo devices can be cascaded to produce an even
larger negative voltage (Figure 4). The unloaded output
voltage is normally -2 x VIN, but this is reduced slightly
by the output resistance of the first device multiplied by
the quiescent current of the second. When cascading
more than two devices, the output resistance rises dra-
matically. For applications requiring larger negative
voltages, see the MAX864 and MAX865 data sheets.
Paralleling DevicesParalleling multiple MAX828s or MAX829s reduces the
output resistance. Each device requires its own pump
capacitor (C1), but the reservoir capacitor (C2) serves
all devices (Figure 5). Increase C2’s value by a factor
of n, where n is the number of parallel devices. The
equation for calculating output resistance is also shown
in Figure 5.
Combined Doubler/InverterIn the circuit of Figure 6, capacitors C1 and C2 form the
inverter, while C3 and C4 form the doubler. C1 and C3
are the pump capacitors; C2 and C4 are the reservoir
capacitors. Because both the inverter and doubler use
part of the charge-pump circuit, loading either output
causes both outputs to decline toward GND. Make sure
the sum of the currents drawn from the two outputs
does not exceed 40mA.
V = I x C2RIPPLE
OUT
OSC +22xIxESROUTC
Table 1. Low-ESR Capacitor ManufacturersMatsuo
AVX
MANUFACTURER(714) 969-2491
(803) 946-0690
(800) 282-4975
PHONE(603) 224-1961
(619) 661-6835
Sprague
Sanyo
(603) 224-1430
(619) 661-1055
(714) 960-6492
(803) 626-3123
FAXSurface-mount, 595D series
Through-hole, OS-CON series
Surface-mount, 267 series
Surface-mount, TPS series
DEVICE TYPEUSA
Japan81-7-2070-630681-7-2070-1174
