MAX871EUK-T ,Switched-Capacitor Voltage Invertersapplications.♦ +1.4V to +5.5V Input Voltage Range Oscillator control circuitry and four power MOSFE ..
MAX8722CEEG+ ,Low-Cost CCFL Backlight ControllerApplicationsPKG PART TEMP RANGE PIN-PACKAGE Notebook Computer DisplaysCODE LCD Monitors 24 QSOP MAX ..
MAX8722CEEG+T ,Low-Cost CCFL Backlight ControllerELECTRICAL CHARACTERISTICS(Circuit of Figure 1. V = 12V, V = V , V = 5.4V, T = 0°C to +85°C. Typica ..
MAX8722EEG ,Low-Cost CCFL Backlight ControllerApplicationsPART TEMP RANGE PIN-PACKAGENotebook Computer DisplaysMAX8722EEG -40°C to +85°C 24 QSOPL ..
MAX8724ETI ,Low-Cost Multichemistry Battery ChargersFeaturesThe MAX1908/MAX8724 highly integrated, multichemistry♦ ±0.5% Output Voltage Accuracy Using ..
MAX8724ETI+ ,Low-Cost Multichemistry Battery ChargersFeaturesThe MAX1908/MAX8724/MAX8765/MAX8765A highly♦ ±0.5% Output Voltage Accuracy Using Internalin ..
MB84VD21183EM-70PBS , Stacked MCP (Multi-Chip Package) FLASH MEMORY & SRAM CMOS
MB84VD21194EM-70PBS , Stacked MCP (Multi-Chip Package) FLASH MEMORY & SRAM CMOS
MB84VD22181FM-70PBS , 32M (X16) FLASH MEMORY & 4M (X16) STATIC RAM
MB84VD22182EE-90 ,32M (x 8/x16) FLASH MEMORY & 4M (x 8/x16) STATIC RAMFUJITSU SEMICONDUCTORDS05-50204-2EDATA SHEETStacked MCP (Multi-Chip Package) FLASH MEMORY & SRAMCMO ..
MB84VD22183EE-90 ,32M (x 8/x16) FLASH MEMORY & 4M (x 8/x16) STATIC RAMFEATURES• Power supply voltage of 2.7 to 3.3 V• High performance90 ns maximum access time (Flash)85 ..
MB84VD22184FM-70 , 32M (X16) FLASH MEMORY & 4M (X16) STATIC RAM
MAX870EUK+T-MAX870EUKT-MAX871EUK+-MAX871EUK-T
Switched-Capacitor Voltage Inverters
General DescriptionThe ultra-small MAX870/MAX871 monolithic, CMOS
charge-pump inverters accept input voltages ranging
from +1.4V to +5.5V. The MAX870 operates at 125kHz,
and the MAX871 operates at 500kHz. Their high efficien-
cy (90%) and low operating current (0.7mA for the
MAX870) make these devices ideal for both battery-pow-
ered and board-level voltage-conversion applications.
Oscillator control circuitry and four power MOSFET
switches are included on-chip. A typical MAX870/
MAX871 application is 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 MAX1720/MAX1721. For applications
requiring more power, the MAX860 delivers up to 50mA
with a voltage drop of 600mV, in a space-saving µMAX
package.
________________________ApplicationsLocal -5V Supply from 5V Logic Supply
Small LCD Panels
Cell Phones
Medical Instruments
Handy-Terminals, PDAs
Battery-Operated Equipment
Features5-Pin SOT23-5 Package 99% Voltage Conversion EfficiencyInvert Input Supply Voltage0.7mA Quiescent Current (MAX870)+1.4V to +5.5V Input Voltage Range Require Only Two Capacitors25mA Output CurrentShutdown Control
MAX870/MAX871
Switched-Capacitor Voltage InvertersTOP VIEW
GNDC1-
C1+OUT
SOT23-55
MAX870
MAX87124
Pin Configuration
NEGATIVE VOLTAGE CONVERTERC1+
C1-
OUT
GND
INPUT
SUPPLY
VOLTAGE
NEGATIVE
OUTPUT
VOLTAGE
MAX870
MAX871
Typical Operating Circuit19-1240; Rev 1; 2/04
PART
MAX870EUK-40°C to +85°C
TEMP RANGEPIN-
PACKAGE5 SOT23-5
Ordering Information
MAX871EUK-40°C to +85°C5 SOT23-5
SOT
TOP MARKABZN
ABZO
MAX870/MAX871
Switched-Capacitor Voltage Inverters
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VIN= +5V, C1 = C2 = 1µF (MAX870), C1 = C2 = 0.33µF (MAX871), TA
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
ELECTRICAL CHARACTERISTICS(VIN= +5V, C1 = C2 = 1µF (MAX870), C1 = C2 = 0.33µF (MAX871), TA
= -40°C to +85°C, unless otherwise noted.) (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 are guaranteed by design.
Note 3:The MAX870/MAX871 may draw high supply current during startup, up to the minimum operating supply voltage. To guarantee
proper startup, the input supply must be capable of delivering 90mA more than the maximum load current.
IN to GND..............................................................+6.0V to -0.3V
OUT to GND..........................................................-6.0V to +0.3V
C1+..............................................................(VIN + 0.3V) to -0.3V
C1-............................................................(VOUT- 0.3V) to +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
MAX870EUK/MAX871EUK...............................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10s).................................+300°C
MAX871
MAX870
RLOAD= 500kΩ,=+25°C
RLOAD= 10kΩ
RLOAD= 10kΩ= +25°C
CONDITIONS2.73.8
0.71.0Supply Current9990Power Efficiency
kHz325500675
1.41.0V1.5Minimum Supply Voltage5.5Maximum Supply Voltage125169
UNITSMINTYPMAXPARAMETER= +25°C= 0°C to + 85°C
MAX871
MAX870
IOUT= 5mA
MAX871
RLOAD= 10kΩ
MAX870
CONDITIONS4.4
1.3Supply Current (Note 3)65Output Resistance
kHz225775Oscillator Frequency1.6Minimum Supply-Voltage Range194
UNITSMINTYPMAXPARAMETER= +25°C (Note 3)
Oscillator Frequency
C1 = C2 = 0.47µF
IOUT=
5mA
C1 = C2 = 1µFOutput Resistance (Note 1)50MAX870= +25°CC1 = C2 = 0.33µF2050
C1 = C2 = 0.22µF25MAX871
C1 = C2 = 0.1µF35TA= 0°C to + 85°C
MAX870
MAX871
MAX870
MAX871
RLOAD= ∞, TA=+25°C%9899.3Voltage Conversion EfficiencyMAX870
MAX871
RLOAD= ∞%97Voltage Conversion Efficiency95
MAX870
MAX871
RLOAD= 10kΩV5.5Maximum Supply-Voltage Range
MAX870/MAX871
Switched-Capacitor Voltage InvertersSUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX870/71-TOC01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)MAX870
MAX871
OUTPUT RESISTANCE
vs. SUPPLY VOLTAGE
MAX828/829-02
SUPPLY VOLTAGE (V)
OUTPUT RESISTANCE (
MAX870
MAX871
MAX870
OUTPUT RESISTANCE vs. TEMPERATURE
MAX870/71 ROC3
TEMPERATURE (°C)
OUTPUT RESISTANCE (
VIN = 1.5V
VIN = 3.3V
VIN = 5.0V0.53.02.5
MAX870
OUTPUT CURRENT vs. CAPACITANCEMAX870/871-04
CAPACITANCE (μF)
OUTPUT CURRENT (mA)
VIN = 3.15V, VOUT = -2.5V
VIN = 1.9V, VOUT = -1.5V
VIN = 4.75V, VOUT = -4.0V0.52.0
MAX871
OUTPUT CURRENT vs. CAPACITANCEMAX870/871-07
CAPACITANCE (μF)
OUTPUT CURRENT (mA)
VIN = 3.15V, VOUT = -2.5V
VIN = 1.9V, VOUT = -1.5V
VIN = 4.75V, VOUT = -4.0V
MAX870
OUTPUT VOLTAGE RIPPLE
vs. CAPACITANCE
MAX870/871-05
CAPACITANCE (μF)
OUTPUT VOLTAGE RIPPLE (mVp-p)
VIN = 4.75V, VOUT = -4.0V
VIN = 3.15V, VOUT = -2.5V
VIN = 1.9V, VOUT = -1.5V
MAX871
OUTPUT RESISTANCE vs. TEMPERATURE
MAX870/71-TOC06
TEMPERATURE (°C)
OUTPUT RESISTANCE (VIN = 1.5V
VIN = 3.3V
VIN = 5.0V
MAX871
OUTPUT VOLTAGE RIPPLE
vs. CAPACITANCE
MAX870/71 TOC08
CAPACITANCE (μF)
OUTPUT VOLTAGE RIPPLE (mVp-p)
VIN = 4.75V, VOUT = -4.0V
VIN = 3.15V, VOUT = -2.5V
VIN = 1.9V, VOUT = -1.5V
__________________________________________Typical Operating Characteristics(Circuit of Figure 1, VIN= +5V, C1 = C2 = C3, TA= +25°C, unless otherwise noted.)
MAX870
OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX870/871-TOC9
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
VIN = 2.0V
VIN = 3.3V
VIN = 5.0V
_____________________Pin Description
MAX870/MAX871
Switched-Capacitor Voltage Inverters
____________________________Typical Operating Characteristics (continued)(Circuit of Figure 1, VIN= +5V, C1 = C2 = C3, TA= +25°C, unless otherwise noted.)
MAX870
EFFICIENCY vs. OUTPUT CURRENT
MAX870/71-TOC10
OUTPUT CURRENT (mA)
EFFICIENCY (%)
VIN = 2.0V
VIN = 3.3VVIN = 5.0V
MAX871
EFFICIENCY vs. OUTPUT CURRENT
MAX870/71 TOC11
OUTPUT CURRENT (mA)
EFFICIENCY (%)
VIN = 2.0VVIN = 3.3V
VIN = 5.0V
PUMP FREQUENCY vs. TEMPERATURE
MAX870/71-TOC12
TEMPERATURE (°C)
PUMP FREQUENCY (kHz)
VIN = 1.5V, MAX871
VIN = 1.5V, MAX870
VIN = 3.3V OR 5.0V, MAX870
VIN = 3.3V OR 5.0V, MAX871
MAX870
OUTPUT NOISE AND RIPPLEMAX870/71-TCC13
2μs/div
VIN = 3.3V, VOUT = -3.18V, IOUT = 5mA,
20mV/div, AC COUPLED
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
0.33μF*
*1μF
(MAX870)
0.33μF*
0.33μF*14
VOUT
GNDC1-
MAX870
MAX871
Figure 1. Test Circuit
MAX871
OUTPUT NOISE AND RIPPLEMAX870/71-TCC14
1μs/div
VIN = 3.3V, VOUT = -3.14V, IOUT = 5mA,
20mV/div, AC COUPLED
_______________Detailed DescriptionThe MAX870/MAX871 capacitive charge pumps invert
the voltage applied to their input. For highest perfor-
mance, use low equivalent series resistance (ESR)
capacitors (e.g., ceramic).
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 MAX870/MAX871 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 MAX870/MAX871 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.fxCRESRESROUT
OSCCC≅()+++12412 +−I
OUT
OUTQ
OUTOUT 1
MAX870/MAX871
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
MAX870/MAX871
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 MAX870/MAX871’s switching
noise. The recommended bypassing depends on the cir-
cuit 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.
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.
The maximum load current and startup current of the
nthcascaded circuit must not exceed the maximum
output current capability of the (n-1)thcircuit to ensure
proper stability.I
f x C2RIPPLEOUT
OSC+22 xIxESROUTC
Table 1. Low-ESR Capacitor ManufacturersSurface-Mount
Tantalum
PRODUCTION
METHOD(714) 969-2491
(803) 946-0690
PHONE(603) 224-1961(603) 224-1430
(714) 960-6492
(803) 626-3123
FAXMANUFACTURERAVX
Matsuo
Sprague
SERIESTPS series
267 series
593D, 595D series
(714) 969-2491
(803) 946-0690AVX
Matsuo(714) 960-6492
(803) 626-3123X7R
X7R
Surface-Mount
Ceramic
Table 2. Capacitor Selection for Minimum Output Resistance or Capacitor Size
fOSC
CAPACITORS TO MINIMIZE SIZE
(RO= 40Ω, TYP)
C1 = C20.1µF
0.33µF125kHz
CAPACITORS TO MINIMIZE
OUTPUT RESISTANCE
(RO= 23Ω, TYP)
C1 = C2500kHz
1µF
0.33µF
MAX870
PARTMAX871
