MAX1721EUT ,SOT23 / Switched-Capacitor Voltage Inverters with ShutdownELECTRICAL CHARACTERISTICS(V = +5V, SHDN = GND (MAX1719), SHDN = IN (MAX1720/MAX1721), C1 = C2 = 10 ..
MAX1721EUT ,SOT23 / Switched-Capacitor Voltage Inverters with ShutdownFeaturesThe ultra-small MAX1719/MAX1720/MAX1721 monolithic,¤ 1nA Logic-Controlled ShutdownCMOS char ..
MAX1721EUT+T ,SOT23, Switched-Capacitor Voltage Inverters with Shutdownapplications.♦ ♦ 25mA Output CurrentOscillator control circuitry and four power MOSFET♦ ♦ Requires ..
MAX1721EUT-T ,SOT23, Switched-Capacitor Voltage Inverters with ShutdownApplicationsMAX1721EUT -40°C to +85°C 6 SOT23-6 AABTLocal Negative Supply from a Positive SupplySma ..
MAX1722EZK+T ,1.5µA IQ, Step-Up DC-DC Converters in TSOT and µDFNElectrical Characteristics(V = 1.2V, V = 3.3V (MAX1722/MAX1723), V = V (MAX1724), SHDN = OUT, R = ∞ ..
MAX1722EZK-T ,1.5uA IQ / Step-Up DC-DC Converters in Thin SOT23-5ELECTRICAL CHARACTERISTICS (continued)(V = 1.2V, V = 3.3V (MAX1722/MAX1723), V = V (MAX1724), SHDN ..
MAX4550CAI ,Serially Controlled / Dual 4x2 / Clickless Audio/Video Analog Crosspoint SwitchesELECTRICAL CHARACTERISTICS—Dual Supplies(V+ = +5V ±5%, V- = -5V ±5%, T = T to T , unless otherwise ..
MAX4550CAI+T ,Serially Controlled, Dual 4x2, Clickless Audio/Video Analog Crosspoint SwitchesApplicationsTOP VIEWSet-Top BoxesSB 1 28 SAPC Multimedia BoardsNO3A 2 27 NO2BHigh-End Audio Systems ..
MAX4551CPE ,15kV ESD-Protected / Quad / Low-Voltage / SPST Analog SwitchesELECTRICAL CHARACTERISTICS—Dual Supplies(V+ = +5V, ±10%, V- = -5V, ±10%, T = T to T , unless otherw ..
MAX4551CSE ,15kV ESD-Protected / Quad / Low-Voltage / SPST Analog SwitchesGeneral Description ________
MAX4551EPE ,15kV ESD-Protected / Quad / Low-Voltage / SPST Analog SwitchesApplications MAX4551CSE 0°C to +70°C 16 Narrow SOMAX4551CPE 0°C to +70°C 16 Plastic DIPBattery-Oper ..
MAX4551ESE ,15kV ESD-Protected / Quad / Low-Voltage / SPST Analog SwitchesApplications MAX4551CSE 0°C to +70°C 16 Narrow SOMAX4551CPE 0°C to +70°C 16 Plastic DIPBattery-Oper ..
MAX1719EUT-MAX1721EUT
SOT23 / Switched-Capacitor Voltage Inverters with Shutdown
General DescriptionThe ultra-small MAX1719/MAX1720/MAX1721 monolithic,
CMOS charge-pump inverters accept input voltages
ranging from +1.5V to +5.5V. The MAX1720 operates at
12kHz, and the MAX1719/MAX1721 operate at 125kHz.
High efficiency, small external components, and logic-
controlled shutdown make these devices ideal for both
battery-powered and board-level voltage conversion
applications.
Oscillator control circuitry and four power MOSFET
switches are included on-chip. A typical MAX1719/
MAX1720/MAX1721 application is generating a -5V
supply from a +5V logic supply to power analog circuitry.
All three parts come in a 6-pin SOT23 package and can
deliver a continuous 25mA output current.
For pin-compatible SOT23 switched-capacitor voltage
inverters without shutdown (5-pin SOT23), see the
MAX828/MAX829 and MAX870/MAX871 data sheets. For
applications requiring more power, the MAX860/MAX861
deliver up to 50mA. For regulated outputs (up to -2 ·VIN),
refer to the MAX868. The MAX860/MAX861 and MAX868
are available in space-saving µMAX packages.
ApplicationsLocal Negative Supply from a Positive Supply
Small LCD Panels
GaAs PA Bias Supply
Handy-Terminals, PDAs
Battery-Operated Equipment
Features1nA Logic-Controlled Shutdown6-Pin SOT23 Package99.9% Voltage Conversion Efficiency50µA Quiescent Current (MAX1719/MAX1720)+1.5V to +5.5V Input Voltage Range25mA Output CurrentRequires Only Two 1µF Capacitors
(MAX1719/MAX1721)
MAX1719/MAX1720/MAX1721
SOT23, Switched-Capacitor
Voltage Inverters with Shutdown
Pin Configuration
Typical Operating Circuit19-1439; Rev 1; 5/99
MAX1719/MAX1720/MAX1721
SOT23, Switched-Capacitor
Voltage Inverters with Shutdown
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VIN= +5V, SHDN = GND (MAX1719), SHDN= IN (MAX1720/MAX1721), C1 = C2 = 10µF (MAX1720), C1 = C2 = 1µF
(MAX1719/MAX1721), circuit of Figure 1, TA
= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
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.
IN to GND.................................................................-0.3V to +6V
OUT to GND.............................................................-6V to +0.3V
C1+, SHDN,SHDN to GND.........................-0.3V to (VIN+ 0.3V)
C1- to GND...............................................(VOUT- 0.3V) to +0.3V
OUT Output Current..........................................................100mA
OUT Short Circuit to GND..............................................Indefinite
Continuous Power Dissipation (TA= +70°C)
6-Pin SOT23 (derate 8.7mW/°C above +70°C).................696mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec).............................+300°C
MAX1719/MAX1720/MAX1721
SOT23, Switched-Capacitor
Voltage Inverters with Shutdown
Typical Operating Characteristics(Circuit of Figure 1, VIN= +5V, SHDN = GND (MAX1719), SHDN= IN (MAX1720/MAX1721), C1 = C2 = C3, TA= +25°C, unless other-
wise noted.)
ELECTRICAL CHARACTERISTICS(VIN= +5V, SHDN = GND (MAX1719), SHDN= IN (MAX1720/MAX1721), C1 = C2 = 10µF (MAX1720), C1 = C2 = 1µF
(MAX1719/MAX1721), circuit of Figure 1, TA
= -40°C to +85°C, unless otherwise noted.) (Note 2)
Note 1:Capacitor contribution (ESR component plus (1/fOSC) ·C) is approximately 20% of output impedance.
Note 2:All specifications from -40°C to +85°C are guaranteed by design, not production tested.
MAX1719/MAX1720/MAX1721
SOT23, Switched-Capacitor
Voltage Inverters with Shutdown
Typical Operating Characteristics (continued)(Circuit of Figure 1, VIN= +5V, SHDN = GND (MAX1719), SHDN= IN (MAX1720/MAX1721), C1 = C2 = C3, TA= +25°C, unless oth-
Detailed DescriptionThe MAX1719/MAX1720/MAX1721 capacitive charge
pumps invert the voltage applied to their input. For high-
est performance, 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, 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.
MAX1719/MAX1720/MAX1721
SOT23, Switched-Capacitor
Voltage Inverters with Shutdown
Typical Operating Characteristics (continued)(Circuit of Figure 1, VIN= +5V, SHDN = GND (MAX1719), SHDN= IN (MAX1720/MAX1721), C1 = C2 = C3, TA= +25°C, unless
otherwise noted.)
MAX1719/MAX1721
OUTPUT CURRENT vs. CAPACITANCEMAX1720/21toc14
CAPACITANCE (μF)
OUTPUT CURRENT (mA)1.01.52.02.50.53.03.54.04.55.0
Pin Description
MAX1719/MAX1720/MAX1721
SOT23, Switched-Capacitor
Voltage Inverters with Shutdown
Charge-Pump OutputThe MAX1719/MAX1720/MAX1721 are not voltage reg-
ulators: the charge pumps’ output resistance is
approximately 23Ωat 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
current draw from OUT (IOUT) times the negative con-
verter’s output resistance (RO):
VDROOP-= IOUT
·RO
The negative output voltage will be:
VOUT= -(VIN- VDROOP-)
Efficiency ConsiderationsThe power efficiency of a switched-capacitor voltage
converter is affected by three factors: the internal loss-
es in the converter IC, the losses in the power switches,
and the resistive losses of the pump capacitors. The
total power loss is:
The internal losses are associated with the IC’s internal
functions, such as driving the switches, oscillator, etc.
These losses are affected by operating conditions such
as input voltage, temperature, and frequency.
The other two losses are associated with the voltage
converter circuit’s output resistance. Switch losses
occur because of the on-resistance of the MOSFET
switches in the IC. Charge-pump capacitor losses
occur because of their ESR. The relationship between
these losses and the output resistance is as follows:
where fOSCis the oscillator frequency. The first term is
the effective resistance from an ideal switched-
capacitor circuit. SeeFigures 3a and 3b.
Shutdown ModeThe MAX1719/MAX1720/MAX1721 have a logic-con-
trolled shutdown input. Driving SHDNlow places the
MAX1720/MAX1721 in a low-power shutdown mode.
The MAX1719’s shutdown input is inverted from that of
the MAX1720/MAX1721. Driving SHDN high places the
MAX1719 in a low-power shutdown mode. The charge-
pump switching halts, supply current is reduced to
1nA, and OUT is actively pulled to ground through a 4Ω
resistance.
