MAX4193 ,CMOS, Micropower, Step-Up Switching RegulatorFeaturesMaxim’s MAX630 and MAX4193 CMOS DC-DC regula-♦ High Efficiency—85% (typ)tors are designed f ..
MAX4193CPA ,CMOS Micropower Step-UP Switching Regulator1mm,- Rwtt 5'”
lVl/JXI/VI
CMOS Micropower
Stop-Up Swltchlng Regulator
General f3tsmtrfp ..
MAX4193CSA ,CMOS Micropower Step-UP Switching RegulatorELECTRICAL CHARACTERISTICS
(+Vs = HMV, Ts = +25° c, Ic = 6.0PA, unless otherwise noted)
opera ..
MAX4193EPA ,CMOS Micropower Step-UP Switching RegulatorELECTRICAL CHARACTERISTICS
(+Vs = HMV, Ts = +25° c, Ic = 6.0PA, unless otherwise noted)
opera ..
MAX4193EPA ,CMOS Micropower Step-UP Switching RegulatorELECTRICAL CHARACTERISTICS
(+Vs = HMV, Ts = +25° c, Ic = 6.0PA, unless otherwise noted)
opera ..
MAX4194ESA ,Micropower / Single-Supply / Rail-to-Rail / Precision Instrumentation AmplifiersMAX4194–MAX419719-1468; Rev 0; 4/99Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentati ..
MAX806TCPA ,3.0V or 3.3V microprocessor supervisory circuit. Reset threshold 3.075V. Active-low reset. Manual reset input. Backup-battery switch. Power-fail threshold accuracy +-2%. Power-fail comparator. Reset window +-2%MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/RReset WindowPower-Fail ComparatorPower-Fail Threshold ..
MAX806TCPA ,3.0V or 3.3V microprocessor supervisory circuit. Reset threshold 3.075V. Active-low reset. Manual reset input. Backup-battery switch. Power-fail threshold accuracy +-2%. Power-fail comparator. Reset window +-2%General Description ________
MAX806TCSA ,3.0V or 3.3V microprocessor supervisory circuit. Reset threshold 3.075V. Active-low reset. Manual reset input. Backup-battery switch. Power-fail threshold accuracy +-2%. Power-fail comparator. Reset window +-2%Features– — — — — –These microprocessor (µP) supervisory circuits reduce' RESET and RESET Outputsth ..
MAX806TCSA ,3.0V or 3.3V microprocessor supervisory circuit. Reset threshold 3.075V. Active-low reset. Manual reset input. Backup-battery switch. Power-fail threshold accuracy +-2%. Power-fail comparator. Reset window +-2%Features– — — — — –These microprocessor (µP) supervisory circuits reduce' RESET and RESET Outputsth ..
MAX806TCSA+ ,3.0V/3.3V Microprocessor Supervisory CircuitsApplications● Battery-Powered Computers and Controllers● Embedded Controllers● Intelligent Instrume ..
MAX806TESA ,3.0V or 3.3V microprocessor supervisory circuit. Reset threshold 3.075V. Active-low reset. Manual reset input. Backup-battery switch. Power-fail threshold accuracy +-2%. Power-fail comparator. Reset window +-2%General Description ________
MAX4193-MAX630
CMOS, Micropower, Step-Up Switching Regulator
General DescriptionMaxim’s MAX630 and MAX4193 CMOS DC-DC regula-
tors are designed for simple, efficient, minimum-size
DC-DC converter circuits in the 5mW to 5W range. The
MAX630 and MAX4193 provide all control and power
handling functions in a compact 8-pin package: a
1.31V bandgap reference, an oscillator, a voltage com-
parator, and a 375mA N-channel output MOSFET. A
comparator is also provided for low-battery detection.
Operating current is only 70µA and is nearly indepen-
dent of output switch current or duty cycle. A logic-level
input shuts down the regulator to less than 1µA quies-
cent current. Low-current operation ensures high effi-
ciency even in low-power battery-operated systems.
The MAX630 and MAX4193 are compatible with most
battery voltages, operating from 2.0V to 16.5V.
The devices are pin compatible with the Raytheon bipo-
lar circuits, RC4191/2/3, while providing significantly
improved efficiency and low-voltage operation. Maxim
also manufactures the MAX631, MAX632, and MAX633
DC-DC converters, which reduce the external compo-
nent count in fixed-output 5V, 12V, and 15V circuits.
See Table 2 at the end of this data sheet for a summary
of other Maxim DC-DC converters.
Applications+5V to +15V DC-DC Converters
High-Efficiency Battery-Powered DC-DC
Converters
+3V to +5V DC-DC Converters
9V Battery Life Extension
Uninterruptible 5V Power Supplies
5mW to 5W Switch-Mode Power Supplies
FeaturesHigh Efficiency—85% (typ)70µA Typical Operating Current1µA Maximum Quiescent Current2.0V to 16.5V Operation525mA (Peak) Onboard Drive Capability±1.5% Output Voltage Accuracy (MAX630)Low-Battery DetectorCompact 8-Pin Mini-DIP and SO PackagesPin Compatible with RC4191/2/3
MAX630/MAX4193
CMOS Micropower Step-Up
Switching Regulator+VSGND
LBD
VFBCX
LBR
TOP VIEW
MAX630
MAX4193
Pin Configuration
Ordering InformationMAX630
+5V IN
470μH
+15V
OUT
47pFLBDLBR
GNDVFBLX
+VS
+5 TO +15V CONVERTER
PARTTEMP RANGEPIN-
PACKAGE
MAX630CPA0°C to +70°C8 PDIP
MAX630CSA0°C to +70°C8 SO
MAX630CJA0°C to +70°C8 CERDIP
MAX630EPA-40°C to +85°C8 PDIP
MAX630ESA-40°C to +85°C8 SO
MAX630EJA-40°C to +85°C8 CERDIP
MAX630MJA-55°C to +125°C8 CERDIP**
MAX630MSA/PR-55°C to +125°C8 SO†AX 630M S A/P R- T-55°C to +125°C8 SO†
MAX4193C/D0°C to +70°CDice*
MAX4193CPA0°C to +70°C8 PDIP
MAX4193CSA0°C to +70°C8 SO
MAX4193CJA0°C to +70°C8 CERDIP
MAX4193EPA-40°C to +85°C8 PDIP
MAX4193ESA-40°C to +85°C8 SO
MAX4193EJA-40°C to +85°C8 CERDIP
MAX4193MJA-55°C to +125°C8 CERDIP**
Typical Operating Circuit19-0915; Rev 2; 9/08
*Dice are specified at TA= +25°C. Contact factory for dice
specifications.
**Contact factory for availability and processing to MIL-STD-883.
†Contact factory for availibility.
MAX630/MAX4193
CMOS Micropower Step-Up
Switching Regulator
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(+VS= +6.0V, TA= +25°C, IC= 5.0µA, unless otherwise noted.)
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.
Supply Voltage.......................................................................18V
Storage Temperature Range ............................-65°C to +160°C
Lead Temperature (soldering, 10s).................................+300°C
Operating Temperature Range
MAX630C, MAX4193C........................................0°C to +70°C
MAX630E, MAX4193E.....................................-40°C to +85°C
MAX630M, MAX4193M..................................-55°C to +125°C
Power Dissipation
8-Pin PDIP(derate 6.25mW/°C above +50°C).............468mW
8-Pin SO(derate 5.88mW/°C above +50°C)................441mW
8-Pin CERDIP(derate 8.33mW/°C above +50°C)........833mW
Input Voltage (Pins 1, 2, 6, 7).....................-0.3V to (+VS+ 0.3V)
Output Voltage, LXand LBD..................................................18V
LX Output Current..................................................525mA (Peak)
LBD Output Current............................................................50mA
MAX630MAX4193PARAMETERSYMBOLCONDITIONSMINTYPMAXMINTYPMAXUNITSOperating2.016.5Supply Voltage+VSStartup1.92.416.5V
Internal Reference VoltageVREF1.291.311.331.241.311.38V
Switch CurrentISWV3 = 400mV7515075150mA
Supply Current (at Pin 5)ISI3 = 0mA7012590µA
Efficiency8585%
Line Regulation0.5V0 < VS < V0
(Note 1)0.080.20.060.5% VOUT
Load RegulationVS = +5V, PLOAD = 0 to
150mW (Note 1)0.20.50.20.5% VOUT
Operating Frequency RangeFO(Note 2)0.140750.12575kHz
Reference Set Internal
Pulldown ResistanceRICV6 = VS0.51.5100.51.510MΩ
Reference Set Input Voltage
ThresholdVIC0.20.81.30.20.81.3V
Switch CurrentISWV3 = 1.0V100100mA
Switch Leakage CurrentICOV3 = 16.5V0.011.00.015.0µA
Supply Current (Shutdown)ISOIC < 0.01µA0.011.00.015.0µA
Low-Battery Bias CurrentILBR0.01100.0110nA
Capacitor Charging CurrentICX3030µA
CX+ Threshold Voltage+VS - 0.1+VS - 0.1V
CX- Threshold Voltage0.10.1V
VFB Input Bias CurrentIFB0.01100.0110nA
Low-Battery Detector Output
CurrentILBDV8 = 0.4V, V1 = 1.1V250600250600µA
Low-Battery Detector Output
LeakageILBDOV8 = 16.5V, V1 = 1.4V0.015.00.015.0µA
MAX630/MAX4193
CMOS Micropower Step-Up
Switching Regulator
LX ON-RESISTANCE vs.
TEMPERATUREMAX630/4193 toc01
TEMPERATURE (°C)
+VS = 2.5V
+VS = 6V
+VS = 16V
SUPPLY CURRENT vs.
TEMPERATUREMAX630/4193 toc02
TEMPERATURE (°C)
SUPPLY CURRENT vs.
SUPPLY VOLTAGE
MAX630/4193 toc03
+VS (V)
IS (12108642
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS(+VS= +6.0V, TA= Full Operating Temperature Range, IC= 5.0µA, unless otherwise noted.)
MAX630MAX4193PARAMETERSYMBOLCONDITIONSMINTYPMAXMINTYPMAXUNITSSupply Voltage+VS2.216.53.516.5V
Internal Reference VoltageVREF1.251.311.371.201.311.42V
Supply Current (Pin 5)ISI3 = 0mA7020090300µA
Line Regulation0.5V0UT < VS < V0UT
(Note 1)0.20.50.51.0% VOUT
Load RegulationVS = 0.5V0, PL = 0 to
150mW (Note 1)0.51.00.51.0% VOUT
0°C ≤ TA ≤
+70°C0.451.5100.451.510
-40°C ≤ TA ≤
+85°C0.41.5100.41.510Reference Set Internal
Pulldown ResistanceRICV6 = VS
-55°C ≤ TA ≤
+125°C0.31.5100.31.510
Reference Set Input Voltage
ThresholdVIC0.20.81.30.20.81.3V
Switch Leakage CurrentICOV3 = 16.5V0.1300.130µA
Supply Current (Shutdown)ISOIC < 0.01µA0.01100.0130µA
Low-Battery Detector Output
CurrentILBDV8 = 0.4V, V1 = 1.1V250600250600µA
Note 1:Guaranteed by correlation with DC pulse measurements.
Note 2:The operating frequency range is guaranteed by design and verified with sample testing.
Detailed DescriptionThe operation of the MAX630 can best be understood
by examining the voltage regulating loop of Figure 1.
R1 and R2 divide the output voltage, which is com-
pared with the 1.3V internal reference by comparator
COMP1. When the output voltage is lower than desired,
the comparator output goes high and the oscillator out-
put pulses are passed through the NOR gate latch,
turning on the output N-channel MOSFET at pin 3, LX.
As long as the output voltage is less than the desired
voltage, pin 3 drives the inductor with a series of pulses
at the oscillator frequency.
Each time the output N-channel MOSFET is turned on,
the current through the external coil, L1, increases,
storing energy in the coil. Each time the output turns off,
the voltage across the coil reverses sign and the volt-
age at LXrises until the catch diode, D1, is forward
biased, delivering power to the output.
When the output voltage reaches the desired level,
1.31V x (1 + R1 / R2), the comparator output goes low
and the inductor is no longer pulsed. Current is then
supplied by the filter capacitor, C1, until the output volt-
age drops below the threshold, and once again LXis
switched on, repeating the cycle. The average duty
cycle at LXis directly proportional to the output current.
Output Driver (LX Pin)The MAX630/MAX4193 output device is a large
N-channel MOSFET with an on-resistance of 4Ωand a
peak current rating of 525mA. One well-known advan-
tage that MOSFETs have over bipolar transistors in
switching applications is higher speed, which reduces
switching losses and allows the use of smaller, lighter,
less costly magnetic components. Also important is that
MOSFETs, unlike bipolar transistors, do not require
base current that, in low-power DC-DC converters,
often accounts for a major portion of input power.
The operating current of the MAX630 and MAX4193
increases by approximately 1µA/kHz at maximum
power output due to the charging current required by
the gate capacitance of the LXoutput driver (e.g., 40µA
increase at a 40kHz operating frequency). In compari-
son, equivalent bipolar circuits typically drive their NPNoutput device with 2mA of base drive, causing the
bipolar circuit’s operating current to increase by a fac-
tor of 10 between no load and full load.
OscillatorThe oscillator frequency is set by a single external, low-
cost ceramic capacitor connected to pin 2, CX. 47pF
sets the oscillator to 40kHz, a reasonable compromise
between lower switching losses at low frequencies and
reduced inductor size at higher frequencies.
MAX630/MAX4193
CMOS Micropower Step-Up
Switching Regulator
Pin Description
PINNAMEFUNCTIONLBRLow-Battery Detection Comparator Input. The LBD output, pin 8, sinks current whenever this pin is
below the low-battery detector threshold, typically 1.31V.
2CXAn external capacitor connected between this terminal and ground sets the oscillator frequency.
47pF = 40 kHz.
3LXThis pin drives the external inductor. The internal N-channel MOSFET that drives LX has an output
resistance of 4Ω and a peak current rating of 525mA.GNDGround
5+VSThe positive supply voltage, from 2.0V to 16.5V (MAX630).
6IC
The MAX630/MAX4193 shut down when this pin is left floating or is driven below 0.2V. For normal
operation, connect IC directly to +VS or drive it high with either a CMOS gate or pullup resistor
connected to +VS. The supply current is typically 10nA in the shutdown mode
7VFB
The output voltage is set by an external resistive divider connected from the converter output to VFB
and ground. The MAX630/MAX4193 pulse the LX output whenever the voltage at this terminal is less
than 1.31V.LBDThe Low-Battery Detector output is an open-drain N-channel MOSFET that sinks up to 600μA (typ)
whenever the LBR input, pin 1, is below 1.31V.
Low-Battery DetectorThe low-battery detector compares the voltage on LBR
with the internal 1.31V reference. The output, LBD, is an
open-drain N-channel MOSFET. In addition to detecting
and warning of a low battery voltage, the comparator
can also perform other voltage-monitoring operations
such as power-failure detection.
Another use of the low-battery detector is to lower the
oscillator frequency when the input voltage goes below
a specified level. Lowering the oscillator frequency
increases the available output power, compensating for
the decrease in available power caused by reduced
input voltage (see Figure 5).
Logic-Level Shutdown InputThe shutdown mode is entered whenever IC(pin 6) is
driven below 0.2V or left floating. When shut down, the
MAX630’s analog circuitry, oscillator, LX, and LBD out-
puts are turned off. The device’s quiescent current dur-
ing shutdown is typically 10nA (1µA max).
Bootstrapped OperationIn most circuits, the preferred source of +VSvoltage for
the MAX630 and MAX4193 is the boosted output volt-
age. This is often referred to as a “bootstrapped” oper-
ation since the circuit figuratively “lifts” itself up.
The on-resistance of the N-channel LX output decreas-
es with an increase in +VS; however, the device operat-
ing current goes up with +VS(see the Typical
Operating Characteristics, ISvs. +VSgraph). In circuits
with very low output current and input voltages greater
than 3V, it may be more efficient to connect +VSdirect-
ly to the input voltage rather than bootstrap.
MAX630/MAX4193
CMOS Micropower Step-Up
Switching RegulatorCOMP 2
+5V INPUT
169kΩ
100kΩ
LOW BATTERY INPUT
1.31V
OSC
RON ≅ 3Ω
40kHzCOMP 1
1.31V
BANDGAP
REFERENCE
AND
BIAS GENERATORLBR
2CX
3LXGND
1N4148
+VS56
VFB7
LBD8LOW-BATTERY OUTPUT
(LOW IF INPUT < 3V)
499kΩ
47.5kΩ
SHUTDOWN
OPERATE
+15V OUTPUT
20mAC1
470μF
25V
MAX630
COMP 2
Figure 1. +5V to +15V Converter and Block Diagram
MAX630/MAX4193
External Components
ResistorsSince the LBR and VFBinput bias currents are specified
as 10nA (max), the current in the dividers R1/R2 and
R3/R4 (Figure 1) may be as low as 1µA without signifi-
cantly affecting accuracy. Normally R2 and R4 are
between 10kΩand 1MΩ, which sets the current in the
voltage-dividers in the 1.3µA to 130µA range. R1 and
R3 can then be calculated as follows:
where VOUTis the desired output voltage and VLBis
the desired low-battery warning threshold.
If the IC(shutdown) input is pulled up through a resistor
rather than connected directly to +VS, the current
through the pullup resistor should be a minimum of 4µA
with ICat the input-high threshold of 1.3V:
Inductor ValueThe available output current from a DC-DC voltage
boost converter is a function of the input voltage, exter-
nal inductor value, output voltage, and the operating
frequency.
The inductor must 1) have the correct inductance, 2) be
able to handle the required peak currents, and 3) have
acceptable series resistance and core losses. If the
inductance is too high, the MAX630 will not be able to
deliver the desired output power, even with the LXout-
put on for every oscillator cycle. The available output
power can be increased by either decreasing the
inductance or the frequency. Reducing the frequency
increases the on-period of the LXoutput, thereby
increasing the peak inductor current. The available out-
put power is increased since it is proportional to the
square of the peak inductor current (IPK).
where POUTincludes the power dissipated in the catch
diode (D1) as well as that in the load. If the inductance
is too low, the current at LXmay exceed the maximum
rating. The minimum allowed inductor value is
expressed by:
where IMAX≈525mA (peak LXcurrent) and tONis the
on-time of the LXoutput.
The most common MAX630 circuit is a boost-mode
converter (Figure 1). When the N-channel output device
is on, the current linearly rises since:
At the end of the on-time (14µs for 40kHz, 55% duty-
cycle oscillator) the current is:
The energy in the coil is:
At maximum load, this cycle is repeated 40,000 times
per second, and the power transferred through the coil
is 40,000 x 5.25 = 210mW. Since the coil only supplies
the voltage above the input voltage, at 15V, the DC-DC
converter can supply 210mW / (15V - 5V) = 21mA. The
coil provides 210mW and the battery directly supplies
another 105mW, for a total of 315mW of output power. If
the load draws less than 21mA, the MAX630 turns on its
output only often enough to keep the output voltage at
a constant 15V.
Reducing the inductor value increases the available
output current: lower L increases the peak current,
thereby increasing the available power. The external
inductor required by the MAX630 is readily obtained
from a variety of suppliers (Table 1). Standard coils are
suitable for most applications.
Types of Inductors
Molded InductorsThese are cylindrically wound coils that look similar to
1W resistors. They have the advantages of low cost and
ease of handling, but have higher resistance, higher
losses, and lower power handling capability than other
types.
ImApkVTs==μ=514
470150=
LMINVTON
MAX=VTfPLIf
andION
OUT
OUTVTON
sin:VVICS≤+−2112131
131=−=− . .RRxVVRRxVV
OUT
CMOS Micropower Step-Up
Switching RegulatorLIpk==μ525.
Potted Toroidal InductorsA typical 1mH, 0.82Ωpotted toroidal inductor (Dale TE-
3Q4TA) is 0.685in in diameter by 0.385in high and
mounts directly onto a PC board by its leads. Such
devices offer high efficiency and mounting ease, but at
a somewhat higher cost than molded inductors.
Ferrite Cores (Pot Cores)Pot cores are very popular as switch-mode inductors
since they offer high performance and ease of design.
The coils are generally wound on a plastic bobbin,
which is then placed between two pot core sections. A
simple clip to hold the core sections together com-
pletes the inductor. Smaller pot cores mount directly
onto PC boards through the bobbin terminals. Cores
come in a wide variety of sizes, often with the center
posts ground down to provide an air gap. The gap pre-
vents saturation while accurately defining the induc-
tance per turn squared.
Pot cores are suitable for all DC-DC converters, but are
usually used in the higher power applications. They are
also useful for experimentation since it is easy to wind
coils onto the plastic bobbins.
Toroidal CoresIn volume production, the toroidal core offers high per-
formance, low size and weight, and low cost. They are,
however, slightly more difficult for prototyping, in that
manually winding turns onto a toroid is more tedious
than on the plastic bobbins used with pot cores.
Toroids are more efficient for a given size since the flux
is more evenly distributed than in a pot core, where the
effective core area differs between the post, side, top,
and bottom.
Since it is difficult to gap a toroid, manufacturers produce
toroids using a mixture of ferromagnetic powder (typically
iron or Mo-Permalloy powder) and a binder. The perme-
ability is controlled by varying the amount of binder,
which changes the effective gap between the ferromag-
netic particles. Mo-Permalloy powder (MPP) cores have
lower losses and are recommended for the highest effi-
ciency, while iron powder cores are lower cost.
DiodesIn most MAX630 circuits, the inductor current returns to
zero before LXturns on for the next output pulse. This
allows the use of slow turn-off diodes. On the other
hand, the diode current abruptly goes from zero to full
peak current each time LXswitches off (Figure 1, D1).
To avoid excessive losses, the diode must therefore
have a fast turn-on time.
For low-power circuits with peak currents less than
100mA, signal diodes such as 1N4148s perform well.
For higher-current circuits, or for maximum efficiency at
low power, the 1N5817 series of Schottky diodes are
recommended. Although 1N4001s and other general-
purpose rectifiers are rated for high currents, they are
unacceptable because their slow turn-on time results in
excessive losses.
MAX630/MAX4193
CMOS Micropower Step-Up
Switching Regulator
MANUFACTURERTYPICAL PART NUMBERDESCRIPTION
MOLDED INDUCTORSDaleIHA-104500µH, 0.5Ω
NytronicsWEE-470470µH, 10Ω
TRWLL-500500µH, 0.75Ω
POTTED TOROIDAL INDUCTORSDaleTE-3Q4TA1mH, 0.82Ω
TRWMH-1600µH, 1.9Ω
Torotel Prod.PT 53-18500µH, 5Ω
FERRITE CORES AND TOROIDSAllen BradleyT0451S100ATor. core, 500nH/T2
SiemensB64290-K38-X38Tor. core, 4µH/T2
Magnetics555130Tor. core, 53nH/T2
Stackpole57-3215Pot core, 14mm x 18mm
MagneticsG-41408-25Pot core, 14 x 8, 250nH/T2
Table 1. Coil and Core Manufacturers
Note:This list does not constitute an endorsement by Maxim Integrated Products and is not intended to be a comprehensive list of
all manufacturers of these components.
