ADP1111AN-3.3 ,Micropower Step Up/Down Switching Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 VSPECIFICATIONS (08C ≤ T ≤ +708C, V = 3 V unless otherwise noted)A INParameter Conditions V Min Typ ..
ADP1111AN-5 , Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V
ADP1111AR ,Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 VAPPLICATIONSW2 Emitter Node of Power Transistor. For step-down configuration, connect to inductor/d ..
ADP1111AR ,Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 Vapplications with only 3 external components.Maximum switch current can be programmed with a single ..
ADP1111AR-12 ,Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 VSpecifications subject to change without notice.REV. 0–2–ADP1111PIN DESCRIPTIONSABSOLUTE MAXIMUM RA ..
ADP1111AR-5 ,Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 VFEATURES FUNCTIONAL BLOCK DIAGRAMSOperates from 2 V to 30 V Input Voltage RangeSET72 kHz Frequency ..
AIVR3K42 , APLUS INTEGRATED CIRCUITS INC
AK002M4-31 , GaAs MMIC Control FET in SOT 143 DC-2.5 GHz
AK130-VS , TCM Integrated Transceiver
AK134-VQ , 2B D TCM Integrated Quad Transceiver
AK2302 , Dual PCM Codec/Filter COMBO LSI
AK2302 , Dual PCM Codec/Filter COMBO LSI
ADP1111AN-3.3
Micropower Step Up/Down Switching Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V
REV.0
Micropower, Step-Up/Step-Down SW
Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V
FUNCTIONAL BLOCK DIAGRAMS
FEATURES
Operates from 2 V to 30 V Input Voltage Range
72 kHz Frequency Operation
Utilizes Surface Mount Inductors
Very Few External Components Required
Operates in Step-Up/Step-Down or Inverting Mode
Low Battery Detector
User Adjustable Current Limit
Internal 1A Power Switch
Fixed or Adjustable Output Voltage
8-Pin DIP or SO-8 Package
APPLICATIONS
3 V to 5 V, 5 V to 12 V Step-Up Converters
9 V to 5 V, 12 V to 5 V Step-Down Converters
Laptop and Palmtop Computers
Cellular Telephones
Flash Memory VPP Generators
Remote Controls
Peripherals and Add-On Cards
Battery Backup Supplies
Uninterruptible Supplies
Portable Instruments
GENERAL DESCRIPTIONThe ADP1111 is part of a family of step-up/step-down switch-
ing regulators that operates from an input voltage supply of 2V
to 12 V in step-up mode and up to 30 V in step-down mode.
The ADP1111 can be programmed to operate in step-up/step-
down or inverting applications with only 3 external components.
The fixed outputs are 3.3 V, 5 V and 12 V; and an adjustable
version is also available. The ADP1111 can deliver 100 mA atV from a 3 V input in step-up mode, or it can deliver 200mA
at 5 V from a 12 V input in step-down mode.
Maximum switch current can be programmed with a single
resistor, and an open collector gain block can be arranged in
multiple configuration for low battery detection, as a post linear
regulator, undervoltage lockout, or as an error amplifier.
If input voltages are lower than 2 V, see the ADP1110.
ADP1111–SPECIFICATIONSINPUT VOLTAGE
COMPARATOR TRIP POINT
OUTPUT SENSE VOLTAGE
SW SATURATION VOLTAGE
GAIN BLOCK OUTPUT LOW
REFERENCE LINE REGULATION
CURRENT LIMIT
CURRENT LIMIT TEMPERATURE
NOTESThis specification guarantees that both the high and low trip points of the comparator fall within the 1.20 V to 1.30 V range.The output voltage waveform will exhibit a sawtooth shape due to the comparator hysteresis. The output voltage on the fixed output versions will always be within
the specified range.100 kΩ resistor connected between a 5 V source and the AO pin.All limits at temperature extremes are guaranteed via correlation using standard statistical methods.
Specifications subject to change without notice.
(08C ≤ TA ≤ +708C, VIN = 3 V unless otherwise noted)
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the ADP1111 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
ORDERING GUIDE*N = Plastic DIP, SO = Small Outline Package.
ABSOLUTE MAXIMUM RATINGSSupply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 V
SW1 Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 V
SW2 Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to VIN
Feedback Pin Voltage (ADP1111) . . . . . . . . . . . . . . . . . 5.5 V
Switch Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 A
Maximum Power Dissipation . . . . . . . . . . . . . . . . . . 500 mW
Operating Temperature Range
ADP1111A . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
Storage Temperature Range . . . . . . . . . . . . . –65°C to 150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . 300°C
PIN DESCRIPTIONS
TYPICAL APPLICATION
SUMIDA
CD54-220K
22µH
100mA
INPUT
MBRS120T3Figure 1.3V to 5V Step-Up Converter
PIN CONFIGURATIONS
8-Lead Plastic DIP8-Lead SOIC
(N-8)(SO-8)
ILIM
SW1
GND
VIN
SW2
*FIXED VERSIONS
FB (SENSE)*
SETA0
ILIM
SW1
GND
VIN
SW2
*FIXED VERSIONS
FB (SENSE)*
SET
ISWITCH CURRENT – A
SATURATION VOLTAGE – VFigure 2.Saturation Voltage vs. ISWITCH Current in
Step-Up Mode
ISWITCH CURRENT – A
ON VOLTAGE – V
0.8Figure 3.Switch ON Voltage vs. ISWITCH Current In
Step-Down Mode
INPUT VOLTAGE – V
QUIESCENT CURRENT – µAFigure 4.Quiescent Current vs. Input Voltage
ADP1111–Typical CharacteristicsFigure 5.Oscillator Frequency vs. Input Voltage
Figure 6.Maximum Switch Current vs. RLIM
Figure 7.Oscillator Frequency vs. Temperature
TEMPERATURE – 8C
ON TIME – µs
070Figure 8. Switch ON Time vs. Temperature
TEMPERATURE – 8C
DUTY CYCLE – %
070Figure 9. Duty Cycle vs. Temperature
TEMPERATURE – 8C
SATURATION VOLTAGE – V
070 Figure 10. Saturation Voltage vs. Temperature in Step-Up
Mode
Figure 11. Switch ON Voltage vs. Temperature in Step-
Down Mode
TEMPERATURE – 8C
QUIESCENT CURRENT – µA
450Figure 12. Quiescent Current vs. Temperature
Figure 13. Feedback Bias Current vs. Temperature
ADP1111
THEORY OF OPERATIONThe ADP1111 is a flexible, low-power, switch-mode power
supply (SMPS) controller. The regulated output voltage can be
greater than the input voltage (boost or step-up mode) or less
than the input (buck or step-down mode). This device uses a
gated-oscillator technique to provide very high performance
with low quiescent current.
A functional block diagram of the ADP1111 is shown on
the first page of this data sheet. The internal 1.25 V reference is
connected to one input of the comparator, while the other input
is externally connected (via the FB pin) to a feedback network
connected to the regulated output. When the voltage at the FB
pin falls below 1.25 V, the 72 kHz oscillator turns on. A driver
amplifier provides base drive to the internal power switch, and
the switching action raises the output voltage. When the voltage
at the FB pin exceeds 1.25 V, the oscillator is shut off. While
the oscillator is off, the ADP1111 quiescent current is only
300μA. The comparator includes a small amount of hysteresis,
which ensures loop stability without requiring external compo-
nents for frequency compensation.
The maximum current in the internal power switch can be set
by connecting a resistor between VIN and the ILIM pin. When the
maximum current is exceeded, the switch is turned OFF. The
current limit circuitry has a time delay of about 1 μs. If an
external resistor is not used, connect ILIM to VIN. Further
information on ILIM is included in the “APPLICATIONS”
section of this data sheet.
The ADP1111 internal oscillator provides 7 μs ON and 7 μs
OFF times that are ideal for applications where the ratio
between VIN and VOUT is roughly a factor of two (such as
converting +3 V to + 5 V). However, wider range conversions
(such as generating +12 V from a +5 V supply) can easily be
accomplished.
An uncommitted gain block on the ADP1111 can be connected
as a low-battery detector. The inverting input of the gain block
is internally connected to the 1.25 V reference. The noninverting
input is available at the SET pin. A resistor divider, connected
between VIN and GND with the junction connected to the SET
pin, causes the AO output to go LOW when the low battery set
The ADP1111 provides external connections for both the
collector and emitter of its internal power switch that permit
both step-up and step-down modes of operation. For the step-
up mode, the emitter (Pin SW2) is connected to GND, and the
collector (Pin SW1) drives the inductor. For step-down mode,
the emitter drives the inductor while the collector is connected
to VIN.
The output voltage of the ADP1111 is set with two external
resistors. Three fixed-voltage models are also available:
ADP1111–3.3 (+3.3 V), ADP1111–5 (+5 V) and ADP1111–12
(+12 V). The fixed-voltage models are identical to the
ADP1111, except that laser-trimmed voltage-setting resistors
are included on the chip. On the fixed-voltage models of the
ADP1111, simply connect the feedback pin (Pin 8) directly to
the output voltage.
COMPONENT SELECTION
General Notes on Inductor SelectionWhen the ADP1111 internal power switch turns on, current
begins to flow in the inductor. Energy is stored in the inductor
core while the switch is on, and this stored energy is transferred
to the load when the switch turns off. Since both the collector
and the emitter of the switch transistor are accessible on the
ADP1111, the output voltage can be higher, lower, or of
opposite polarity than the input voltage.
To specify an inductor for the ADP1111, the proper values of
inductance, saturation current and dc resistance must be
determined. This process is not difficult, and specific equations
for each circuit configuration are provided in this data sheet. In
general terms, however, the inductance value must be low
enough to store the required amount of energy (when both
input voltage and switch ON time are at a minimum) but high
enough that the inductor will not saturate when both VIN and
switch ON time are at their maximum values. The inductor
must also store enough energy to supply the load, without
saturating. Finally, the dc resistance of the inductor should be
low so that excessive power will not be wasted by heating the
windings. For most ADP1111 applications, an inductor ofμH to 100 μH with a saturation current rating of 300 mA to
1 A and dc resistance <0.4 Ω is suitable. Ferrite-core inductors
that meet these specifications are available in small, surface-
mount packages.
To minimize Electro-Magnetic Interference (EMI), a toroid or
pot-core type inductor is recommended. Rod-core inductors are
a lower-cost alternative if EMI is not a problem.
CALCULATING THE INDUCTOR VALUESelecting the proper inductor value is a simple three step
process:Define the operating parameters: minimum input voltage,
maximum input voltage, output voltage and output current.Select the appropriate conversion topology (step-up, step-
down, or inverting).Calculate the inductor value using the equations in the
following sections.
TEMPERATURE – 8C
BIAS CURRENT – µA
070Figure 14.Set Pin Bias Current vs. Temperature
INDUCTOR SELECTION–STEP-UP CONVERTERIn a step-up or boost converter (Figure 18), the inductor must
store enough power to make up the difference between the input
voltage and the output voltage. The power that must be stored
is calculated from the equation: PL=VOUT+VD−VIN(MIN)()•IOUT()(Equation 1)
where VD is the diode forward voltage (0.5 V for a 1N5818
Schottky). Because energy is only stored in the inductor while
the ADP1111 switch is ON, the energy stored in the inductor
on each switching cycle must be equal to or greater than:
OSC
(Equation 2)
in order for the ADP1111 to regulate the output voltage.
When the internal power switch turns ON, current flow in the
inductor increases at the rate of: t()=VIN1−e
−R©t(Equation 3)
where L is in Henrys and R' is the sum of the switch equivalent
resistance (typically 0.8 Ω at +25°C) and the dc resistance of
the inductor. In most applications, the voltage drop across the
switch is small compared to VIN so a simpler equation can be
used:t()=VINt(Equation 4)
Replacing ‘t’ in the above equation with the ON time of the
ADP1111 (7 μs, typical) will define the peak current for a given
inductor value and input voltage. At this point, the inductor
energy can be calculated as follows: =1L•I2PEAK(Equation 5)
As previously mentioned, EL must be greater than PL/fOSC so
that the ADP1111 can deliver the necessary power to the load.
For best efficiency, peak current should be limited to 1 A or
less. Higher switch currents will reduce efficiency because of
increased saturation voltage in the switch. High peak current
also increases output ripple. As a general rule, keep peak current
as low as possible to minimize losses in the switch, inductor and
diode.
In practice, the inductor value is easily selected using the
equations above. For example, consider a supply that will
generate 12 V at 40 mA from a 9 V battery, assuming a 6 V
end-of-life voltage. The inductor power required is, from
Equation 1: PL=12V+0.5V−6V()•40mA()=260mW
On each switching cycle, the inductor must supply:
fOSC=260mWkHz=3.6μJ
Since the required inductor power is fairly low in this example,
the peak current can also be low. Assuming a peak current of
Substituting a standard inductor value of 68 μH with 0.2 Ω dc
resistance will produce a peak switch current of:
IPEAK=6V
1.0Ω1−e
−1.0Ω•7μs
68μH=587mA
Once the peak current is known, the inductor energy can be
calculated from Equation 5: EL=168μH()•587mA()=11.7μJ
Since the inductor energy of 11.7 μJ is greater than the PL/fOSC
requirement of 3.6 μJ, the 68 μH inductor will work in this
application. By substituting other inductor values into the same
equations, the optimum inductor value can be selected.
When selecting an inductor, the peak current must not exceed
the maximum switch current of 1.5 A. If the equations shown
above result in peak currents > 1.5 A, the ADP1110 should be
considered. Since this device has a 70% duty cycle, more energy
is stored in the inductor on each cycle. This results is greater
output power.
The peak current must be evaluated for both minimum and
maximum values of input voltage. If the switch current is high
when VIN is at its minimum, the 1.5 A limit may be exceeded at
the maximum value of VIN. In this case, the ADP1111’s current
limit feature can be used to limit switch current. Simply select a
resistor (using Figure 6) that will limit the maximum switch
current to the IPEAK value calculated for the minimum value of
VIN. This will improve efficiency by producing a constant IPEAK
as VIN increases. See the “Limiting the Switch Current” section
of this data sheet for more information.
Note that the switch current limit feature does not protect the
circuit if the output is shorted to ground. In this case, current is
only limited by the dc resistance of the inductor and the forward
voltage of the diode.
INDUCTOR SELECTION–STEP-DOWN CONVERTERThe step-down mode of operation is shown in Figure 19.
Unlike the step-up mode, the ADP1111’s power switch does not
saturate when operating in the step-down mode; therefore,
switch current should be limited to 650 mA in this mode. If the
input voltage will vary over a wide range, the ILIM pin can be
used to limit the maximum switch current. Higher switch
current is possible by adding an external switching transistor as
shown in Figure 21.
The first step in selecting the step-down inductor is to calculate
the peak switch current as follows:
IPEAK=2IOUT
VOUT+VD
VIN−VSW+VD(Equation 6)
whereDC= duty cycle (0.5 for the ADP1111)
VSW= voltage drop across the switch= diode drop (0.5 V for a 1N5818)
ADP1111As previously mentioned, the switch voltage is higher in step-
down mode than in step-up mode. VSW is a function of switch
current and is therefore a function of VIN, L, time and VOUT.
For most applications, a VSW value of 1.5 V is recommended.
The inductor value can now be calculated:=
VINMIN()−VSW−VOUT
IPEAK•tON(Equation 7)
where tON = switch ON time (7 μs).
If the input voltage will vary (such as an application that must
operate from a 9 V, 12 V or 15 V source), an RLIM resistor
should be selected from Figure 6. The RLIM resistor will keep
switch current constant as the input voltage rises. Note that
there are separate RLIM values for step-up and step-down modes
of operation.
For example, assume that +5 V at 300 mA is required from a
+12 V to +24 V source. Deriving the peak current from
Equation 6 yields:
IPEAK=2•300mA
5+0.5−1.5+0.5=600mA
Then, the peak current can be inserted into Equation 7 to
calculate the inductor value: =12−1.5−5
600mA•7μs=64μH
Since 64 μH is not a standard value, the next lower standard
value of 56 μH would be specified.
To avoid exceeding the maximum switch current when the
input voltage is at +24 V, an RLIM resistor should be specified.
Using the step-down curve of Figure 6, a value of 560 Ω will
limit the switch current to 600 mA.
INDUCTOR SELECTION–POSITIVE-TO-NEGATIVE
CONVERTERThe configuration for a positive-to-negative converter using the
ADP1111 is shown in Figure 22. As with the step-up converter,
all of the output power for the inverting circuit must be supplied
by the inductor. The required inductor power is derived from
the formula: P = ILOUTOUTD+()•() (Equation 8)
The ADP1111 power switch does not saturate in positive-to-
negative mode. The voltage drop across the switch can be
modeled as a 0.75 V base-emitter diode in series with a 0.65 Ω
resistor. When the switch turns on, inductor current will rise at
a rate determined by: t()=VL1−e
−R©t(Equation 9)
where:R' = 0.65 Ω + RL(DC)
VL = VIN – 0.75 V
For example, assume that a –5 V output at 50 mA is to be
During each switching cycle, the inductor must supply the
following energy:
fOSC=275mW
72kHz=3.8μJ
Using a standard inductor value of 56 μH with 0.2 Ω dc
resistance will produce a peak switch current of:
IPEAK=4.5V−0.75V
0.65Ω+0.2Ω1−e
−0.85Ω•7μs
56μH=445mA
Once the peak current is known, the inductor energy can be
calculated from (Equation 9): EL=156μH()•445mA()=5.54μJ
Since the inductor energy of 5.54 μJ is greater than the PL/fOSC
requirement of 3.82 μJ, the 56 μH inductor will work in this
application.
The input voltage only varies between 4.5 V and 5.5 V in this
application. Therefore, the peak current will not change enough
to require an RLIM resistor and the ILIM pin can be connected
directly to VIN. Care should be taken, of course, to ensure that
the peak current does not exceed 650 mA.
CAPACITOR SELECTIONFor optimum performance, the ADP1111’s output capacitor
must be selected carefully. Choosing an inappropriate capacitor
can result in low efficiency and/or high output ripple.
Ordinary aluminum electrolytic capacitors are inexpensive but
often have poor Equivalent Series Resistance (ESR) and
Equivalent Series Inductance (ESL). Low ESR aluminum
capacitors, specifically designed for switch mode converter
applications, are also available, and these are a better choice
than general purpose devices. Even better performance can be
achieved with tantalum capacitors, although their cost is higher.
Very low values of ESR can be achieved by using OS-CON
capacitors (Sanyo Corporation, San Diego, CA). These devices
are fairly small, available with tape-and-reel packaging and have
very low ESR.
The effects of capacitor selection on output ripple are demon-
strated in Figures 15, 16 and 17. These figures show the output
of the same ADP1111 converter that was evaluated with three
different output capacitors. In each case, the peak switch
current is 500 mA, and the capacitor value is 100 μF. Figure 15
shows a Panasonic HF-series 16-volt radial cap. When the
switch turns off, the output voltage jumps by about 90 mV and
then decays as the inductor discharges into the capacitor. The
rise in voltage indicates an ESR of about 0.18 Ω. In Figure 16,
the aluminum electrolytic has been replaced by a Sprague 293D
series, a 6 V tantalum device. In this case the output jumps
about 30 mV, which indicates an ESR of 0.06 Ω. Figure 17
shows an OS-CON 16–volt capacitor in the same circuit, and
ESR is only 0.02 Ω.
