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ADP1073 の電気的特性と機能

ADP1073のメーカーはAnalog Devicesです、この部品の機能は「Micropower DC.DC Converter Adjustable and Fixed 3.3 V/ 5 V/ 12 V」です。


製品の詳細 ( Datasheet PDF )

部品番号 ADP1073
部品説明 Micropower DC.DC Converter Adjustable and Fixed 3.3 V/ 5 V/ 12 V
メーカ Analog Devices
ロゴ Analog Devices ロゴ 




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ADP1073 Datasheet, ADP1073 PDF,ピン配置, 機能
a
Micropower DC–DC Converter
Adjustable and Fixed 3.3 V, 5 V, 12 V
ADP1073
FEATURES
Operates at Supply Voltages from 1.0 V to 30 V
Ground Current 100 A
Works in Step-Up or Step-Down Mode
Very Few External Components Required
Low Battery Detector On-Chip
User-Adjustable Current Limit
Internal 1 A Power Switch
Fixed and Adjustable Output Voltage Versions
8-Lead DIP or SO-8 Package
APPLICATIONS
Single-Cell to 5 V Converters
Laptop and Palmtop Computers
Pagers
Cameras
Battery Backup Supplies
Cellular Telephones
Portable Instruments
4 mA–20 mA Loop Powered Instruments
Hand-Held Inventory Computers
GENERAL DESCRIPTION
The ADP1073 is part of a family of step-up/step-down switch-
ing regulators that operates from an input supply voltage of as
little as 1.0 V. This extremely low input voltage allows the
ADP1073 to be used in applications requiring use of a single
cell battery as the primary power source.
The ADP1073 can be configured to operate in either step-up or
step-down mode but for input voltages greater than 3 V, the
ADP1173 is recommended.
An auxiliary gain amplifier can serve as a low battery detector or
linear regulator. Quiescent current on the ADP1073-5 is only
100 µA unloaded, making it ideal for systems where long battery
life is required.
The ADP1073 can deliver 40 mA at 5 V from an input voltage
range as low as 1.25 V, or 10 mA at 5 V from a 1.0 V input.
Current limiting is available by adding an external resistor.
FUNCTIONAL BLOCK DIAGRAMS
SET
VIN
212mV
REFERENCE
A2
GAIN BLOCK/
ERROR AMP
ADP1073
A1 OSCILLATOR
COMPARATOR
DRIVER
GND
FB
AO
ILIM
SW1
SW2
ADP1073
SET
VIN
212mV
REFERENCE
ADP1073-3.3
ADP1073-5
ADP1073-12
A2
GAIN BLOCK/
ERROR AMP
A1 OSCILLATOR
AO
ILIM
SW1
R1
GND
COMPARATOR
DRIVER
R2
904k
ADP1073-3.3: R1 = 62.1k
ADP1073-5: R1 = 40k
ADP1073-12: R1 = 16.3k
SENSE
ADP1073-3.3, 5, 12
SW2
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 1997

1 Page





ADP1073 pdf, ピン配列
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage, Step-Up Mode . . . . . . . . . . . . . . . 15 V
Input Supply Voltage, Step-Down Mode . . . . . . . . . . . . . 36 V
SW1 Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 V
SW2 Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . .–0.4 V to VIN
Feedback Pin Voltage (ADP1073) . . . . . . . . . . . . . . . . . . . 5 V
Switch Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5 A
Maximum Power Dissipation . . . . . . . . . . . . . . . . . . 500 mW
Operating Temperature Range (A) . . . . . . . . . . 0°C to +70°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . +300°C
1.5V
AA CELL*
CADDELL-BURNS
7200-12
82H
ILIM
VIN
SW1
ADP1073-5
SENSE
GND SW2
1N5818
+5V
40mA
100F
SANYO
OS-CON
OPERATES WITH CELL VOLTAGEՆ1.0V
*ADD 10F DECOUPLING CAPACITOR IF BATTERY
IS MORE THAN 2 INCHES AWAY FROM ADP1073
Figure 1. Typical Application
ORDERING GUIDE
Model*
Output
Voltage
ADP1073AN
ADP1073AR
ADP1073AN-3.3
ADP1073AR-3.3
ADP1073AN-5
ADP1073AR-5
ADP1073AN-12
ADP1073AR-12
ADJ
ADJ
3.3 V
3.3 V
5V
5V
12 V
12 V
NOTES
**Temperature Range: 0°C to +70°C.
**N = Plastic DIP; SO = Small Outline Package.
Package
Options**
N-8
SO-8
N-8
SO-8
N-8
SO-8
N-8
SO-8
ADP1073
PIN FUNCTION DESCRIPTIONS
Pin Mnemonic Function
1 ILIM
For normal conditions this pin is con-
nected to VIN. When a lower current
limit is required, a resistor should be
connected between ILIM and VIN. Limit-
ing the switch current to 400 mA is
achieved by connecting a 220 resistor.
2 VIN
3 SW1
Input Voltage.
Collector Node of Power Transistor.
For step-down configuration, connect to
VIN; for step-up configuration, connect
to an inductor/diode.
4 SW2
Emitter Node of Power Transistor. For
step- down configuration, connect to
inductor/diode; for step-up configura-
tion, connect to ground. Do not allow
this pin to drop more than a diode drop
below ground.
5 GND
Ground.
6 AO
Auxiliary Gain (GB) Output. The open
collector can sink 100 µA.
7 SET
Gain Amplifier Input. The amplifier’s
positive input is connected to the SET
pin and its negative input is connected
to the 212 mV reference.
8 FB/SENSE On the ADP1073 (adjustable) version
this pin is connected to the comparator
input. On the ADP1073-3.3, ADP1073-
5 and ADP1073-12, the pin goes di-
rectly to the internal application resistor
that sets output voltage.
PIN CONFIGURATIONS
8-Lead Plastic DIP
(N-8)
8-Lead Small Outline Package
(SO-8)
ILIM 1
8 FB (SENSE)*
VIN 2 ADP1073 7 SET
TOP VIEW
SW1 3 (Not to Scale) 6 AO
SW2 4
5 GND
* FIXED VERSIONS
ILIM 1
8 FB (SENSE)*
VIN 2 ADP1073 7 SET
TOP VIEW
SW1 3 (Not to Scale) 6 AO
SW2 4
5 GND
* FIXED VERSIONS
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the ADP1073 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.
REV. 0
–3–
WARNING!
ESD SENSITIVE DEVICE


3Pages


ADP1073 電子部品, 半導体
ADP1073
COMPONENT SELECTION
General Notes on Inductor Selection
When the ADP1073 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 then trans-
ferred to the load when the switch turns off. Both the collector
and the emitter of the switch transistor are accessible on the
ADP1073, so the output voltage can be higher, lower or of
opposite polarity than the input voltage.
To specify an inductor for the ADP1073, the proper values of
inductance, saturation current and dc resistance must be deter-
mined. 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 satu-
rating. Finally, the dc resistance of the inductor should be low
so that excessive power will not be wasted by heating the
windings. For most ADP1073 applications, an 82 µH to
1000 µH inductor with a saturation current rating of 300 mA to
1 A is suitable. Ferrite core inductors that meet these specifica-
tions 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 Value
Selecting the proper inductor value is a simple three-step process:
1. Define the operating parameters: minimum input voltage,
maximum input voltage, output voltage and output current.
2. Select the appropriate conversion topology (step-up, step-
down or inverting).
3. Calculate the inductor value, using the equations in the
following sections.
Inductor Selection—Step-Up Converter
In a step-up, or boost, converter (Figure 15), 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 +V D V IN(MIN ) × IOUT
(1)
where VD is the diode forward voltage (0.5 V for a 1N5818
Schottky). Energy is only stored in the inductor while the
ADP1073 switch is ON, so the energy stored in the inductor on
each switching cycle must be must be equal to or greater than:
PL
f OSC
(2)
in order for the ADP1073 to regulate the output voltage.
When the internal power switch turns ON, current flow in the
inductor increases at the rate of:
I
L
(t
)
=
V IN
R
1–
e
Rt
L

(3)
where L is in henrys and R' is the sum of the switch equivalent
resistance (typically 0.8 at +25°C) and the dc resistance of
the inductor. If the voltage drop across the switch is small com-
pared to VIN, a simpler equation can be used:
IL
(t)
=V IN
L
t
(4)
Replacing t in the above equation with the ON time of the ADP1073
(38 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:
EL
=
1
2
L
×
I 2PEAK
(5)
As previously mentioned, EL must be greater than PL/fOSC so the
ADP1073 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 satu-
ration 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 equa-
tions above. For example, consider a supply that will generate
5 V at 25 mA from two alkaline batteries with a 2 V end-of-life
voltage. The inductor power required is, from Equation 1:
PL = (5V + 0.5V – 2V )×(25 mA) = 87.5 mW
On each switching cycle, the inductor must supply:
PL = 87.5 mW = 4.6 µJ
f OSC 19 kHz
Since the inductor power is low, the peak current can also be
low. Assuming a peak current of 100 mA as a starting point,
Equation 4 can be rearranged to recommend an inductor value:
L = V IN t = 2V 38 µs = 760 µH
IL(MAX ) 100 mA
Substituting a standard inductor value of 470 µH, with 1.2 dc
resistance, will produce a peak switch current of:
I PEAK
=
2V
2.0
1 –
–2.0 Ω × 38 µs
e 470 µH 
= 149
mA
Once the peak current is known, the inductor energy can be
calculated from Equation 5:
EL
=
1 (470
2
µH
)×
(149
mA)2
=
5.2
µJ
The inductor energy of 5.2 µJ is greater than the PL/fOSC re-
quirement of 4.6 µJ, so the 470 µH inductor will work in this
application. The optimum inductor value can be determined
by substituting other inductor values into the same equations.
When selecting an inductor, the peak current must not exceed
the maximum switch current of 1.5 A.
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, then the 1.5 A limit may be exceeded
at the maximum value of VIN. In this case, the ADP1073’s current
–6– REV. 0

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部品番号部品説明メーカ
ADP1073

Micropower DC.DC Converter Adjustable and Fixed 3.3 V/ 5 V/ 12 V

Analog Devices
Analog Devices


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