a
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
Micropower DC–DC Converter
Adjustable and Fixed 3.3 V, 5 V, 12 V
ADP1073
FUNCTIONAL BLOCK DIAGRAMS
SET
ADP1073
A2
V
IN
GAIN BLOCK/
ERROR AMP
212mV
REFERENCE
I
LIM
SW1
A1
OSCILLATOR
DRIVER
SW2
AO
COMPARATOR
GND
FB
ADP1073
SET
ADP1073-3.3
ADP1073-5
ADP1073-12
V
IN
A2
GAIN BLOCK/
ERROR AMP
212mV
REFERENCE
A1
OSCILLATOR
DRIVER
SW2
AO
I
LIM
SW1
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.
R1
COMPARATOR
R2
904k
ADP1073-3.3: R1 = 62.1k
ADP1073-5: R1 = 40k
ADP1073-12: R1 = 16.3k
SENSE
GND
ADP1073-3.3, 5, 12
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
ADP1073–SPECIFICATIONS
(@ T = 0 C to +70 C, V
A
IN
= 1.5 V unless otherwise noted)
Symbol
I
Q
I
Q
Min
Typ
100
100
100
100
1.15
1.0
200
V
OUT
3.14
4.75
11.4
212
3.30
5.00
12.00
5
90
125
300
f
OSC
14
57
28
19
72
38
60
100
0.15
0.35
0.05
V
CESAT
300
400
700
A
V
I
REV
I
LIM
400
1000
750
400
–0.3
12.6
12.6
30
222
3.47
5.25
12.6
10
130
250
600
24
80
50
300
220
0.4
0.15
450
600
550
750
1000
1500
Max
165
Units
µA
µA
µA
µA
V
V
V
mV
V
V
V
mV
mV
mV
mV
kHz
%
µs
nA
nA
V
%/V
%/V
mV
mV
mV
mV
mV
mV
V/V
mA
mA
%/°C
15
–350
µA
mV
Parameter
QUIESCENT CURRENT
QUIESCENT CURRENT, STEP-UP
MODE CONFIGURATION
INPUT VOLTAGE
Conditions
Switch Off
No Load, ADP1073-3.3
ADP1073-5
ADP1073-12, T
A
= +25°C
Step-Up Mode
Step-Up Mode, T
A
= +25°C
Step-Down Mode
ADP1073
1
ADP1073-3.3
2
ADP1073-5
2
ADP1073-12
2
ADP1073
ADP1073-3.3
ADP1073-5
ADP1073-12
V
IN
COMPARATOR TRIP POINT VOLTAGE
OUTPUT SENSE VOLTAGE
COMPARATOR HYSTERESIS
OUTPUT HYSTERESIS
OSCILLATOR FREQUENCY
MAXIMUM DUTY CYCLE
SWITCH ON TIME
FEEDBACK PIN BIAS CURRENT
SET PIN BIAS CURRENT
AO OUTPUT LOW
REFERENCE LINE REGULATION
SWITCH SATURATION VOLTAGE
STEP-UP MODE
ADP1073 V
FB
= 0 V
V
SET
= V
REF
I
AO
= 100
µA
1.0 V
≤
V
IN
≤
1.5 V
1.5 V
≤
V
IN
≤
12 V
V
IN
= 1.5 V, I
SW
= 400 mA, +25°C
T
MIN
to T
MAX
V
IN
= 1.5 V, I
SW
= 500 mA, +25°C
T
MIN
to T
MAX
V
IN
= 5 V, I
SW
= 1 A, +25°C
T
MIN
to T
MAX
R
L
= 100 kΩ
3
T
A
= +25°C
220
Ω
Between I
LIM
and V
IN
T
A
= +25°C
Full Load (V
FB
< V
REF
)
DC
t
ON
I
FB
I
SET
V
AO
A2 ERROR AMP GAIN
REVERSE BATTERY CURRENT
4
CURRENT LIMIT
CURRENT LIMIT TEMPERATURE
COEFFICIENT
SWITCH-OFF LEAKAGE CURRENT
MAXIMUM EXCURSION BELOW GND
Measured at SW1 Pin
T
A
= +25°C
I
SW1
≤
10
µA,
Switch Off
T
A
= +25°C
I
LEAK
V
SW2
1
–400
NOTES
1
This specification guarantees that both the high and low trip point of the comparator fall within the 200 mV to 222 mV range.
2
This specification guarantees that the output voltage of the fixed versions will always fall within the specified range. The waveform at the sense pin will exhibit a
sawtooth shape due to the comparator hysteresis.
3
100 kΩ resistor connected between a 5 V source and the AO pin.
4
The ADP1073 is guaranteed to withstand continuous application of +1.6 V applied to the GND and SW2 pins while V
IN
, I
LIM
and SW1 pins are grounded.
All limits at temperature extremes are guaranteed via correlation using standard Quality Control methods.
Specifications subject to change without notice.
–2–
REV. 0
ADP1073
ABSOLUTE MAXIMUM RATINGS
PIN FUNCTION DESCRIPTIONS
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 V
IN
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
CADDELL-BURNS
7200-12
82 H
1N5818
I
LIM
1.5V
AA CELL*
V
IN
SW1
+5V
40mA
Pin
1
Mnemonic
I
LIM
Function
For normal conditions this pin is con-
nected to V
IN
. When a lower current
limit is required, a resistor should be
connected between I
LIM
and V
IN.
Limit-
ing the switch current to 400 mA is
achieved by connecting a 220
Ω
resistor.
Input Voltage.
Collector Node of Power Transistor.
For step-down configuration, connect to
V
IN
; for step-up configuration, connect
to an inductor/diode.
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.
Ground.
Auxiliary Gain (GB) Output. The open
collector can sink 100
µA.
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.
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.
2
3
V
IN
SW1
4
SW2
ADP1073-5
SENSE
GND
SW2
100 F
SANYO
OS-CON
OPERATES WITH CELL VOLTAGE 1.0V
*ADD 10 F DECOUPLING CAPACITOR IF BATTERY
IS MORE THAN 2 INCHES AWAY FROM ADP1073
5
6
7
GND
AO
SET
Figure 1. Typical Application
ORDERING GUIDE
Model*
ADP1073AN
ADP1073AR
ADP1073AN-3.3
ADP1073AR-3.3
ADP1073AN-5
ADP1073AR-5
ADP1073AN-12
ADP1073AR-12
Output
Voltage
ADJ
ADJ
3.3 V
3.3 V
5V
5V
12 V
12 V
Package
Options**
N-8
SO-8
N-8
SO-8
N-8
SO-8
N-8
SO-8
8
FB/SENSE
PIN CONFIGURATIONS
8-Lead Plastic DIP
(N-8)
I
LIM
1
V
IN
2
8 FB (SENSE)*
8-Lead Small Outline Package
(SO-8)
I
LIM
1
V
IN
2
8 FB (SENSE)*
NOTES
**Temperature
Range: 0°C to +70°C.
**N = Plastic DIP; SO = Small Outline Package.
7 SET
TOP VIEW
SW1 3 (Not to Scale) 6 AO
SW2 4
5 GND
ADP1073
7 SET
TOP VIEW
SW1 3 (Not to Scale) 6 AO
SW2 4
5 GND
ADP1073
* FIXED VERSIONS
* 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.
WARNING!
ESD SENSITIVE DEVICE
REV. 0
–3–
ADP1073 –Typical Performance Characteristics
1.2
V
IN
= 1.5V
1
VCE (SAT) – Volts
V
IN
= 5.0V
0.8
V
IN
= 3.0V
0.6
0.4
V
IN
= 1.25V
0.2
V
IN
= 1.0V
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
SWITCH CURRENT – Amps
V
IN
= 2.0V
SWITCH ON VOLTAGE – Volts
2
1.8
SWITCH CURRENT – mA
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0.05 0.1
0
0.2
0.3
0.4
0.5
0.6
SWITCH CURRENT – Amps
0.7
10 30
50 70
90 200 400 600 800 1000
R
LIM
–
SATURATION VOLTAGE
1400
1200
1000
800
600
400
200
V
IN
= 1.5V
WITH L = 82 H
V
IN
= 3V
WITH L = 82 H
V
IN
= 12V
WITH L = 150 H
Figure 2. Saturation Voltage vs.
Switch Current in Step-Up Mode
Figure 3. Switch ON Voltage vs.
Switch Current in Step-Down Mode
Figure 4. Maximum Switch Current
vs. R
LIM
1000
120
110
SET PIN BIAS CURRENT – nA
160
140
SUPPLY CURRENT – A
V
IN
= 1.5V
120
100
80
60
40
40
0
25
70
TEMPERATURE – C
85
40
OUTPUT CURRENT – mA
100
90
80
70
60
50
40
100
10
FOR V
IN
> 1.6V,
R
LIM
= 68
0
1
1.5
2
2.5
3
INPUT VOLTAGE – Volts
3.5
0
25
70
TEMPERATURE – C
85
Figure 5. Guaranteed Minimum
Output Current at V
OUT
= 5 V vs.
Input Voltage
Figure 6. Set Pin Bias Current vs.
Temperature
Figure 7. Supply Current vs.
Temperature
22
OSCILLATOR FREQUENCY – kHz
21
20
19
18
17
16
15
14
40
0
25
70
TEMPERATURE – C
85
DUTY CYCLE – %
70
68
66
64
62
60
58
56
SWITCH-ON TIME – s
34.5
34
33.5
33
32.5
32
31.5
31
30.5
40
0
25
70
TEMPERATURE – C
85
30
40
0
25
70
TEMPERATURE – C
85
Figure 8. Oscillator Frequency vs.
Temperature
Figure 9. Duty Cycle vs. Temperature
Figure 10. Switch ON Time vs.
Temperature
–4–
REV. 0
ADP1073
2300
2100
GAIN BLOCK GAIN – V/V
1900
1700
1500
1300
1100
40
V
IN
= 1.5V
R
L
= 100k
0
25
70
TEMPERATURE – C
85
Figure 11. “Gain Block” Gain vs. Temperature
THEORY OF OPERATION
The ADP1073 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 ADP1073 is shown on the
front page. The internal 212 mV 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
212 mV, the 19 kHz oscillator turns on. A driver amplifier pro-
vides base drive to the internal power switch and the switching
action raises the output voltage. When the voltage at the FB pin
exceeds 212 mV, the oscillator is shut off. While the oscillator is
off, the ADP1073 quiescent current is only 100
µA.
The com-
parator includes a small amount of hysteresis, which ensures
loop stability without requiring external components for fre-
quency compensation.
The maximum current in the internal power switch can be set
by connecting a resistor between V
IN
and the I
LIM
pin. When
the maximum current is exceeded, the switch is turned OFF.
The current limit circuitry has a time delay of about 2
µs.
If an
external resistor is not used, connect I
LIM
to V
IN
. Further infor-
mation on I
LIM
is included in the Limiting the Switch Current
section of this data sheet.
The ADP1073 internal oscillator provides 38
µs
ON and 15
µs
OFF times, which is ideal for applications where the ratio be-
tween V
IN
and V
OUT
is roughly a factor of three (such as gener-
ating +5 V from a single 1.5 V cell). Wider range conversions,
as well as step-down converters, can also be accomplished with
a slight loss in the maximum output power that can be obtained.
An uncommitted gain block on the ADP1073 can be connected
as a low-battery detector, linear post-regulator or undervoltage
lockout detector. The inverting input of the gain block is inter-
nally connected to the 212 mV reference. The noninverting
input is available at the SET pin. A resistor divider, connected
between V
IN
and GND with the junction connected to the SET
pin, causes the AO output to go LOW when the input voltage
goes below the low battery set point. The AO output is an open
collector NPN transistor that can sink 100
µA.
The ADP1073 provides external connections for both the col-
lector and emitter of its internal power switch, which permits
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 V
IN
.
The output voltage of the ADP1073 is set with two external
resistors. Three fixed-voltage models are also available:
ADP1073-3.3 (+3.3 V), ADP1073-5 (+5 V) and ADP1073-12
(+12 V). The fixed-voltage models are identical to the ADP1073,
except that laser-trimmed voltage-setting resistors are included
on the chip. Only three external components are required to
form a +3.3 V, +5 V or +12 V converter. On the fixed-voltage
models of the ADP1073, simply connect the feedback pin (Pin
8) directly to the output voltage.
The ADP1073 oscillator only turns on when the output voltage
is below the programmed voltage. When the output voltage is
above the programmed voltage, the ADP1073 remains in its
quiescent state to conserve power. Output ripple, which is in-
herent in gated oscillator converters, is typically 125 mV for a
5 V output and 300 mV for a 12 V output. This ripple voltage
can be greatly reduced by inserting the gain-block between the
output and the FB pin. Further information and a typical circuit
are shown in the Programming the Gain Block section.
REV. 0
–5–
嵌入式系统
