a
FEATURES
Greater Than 95% Efficiency
Current Mode Switching Architecture Provides
Superior Load and Line Transient Response
Wide Input Voltage Range 3.5 V* to 16 V
User Defined Current Limit
Short Circuit Protection
Shutdown Pin
Low Dropout Voltage
Low Standby Current 160 A typ
Low Cost
Available in 8-Lead PDIP or 8-Lead SOIC
APPLICATIONS
Portable Computers
Modems
Cellular Telephones
Portable Equipment
GPS Systems
Handheld Instruments
GENERAL DESCRIPTION
High Efficiency Step-Down
Switching Regulator Controllers
ADP1147-3.3/ADP1147-5
FUNCTIONAL BLOCK DIAGRAM
V
IN
P-DRIVE GROUND
SENSE(+) SENSE(–)
ADP1147
2
R
Q
S
SLEEP
1
Q
R
S
S
V
TH2
V
TH1
T
OFF-TIME
CONTROL
V
IN
V
B
C 10mV to 150mV
V
OS
13k
G
1.25V
5pF
100k
REFERENCE
SENSE(–)
C
T
I
TH
SHUTDOWN
The ADP1147 is part of a family of High Efficiency Step-Down
Switching Regulators. These regulators offer superior load and
line transient response, a user defined current limit and an
automatic power savings mode. The automatic power savings
mode is used to maintain efficiency at lower output currents.
The ADP1147 incorporates a constant off-time, current mode
switching architecture to drive an external P-channel MOSFET
at frequencies up to 250 kHz. Constant off-time switching gen-
erates a constant ripple current in the external inductor. This
results in a wider input voltage operating range of 3.5 V* to
16 V, and a less complex circuit design.
*3.5
volt operation is for the ADP1147-3.3.
P-CHANNEL
IRF7204
L
*
50 H
D1
30BQ040
V
IN
P-DRIVE
R
SENSE
**
0.05
A very low dropout voltage with excellent output regulation can
be obtained by minimizing the dc resistance of the Inductor, the
R
SENSE
resistor, and the R
DS(ON)
of the P-MOSFET. The power
savings mode conserves power by reducing switching losses at
lower output currents. When the output load current falls below
the minimum required for the continuous mode the ADP1147
will automatically switch to the power savings mode. It will remain
in this mode until the inductor requires additional current or the
sleep mode is entered. In sleep mode with no load the standby
power consumption of the device is reduced to 2.0 mW typical
at V
IN
= 10 V.
For designs requiring even greater efficiencies refer to the
ADP1148 data sheet.
100
95
V
IN
= 6 VOLTS
V
IN
(5.2V TO 12V)
+
1 F
+
C
IN
V
OUT
5V/2A
OUT
90
EFFICIENCY – %
V
IN
= 10 VOLTS
85
80
75
70
65
100 F
0V = NORMAL
1.5V = SHUTDOWN
C
C
R
C
3300pF 1k
+
C
390 F
ADP1147
SHUTDOWN
I
TH
SENSE(+)
C
T
SENSE(–)
GND
*COILTRONICS CTX 50–2MP
**KRL SL-1-C1-0R050J
SHUTDOWN
1000pF
C
T
470pF
60
1
10
100
LOAD CURRENT – mA
1k
10k
Figure 1. High Efficiency Step-Down Converter
(Typical Application)
Figure 2. ADP1147-5 Typical Efficiency, Figure 1 Circuit
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., 1998
ADP1147-3.3/ADP1147-5–SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
(0 C
≤
T
≤
+70 C , V
1
A
IN
= 10 V, V
SHUTDOWN
= 0 V unless otherwise noted)
V
S
V
OUT
3.23
4.90
∆V
OUT
–40
∆V
OUT
0
40
60
50
1.6
160
160
10
+40
65
100
mV
mV
mV
mV p-p
mA
µA
µA
µA
3.33
5.05
3.43
5.20
V
V
ADP1147
Min Typ Max
Units
Parameter
REGULATED OUTPUT VOLTAGE
ADP1147-3-3
ADP1147-5
OUTPUT VOLTAGE LINE REGULATION
Conditions
V
IN
= 9 V
I
LOAD
= 700 mA
I
LOAD
= 700 mA
T
A
= +25°C
V
IN
= 7 V to 12 V,
I
LOAD
= 50 mA
5 mA < I
LOAD
< 2 A
5 mA < I
LOAD
< 2 A
T
A
= +25°C, I
LOAD
= 0 A
T
A
= +25°C
4 V < V
IN
< 16 V
4 V < V
IN
< 16 V
4 V < V
IN
< 16 V
V
SHUTDOWN
= 2.1 V, 4 V < V
IN
< 16 V
V
SENSE
(–) = V
OUT+
100 mV (
Forced
)
T
A
= +25°C
V
SENSE
(–) = V
OUT–
100 mV (
Forced
)
V
SENSE
(–) = V
OUT+
100 mV (
Forced
)
T
A
= +25°C
V
SENSE
(–) = V
OUT–
100 mV (
Forced
)
T
A
= +25°C
0 V < V
SHUTDOWN
< 8 V, V
IN
= 16 V
T
A
= +25°C
T
A
= +25°C, V
OUT
in Regulation,
V
SENSE
(–) = V
OUT,
V
OUT
= 0 V
C
T
= 390 pF, I
LOAD
= 700 mA
T
A
= +25°C
C
L
= 3000 pF (Pin 8) V
IN
= 6 V
OUTPUT VOLTAGE LOAD REGULATION
ADP1147-3.3
ADP1147-5
Sleep Mode Output Ripple
INPUT DC SUPPLY CURRENT
2
Normal Mode
Sleep Mode (ADP1147-3.3)
Sleep Mode (ADP1147-5)
Shutdown
CURRENT SENSE THRESHOLD VOLTAGE
ADP1147-3.3
I
Q
2.3
250
250
22
V
5
–V
4
120
10
150
170
mV
mV
ADP1147-5
120
V
6
I
6
50
I
2
t
OFF
tr, tf
4
0.6
10
150
0.8
1.2
70
2
5
100
170
2
5
90
10
6
200
mV
mV
V
µA
µA
µA
µs
ns
SHUTDOWN PIN THRESHOLD
SHUTDOWN PIN INPUT CURRENT
C
T
PIN DISCHARGE CURRENT
OFF-TIME
DRIVER OUTPUT TRANSITION TIMES
NOTES
1
All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.
2
Dynamic supply current is higher due to the gate charge being delivered at the switching frequency.
Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage (Pin 1) . . . . . . . . . . . . . . 16 V to –0.3 V
Continuous Output Current (Pin 8) . . . . . . . . . . . . . . 50 mA
Sense Voltages (Pins 4, 5) . . . . . . . . . . . . . . . . 10 V to –0.3 V
Operating Ambient Temperature Range . . . . . 0°C to +70°C
Extended Commercial Temperature Range . . –40°C to +85°C
Junction Temperature* . . . . . . . . . . . . . . . . . . . . . . . +150°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . +300°C
*T
J
is calculated from the ambient temperature, T
A,
and power dissipation, P
D
,
according to the following formulas: ADP1147AN-3.3, ADP1147AN-5: T
J
= T
A
+
(P
D
×
110°C/W). ADP1147AR-3.3, ADP1147AR-5: T
J
= T
A
+(P
D
×
150°C/W).
ORDERING GUIDE
Model
ADP1147AN-3.3
ADP1147AR-3.3
ADP1147AN-5
ADP1147AR-5
Output
Voltage
3.3 V
3.3 V
5V
5V
Package
Description
Plastic DIP
SOIC
Plastic DIP
SOIC
Package
Option
N-8
SO-8
N-8
SO-8
–2–
REV. 0
ADP1147-3.3/ADP1147-5
ELECTRICAL CHARACTERISTICS
(–40 C
≤
T
Parameter
REGULATED OUTPUT VOLTAGE
ADP1147-3.3
ADP1147-5
INPUT DC SUPPLY CURRENT
Normal Mode
Sleep Mode (ADP1147-3.3)
Sleep Mode (ADP1147-5)
Shutdown
CURRENT SENSE THRESHOLD VOLTAGE
ADP1147-3.3
A
≤
+85 C , V
IN
= 10 V, unless otherwise noted)
V
S
V
OUT
ADP1147
Min Typ Max
3.17
4.85
3.33
5.05
1.6
160
160
10
3.4
5.2
2.6
280
280
28
Units
V
V
mA
µA
µA
µA
1
Conditions
V
IN
= 9 V
I
LOAD
= 700 mA
I
LOAD
= 700 mA
4 V < V
IN
< 16 V
4 V < V
IN
< 16 V
5 V < V
IN
< 16 V
V
SHUTDOWN
= 2.1 V, 4 V < V
IN
< 16 V
V
SENSE
(–) = V
OUT+
100 mV (Forced)
T
A
= +25°C
V
SENSE
(–) = V
OUT–
100 mV (
Forced
)
V
SENSE
(–) = V
OUT+
100 mV (
Forced
)
T
A
= +25°C
V
SENSE
(–) = V
OUT–
100 mV (
Forced
)
C
T
= 390 pF, I
LOAD
= 700 mA
I
Q
V
5
–V
4
120
25
150
25
150
0.8
5
175
mV
mV
mV
mV
V
µs
ADP1147-5
120
V
6
t
OFF
0.55
3.8
175
2
6
SHUTDOWN PIN THRESHOLD
OFF-TIME
NOTES
1
All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.
Specifications subject to change without notice.
PIN FUNCTION DESCRIPTIONS
Pin
No.
1
2
3
4
5
6
7
8
Mnemonic
V
IN
C
T
I
TH
SENSE(–)
SENSE(+)
SHUTDOWN
GND
P-DRIVE
Function
Input Voltage.
External Capacitor Connection. This capacitor sets the operating frequency of the device. The frequency is
also dependent on the input voltage level.
Error Amplifier Decoupling Pin. Pin 3 voltage level causes the comparator current threshold to increase.
This connects to internal resistive divider, which senses the output voltage. Pin 4 is also the (–) input for the
current comparator.
This provides the + input to the current comparator. The offset between Pins 4 and 5 together with R
SENSE
establish the current trip threshold.
When this pin is pulled high, it keeps the MOSFET turned off. When the pin is pulled to ground, the
ADP1147 functions normally. This pin cannot be left floating.
Independent ground lines must be connected separately to (a) the negative pin of C
OUT
and (b) the cathode
of the Schottky diode and the negative terminal of C
IN
.
Provides high current drive for the MOSFET. Voltage swing is from V
IN
to ground at this pin.
PIN CONFIGURATIONS
8-Lead SOIC (SO-8)
8-Lead Plastic DIP (N-8)
V
IN
1
C
T
2
8 P-DRIVE
V
IN
1
C
T
2
I
TH
3
SENSE– 4
TOP VIEW
(Not to Scale)
8 P-DRIVE
7 GND
TOP VIEW
I
TH
3 (Not to Scale) 6 SHUTDOWN
SENSE– 4
5 SENSE+
ADP1147
ADP1147
7 GND
6 SHUTDOWN
5 SENSE+
T
JMAX
= 125 C,
JA
= 110 C/W
T
JMAX
= 125 C,
JA
= 150 C/W
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 ADP1147 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–
ADP1147-3.3/ADP1147-5–Performance Characteristics
200
1000
V
SENSE
= V
OUT
= +5V
800
1000
L = 50 H
R
SENSE
= 0.02
L = 25 H
R
SENSE
= 0.02
C
OUT
– F
800
CAPACITANCE – pF
150
600
V
IN
= +12V
400
V
IN
= +10V
600
R
SENSE
– m
100
400
L = 50 H
R
SENSE
= 0.05
50
200
V
IN
= +7V
200
0
0
1
2
3
4
5
MAXIMUM OUTPUT CURRENT – Amps
0
0
100
200
FREQUENCY – kHz
300
0
0
1
2
3
4
(V
IN
– V
OUT
) VOLTAGE – Volts
5
Figure 3. Selecting R
SENSE
vs.
Maximum Output Current
Figure 4. Operating Frequency vs.
Timing Capacitor
Figure 5. Selecting Minimum Output
Capacitor vs. (V
IN
– V
OUT
) and Inductor
100
GATE CHARGE
95
EFFICIENCY – %
I
2
R
100
FIGURE 1 CIRCUIT
95
EFFICIENCY – %
5.11
FIGURE 1 CIRCUIT
5.10
OUTPUT VOLTAGE – V
1 AMP
5.09
100mA
5.08
5.07
5.06
5.05
5.04
1 AMP
4
8
12
INPUT VOLTAGE – V
16
300mA
ADP1147 I
Q
90
0.1 AMP
90
SCHOTTKY
DIODE
85
80
85
75
80
10m
70
30m
0.1
0.3
I
OUT
– Amps
1
3
5
8
11
14
17
INPUT VOLTAGE – Volts
20
5.03
Figure 6. Typical Efficiency Losses
Figure 7. Efficiency vs. Input Voltage
Figure 8. ADP1147-5 Output Voltage
vs. Input Voltage
40
35
5.11
FIGURE 1 CIRCUIT
5.10
SUPPLY CURRENT – mA
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
SLEEP MODE
SUPPLY CURRENT – A
OUTPUT VOLTAGE – V
5.09
5.08
V
IN
= 6 VOLTS
5.07
5.06
5.05
5.04
5.03
5.02
0
400
800
1200
1600
LOAD CURRENT – mA
2000
V
IN
= 12 VOLTS
ACTIVE MODE
V
SHUTDOWN
= +2V
30
25
20
15
10
5
0
4
6
8
10
12
14
16
INPUT VOLTAGE – Volts
18
20
0
4
6
8
10 12 14
16
INPUT VOLTAGE – Volts
18
20
Figure 9. Load Regulation
Figure 10. DC Supply Current
Figure 11. Supply Current in
Shutdown
–4–
REV. 0
ADP1147-3.3/ADP1147-5
1.8
0°C
1.6
30
80
70
60
GATE CHARGE CURRENT – mA
NORMALIZED FREQUENCY
25
1.4
+25°C
1.2
1.0
0.8
0.6
0.4
0.2
0
1
2
4
6
8
(V
IN
– V
OUT
) – Volts
10
12
+70°C
OFF-TIME – s
20
Q
N
+ Q
P
= 100nC
15
10
5
Q
N
+ Q
P
= 50nC
0
20
50 80 110 140 170 200 230 260
OPERATING FREQUENCY – kHz
50
+5V
40
30
20
10
+3.3V
0
0.3 0.5 1 1.5 2 2.5 3 3.3 3.5 4 4.5 5
OUTPUT VOLTAGE – Volts
Figure 12. Operating Frequency vs.
(V
IN
–V
OUT
)
Figure 13. Gate Charge Supply
Current
Figure 14. Off-Time vs. V
OUT
155
MAXIMUM THRESHOLD
150
SENSE VOLTAGE – mV
EFFICIENCY – %
95
3.35
100mA
3.34
90
OUTPUT VOLTAGE – V
1 AMP
85
0.1 AMP
80
3.33
3.32
3.31
300mA
145
140
1 AMP
3.30
3.29
3.28
135
75
130
0
25
70
85
TEMPERATURE – C
100
70
5
8
11
14
17
INPUT VOLTAGE – Volts
20
3.27
4
8
12
INPUT VOLTAGE – Volts
16
Figure 15. Current Sense Threshold
Voltage
Figure 16. Efficiency vs. Input
Voltage at V
O
= 3.3 V; Figure 1
Circuit with ADP1147-3.3
Figure 17. Output Voltage vs. Input
Voltage (V
O
= 3.3 V); Figure 1 Circuit
with ADP1147-3.3
3.36
3.34
OUTPUT VOLTAGE – V
3.32
3.30
3.28
3.26
3.24
3.22
3.20
3.18
0
400
800
1200
1600
LOAD CURRENT – mA
2000
V
IN
= 12 VOLTS
V
IN
= 6 VOLTS
Figure 18. Load Regulation (V
O
= 3.3 V);
Figure 1 Circuit with ADP1147-3.3
REV. 0
–5–
Embedded System
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