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FEATURES
Inverts Input Supply Voltage
99% Voltage Conversion Efficiency
25 mA Output Current
Shutdown Function
Requires Only Two Capacitors
1 F Capacitors
18 Output Resistance
+1.5 V to +5.5 V Input Range
600 A Quiescent Current
20 nA Shutdown Current (ADM8828)
APPLICATIONS
Handheld Instruments
LCD Panels
Cellular Phones
PDAs
Remote Data Acquisition
Op Amp Power Supplies
Switched-Capacitor
Voltage Inverter with Shutdown
ADM8828/ADM8829
FUNCTIONAL BLOCK DIAGRAMS
OUT 1
IN 2
6 CAP+
5 SHDN
TOP VIEW
(Not to Scale) 4
CAP– 3
GND
ADM8828
OUT 1
IN 2
6 CAP+
5 NC
TOP VIEW
(Not to Scale) 4
CAP– 3
GND
NC = NO CONNECT
ADM8829
GENERAL DESCRIPTION
The ADM8828/ADM8829 is a charge-pump voltage inverter
which may be used to generate a negative supply from a positive
input. Input voltages ranging from +1.5 V to +5.5 V can be
inverted into a negative –1.5 V to –5.5 V output supply. This
inverting scheme is ideal for generating a negative rail in single
power-supply systems. Only two small external capacitors are
needed for the charge pump. Output currents up to 25 mA with
greater than 99% efficiency are achievable.
The ADM8828 also features a low power shutdown (SHDN)
pin. This can be used to disable the device and reduce the quies-
cent current to 20 nA.
The ADM8828/ADM8829 is available in a 6-lead SOT-23
package.
+1.5V TO +5.5V
INPUT
CAP+
C1 +
1 F
IN
ADM8828/
ADM8829
CAP–
SHDN
SHUTDOWN
CONTROL
INVERTED
NEGATIVE
OUTPUT
GND
OUT
C2
+1 F
Figure 1. Typical Circuit Configuration
REV. A
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., 1999
ADM8828/ADM8829–SPECIFICATIONS
Parameter
Input Voltage, IN
Supply Current
Output Current
Output Resistance
Output Ripple
Charge-Pump Frequency
Power Efficiency
Voltage Conversion Efficiency
99.5
25
18
25
130
50
65
120
90
87
99.96
98
91
0.02
2.0
0.8
Shutdown Exit Time
175
NOTES
1
C1 and C2 are low ESR (<0.2
Ω)
electrolytic capacitors. High ESR will degrade performance.
Specifications subject to change without notice.
(V
IN
= +5 V, C1, C2 = 1 F,
1
T
A
= T
MIN
to T
MAX
unless other-
wise noted)
Units
V
µA
mA
Ω
mV p-p
mV p-p
kHz
kHz
%
%
%
%
%
Test Conditions/Comments
R
L
= 10 kΩ
Unloaded
I
L
= 5 mA
I
L
= 5 mA
I
L
= 25 mA
V
IN
= +2.25 V
R
L
= 200
Ω
R
L
= 1 kΩ
No Load
R
L
= 1 kΩ
R
L
= 200
Ω
SHDN = IN
SHDN High = Disabled
SHDN Low = Enabled
I
L
= 5 mA
Min
1.5
Typ
Max
5.5
600
1000
28
190
Shutdown Supply Current, I
SHDN
Shutdown Input Voltage, V
SHDN
2
µA
V
V
µs
ABSOLUTE MAXIMUM RATINGS*
(T
A
= +25°C unless otherwise noted)
PIN FUNCTION DESCRIPTIONS
Input Voltage (IN to GND) . . . . . . . . . . . . . . . –0.3 V to +6 V
OUT to GND . . . . . . . . . . . . . . . . . . . . . . . . –6.0 V to +0.3 V
OUT, IN Output Current (Continuous) . . . . . . . . . . . . 50 mA
Output Short Circuit Duration to GND . . . . . . . . . . . 10 secs
Power Dissipation, RT-6 . . . . . . . . . . . . . . . . . . . . . . 570 mW
(Derate 8.3 mW/°C above +70°C)
θ
JA
, Thermal Impedance . . . . . . . . . . . . . . . . . . . . 120°C/W
Operating Temperature Range
Industrial (A Version) . . . . . . . . . . . . . . . . – 40°C to +85°C
Storage Temperature Range . . . . . . . . . . . –65°C to +150°C
Lead Temperature Range (Soldering 10 sec) . . . . . . . . +300°C
Vapor Phase (70 sec) . . . . . . . . . . . . . . . . . . . . . . . . +215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . +220°C
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >3500 V
*This is a stress rating only and functional operation of the device at these or any
other conditions above those indicated in the operation section of this specification
is not implied. Exposure to absolute maximum rating conditions for extended
periods may affect device reliability.
Mnemonic
CAP+
GND
CAP–
OUT
SHDN
Function
Positive Charge-Pump Capacitor Terminal.
Power Supply Ground.
Negative Charge-Pump Capacitor Terminal.
Output, Negative Voltage.
Shutdown Control Input. This input, when
high, is used to disable the charge pump
thereby reducing the power consumption.
Positive Power Supply Input.
IN
PIN CONFIGURATIONS
OUT 1
IN 2
6 CAP+
5 SHDN
TOP VIEW
(Not to Scale) 4
CAP– 3
GND
ADM8828
ORDERING GUIDE
Model
ADM8828ART
ADM8829ART
Temperature
Range
–40°C to +85°C
–40°C to +85°C
Branding
Information
MM0
MN0
Package
Option*
RT-6
RT-6
OUT 1
IN 2
6 CAP+
5 NC
TOP VIEW
(Not to Scale) 4
CAP– 3
GND
NC = NO CONNECT
ADM8829
*RT-6 = 6-lead SOT-23.
–2–
REV. A
Typical Performance Characteristics– ADM8828/ADM8829
0.8
60
I
L
= 5mA
OUTPUT VOLTAGE RIPPLE – mV p-p
0.7
50
SUPPLY CURRENT – mA
0.6
0.5
0.4
0.3
0.2
0.1
0
1
1.5
2
2.5
3
3.5
4
SUPPLY VOLTAGE – V
4.5
5
5.5
OUTPUT VOLTAGE RIPPLE
@ V
IN
= 4.75V
40
30
OUTPUT VOLTAGE RIPPLE
@ V
IN
= 1.9V
20
OUTPUT VOLTAGE RIPPLE
@ V
IN
= 3.15V
10
0
0.47
1
2.2
CAPACITANCE – F
3.3
Figure 2. Power Supply Current vs. Voltage
Figure 5. Output Voltage Ripple vs. Capacitance
35
30
350
OUTPUT VOLTAGE RIPPLE – mV p-p
300
OUTPUT VOLTAGE RIPPLE
@ V
IN
= 4.75V, V
OUT
= –4.0V
OUTPUT RESISTANCE –
25
20
15
250
200
150
OUTPUT VOLTAGE RIPPLE
@ V
IN
= 3.15V, V
OUT
= –2.5V
10
5
0
1.5
100
50
OUTPUT VOLTAGE RIPPLE
@ V
IN
= 1.9V, V
OUT
= –1.5V
2.2
1
CAPACITANCE – F
3.3
2
2.5
3
3.5
4
SUPPLY VOLTAGE – V
4.5
5
5.5
0
0.47
Figure 3. Output Source Resistance vs. Supply Voltage
Figure 6. Output Voltage Ripple vs. Capacitance
20
18
16
OUTPUT CURRENT @ V
IN
= 4.75V
0
–0.5
–1
OUTPUT VOLTAGE @ V
IN
= 2.0V
OUTPUT CURRENT – mA
14
12
10
8
6
4
2
0
0.47
2.2
1
CAPACITANCE – F
3.3
OUTPUT CURRENT @ V
IN
= 1.9V
OUTPUT CURRENT @ V
IN
= 3.15V
OUTPUT VOLTAGE – V
–1.5
–2
OUTPUT VOLTAGE @ V
IN
= 3.3V
–2.5
–3
–3.5
–4
–4.5
–5
0
5
10
15
20
25
30
OUTPUT CURRENT – mA
35
40
45
OUTPUT VOLTAGE @ V
IN
= 5.0V
Figure 4. Output Current vs. Capacitance
Figure 7. Output Voltage vs. Output Current
REV. A
–3–
ADM8828/ADM8829
100
P
EFF
@ V
IN
= 5.0V
90
80
70
200
180
160
PUMP FREQUENCY – kHz
P
EFF
@ V
IN
= 3.3V
P
EFF
@ V
IN
= 2.0V
PUMP FREQUENCY
@ V
IN
= 3.3V
PUMP FREQUENCY
@ V
IN
= 5.0V
140
120
100
80
60
40
20
PUMP FREQUENCY
@ V
IN
= 1.5V
P
EFF
– %
60
50
40
30
20
10
0
0
5
10
15
20
25
30
I
OUT
– mA
35
40
45
50
0
–50
–30
–10
10
25
40
60
80
TEMPERATURE – C
90
110
125
Figure 8. Power Efficiency vs. Output Current
Figure 10. Charge Pump Frequency vs. Temperature
50
45
40
OUTPUT RESISTANCE –
RESISTANCE ( ) @ V
IN
= 1.5V
35
30
25
20
15
10
5
0
–50
–30
–10
10
25
40
60
80
TEMPERATURE – C
90
110
125
RESISTANCE ( ) @ V
IN
= 5.0V
RESISTANCE ( ) @ V
IN
= 3.3V
Figure 9. Output Resistance vs. Temperature
–4–
REV. A
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