LTC1144
Switched-Capacitor
Wide Input Range
Voltage Converter
with Shutdown
FeaTures
n
n
n
n
n
n
DescripTion
The
LTC
®
1144
is a monolithic CMOS switched-capacitor
voltage converter. It performs supply voltage conversion
from positive to negative from an input range of 2V to
18V, resulting in complementary output voltages of –2V to
–18V. Only two noncritical external capacitors are needed
for the charge pump and charge reservoir functions.
The converter has an internal oscillator that can be
overdriven by an external clock or slowed down when
connected to a capacitor. The oscillator runs at a 10kHz
frequency when unloaded. A higher frequency outside the
audio band can also be obtained if the Boost Pin is tied to
V
+
. The
SHDN
pin reduces supply current to 8µA and can
be used to save power when the converter is not in use.
The LTC1144 contains an internal oscillator, divide-by- two,
voltage level shifter, and four power MOSFETs. A special
logic circuit will prevent the power N-channel switch
substrate from turning on.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
n
n
Wide Operating Supply Voltage Range: 2V to 18V
Boost Pin (Pin 1) for Higher Switching Frequency
Simple Conversion of 15V to –15V Supply
Low Output Resistance: 120Ω Maximum
Power Shutdown to 8µA with
SHDN
Pin
Open Circuit Voltage Conversion Efficiency:
99.9% Typical
Power Conversion Efficiency: 93% Typical
Easy to Use
applicaTions
n
n
n
n
n
n
n
Conversion of 15V to ±15V Supplies
Inexpensive Negative Supplies
Data Acquisition Systems
High Voltage Upgrade to LTC1044 or 7660
Voltage Division and Multiplications
Automotive Applications
Battery Systems with Wall Adapter/Charger
Typical applicaTion
Generating –15V from 15V
LTC1144
1
BOOST
CAP
+
GND
CAP
–
V
+
OSC
SHDN
V
OUT
8
7
OUTPUT VOLTAGE (V)
6
5
10µF
1144 TA01
Output Voltage vs Load Current, V
+
= 15V
–15
R
OUT
= 56
T
A
= 25°C
15V INPUT
–14
10µF
+
2
3
4
–15V OUTPUT
–13
+
–12
–11
–10
0
10
30
40
20
LOAD CURRENT (mA)
50
1144 TA02
1144fa
For more information
www.linear.com/LTC1144
1
LTC1144
absoluTe MaxiMuM raTings
(Note 1)
Supply Voltage (V
+
) (Transient) ...............................20V
Supply Voltage (V
+
) (Operating) .............................. 18V
Input Voltage on Pins 1, 6, 7
(Note 2) ............................ –0.3V < V
IN
< (V
+
) + 0.3V
Output Short-Circuit Duration
V
+
≤ 10V ..................................................... Indefinite
V
+
≤ 15V .......................................................... 30 sec
V
+
≤ 20V ............................................. Not Protected
Power Dissipation ............................................. 500mW
Operating Temperature Range
LTC1144C................................................. 0°C to 70°C
LTC1144I ..............................................–40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
pin conFiguraTion
TOP VIEW
BOOST 1
CAP
+
2
GND 3
CAP
–
4
8
7
6
5
V
+
OSC
SHDN
V
OUT
BOOST 1
CAP
+
2
GND 3
CAP
–
4
TOP VIEW
8
7
6
5
V
+
OSC
SHDN
V
OUT
N8 PACKAGE
8-LEAD PLASTIC DIP
T
JMAX
= 110°C,
θ
JA
= 100°C/W
S8 PACKAGE
8-LEAD PLASTIC SOIC
T
JMAX
= 110°C,
θ
JA
= 130°C/W
orDer inForMaTion
LEAD FREE FINISH
LTC1144CN8#PBF
LTC1144IN8#PBF
LTC1144CS8#PBF
LTC1144IS8#PBF
TAPE AND REEL
LTC1144CN8#TRPBF
LTC1144IN8#TRPBF
LTC1144CS8#TRPBF
LTC1144IS8#TRPBF
PART MARKING
LTC1144CN8
LTC1144IN8
1144
1144I
PACKAGE DESCRIPTION
8-Lead Plastic DIP
8-Lead Plastic DIP
8-Lead Plastic SOIC
8-Lead Plastic SOIC
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
1144fa
2
For more information
www.linear.com/LTC1144
LTC1144
The
l
denotes the specifications which apply over the full operating
temperature range,V = 15V, C
OSC
= 0pF, Test Circuit Figure 1, otherwise specifications are at T
A
= 25°C.
LTC1144C
SYMBOL
I
S
PARAMETER
Supply Voltage Range
Supply Current
CONDITIONS
R
L
= 10k
l
elecTrical
+
characTerisTics
LTC1144I
MAX
18
1.1
1.3
MIN
2
TYP
MAX
18
1.1
1.6
0.008
0.035
0.10
0.15
0.002
56
90
10
4
90
97.0
93
99.9
0.5
4
0.018
100
140
300
UNITS
V
mA
mA
mA
mA
mA
mA
Ω
Ω
Ω
kHz
kHz
%
%
µA
µA
MIN
2
TYP
R
L
= ∞, Pins 1, 6 No Connection,
l
f
OSC
= 10kHz
SHDN
= 0V, R
L
= ∞, Pins 1, 7
No Connection
V
+
= 5V, R
L
= ∞, Pins 1, 6
No Connection, f
OSC
= 4kHz
V
+
= 5V,
SHDN
= 0V, R
L
= ∞,
Pins 1, 7 No Connection
l
0.008
0.03
0.10
0.13
l
l
0.002
56
0.015
100
120
250
R
OUT
Output Resistance
V
+
= 15V, I
L
= 20mA at 10kHz
l
V
+
= 5V, I
L
= 3mA at 4kHz
f
OSC
Oscillator Frequency
Power Efficiency
Voltage Conversion Efficiency
V
+
= 15V (Note 3)
V
+
= 5V
R
L
= 2k at 10kHz
R
L
= ∞
l
90
10
4
l
l
90
97.0
93
99.9
0.5
4
Oscillator Sink or Source Current V
+
= 5V (V
OSC
= 0V to 5V)
V
+
= 15V (V
OSC
= 0V to 15V)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
Connecting any input terminal to voltages greater than V
+
or less
than ground may cause destructive latch-up. It is recommended that no
inputs from sources operating from external supplies be applied prior to
power-up of the LTC1144.
Note 3:
f
OSC
is tested with C
OSC
= 100pF to minimize the effects of test
fixture capacitance loading. The 0pF frequency is correlated to this 100pF
test point, and is intended to simulate the capacitance at pin 7 when the
device is plugged into a test socket and no external capacitor is used.
1144fa
For more information
www.linear.com/LTC1144
3
LTC1144
Typical perForMance characTerisTics
Output Resistance
vs Supply Voltage
300
250
OUTPUT RESISTANCE ( )
OUTPUT RESISTANCE ( )
200
150
100
50
0
T
A
= 25°C
140
120
100
80
60
40
20
–55 –25
V
+
= 5V
I
L
= 3mA
Output Resistance vs
Temperature
1000
OSCILLATOR FREQUENCY (kHz)
Oscillator Frequency
vs Supply Voltage
T
A
= 25°C
C
OSC
= 0
BOOST = V
+
100
V
+
= 15V
I
L
= 20mA
10
BOOST = OPEN OR GROUND
2
4
6
10 12 14
8
SUPPLY VOLTAGE (V)
16
18
50
25
75
0
TEMPERATURE (°C)
100
125
1
2
4
6
8
10 12
14
SUPPLY VOLTAGE (V)
16
18
LTC1144 • TPC01
LTC1144 • TPC02
LTC1144 • TPC03
Oscillator Frequency as a
Function of C
OSC
1000
OSCILLATOR FREQUENCY (kHz)
100
BOOST = V
+
10
1
BOOST = OPEN OR GROUND
0.1
T
A
= 25°C
V
+
= 15V
Oscillator Frequency
vs Temperature
1000
OSCILLATOR FREQUENCY (kHz)
T
A
= 25°C
V
+
= 15V
OUTPUT VOLTAGE (V)
BOOST = V
+
0
Output Voltage vs Load Current
T
A
= 25°C
V
+
= 15V
C1 = C2 = 10µF
BOOST = OPEN
100
–5
10
BOOST = OPEN OR GROUND
–10
R
OUT
= 56Ω
0.01
100
10
1000
1
10000
EXTERNAL CAPACITANCE (PIN 7 TO GND), C
OSC
(pF)
LTC1144 • TPC04
1
–55 –25
0
25
50
75
TEMPERATURE (°C)
100
125
–15
0
10
20
30
40
LOAD CURRENT (mA)
50
60
LTC1144 • TPC05
LTC1144 • TPC06
Output Voltage vs Load Current
0
T
A
= 25°C
V
+
= 5V
C1 = C2 = 10µF
BOOST = OPEN
10000
Supply Current as a Function of
Oscillator Frequency
POWER CONVERSION EFFICIENCY (%)
T
A
= 25°C
C1 = C2 = 10µF
100
Power Conversion Efficiency and
Supply Current vs Load Current
100
P
EFF
80
I
S
80
SUPPLY CURRENT (mA)
–1
OUTPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
1000
V
+
= 15V
100
V
+
= 5V
10
–2
60
40
20
60
40
T
A
= 25°C
V
+
= 15V
20
C1 = C2 = 10µF
BOOST = OPEN
(SEE TEST CIRCUIT)
0
10
30
40
50
20
LOAD CURRENT (mA)
LTC1144 • TPC09
–3
R
OUT
= 90
–4
–5
0
5
10
15
20
LOAD CURRENT (mA)
25
30
1
0.01
1
10
0.1
OSCILLATOR FREQUENCY (kHz)
100
0
0
LTC1144 • TPC07
LTC1144 • TPC08
1144fa
4
For more information
www.linear.com/LTC1144
LTC1144
Typical perForMance characTerisTics
Power Conversion Efficiency and
Supply Current vs Load Current
100
POWER CONVERSION EFFICIENCY (%)
P
EFF
50
POWER CONVERSION EFFICIENCY (%)
100
95
90
85
80
75
70
I
L
= 20mA
0.1
1
10
OSCILLATOR FREQUENCY (kHz)
100
0
0.1
1µF
1µF
100µF
100µF
10µF
10µF
I
L
= 3mA
Power Conversion Efficiency
vs Oscillator Frequency
T
A
= 25°C, V
+
= 15V
BOOST = OPEN
3000
Output Resistance
vs Oscillator Frequency
T
A
= 25°C
V
+
= 15V
60
40
20
30
20
T
A
= 25°C
V
+
= 5V
C1 = C2 = 10µF
BOOST = OPEN
(SEE TEST CIRCUIT)
20
10
OUTPUT RESISTANCE ( )
80
40
SUPPLY CURRENT (mA)
2000
10µF
1µF
I
S
1000
100µF
1
10
OSCILLATOR FREQUENCY (kHz)
100
0
0
4
12
16
8
LOAD CURRENT (mA)
0
LTC1144 • TPC10
LTC1144 • TPC11
LTC1144 • TPC12
Ripple Voltage vs Load Current
1500
V
+
= 5V
T
A
= 25°C
C1 = C2
BOOST = 5V
BOOST =
OPEN
0
–1
OUTPUT VOLTAGE (V)
1µF
0.1µF
0.1µF
500
10µF
1µF
Output Voltage vs Load Current
V
+
= 5V
T
A
= 25°C
C1 = C2
BOOST = 5V
BOOST = OPEN
0.1µF
0
Output Voltage vs Load Current
V
+
= 15V
T
A
= 25°C
C1 = C2
BOOST = 15V
BOOST = OPEN
RIPPLE VOLTAGE (mV)
OUTPUT VOLTAGE (V)
1000
–2
0.1µF 10µF
1µF
–5
–3
–4
1µF
10µF
0.1µF
–10
0.1µF
1µF
1µF
10µF
10µF
0.01
10
0.1
1
LOAD CURRENT (mA)
100
10µF
0
0.01
0.1
1
10
LOAD CURRENT (mA)
100
LTC1144 • TPC13
–5
0.001
0.01
0.1
1
10
LOAD CURRENT (mA)
100
–15
0.001
LTC1144 • G14
LTC1144 • TPC15
pin FuncTions
Boost (Pin 1):
This pin will raise the oscillator frequency
by a factor of 10 if tied high.
CAP
+
(Pin 2):
Positive Terminal for Pump Capacitor.
GND (Pin 3):
Ground Reference.
CAP
–
(Pin 4):
Negative Terminal for Pump Capacitor.
V
OUT
(Pin 5):
Output of the Converter.
SHDN
(Pin 6):
Shutdown Pin. Tie to V
+
pin or leave float-
ing for normal operation. Tie to ground when in shutdown
mode.
OSC (Pin 7):
Oscillator Input Pin. This pin can be overdriven
with an external clock or can be slowed down by connect-
ing an external capacitor between this pin and ground.
V
+
(Pin 8):
Input Voltage.
1144fa
For more information
www.linear.com/LTC1144
5
京公网安备 11010802033920号
EEWORLD
