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PDF LTC1054 Data sheet ( Hoja de datos )
| Número de pieza | LTC1054 | |
| Descripción | Switched Capacitor Voltage Converter | |
| Fabricantes | Linear Technology Corporation | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de LTC1054 (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
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LT1054/LT1054L
Switched-Capacitor Voltage
Converter with Regulator
FEATURES
s Available in Space Saving SO-8 Package
s Output Current: 100mA (LT1054)
125mA (LT1054L)
s Low Loss: 1.1V at 100mA
www.DataShseetO4Up.ecoramting Range:3.5V to 15V (LT1054)
3.5V to 7V (LT1054L)
s Reference and Error Amplifier for Regulation
s External Shutdown
s External Oscillator Synchronization
s Can Be Paralleled
s Pin Compatible with the LTC®1044/LTC7660
APPLICATI S
s Voltage Inverter
s Voltage Regulator
s Negative Voltage Doubler
s Positive Voltage Doubler
, LTC and LT are registered trademarks of Linear Technology Corporation.
DESCRIPTIO
The LT®1054 is a monolithic, bipolar, switched-capacitor
voltage converter and regulator. The LT1054 provides
higher output current than previously available converters
with significantly lower voltage losses. An adaptive switch
driver scheme optimizes efficiency over a wide range of
output currents. Total voltage loss at 100mA output current
is typically 1.1V. This holds true over the full supply voltage
range of 3.5V to 15V. Quiescent current is typically 2.5mA.
The LT1054 also provides regulation, a feature not previ-
ously available in switched-capacitor voltage converters.
By adding an external resistive divider a regulated output
can be obtained. This output will be regulated against
changes in both input voltage and output current. The
LT1054 can also be shut down by grounding the feedback
pin. Supply current in shutdown is less than 100µA.
The internal oscillator of the LT1054 runs at a nominal
frequency of 25kHz. The oscillator pin can be used to adjust
the switching frequency or to externally synchronize the
LT1054.
The LT1054 is pin compatible with previous converters
such the LTC1044/LTC7660.
BLOCK DIAGRAM
VREF
6
REFERENCE
R
+
2.5V
1
FEEDBACK/
SHUTDOWN
–
R
OSC
7
OSC
VIN
8
DRIVE
CAP + 2
+
Q CIN*
Q
CAP– 4
DRIVE
DRIVE
*EXTERNAL CAPACITORS
DRIVE
3 GND
+
COUT*
5 –VOUT
LT1054 • BD
LT1054/LT1054L Voltage Loss
2
3.5V ≤ VIN ≤ 15V (LT1054)
3.5V ≤ VIN ≤ 7V (LT1054L)
CIN = COUT = 100µF
INDICATES GUARANTEED
TEST POINT
LT1054L
LT1054
1
TJ = 125°C
TJ = 25°C
TJ = –55°C
0
0 25 50 75 100 125
OUTPUT CURRENT (mA)
1054 TA01•
1
1 page  
LT1054/LT1054L
TYPICAL PERFOR A CE CHARACTERISTICS
www.DataSheet4U.com
Regulated Output Voltage
–4.7
–4.8
–4.9
–5.0
–5.1
–11.6
–11.8
–12.0
–12.2
–12.4
–12.6
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
LT1054 • TPC09
Reference Voltage Temperature
Coefficient
100
80 VREF AT 0 = 2.500V
60
40
20
0
–20
–40
–60
–80
–100
–50 –25
0 25 50 75 100 125
TEMPERATURE (°C)
LT1054 • TPC10
PIN FUNCTIONS
FB/SHDN (Pin 1): Feedback/Shutdown Pin. This pin has
two functions. Pulling Pin 1 below the shutdown threshold
(≈ 0.45V) puts the device into shutdown. In shutdown the
reference/regulator is turned off and switching stops. The
switches are set such that both CIN and COUT are dis-
charged through the output load. Quiescent current in
shutdown drops to approximately 100µA (see Typical
Performance Characteristics). Any open-collector gate can
be used to put the LT1054 into shutdown. For normal
(unregulated) operation the device will start back up when
the external gate is shut off. In LT1054 circuits that use the
regulation feature, the external resistor divider can provide
enough pull-down to keep the device in shutdown until the
output capacitor (COUT) has fully discharged. For most
applications where the LT1054 would be run intermittently,
this does not present a problem because the discharge time
of the output capacitor will be short compared to the off-
time of the device. In applications where the device has to
start up before the output capacitor (COUT) has fully dis-
charged, a restart pulse must be applied to Pin 1 of the
LT1054. Using the circuit of Figure 5, the restart signal can
be either a pulse (tp > 100µs) or a logic high. Diode coupling
the restart signal into Pin 1 will allow the output voltage to
come up and regulate without overshoot. The resistor
divider R3/R4 in Figure 5 should be chosen to provide a
signal level at pin 1 of 0.7V to 1.1V.
Pin 1 is also the inverting input of the LT1054’s error
amplifier and as such can be used to obtain a regulated
output voltage.
CAP +/CAP – (Pin 2/Pin 4): Pin 2, the positive side of the
input capacitor (CIN), is alternately driven between V + and
ground. When driven to V +, Pin 2 sources current from V +.
When driven to ground Pin 2 sinks current to ground. Pin
4, the negative side of the input capacitor, is driven alter-
nately between ground the VOUT. When driven to ground,
Pin 4 sinks current to ground. When driven to VOUT Pin 4
sources current from COUT. In all cases current flow in the
switches is unidirectional as should be expected using
bipolar switches.
VOUT (Pin 5): In addition to being the output pin this pin is
also tied to the substrate of the device. Special care must
be taken in LT1054 circuits to avoid pulling this pin
positive with respect to any of the other pins. Pulling Pin
5 positive with respect to Pin 3 (GND) will forward bias the
substrate diode which will prevent the device from starting.
This condition can occur when the output load driven by the
LT1054 is referred to its positive supply (or to some other
positive voltage). Note that most op amps present just such
a load since their supply currents flow from their V+
terminals to their V– terminals. To prevent start-up prob-
lems with this type of load an external transistor must be
added as shown in Figure 1. This will prevent VOUT (Pin 5)
5
5 Page 
LT1054/LT1054L
TYPICAL APPLICATIONS N
www.DataSheet4U.com
Bipolar Supply Doubler
VIN
3.5V TO 15V
+VOUT
+
–
+
100µF
+
10µF
+
10µF
+
10µF
FB/SHDN V+
CAP+ OSC
LT1054
GND VREF
CAP – VOUT
100µF
+
VIN = 3.5V TO 15V
+VOUT ≈ 2VIN – (VL + 2VDIODE)
–VOUT ≈ –2VIN + (VL + 2VDIODE)
VL = LT1054 VOLTAGE LOSS
= 1N4001
100µF
–VOUT
LT1054 • TAO7
+
10µF
+
5µF
FB/SHDN V+
CAP+ OSC
LT1054 #1
GND VREF
CAP – VOUT
5V to ±12V Converter
VIN = 5V
VOUT ≈ 12V
IOUT = 25mA
100µF
2N2219
1k
1N914
+
100µF
5µF
1N914
+
10µF FB/SHDN V+
+ CAP+ OSC
10µF LT1054 #2
GND VREF
CAP – VOUT
TO PIN 4
LT1054 #1
20k
100µF
VOUT ≈ –12V
IOUT = 25mA
LT1054 • TAO8
INPUT TTL
OR CMOS
LOW FOR ON
Strain Gauge Bridge Signal Conditioner
10k
10k
2N2907
5V
0.022µF 8
2
1 A1
1/2 LT1013
3
200k
100k
100k
10k
40Ω ZERO
TRIM
301k
350Ω
+
10µF
5k
GAIN
5k TRIM
6–
A2
10k 5 +1/2 LT1013
4
1µF
1M
7
+
10µF
FB/SHDN V+ 5V
CAP+ OSC
3k
2N2222
LT1054
GND VREF
CAP – VOUT
+ 100µF
TANTALUM
LT1054 • TAO9
A = 125 FOR 0V TO 3V OUT FROM FULL-SCALE
BRIDGE OUTPUT OF 24mV
11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet LTC1054.PDF ] | |
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