LT1054LCS8#TR Linear Technology, LT1054LCS8#TR Datasheet - Page 5

• Manufacturer Part Number: LT1054LCS8#TR
• Description: IC CONV VOLT SW CAP REG 8SOIC
• Manufacturer: Linear Technology
• Type: Switched Capacitor (Charge Pump), Doubler, Invertingr

Specifications of LT1054LCS8#TR

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: Adjustable
• Current - Output: 120mA
• Frequency - Switching: 25kHz
• Voltage - Input: 3.5 ~ 7 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Not Compliant

TYPICAL PERFORMANCE CHARACTERISTICS
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 C
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 (C
tions 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 (C
discharged, 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 (t
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.
OUT
) has fully discharged. For most applica-
–12.6
–11.6
–11.8
–12.0
–12.2
–12.4
–4.7
–4.8
–4.9
–5.0
–5.1
–50
Regulated Output Voltage
p
–25
> 100µs) or a logic high. Diode
0
TEMPERATURE (°C)
IN
25
and C
50
OUT
75
are discharged
OUT
LT1054 • TPC09
100
) has fully
125
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
input capacitor (C
and ground. When driven to V
from V
ground. Pin 4, the negative side of the input capacitor, is
driven alternately between ground and V
to ground, Pin 4 sinks current to ground. When driven to
V
flow in the switches is unidirectional as should be expected
using bipolar switches.
V
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
start-up problems with this type of load an external
OUT
OUT
+
/CAP
Pin 4 sources current from C
–100
(Pin 5): In addition to being the output pin this pin
–20
–40
–60
–80
100
+
80
60
40
20
0
. When driven to ground Pin 2 sinks current to
–50
Reference Voltage Temperature
Coefficient
–
V
REF
(Pin 2/Pin 4): Pin 2, the positive side of the
+
–25
terminals to their V
AT 0 = 2.500V
0
TEMPERATURE (°C)
IN
), is alternately driven between V
25
LT1054/LT1054L
50
75
+
, Pin 2 sources current
LT1054 • TPC10
OUT
–
100
terminals. To prevent
. In all cases current
125
OUT
. When driven
1954lff
5
+