LTC1261
3
1261fb
For more information www.linear.com/LTC1261
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 3V to 6.5V unless otherwise specified.
SYMBOL PARAMETER CONDITIONS
0°C ≤ T
A
≤ 70°C
–40°C ≤ T
A
≤ 85°C
(Note 7)
UNITSMIN TYP MAX MIN TYP MAX
V
REF
Reference Voltage
l
1.20 1.24 1.28 1.20 1.24 1.28 V
I
S
Supply Current No Load, SHDN Floating, Doubler Mode
No Load, SHDN Floating, Tripler Mode
No Load, V
SHDN
= V
CC
l
l
l
600
900
5
1000
1500
20
600
900
5
1500
2000
20
µA
µA
µA
f
OSC
Internal Oscillator Frequency 550 550 kHz
P
EFF
Power Efficiency 65 65 %
V
OL
REG Output Low Voltage I
REG
= 1mA
l
0.1 0.8 0.1 0.8 V
I
REG
REG Sink Current V
REG
= 0.8V, V
CC
= 3.3V
V
REG
= 0.8V, V
CC
= 5.0V
l
l
5
8
8
15
5
8
8
15
mA
mA
I
ADJ
Adjust Pin Current V
ADJ
= 1.24V
l
0.01 1 0.01 1 µA
V
IH
SHDN Input High Voltage
l
2 2 V
V
IL
SHDN Input Low Voltage
l
0.8 0.8 V
I
IN
SHDN Input Current V
SHDN
= V
CC
l
5 20 5 25 µA
t
ON
Turn-On Time I
OUT
= 15mA 500 500 µs
Doubler Mode. V
CC
= 5V ±10%, C1 = 0.1µF, C2 = 0 (Note 4), C
OUT
= 3.3µF unless otherwise specified.
∆V
OUT
Output Regulation (Note 2) –1.24V ≥ V
OUT
≥ –4V, 0 ≤ I
OUT
≤ 8mA
–1.24V ≥ V
OUT
≥ –4V, 0 ≤ I
OUT
≤ 7mA
–4V ≥ V
OUT
≥ –5V, 0 ≤ I
OUT
≤ 8mA (Note 6)
l
l
1
2
5
1
2
5
%
%
%
I
SC
Output Short-Circuit Current V
OUT
= 0V
l
60 125 60 125 mA
V
RIP
Output Ripple Voltage I
OUT
= 5mA, V
OUT
= –4V 5 5 mV
LTC1261CS Only. Tripler Mode. V
CC
= 2.7V, C1 = C2 = 0.1µF (Note 4), C
OUT
= 3.3µF unless otherwise specified.
∆V
OUT
Output Regulation –1.24V ≥ V
OUT
≥ –4V, 0 ≤ I
OUT
≤ 5mA
l
1 5 1 5 %
I
SC
Output Short-Circuit Current V
OUT
= 0V
l
60 125 60 125 mA
V
RIP
Output Ripple Voltage I
OUT
= 5mA, V
OUT
= –4V 5 5 mV
LTC1261CS Only. Tripler Mode. V
CC
= 3.3V ±10%, C1 = C2 = 0.1µF (Note 4), C
OUT
= 3.3µF unless otherwise specified.
∆V
OUT
Output Regulation (Note 2) –1.24V ≥ V
OUT
≥ –4.5V, 0 ≤ I
OUT
≤ 6mA
–4.5V ≥ V
OUT
≥ –5V, 0 ≤ I
OUT
≤ 3.5mA
l
l
1
2
5
5
1
2
5 %
%
I
SC
Output Short-Circuit Current V
OUT
= 0V
l
35 75 35 75 mA
V
RIP
Output Ripple Voltage I
OUT
= 5mA, V
OUT
= –4V 5 5 mV
LTC1261CS Only. Tripler Mode. V
CC
= 5V ±10%, C1 = C2 = 0.1µF (Note 4), C
OUT
= 3.3µF unless otherwise specified.
∆V
OUT
Output Regulation –1.24V ≥ V
OUT
≥ –4V, 0 ≤ I
OUT
≤ 12mA
–4V ≥ V
OUT
≥ –5V, 0 ≤ I
OUT
≤ 10mA
l
l
1
2
5
5
1
2
5
5
%
%
I
SC
Output Short-Circuit Current V
OUT
= 0V
l
35 75 35 75 mA
V
RIP
Output Ripple Voltage I
OUT
= 5mA, V
OUT
= –4V 5 5 mV
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: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3: All typicals are given at T
A
= 25°C.
Note 4: C1 = C2 = 0.1µF means the specifications apply to tripler mode
where V
CC
– V
OUT
= 3V
CC
(LTC1261CS only; the LTC1261CS8 cannot be
connected in tripler
mode) with C1 connected between C1
+
and C1
–
and
C2 connected between C2
+
and C2
–
. C2 = 0 implies doubler mode where
V
CC
– V
OUT
= 2V
CC
; for the LTC1261CS this means C1 connects from C1
+
to C2
–
with C1
–
and C2
+
floating. For the LTC1261CS8 in doubler mode,
C1 connects from C1
+
to C1
–
; there are no C2 pins.
Note 5: Setting output to <–7V will exceed the absolute voltage maximum
rating with a 5V supply. With supplies higher than 5V, the output should
never be set to exceed V
CC
– 12V.
Note 6: For output voltages below –4.5V the LTC1261 may reach 50%
duty cycle and fall out of regulation with heavy load or low input voltages.
Beyond this point, the output will follow the
input with no regulation.
Note 7: The LTC1261C is guaranteed to meet specifications from 0°C
to 70°C and is designed, characterized and expected to meet industrial
temperature limits, but is not tested at –40°C and 85°C. The LTC1261IS8
is guaranteed to meet specifications from –40°C and 85°C.
