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 TA = 25°C. VCC = 3V to 6.5V unless otherwise specified.
SYMBOL PARAMETER CONDITIONS
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
(Note 7)
UNITSMIN TYP MAX MIN TYP MAX
VREF Reference Voltage l1.20 1.24 1.28 1.20 1.24 1.28 V
ISSupply Current No Load, SHDN Floating, Doubler Mode
No Load, SHDN Floating, Tripler Mode
No Load, VSHDN = VCC
l
l
l
600
900
5
1000
1500
20
600
900
5
1500
2000
20
µA
µA
µA
fOSC Internal Oscillator Frequency 550 550 kHz
PEFF Power Efficiency 65 65 %
VOL REG Output Low Voltage IREG = 1mA l0.1 0.8 0.1 0.8 V
IREG REG Sink Current VREG = 0.8V, VCC = 3.3V
VREG = 0.8V, VCC = 5.0V
l
l
5
8
8
15
5
8
8
15
mA
mA
IADJ Adjust Pin Current VADJ = 1.24V l0.01 1 0.01 1 µA
VIH SHDN Input High Voltage l2 2 V
VIL SHDN Input Low Voltage l0.8 0.8 V
IIN SHDN Input Current VSHDN = VCC l5 20 5 25 µA
tON Turn-On Time IOUT = 15mA 500 500 µs
Doubler Mode. VCC = 5V ±10%, C1 = 0.1µF, C2 = 0 (Note 4), COUT = 3.3µF unless otherwise specified.
∆VOUT Output Regulation (Note 2) –1.24V ≥ VOUT ≥ –4V, 0 ≤ IOUT ≤ 8mA
–1.24V ≥ VOUT ≥ –4V, 0 ≤ IOUT ≤ 7mA
–4V ≥ VOUT ≥ –5V, 0 ≤ IOUT ≤ 8mA (Note 6)
l
l
1
2
5
1
2
5
%
%
%
ISC Output Short-Circuit Current VOUT = 0V l60 125 60 125 mA
VRIP Output Ripple Voltage IOUT = 5mA, VOUT = –4V 5 5 mV
LTC1261CS Only. Tripler Mode. VCC = 2.7V, C1 = C2 = 0.1µF (Note 4), COUT = 3.3µF unless otherwise specified.
∆VOUT Output Regulation –1.24V ≥ VOUT ≥ –4V, 0 ≤ IOUT ≤ 5mA l1 5 1 5 %
ISC Output Short-Circuit Current VOUT = 0V l60 125 60 125 mA
VRIP Output Ripple Voltage IOUT = 5mA, VOUT = –4V 5 5 mV
LTC1261CS Only. Tripler Mode. VCC = 3.3V ±10%, C1 = C2 = 0.1µF (Note 4), COUT = 3.3µF unless otherwise specified.
∆VOUT Output Regulation (Note 2) –1.24V ≥ VOUT ≥ –4.5V, 0 ≤ IOUT ≤ 6mA
–4.5V ≥ VOUT ≥ –5V, 0 ≤ IOUT ≤ 3.5mA
l
l
1
2
5
5
1
2
5 %
%
ISC Output Short-Circuit Current VOUT = 0V l35 75 35 75 mA
VRIP Output Ripple Voltage IOUT = 5mA, VOUT = –4V 5 5 mV
LTC1261CS Only. Tripler Mode. VCC = 5V ±10%, C1 = C2 = 0.1µF (Note 4), COUT = 3.3µF unless otherwise specified.
∆VOUT Output Regulation –1.24V ≥ VOUT ≥ –4V, 0 ≤ IOUT ≤ 12mA
–4V ≥ VOUT ≥ –5V, 0 ≤ IOUT ≤ 10mA
l
l
1
2
5
5
1
2
5
5
%
%
ISC Output Short-Circuit Current VOUT = 0V l35 75 35 75 mA
VRIP Output Ripple Voltage IOUT = 5mA, VOUT = –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 TA = 25°C.
Note 4: C1 = C2 = 0.1µF means the specifications apply to tripler mode
where VCC – VOUT = 3VCC (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
VCC – VOUT = 2VCC; 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 VCC – 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.