LTC1429 Datasheet, PDF (3/12 Pages) Linear Technology – Clock-Synchronized Switched Capacitor Regulated Voltage Inverter

LTC1429
ELECTRICAL CHARACTERISTICS Tripler Mode,V_CC = 3.3V, C1 = C2 = 0.1µF (Note 4), C_OUT = 3.3µF,
F_SYNC = 700kHz with 50% duty cycle square wave, unless otherwise noted.
SYMBOL
∆V_OUT
I_SC
V_RIP
PARAMETER
Output Regulation
Output Short Circuit Current
Output Ripple Voltage
CONDITIONS
– 1.24V ≥ V_OUT ≥ – 4V, 0 ≤ I_OUT ≤ 12mA
– 4V ≥ V_OUT ≥ – 5V, 0 ≤ I_OUT ≤ 8mA
V_OUT = 0V
I_OUT = 5mA, V_OUT = – 4V
MIN
q
q
q
LTC1429CS
TYP
MAX
1
5
2
5
35
75
5
UNITS
%
%
mA
mV
Doubler Mode, V_CC = 5V, C1 = 0.1µF, C2 = 0 (Note 4), C_OUT = 3.3µF, F_SYNC =700kHz with 50% duty cycle, unless otherwise noted.
LTC1429CS8/LTC1429CS
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
∆V_OUT
V_OUT
I_SC
V_RIP
Output Regulation
Output Voltage
Output Short Circuit Current
Output Ripple Voltage
– 1.24V ≥ V_OUT ≥ – 4V, 0 ≤ I_OUT ≤ 10mA
q
– 4V ≥ V_OUT ≥ – 4.5V, 0 ≤ I_OUT ≤ 10mA (Note 6) q
1
5
%
2
5
%
V_OUT Set to – 4V, 0 ≤ I_OUT ≤ 10mA
q – 3.80
– 4.00 – 4.20
V
V_OUT = 0V
q
80
125
mA
I_OUT = 5mA, V_OUT = – 4V
10
mV
The q denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: Setting output to < – 7V will exceed the total voltage maximum
rating with a 5V supply. With supplies higher than 4V the output should
never be set to exceed (V_CC – 12V).
Note 3: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground, unless otherwise
specified. 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 = 3.3V_CC (LTC1429CS only; the LTC1429CS8 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 LTC1429CS, this means C1 connects from C1⁺
to C2^– with C1^– and C2⁺ floating. For the LTC1429CS8 in doubler mode,
C1 connects from C1⁺ to C1^– ; there are no C2 pins.
Note 5: Adjustable output parts only; does not apply to fixed output parts.
Note 6: For output voltages below – 4.5V, the LTC1429 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: LTC1429 will operate with square wave of 40% to 60% duty cycle.
For best performance, use a square wave with 50% duty cycle.
Note 8: Maximum frequency is not tested. Typical part can be used
beyond 2MHz.
TYPICAL PERFORMANCE CHARACTERISTICS
(See Test Circuits; Figure 1 for Doubler Mode, Figure 2 for Tripler Mode)
Output Voltage vs Output Current
–4.10
–4.08
–4.06
T_A = 25°C
–4.04
–4.02
–4.00
–3.98
V_CC = 3.3V
TRIPLER MODE
V_CC = 5V
DOUBLER MODE
–3.96
– 3.94
–3.92
–3.90
0 1 2 3 4 5 6 7 8 9 10
OUTPUT CURRENT (mA)
LTC1429 • TPC01
Output Voltage vs Supply Voltage
–4.08
–4.07
T_A = 25°C
–4.06
–4.05
–4.04
DOUBLER MODE
I_L = 5mA
–4.03
–4.02
TRIPLER MODE
I_L = 5mA
–4.01
–4.00
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
SUPPLY VOLTAGE (V)
LTC1429 • TPC02
Maximum Output Current vs
Supply Voltage
45
40 ^{VOUT = –4V ± 5%}
T_A = 25°C
35
30
25
20
TRIPLER MODE
DOUBLER MODE
15
10
5
0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
SUPPLY VOLTAGE (V)
LTC1429 • TPC03
3