LTC3255_15 Datasheet, PDF (3/16 Pages) Linear Technology – Wide VIN Range Fault Protected 50mA Step-Down Charge Pump

LTC3255
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T_A = 25°C. V_IN = 12V unless otherwise noted. (Notes 2, 3)
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
UNITS
V_IN
V_OUT
V_{UVLO_BK}
Input Voltage Range (Note 7)
Output Voltage Range
V_IN Undervoltage Lockout Threshold
with Shunt Disabled
V_IN Rising, SHUNT = GND
Hysteresis, SHUNT = GND
l4
48
V
l 2.4
12.5
V
2.4
2.7
V
50
mV
V_{UVLO_SH}
V_IN Undervoltage Lockout Threshold
with Shunt Enabled
V_IN Rising, SHUNT= BIAS
Hysteresis, SHUNT= BIAS
5
5.7
V
200
mV
I_VIN
V_IN Quiescent Current
EN Low
EN High, SHUNT = GND
EN High, SHUNT = BIAS
Shutdown
Enabled, Output in Regulation
Enabled, Output in Regulation
3
6
µA
16
35
µA
30
45
µA
I_VOUT
Available Output Current
Shunt Disabled
SHUNT = GND
l 50
mA
Shunt Enabled
SHUNT = BIAS, I_VIN = 4mA, V_OUT = 3.3V
l 7.4
7.8
mA
V_FB
Regulated Feedback Voltage
l 1.176 1.200 1.224
V
I_FB
FB Pin Leakage
V_FB = 1.3V
±10
nA
V_{EN_VIH}
EN High Level Input Voltage
l 1.4
V
V_{EN_VIL}
EN Low Level Input Voltage
l
0.4
V
I_EN
EN Pin Input Current
V_EN = 12V
V_EN = 0V
0
±1
µA
0
±1
µA
I_LIM
V_OUT Current Limit
120
mA
f_OSC
Oscillator Frequency
500
kHz
V_PGTHRESH
PGOOD Rising Threshold
% of Final Regulation Voltage
l 90
94
98
%
V_PG(LOW)
PGOOD Output Low Voltage
I_PGOOD = 200µA
0.1
0.4
V
PGOOD High Impedance Leakage
V_PGOOD = 12V
l
1
µA
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 voltages are referenced to GND unless otherwise specified.
Note 3: The LTC3255E is guaranteed to meet performance specifications
from 0°C to 85°C operating junction temperature. Specifications over
the –40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LTC3255I is guaranteed over the –40°C to 125°C operating junction
temperature range. The LTC3255H is guaranteed over the –40°C to 150°C
operating junction temperature range. The LTC3255MP is guaranteed over
the –55°C to 150°C operating junction temperature range. High junction
temperatures degrade operating lifetimes; operating lifetime is derated
for junction temperatures greater than 125°C. Note that the maximum
ambient temperature consistent with these specifications is determined by
specific operating conditions in conjunction with board layout, the rated
package thermal resistance and other environmental factors.
The junction temperature (T_J, in °C) is calculated from the ambient
temperature (T_A, in °C) and power dissipation (P_D, in Watts) according to
the formula:
T_J = T_A + (P_D • θ_JA)
where θ_JA (in °C/W) is the package thermal impedance.
Note 4: The LTC3255 has an internal diode that conducts whenever V_OUT
is pulled below GND. When so pulled, absolute maximum current out of
V_OUT is 50mA.
Note 5: The LTC3255 has an internal diode that conducts whenever
PGOOD is pulled below GND. When so pulled, absolute maximum current
out of PGOOD is 100µA.
Note 6: This IC has overtemperature protection that is intended to protect
the device during momentary overload conditions. Junction temperatures
will exceed 150°C when overtemperature protection is active. Continuous
operation above the specified maximum operating junction temperature
may impair device reliability.
Note 7: This IC has input overvoltage protection that shuts down the
device whenever V_IN exceeds the specified input voltage range. Shutdown
typically occurs when V_IN exceeds 52V. V_IN subsequently must fall below
50V (typical) for the IC to re-enable.
3255f
For more information www.linear.com/LTC3255
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