LTC3642 Datasheet, PDF (3/20 Pages) Linear Technology – High Effi ciency, High Voltage 50mA Synchronous Step-Down Converter

LTC3642
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T_A = 25°C. V_IN = 10V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Supply (V_IN)
V_IN
Input Voltage Operating Range
UVLO
V_IN Undervoltage Lockout
V_IN Rising
V_IN Falling
Hysteresis
4.5
45
V
l 3.80
4.15
4.40
V
l 3.75
4.00
4.25
V
150
mV
OVLO
V_IN Overvoltage Lockout
V_IN Rising
V_IN Falling
Hysteresis
47
50
52
V
45
48
50
V
2
V
I_Q
DC Supply Current (Note 3)
Active Mode
Sleep Mode
Shutdown Mode
V_RUN = 0V
125
220
μA
l
12
22
μA
l
3
6
μA
Output Supply (V_OUT/V_FB)
V_OUT
Output Voltage Trip Thresholds
LTC3642-3.3V, V_OUT Rising
LTC3642-3.3V, V_OUT Falling
l 3.277
3.310
3.343
V
l 3.257
3.290
3.323
V
LTC3642-5V, V_OUT Rising
LTC3642-5V, V_OUT Falling
l 4.965
5.015
5.065
V
l 4.935
4.985
5.035
V
V_FB
Feedback Comparator Trip Voltage
V_FB Rising
l 0.792
0.800
0.808
V
V_HYST
Feedback Comparator Hysteresis
l 3.5
5
6.5
mV
I_FB
Feedback Pin Current
Adjustable Output Version, V_FB = 1V
-10
0
10
nA
ΔV_LINEREG
Feedback Voltage Line Regulation
V_IN = 4.5V to 45V
LTC3642-5, V_IN = 6V to 45V
0.001
%/V
Operation
V_RUN
Run Pin Threshold
RUN Rising
RUN Falling
Hysteresis
1.17
1.21
1.25
V
1.06
1.10
1.14
V
110
mV
I_RUN
Run Pin Leakage Current
RUN = 1.3V
–10
0
10
nA
V_HYSTL
Hysteresis Pin Voltage Low
RUN < 1V, I_HYST = 1mA
0.07
0.1
V
I_HYST
Hysteresis Pin Leakage Current
V_HYST = 1.3V
–10
0
10
nA
I_SS
Soft-Start Pin Pull-Up Current
V_SS < 1.5V
4.5
5.5
6.5
μA
t_INTSS
Internal Soft-Start Time
SS Pin Floating
0.75
ms
I_PEAK
Peak Current Trip Threshold
I_SET Floating
l 100
115
130
mA
500k Resistor from I_SET to GND
55
mA
I_SET Shorted to GND
20
25
32
mA
R_ON
Power Switch On-Resistance
Top Switch
Bottom Switch
I_SW = –25mA
I_SW = 25mA
3.0
Ω
1.5
Ω
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: The LTC3642E is guaranteed to meet specifications from 0°C
to 85°C with specifications over the –40°C to 125°C operating junction
temperature range assured by design, characterization and correlation
with statistical process controls. The LTC3642I is guaranteed to meet
specifications from –40°C to 125°C.
T_J is calculated from the ambient temperature T_A and power dissipation P_D
according to the following formula:
T_J = T_A + (P_D • θ_JA°C/W)
Note 3: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
3642f
3