Datasheet

LTC3642
3
3642fc
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are for T
A
= 25°C (Note 2). V
IN
= 10V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Input Supply (V
IN
)
V
IN
Input Voltage Operating Range 4.5 45 V
UVLO V
IN
Undervoltage Lockout V
IN
Rising
V
IN
Falling
Hysteresis
l
l
3.80
3.75
4.15
4.00
150
4.50
4.35
V
V
mV
OVLO V
IN
Overvoltage Lockout V
IN
Rising
V
IN
Falling
Hysteresis
47
45
50
48
2
52
50
V
V
V
I
Q
DC Supply Current (Note 3)
Active Mode
Sleep Mode
Shutdown Mode V
RUN
= 0V
125
12
3
220
22
6
µA
µA
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
l
3.260
3.240
3.310
3.290
3.360
3.340
V
V
LTC3642-5V, V
OUT
Rising
LTC3642-5V, V
OUT
Falling
l
l
4.940
4.910
5.015
4.985
5.090
5.060
V
V
V
FB
Feedback Comparator Trip Voltage V
FB
Rising
l
0.792 0.800 0.808 V
V
HYST
Feedback Comparator Hysteresis Voltage
l
3 5 7 mV
I
FB
Feedback Pin Current Adjustable Output Version, V
FB
= 1V –10 0 10 nA
∆V
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 Voltage RUN Rising
RUN Falling
Hysteresis
1.17
1.06
1.21
1.10
110
1.25
1.14
V
V
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
500k Resistor from I
SET
to GND
I
SET
Shorted to GND
l
100
20
115
55
25
130
32
mA
mA
mA
R
ON
Power Switch On-Resistance
Top Switch
Bottom Switch
I
SW
= –25mA
I
SW
= 25mA
3.0
1.5
Ω
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 LTC3642 is tested under pulsed load conditions such that T
J
≈ T
A
.
LTC3642E is guaranteed to meet specifications from 0°C to 85°C 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 LTC3642I is guaranteed over the
full –40°C to 125°C operating junction temperature range. 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 impedance 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 3: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.