Datasheet

LTC3631
3
3631fe
For more information www.linear.com/LTC3631
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 LTC3631-3.3V, V
OUT
Rising
LTC3631-3.3V, V
OUT
Falling
l
l
3.260
3.240
3.310
3.290
3.360
3.340
V
V
LTC3631-5V, V
OUT
Rising
LTC3631-5V, 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
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
LTC3631-5, 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
200
40
225
120
50
280
65
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 LTC3631 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3631E 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
LTC3631I 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 (PD, in Watts) according to the formula:
T
J
= T
A
+ (PD • 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.
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