LTC3631 Datasheet, PDF (3/22 Pages) Linear Technology – High Effi ciency, High Voltage 100mA Synchronous Step-Down Converter

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
UVLO
V_IN Undervoltage Lockout
V_IN Rising
V_IN Falling
Hysteresis
4.5
45
V
l 3.80
4.15
4.50
V
l 3.75
4.00
4.35
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
12
22
μA
3
6
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 3.260
3.310
3.360
V
l 3.240
3.290
3.340
V
LTC3631-5V, V_OUT Rising
LTC3631-5V, V_OUT Falling
l 4.940
5.015
5.090
V
l 4.910
4.985
5.060
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
ΔV_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
1.21
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 200
225
280
mA
500k Resistor from I_SET to GND
120
mA
I_SET Shorted to GND
40
50
65
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 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.
3631fb
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