LTC3872_15 Datasheet, PDF (3/22 Pages) Linear Technology – No RSENSE Current Mode Boost DC/DC Controller

LTC3872
Electrical Characteristics The l denotes the specifications which apply over the specified operating
temperature range, otherwise specifications are at T_A = 25°C (Note 2). V_IN = 4.2V unless otherwise noted.
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Input Voltage Range
l 2.75
9.8
V
Input DC Supply Current
Normal Operation
Shutdown
UVLO
Typicals at V_IN = 4.2V (Note 4)
2.75V ≤ V_IN ≤ 9.8V
V_RUN/SS = 0V
V_IN < UVLO Threshold
250
400
µA
8
20
µA
20
35
µA
Undervoltage Lockout Threshold
V_IN Rising
V_IN Falling
l 2.3
2.45 2.75
V
l 2.05
2.3
2.55
V
Shutdown Threshold (at RUN/SS)
V_RUN/SS Falling
V_RUN/SS Rising
l 0.6
0.85 1.05
V
l 0.65 0.95 1.15
V
Regulated Feedback Voltage
(Note 5) LTC3872E
LTC3872I and LTC3872H
l 1.182 1.2 1.218
V
l 1.178 1.2 1.218
V
Feedback Voltage Line Regulation
2.75V < V_IN < 9V (Note 5)
0.14
mV/V
Feedback Voltage Load Regulation
V_ITH = 1.6V (Note 5)
V_ITH = 1V (Note 5)
0.05
%
–0.05
%
V_FB Input Current
RUN/SS Pull Up Current
Oscillator Frequency
Normal Operation
Gate Drive Rise Time
Gate Drive Fall Time
Peak Current Sense Voltage
(Note 5)
V_RUN/SS = 0
V_FB = 1V
C_LOAD = 3000pF
C_LOAD = 3000pF
IPRG = GND (Note 6)
LTC3872E
LTC3872I
LTC3872H
25
50
nA
0.35
0.7
1.25
µA
500
550
650
kHz
40
ns
40
ns
l 80
100
120
mV
l 70
100
120
mV
l 65
100
120
mV
IPRG = Float
LTC3872E
LTC3872I
LTC3872H
l 145
170
195
mV
l 135
170
195
mV
l 130
170
195
mV
IPRG = V_IN
LTC3872E
LTC3872I
LTC3872H
l 240
270
290
mV
l 225
270
290
mV
l 215
270
290
mV
Default Internal Soft-Start Time
1
ms
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 LTC3872 is tested under pulsed load conditions such that
T_J ≈ T_A. The LTC3872E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3872I is guaranteed
over the –40°C to 125°C operating junction temperature range. The
LTC3872H is guaranteed over the full –40°C to 150°C operating junction
temperature range. 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.
Note 3: T_J is calculated from the ambient temperature T_A and power
dissipation P_D according to the following formula:
LTC3872TS8: T_J = T_A + (P_D • 195°C/W)
LTC3872DDB: T_J = T_A + (P_D • 76°C/W)
Note 4: The dynamic input supply current is higher due to power MOSFET
gate charging (Q_G • f_OSC). See Applications Information.
Note 5: The LTC3872 is tested in a feedback loop which servos V_FB to
the reference voltage with the I_TH pin forced to the midpoint of its voltage
range (0.7V ≤ V_ITH ≤ 1.9V, midpoint = 1.3V).
Note 6: Rise and fall times are measured at 10% and 90% levels.
For more information www.linear.com/LTC3872
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