LTC3772_15 Datasheet, PDF (3/20 Pages) Linear Technology – Micropower No RSENSE Constant Frequency Step-Down DC/DC Controller

LTC3772
ELECTRICAL CHARACTERISTICS The ● indicates specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_IN = 4.2V unless otherwise noted. (Note 2)
PARAMETER
CONDITIONS
MIN TYP MAX
V_FB Input Current
(Note 5)
–10
2
10
Overvoltage Protect Threshold
Overvoltage Protect Hysteresis
Measured at V_FB
0.850
0.880
40
0.910
Oscillator Frequency
Normal Operation
Output Short Circuit
V_FB = 0.8V
V_FB = 0V
500
550
650
200
Gate Drive Rise Time
C_LOAD = 3000pF
40
Gate Drive Fall Time
Peak Current Sense Voltage
C_LOAD = 3000pF
I_PRG = GND (Note 6)
I_PRG = Floating
I_PRG = V_IN
40
● 90
105
120
● 160
175
190
● 228
245
262
Default Soft-Start Time
0.6
UNITS
nA
V
mV
kHz
kHz
ns
ns
mV
mV
mV
ms
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTC3772ETS8/LTC3772EDDB are guaranteed to meet
specifications from 0°C to 70°C. Specifications over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 3: 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 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 5: The LTC3772 are tested in a feedback loop that servos V_FB to the
output of the error amplifier while maintaining I_TH/RUN at the midpoint of
the current limit range.
Note 6: Peak current sense voltage is reduced dependent on duty cycle as
given in Figure 1.
TYPICAL PERFOR A CE CHARACTERISTICS
Quiescent Current (No Load)
vs Input Voltage
60
55
50
45
40
35
30
25
20
2 3 4 5 6 7 8 9 10
INPUT VOLTAGE (V)
3772 G01
Quiescent Current (No Load)
vs Temperature
55
50
45
40
35
30
25
20
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3772 G02
Quiescent Current (Shutdown)
vs Input Voltage
25
20
15
10
5
0
2 3 4 5 6 7 8 9 10
INPUT VOLTAGE (V)
3772 G03
3772f
3