LTC1772 Datasheet, PDF (2/16 Pages) Linear Technology – Constant Frequency Current Mode Step-Down DC/DC Controller in SOT-23

LTC1772
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Supply Voltage (V_IN).........................– 0.3V to 10V
SENSE ^–, PGATE Voltages ............. – 0.3V to (V_IN + 0.3V)
V_FB, I_TH/RUN Voltages ..............................– 0.3V to 2.4V
PGATE Peak Output Current (< 10µs) ....................... 1A
Storage Ambient Temperature Range ... – 65°C to 150°C
Operating Temperature Range (Note 2) ....... 0°C to 70°C
Junction Temperature (Note 3) ............................. 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
I_TH/RUN 1
GND 2
V_FB 3
6 PGATE
5 V_IN
4 SENSE^–
S6 PACKAGE
6-LEAD PLASTIC SOT-23
T_JMAX = 150°C, θ_JA = 230°C/ W
ORDER PART
NUMBER
LTC1772CS6
S6 PART MARKING
LTIL
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS The q denotes specifications that apply over the full operating temperature
range, otherwise specifications are at T_A = 25°C. V_IN = 4.2V unless otherwise specified. (Note 2)
PARAMETER
CONDITIONS
MIN TYP MAX
UNITS
Input DC Supply Current
Normal Operation
Sleep Mode
Shutdown
UVLO
Undervoltage Lockout Threshold
Shutdown Threshold (at I_TH/RUN)
Start-Up Current Source
Regulated Feedback Voltage
Typicals at V_IN = 4.2V (Note 4)
2.4V ≤ V_IN ≤ 9.8V
2.4V ≤ V_IN ≤ 9.8V
2.4V ≤ V_IN ≤ 9.8V, V_ITH/RUN = 0V
V_IN < UVLO Threshold
V_IN Falling
V_IN Rising
V_ITH/RUN = 0V
(Note 5)
270 420
µA
230 370
µA
8
22
µA
6
10
µA
q 1.6
2.0
2.3
V
1.85
2.3
2.5
V
q 0.2
0.35
0.5
V
0.25
0.5
0.85
µA
q 0.780 0.800 0.820
V
Output Voltage Line Regulation
Output Voltage Load Regulation
V_FB Input Current
Overvoltage Protect Threshold
Overvoltage Protect Hysteresis
2.4V ≤ V_IN ≤ 9.8V (Note 5)
I_TH/RUN Sinking 5µA (Note 5)
I_TH/RUN Sourcing 5µA (Note 5)
(Note 5)
Measured at V_FB
0.820
0.05
2.5
2.5
10
0.860
20
50
0.895
mV/V
mV/µA
mV/µA
nA
V
mV
Oscillator Frequency
Gate Drive Rise Time
Gate Drive Fall Time
Maximum Current Sense Voltage
V_FB = 0.8V
V_FB = 0V
C_LOAD = 3000pF
C_LOAD = 3000pF
500 550 650
kHz
120
kHz
40
ns
40
ns
120
mV
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTC1772 is guaranteed to meet specified performance over
the 0°C to 70°C operating temperature range.
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_J°C/W)
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 5: The LTC1772 is tested in a feedback loop that servos V_FB to the
output of the error amplifier.
2