LTC3801 Datasheet, PDF (2/12 Pages) Linear Technology – Micropower Constant Frequency Step-Down DC/DC Controllers in ThinSOT

LTC3801/LTC3801B
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
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Junction Temperature (Note 3) ............................ 150°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
ORDER PART
NUMBER
I_TH/RUN 1
GND 2
V_FB 3
6 PGATE
5 V_IN
4 SENSE^–
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T_JMAX = 150°C, θ_JA = 230°C/W
LTC3801ES6
LTC3801BES6
S6 PART MARKING
LTACR
LTAHN
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The q 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
Input Voltage Range
q 2.4
9.8
Input DC Supply Current
Normal Operation
SLEEP Mode
Shutdown
UVLO
Undervoltage Lockout Threshold
Start-Up Current Source
Shutdown Threshold (at I_TH/RUN)
Typicals at V_IN = 4.2V (Note 4)
2.4V ≤ V_IN ≤ 9.8V, V_ITH/RUN = 1.3V
2.4V ≤ V_IN ≤ 9.8V (LTC3801 Only)
2.4V ≤ V_IN ≤ 9.8V, V_ITH/RUN = 0V (LTC3801)
2.4V ≤ V_IN ≤ 9.8V, V_ITH/RUN = 0V (LTC3801B)
V_IN < UVLO Threshold
V_IN Rising
q
V_IN Falling
q
V_ITH/RUN = 0V (LTC3801)
0.5
V_ITH/RUN = 0V (LTC3801B)
1.0
V_ITH/RUN Rising
q 0.3
195
300
16
30
6
15
8
17
1
2
1.8
2.3
1.7
2.2
1
1.5
2
3.0
0.6 0.95
Regulated Feedback Voltage
Feedback Voltage Line Regulation
Feedback Voltage Load Regulation
V_FB Input Current
Overvoltage Protect Threshold
Overvoltage Protect Hysteresis
0°C ≤ T_A ≤ 85°C (Note 5)
–40°C ≤ T_A ≤ 85°C (Note 5)
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
0.788 0.800 0.812
q 0.780 0.800 0.812
0.05
2
2
2
10
0.850 0.880 0.910
40
Oscillator Frequency
Normal Operation
Output Short Circuit
Gate Drive Rise Time
Gate Drive Fall Time
V_FB = 0.8V
V_FB = 0V
C_LOAD = 3000pF
C_LOAD = 3000pF
500
550
650
210
40
40
Peak Current Sense Voltage
Duty Cycle < 40% (Note 6)
LTC3801
LTC3801B
q 109
117
125
q 95
104
113
Peak Current Sense Voltage in Burst Mode Operation LTC3801 Only
26
Default Soft-Start Time
0.6
UNITS
V
µA
µA
µA
µA
µA
V
V
µA
µA
V
V
V
mV/V
mV/µA
mV/µA
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 LTC3801ES6/LTC3801BES6 are guaranteed to meet specifica-
tions 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 LTC3801/LTC3801B 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.
3801f
2