Datasheet

LTC3809-1
3
38091fc
ELECTRICAL CHARACTERISTICS
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 LTC3809E-1 is guaranteed to meet specifi ed performance
from 0°C to 85°C. Specifi cations over the – 40°C to 85°C operating range
are assured by design characterization, and correlation with statistical
process controls. The LTC3809I-1 is guaranteed to meet specifi ed
performance over the full –40°C to 85°C operating temperature range.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loops
Input DC Supply Current
Normal Operation
Sleep Mode
Shutdown
UVLO
(Note 4)
RUN = 0V
V
IN
= UVLO Threshold –200mV
350
105
9
9
500
150
20
20
μA
μA
μA
μA
Undervoltage Lockout Threshold (UVLO) V
IN
Falling
V
IN
Rising
l
l
1.95
2.15
2.25
2.45
2.55
2.75
V
V
Shutdown Threshold of RUN Pin 0.8 1.1 1.4 V
Start-Up Current Source TRACK/SS = 0V 0.65 1 1.35 μA
Regulated Feedback Voltage (Note 5)
l
0.591 0.6 0.609 V
Output Voltage Line Regulation 2.75V < V
IN
< 9.8V (Note 5) 0.01 0.04 %/V
Output Voltage Load Regulation I
TH
= 0.9V (Note 5)
I
TH
= 1.7V
0.1
–0.1
0.5
–0.5
%
%
V
FB
Input Current (Note 5) 9 50 nA
Overvoltage Protect Threshold Measured at V
FB
0.66 0.68 0.7 V
Overvoltage Protect Hysteresis 20 mV
Auxiliary Feedback Threshold 0.325 0.4 0.475 V
Top Gate (TG) Drive Rise Time C
L
= 3000pF 40 ns
Top Gate (TG) Drive Fall Time C
L
= 3000pF 40 ns
Bottom Gate (BG) Drive Rise Time C
L
= 3000pF 50 ns
Bottom Gate (BG) Drive Fall Time C
L
= 3000pF 40 ns
Maximum Current Sense Voltage (ΔV
SENSE(MAX)
)
(V
IN
– SW)
IPRG = Floating (Note 6)
IPRG = 0V (Note 6)
IPRG = V
IN
(Note 6)
l
l
l
110
70
185
125
85
204
140
100
223
mV
mV
mV
Soft-Start Time (Internal) Time for V
FB
to Ramp from 0.05V to 0.55V 0.5 0.74 0.9 ms
Oscillator Frequency 480 550 600 kHz
The l indicates specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 4.2V unless otherwise noted.
Note 3: T
J
is calculated from the ambient temperature TA 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 gate charge being
delivered at the switching frequency.
Note 5: The LTC3809-1 is tested in a feedback loop that servos I
TH
to
a specifi ed voltage and measures the resultant V
FB
voltage.
Note 6: Peak current sense voltage is reduced dependent on duty cycle
to a percentage of value as shown in Figure 1.