Datasheet

LTC3605A
3
3605afg
For more information www.linear.com/LTC3605A
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. Absolute Maximum Ratings are those values
beyond which the life of a device may be impaired.
Note 2: The LTC3605A is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3605AE (E-grade) is guaranteed to meet specifications
from 0°C to 85°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3605AI (I-grade) is guaranteed over the full –40°C to 125°C operating
temperature range.
The junction temperature (T
J
) is calculated from the ambient temperature
(T
A
) and power dissipation (P
D
) according to the formula:
T
J
= T
A
+ (P
D
• θ
JA
°C/W)
where θ
JA
is the package thermal impedance. Note that the maximum
ambient temperature is determined by specific operating conditions
in conjunction with board layout, the rated thermal package thermal
resistance and other environmental factors.
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
J
≈ T
A
= 25°C (Note 2). V
IN
= 12V unless otherwise noted.
Note 3: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 4: The LTC3605A is tested in a feedback loop that adjusts V
FB
to
achieve a specified error amplifier output voltage (ITH).
Note 5: T
J
is calculated from the ambient temperature T
A
and
power dissipation as follows: T
J
= T
A
+ P
D
• (37°C/W). See Thermal
Considerations section.
Note 6: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
LIM
Positive Inductor Valley Current Limit
Negative Inductor Valley Current Limit
5 6
–5
7.5 A
A
R
TOP
Top Power NMOS On-Resistance INTV
CC
= 3.3V 70 150 mΩ
R
BOTTOM
Bottom Power NMOS On-Resistance INTV
CC
= 3.3V 35 60 mΩ
V
UVLO
INTV
CC
Undervoltage Lockout
Threshold
INTV
CC
Falling
INTV
CC
Hysteresis (Rising)
2.4 2.6
0.25
2.8 V
V
V
RUN
Run Threshold 2 (I
Q
≥ 1mA)
Run Threshold 1 (I
Q
≥ 100µA)
RUN Rising
RUN Rising
1.1
0.45
1.2
0.6
1.3
0.75
V
V
V
INTVCC
Internal V
CC
Voltage 4V < V
IN
< 20V 3.2 3.3 3.4 V
DV
INTVCC
INTV
CC
Load Regulation I
LOAD
= 0mA to 20mA 0.5 %
OV Output Overvoltage
PGOOD Upper Threshold
V
FB
Rising 7 10 13 %
UV Output Undervoltage
PGOOD Lower Threshold
V
FB
Falling –13 –10 –7 %
DV
FB(HYS)
PGOOD Hysteresis V
FB
Returning 1.5 %
R
PGOOD
PGOOD Pull-Down Resistance 12 25 Ω
I
PGOOD
PGOOD Leakage 0.54V < V
FB
< 0.66V 2 µA
I
TRACK/SS
TRACK Pull-Up Current 2.5 4 µA
f
OSC
Oscillator Frequency R
T
= 162k
l
0.85 1 1.2 MHz
CLKIN CLKIN Threshold CLKIN V
IL
CLKIN V
IH
1
0.3 V
V
V
VIN_OV
V
IN
Overvoltage Lockout Threshold V
IN
Rising
V
IN
Falling
22.8
20.8
23.5
21.5
24.2
22.1
V
V
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