Datasheet

LTC3615/LTC3615-1
4
3615fb
For more information www.linear.com/LTC3615
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
j
SW1–SW2
Output Phase Shift Between SW1
and SW2 (LTC3615)
V
PHASE
< 0.15 • SV
IN
0 Deg
0.35 • SV
IN
< V
PHASE
< 0.65 • SV
IN
90 Deg
V
PHASE
> 0.85 • SV
IN
180 Deg
Output Phase Shift Between SW1
and SW2 (LTC3615-1)
V
PHASE
< 0.65 • SV
IN
140 Deg
V
PHASE
> 0.85 • SV
IN
180 Deg
V
SRLIM
Voltage at SRLIM to Enable DDR
Mode
(Note 9) SV
IN
– 0.3 V
V
MODE
(Note 9)
Internal Burst Mode Operation 0.3
V
Pulse-Skipping Mode SV
IN
– 0.3 V
Forced Continuous Mode 1.1 SV
IN
• 0.58 V
External Burst Mode Operation 0.5 0.85 V
PGOOD Power Good Voltage Windows TRACK/SSx = SV
IN
, Entering Window
V
FBx
Ramping Up
V
FBx
Ramping Down
–3.5
3.5
–6
6
%
%
TRACK/SSx = SV
IN
, Leaving Window
V
FBx
Ramping Up
V
FBx
Ramping Down
9
–9
11
–11
%
%
t
PGOOD
Power Good Blanking Time Entering/Leaving Window 70 105 140 µs
R
PGOOD
Power Good Pull-Down On-Resistance I = 10mA 8 12 30 Ω
V
RUN
Enable Pin Input High
Input Low
l
l
1
0.4
V
V
Pull-Down Resistance 4 MΩ
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 LTC3615/LTC3615-1 are tested under pulsed load conditions
such
that T
J
≈ T
A
. The LTC3615E/LTC3615E-1 are guaranteed to meet
performance specifications over the 0°C to 85°C operating junction
temperature range. Specifications over the –40°C to 125°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3615I/LTC3615I-1
are guaranteed to meet specifications over the –40°C to 125°C operating
junction temperature range. The LTC3615H/LTC3615H-1 are guaranteed
to meet specifications over the –40°C to 150°C operating temperature
range. The LTC3615MP/LTC3615MP-1 are tested and guaranteed to meet
specifications over the full –55°C to 150°C operating junction temperature
range. High junction temperatures degrade operating lifetime; operating
lifetime is derated for junction temperatures greater than 125°C. Note that
the maximum ambient temperature consistent with these specifications
is determined by specific operating conditions in conjunction with board
layout, the rated package thermal impedance and other environmental
factors. The junction temperature (T
J
, in °C) is calculated from the ambient
temperature
(T
A
, in °C) and power dissipation (P
D
, in watts) according to the formula:
T
J
= T
A
+ (P
D
• θ
JA
)
where θ
JA
(in °C/W) is the package thermal impedance.
Note 3: This parameter is tested in a feedback loop which servos V
FB1,2
to
the midpoint for the error amplifier (V
ITH1,2
= 0.75V).
Note 4: External compensation on ITH pin.
Note 5: Tying the ITH pin to SV
IN
enables internal compensation and AVP
mode for the selected channel.
Note 6: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 7: See description of the TRACK/SS pin in the Pin Functions section.
Note 8: When sourcing current, the average output current is defined
as flowing out of the SW pin. When sinking current, the average output
current is defined as flowing into the SW pin. Sinking mode requires the
use of forced continuous mode.
Note 9: See description of the MODE pin in the Pin Functions section.
Note 10: Guaranteed by design and correlation to wafer level
measurements for QFN packages.
Note 11: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 150°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability or permanently damage the
device.
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2), SV
IN
= PV
INx
= 3.3V, R
T
= 178k, R
SRLIM
= 40.2k, unless
otherwise specified.
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