Datasheet

LTC3618
3
3618fc
For more information www.linear.com/LTC3618
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Operating Voltage Range
l
2.25 5.5 V
V
UVLO
Undervoltage Lockout Threshold SV
IN
Ramping Down 1.8 V
SV
IN
Ramping Up 2.2 V
OVLO Overvoltage Lockout Threshold SV
IN
Ramping Down
Hysteresis
6.2
300
V
mV
V
FB1
V
DDQ
Feedback Voltage Internal
Reference with Line and Load
Regulation
(Note 3) V
TRACK/SS1
= SV
IN
0°C < T
J
< 85°C
–40°C < T
J
< 125°C
l
0.592
0.590
0.6 0.608
0.610
V
V
Feedback V
oltage External Reference
(Note 6)
(Note 3) V
TRACK/SS1
= 0.3V 0.289 0.3 0.311 V
(Note 3) V
TRACK/SS1
= 0.5V 0.489 0.5 0.511 V
V
FB2
V
TT
Feedback Reference Voltage with
Line and Load Regulation
VDDQIN = 1.5V
l
VTTR – 6 VTTR VTTR + 6 mV
VTTR VTTR Output Voltage with Line and
Load Regulation
VDDQIN = 1.5V, I
LOAD
= ±10mA,
C
LOAD
= < 0.1µF
l
0.49 • V
DDQ
0.5 • V
DDQ
0.51 • V
DDQ
V
I
FB
Feedback Input Current V
FBx
= 0.6V
l
0 ±30 nA
VTTR Maximum Output Current ±10 mA
I
S
Input Supply Current, Active Mode V
FB1
= 0.5V, V
MODE
= SV
IN
, V
RUN1
= SV
IN
,
V
RUN2
= 0V, (Note 5)
2.4 mA
V
FBx
= 0.5V, V
MODE
= SV
IN
, V
RUNx
= SV
IN
,
(Note 5)
2.8 mA
Input Supply Current, Shutdown
SV
IN
= PV
IN
= 5.5V, V
RUNx
= 0V 0.1 1 µA
R
DS(ON)
Top Switch On-Resistance PV
INx
= 3.3V (Note 9) 75 mΩ
Bottom Switch On-Resistance PV
INx
= 3.3V (Note 9) 55 mΩ
I
LIMX
Peak Current Limit
Positive Limit
Negative Limit
Sourcing (Note 7), V
FBX
= 0.5V
Sinking (Note 7), V
FBX
= 0.7V
4.2
–2.5
5.5
–3.5
8.0
–5.5
A
A
I
SW(LKG)
Switch Leakage Current SV
IN
= PV
IN
= 5.5V, V
RUNx
= 0V 0.01 1 µA
g
m(EA)
Error Amplifier Transconductance –5µA < I
TH
< 5µA 240 µmho
I
EAO
Error Amplifier Output Current (Note 4) ±30 µA
t
SOFT-START1
V
DDQ
Internal Soft-Start Time V
FB1
from 0.06V to 0.54V,
TRACK/SS1 = SV
IN
0.5 1.1 2 ms
t
SOFT-START2
V
TT
Internal Soft-Start Time V
FB2
from 0V to 0.75V 0.25 0.6 1 ms
R
ON(TRACK/SS1_DIS)
TRACK/SS1 Pull-Down Resistance
at Start-Up
200 Ω
t
TRACK/SS1_DIS
Soft-Start Discharge Time at Start-Up 65 µs
f
OSC
Oscillator Frequency R
RT
= 178k
l
1.85 2.25 2.65 MHz
Internal Default Oscillator Frequency V
RT
= SV
IN
l
1.8 2.25 2.7 MHz
f
SYNC
Synchronization Frequency t
LOW
, t
HIGH
> 30ns 0.4 4 MHz
V
MODE/SYNC
SYNC Level High Voltage 1.2 V
SYNC Level Low Voltage 0.3 V
j
SW1–SW2
Output Phase Shift Between SW1
and SW2
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
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2), SV
IN
= PV
INx
= 3.3V, R
T
= 178k, unless otherwise
specified.
elecTrical characTerisTics