Datasheet

LTC3869/LTC3869-2
3
38692fa
For more information www.linear.com/LTC3869
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loops
V
IN
Input Voltage Range 4 38 V
V
OUT
Output Voltage Range 0.6 12.5 V
V
FB1,2
Regulated Feedback Voltage
(Notes 2, 4)
I
TH1,2
Voltage = 1.2V, 0°C to 85°C
I
TH1,2
Voltage = 1.2V, –40°C to 125°C
l
l
0.5955
0.5940
0.600
0.600
0.6045
0.6060
V
V
I
FB1,2
Feedback Current (Note 4) –15 –50 nA
V
REFLNREG
Reference Voltage Line Regulation V
IN
= 4.0V to 38V (Note 4) 0.002 0.01 %/V
V
LOADREG
Output Voltage Load Regulation (Note 4)
Measured in Servo Loop; ∆I
TH
Voltage = 1.2V to 0.7V
Measured in Servo Loop; ∆I
TH
Voltage = 1.2V to 1.6V
l
l
0.01
–0.01
0.1
–0.1
%
%
g
m1,2
Transconductance Amplifier g
m
I
TH1,2
= 1.2V; Sink/Source 5µA; (Note 4) 2 mmho
I
Q
Input DC Supply Current
Normal Mode
Shutdown
(Note 5)
V
IN
= 15V
V
RUN1,2
= 0V
3
30 50
mA
µA
DF
MAX
Maximum Duty Factor In Dropout 94 95 %
UVLO Undervoltage Lockout V
INTVCC
Ramping Down
l
3.0 3.2 3.4 V
UVLO
HYS
UVLO Hysteresis 0.6 V
V
OVL
Feedback Overvoltage Lockout Measured at V
FB1,2
l
0.64 0.66 0.68 V
I
SENSE
Sense Pins Bias Current (Each Channel); V
SENSE1,2
= 3.3V
l
±1 ±2 µA
I
TK/SS1,2
Soft-Start Charge Current V
TK/SS1,2
= 0V
l
1.0 1.25 1.5 µA
V
RUN1,2
RUN Pin On Threshold V
RUN1
, V
RUN2
Rising
l
1.1 1.22 1.35 V
V
RUN1,2(HYS)
RUN Pin On Hysteresis 80 mV
V
SENSE(MAX)
Maximum Current Sense Threshold,
0°C to 85°C (Note 2)
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= 0V
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= Float
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= INTV
CC
l
l
l
25
45
68
30
50
75
35
55
82
mV
mV
mV
Maximum Current Sense Threshold,
–40°C to 125°C (Note 2)
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= 0V
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= Float
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, I
LIM
= INTV
CC
V
FB1,2
= 0.5V, V
SENSE1,2
= 3.3V, LTC3869IGN-2
l
l
l
l
23
43
68
40
30
50
75
50
37
57
82
60
mV
mV
mV
mV
V
MISMATCH
Channel to Channel Current Sense
Mismatch Voltage of V
SENSE(MAX)
I
LIM
= Float 2 mV
TG1, 2 t
r
TG1, 2 t
f
TG Transition Time:
Rise Time
Fall Time
(Note 8)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
25
25
ns
ns
BG1, 2 t
r
BG1, 2 t
f
BG Transition Time:
Rise Time
Fall Time
(Note 8)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
25
25
ns
ns
TG/BG t
1D
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
C
LOAD
= 3300pF Each Driver (Note 6) 30 ns
BG/TG t
2D
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
C
LOAD
= 3300pF Each Driver (Note 6) 30 ns
t
ON(MIN)
Minimum On-Time (Note 7) 90 ns
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN1,2
= 5V unless otherwise noted.