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LTC3869-2_15 Datasheet, PDF (3/42 Pages) Linear Technology – Dual, 2-Phase Synchronous Step-Down DC/DC Controllers
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LTC3869/LTC3869-2
Electrical Characteristics The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 15V, VRUN1,2 = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP MAX UNITS
Main Control Loops
VIN
Input Voltage Range
VOUT
Output Voltage Range
VFB1,2
Regulated Feedback Voltage
ITH1,2 Voltage = 1.2V, 0°C to 85°C
l
(Notes 2, 4)
ITH1,2 Voltage = 1.2V, –40°C to 125°C
l
IFB1,2
Feedback Current
(Note 4)
VREFLNREG Reference Voltage Line Regulation VIN = 4.0V to 38V (Note 4)
VLOADREG Output Voltage Load Regulation
(Note 4)
Measured in Servo Loop; ∆ITH Voltage = 1.2V to 0.7V l
Measured in Servo Loop; ∆ITH Voltage = 1.2V to 1.6V l
gm1,2
Transconductance Amplifier gm
ITH1,2 = 1.2V; Sink/Source 5µA; (Note 4)
IQ
Input DC Supply Current
Normal Mode
Shutdown
(Note 5)
VIN = 15V
VRUN1,2 = 0V
DFMAX
Maximum Duty Factor
In Dropout
UVLO
Undervoltage Lockout
VINTVCC Ramping Down
l
UVLOHYS UVLO Hysteresis
VOVL
Feedback Overvoltage Lockout
Measured at VFB1,2
l
ISENSE
Sense Pins Bias Current
(Each Channel); VSENSE1,2 = 3.3V
l
ITK/SS1,2
Soft-Start Charge Current
VTK/SS1,2 = 0V
l
VRUN1,2
RUN Pin On Threshold
VRUN1, VRUN2 Rising
l
VRUN1,2(HYS) RUN Pin On Hysteresis
VSENSE(MAX) Maximum Current Sense Threshold, VFB1,2 = 0.5V, VSENSE1,2 = 3.3V, ILIM = 0V
l
0°C to 85°C (Note 2)
VFB1,2 = 0.5V, VSENSE1,2 = 3.3V, ILIM = Float
l
VFB1,2 = 0.5V, VSENSE1,2 = 3.3V, ILIM = INTVCC
l
Maximum Current Sense Threshold, VFB1,2 = 0.5V, VSENSE1,2 = 3.3V, ILIM = 0V
l
–40°C to 125°C (Note 2)
VFB1,2 = 0.5V, VSENSE1,2 = 3.3V, ILIM = Float
l
VFB1,2 = 0.5V, VSENSE1,2 = 3.3V, ILIM = INTVCC
l
VFB1,2 = 0.5V, VSENSE1,2 = 3.3V, LTC3869IGN-2
l
VMISMATCH Channel to Channel Current Sense
Mismatch Voltage of VSENSE(MAX)
ILIM = Float
TG1, 2 tr
TG1, 2 tf
TG Transition Time:
Rise Time
Fall Time
(Note 8)
CLOAD = 3300pF
CLOAD = 3300pF
BG1, 2 tr
BG1, 2 tf
BG Transition Time:
Rise Time
Fall Time
(Note 8)
CLOAD = 3300pF
CLOAD = 3300pF
TG/BG t1D Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver (Note 6)
Synchronous Switch-On Delay Time
4
0.6
0.5955
0.5940
94
3.0
0.64
1.0
1.1
25
45
68
23
43
68
40
0.600
0.600
–15
0.002
38
V
12.5
V
0.6045
V
0.6060
V
–50
nA
0.01 %/V
0.01
–0.01
2
0.1
%
–0.1
%
mmho
3
mA
30
50
µA
95
%
3.2
3.4
V
0.6
V
0.66 0.68
V
±1
±2
µA
1.25
1.5
µA
1.22 1.35
V
80
mV
30
35
mV
50
55
mV
75
82
mV
30
37
mV
50
57
mV
75
82
mV
50
60
mV
2
mV
25
ns
25
ns
25
ns
25
ns
30
ns
BG/TG t2D Bottom Gate Off to Top Gate On Delay CLOAD = 3300pF Each Driver (Note 6)
Top Switch-On Delay Time
30
ns
tON(MIN)
Minimum On-Time
(Note 7)
90
ns
For more information www.linear.com/LTC3869
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