Datasheet

LTC3890
3
3890fc
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
FB1,2
Feedback Current (Note 4) ±5 ±50 nA
V
REFLNREG
Reference Voltage Line Regulation (Note 4) V
IN
= 4.5V to 60V 0.002 0.02 %/V
V
LOADREG
Output Voltage Load Regulation (Note 4)
Measured in Servo Loop,
∆
ITH
Voltage = 1.2V to 0.7V
l
0.01 0.1 %
(Note 4)
Measured in Servo Loop,
∆
ITH
Voltage = 1.2V to 2V
l
–0.01 –0.1 %
g
m1,2
Transconductance Amplifier g
m
(Note 4) I
TH1,2
= 1.2V, Sink/Source = 5µA 2 mmho
I
Q
Input DC Supply Current (Note 5)
Pulse-Skipping or Forced Continuous
Mode (One Channel On)
RUN1 = 5V and RUN2 = 0V, V
FB1
= 0.83V or
RUN1 = 0V and RUN2 = 5V, V
FB2
= 0.83V
1.3 mA
Pulse-Skipping or Forced Continuous
Mode (Both Channels On)
RUN1,2 = 5V, V
FB1,2
= 0.83V (No Load) 2 mA
Sleep Mode (One Channel On) RUN1 = 5V and RUN2 = 0V, V
FB1
= 0.83V (No Load) or
RUN1 = 0V and RUN2 = 5V, V
FB2
= 0.83V (No Load)
50 75 µA
Sleep Mode (Both Channels On) RUN1,2 = 5V, V
FB1,2
= 0.83V (No Load) 60 100 µA
Shutdown RUN1,2 = 0V 14 25 µA
UVLO Undervoltage Lockout INTV
CC
Ramping Up
INTV
CC
Ramping Down
l
l
3.6
3.92
3.80
4.2
4.0
V
V
Feedback Overvoltage Protection Measured at V
FB1,2
, Relative to Regulated V
FB1,2
7 10 13 %
I
SENSE
+
SENSE
+
Pin Current Each Channel ±1 µA
I
SENSE
–
SENSE
–
Pins Current Each Channel
V
SENSE
–
< INTV
CC
– 0.5V
V
SENSE
–
> INTV
CC
+ 0.5V 700
±1 µA
µA
Maximum TG1,2 Duty Factor In Dropout 98 99 %
I
TRACK/SS1,2
Soft-Start Charge Current V
TRACK/SS1,2
= 0V 0.7 1.0 1.4 µA
V
RUN1
V
RUN2
RUN1 Pin On Threshold
RUN2 Pin On Threshold
V
RUN1
Rising
V
RUN2
Rising
l
l
1.15
1.20
1.21
1.25
1.27
1.30
V
V
RUN1,2 Pin Hysteresis 50 mV
V
SENSE(MAX)
Maximum Current Sense Threshold V
FB1,2
= 0.7V, V
SENSE1
–,
2
– = 3.3V, I
LIM
= 0
V
FB1,2
= 0.7V, V
SENSE1
–,
2
– = 3.3V, I
LIM
= INTV
CC
V
FB1,2
= 0.7V, V
SENSE1
–,
2
– = 3.3V, I
LIM
= FLOAT
l
l
l
22
43
64
30
50
75
36
57
85
mV
mV
mV
Gate Driver
TG1,2 Pull-Up On-Resistance
TG1,2 Pull-Down On-Resistance
2.5
1.5
Ω
Ω
BG1,2 Pull-Up On-Resistance
BG1,2 Pull-Down On-Resistance
2.4
1.1
Ω
Ω
TG1,2 t
r
TG1,2 t
f
TG Transition Time:
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
25
16
ns
ns
BG1,2 t
r
BG1,2 t
f
BG Transition Time:
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
28
13
ns
ns
TG/BG t
1D
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 30 ns
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
RUN1,2
= 5V, EXTV
CC
= 0V unless otherwise noted.
(Note 2)
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