LTC3890
elecTrical characTerisTics The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted.
(Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
5
MAX
50
UNITS
nA
I
Feedback Current
(Note 4)
FB1,2
V
V
Reference Voltage Line Regulation
Output Voltage Load Regulation
(Note 4) V = 4.5V to 60V
0.002
0.02
%/V
REFLNREG
LOADREG
IN
(Note 4)
l
l
Measured in Servo Loop,
0.01
0.1
%
∆
Voltage = 1.2V to 0.7V
ITH
(Note 4)
Measured in Servo Loop,
–0.01
2
–0.1
%
∆
Voltage = 1.2V to 2V
ITH
g
m1,2
Transconductance Amplifier g
Input DC Supply Current
(Note 4) I = 1.2V, Sink/Source = 5µA
TH1,2
mmho
m
I
Q
(Note 5)
Pulse-Skipping or Forced Continuous
Mode (One Channel On)
RUN1 = 5V and RUN2 = 0V, V = 0.83V or
1.3
2
mA
mA
µA
FB1
RUN1 = 0V and RUN2 = 5V, V = 0.83V
FB2
Pulse-Skipping or Forced Continuous
Mode (Both Channels On)
RUN1,2 = 5V, V
= 0.83V (No Load)
FB1,2
Sleep Mode (One Channel On)
RUN1 = 5V and RUN2 = 0V, V = 0.83V (No Load) or
50
75
FB1
RUN1 = 0V and RUN2 = 5V, V = 0.83V (No Load)
FB2
Sleep Mode (Both Channels On)
Shutdown
RUN1,2 = 5V, V
RUN1,2 = 0V
= 0.83V (No Load)
60
14
100
25
µA
µA
FB1,2
l
l
UVLO
Undervoltage Lockout
INTV Ramping Up
3.92
3.80
4.2
4.0
V
V
CC
INTV Ramping Down
3.6
7
CC
Feedback Overvoltage Protection
Measured at V , Relative to Regulated V
FB1,2
Each Channel
10
13
1
%
FB1,2
+
–
+
I
I
SENSE Pin Current
µA
SENSE
–
SENSE Pins Current
Each Channel
SENSE
–
–
V
V
< INTV – 0.5V
1
µA
µA
SENSE
SENSE
CC
> INTV + 0.5V
700
99
CC
Maximum TG1, 2 Duty Factor
Soft-Start Charge Current
In Dropout
98
%
I
V
= 0V
TRACK/SS1,2
0.7
1.0
1.4
µA
TRACK/SS1,2
l
l
V
RUN1
V
RUN2
RUN1 Pin On Threshold
RUN2 Pin On Threshold
V
RUN1
V
RUN2
Rising
Rising
1.15
1.20
1.21
1.25
1.27
1.30
V
V
RUN1,2 Pin Hysteresis
50
mV
l
l
l
V
Maximum Current Sense Threshold
V
FB1,2
V
FB1,2
V
FB1,2
= 0.7V, V
= 0.7V, V
= 0.7V, V
–, – = 3.3V, I = 0
22
43
64
30
50
75
36
57
85
mV
mV
mV
SENSE(MAX)
SENSE1
SENSE1
SENSE1
2
LIM
–, – = 3.3V, I = INTV
2
LIM
CC
–, – = 3.3V, I = FLOAT
2
LIM
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
TG Transition Time:
Rise Time
Fall Time
(Note 6)
TG1,2 t
TG1,2 t
C
C
= 3300pF
25
16
ns
ns
r
f
LOAD
LOAD
= 3300pF
BG Transition Time:
Rise Time
Fall Time
(Note 6)
LOAD
LOAD
BG1,2 t
BG1,2 t
C
C
= 3300pF
= 3300pF
28
13
ns
ns
r
f
TG/BG t
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
C
= 3300pF Each Driver
30
ns
1D
LOAD
3890fb
3
Linear Systems [ Linear Systems ]
