Datasheet

LTC3789
3
3789fa
elecTrical characTerisTics
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Input Supply Voltage 4 38 V
V
OUT
Output Voltage 0.8 38 V
V
FB
Regulated Feedback Voltage I
TH
Voltage = 1.2V (Note 4), T
A
= –40°C to 85°C
I
TH
= 1.2V, T
A
= 125°C, T
A
= –40°C to 125°C
l
l
0.792
0.788
0.800
0.800
0.808
0.812
V
V
I
FB
Feedback Current (Note 4) –15 –50 nA
V
REFLNREG
Reference Voltage Line Regulation V
IN
= 4V to 38V (Note 4) 0.002 0.02 %/V
V
LOADREG
Output Voltage Load Regulation (Note 4)
Measured in Servo Loop, ∆I
TH
Voltage = 1.4V to 2V
Measured in Servo Loop, ∆I
TH
Voltage = 2V to 2.5V
l
l
0.01
–0.01
0.1
–0.1
%
%
g
m
Transconductance Amplifier g
m
I
TH
= 1.2V, Sink/Source 5µA (Note 4) 1.5 mmho
I
Q
Input DC Supply Current
Normal Mode
Shutdown
(Note 5)
V
RUN
= 0V
3
40 60
mA
µA
UVLO Undervoltage Lockout INTV
CC
Ramping Down 3.4 3.6 V
UVLO Hyst Undervoltage Hysteresis 0.4 V
I
SENSE
+
I
SENSE
–
SENSE Pins Current V
SENSE
–
= V
SENSE
+
= 0V 0.2 ±1 µA
I
IOSENSE
+
I
IOSENSE
–
I
OSENSE
Pins Current V
IOSENSE
–
= V
IOSENSE
+
= 10V 10 14 µA
I
SS
Soft-Start Charge Current V
SS
= 0V 2 3 4 µA
V
RUN(ON)
RUN Pin On-Threshold V
RUN
Rising 1.22 V
V
RUN(HYS)
RUN Pin On-Hysteresis 150 mV
I
RUN
RUN Pin Source Current 1.2 µA
I
RUN(HYS)
RUN Pin Hysteresis Current 5 µA
V
SENSE(MAX)
Maximum Current Sense Threshold
Buck Region, (I
L
Valley)
Boost Region, (I
L
Peak)
V
FB
= 0.7V
V
FB
= 0.7V
l
l
73
123
90
140
107
157
mV
mV
V
SENSE(IAVG)
Maximum Input/Output Average
Current Sense Threshold
I
LIM
= 0V
I
LIM
Floating
I
LIM
= INTV
CC
48
90
130
50
100
145
52.5
106
160
mV
mV
mV
R
DSPFET(ON)
Driver Pull-Up On-Resistance 2.6 Ω
R
DSNFET(ON)
Driver Pull-Down On-Resistance 1.5 Ω
TG t
r
TG t
f
Top Gate Rise Time
Top Gate Fall Time
25
25
ns
ns
BG t
r
BG t
f
Bottom Gate Rise Time
Bottom Gate Fall Time
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) 60 ns
BG/TG t
1D
Bottom Gate Off to Top Gate On
Delay Top Switch-On Delay Time
C
LOAD
= 3300pF Each Driver (Note 6) 60 ns
DF
MAX,BOOST
Maximum Duty Factor % Switch C On 90 %
D
ON(MIN,BOOST)
Minimum Duty Factor for Main
Switch in Boost Operation
% Switch C On 9 %
D
ON(MIN,BUCK)
Minimum Duty Factor for Main
Switch in Buck Operation
% Switch B On 9 %
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN
= 5V, unless otherwise noted.