Datasheet

LTC3729
3
3729fb
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loop
V
EAIN
Regulated Feedback Voltage (Note 3); I
TH
Voltage = 1.2V
l
0.792 0.800 0.808 V
V
SENSEMAX
Maximum Current Sense Threshold V
SENSE
–
= 5V
V
SENSE1, 2
= 5V
l
62
65
75
75
88
85
mV
mV
I
INEAIN
Feedback Current (Note 3) –5 –50 nA
V
LOADREG
Output Voltage Load Regulation (Note 3)
Measured in Servo Loop; I
TH
Voltage = 0.7V
Measured in Servo Loop; I
TH
Voltage = 2V
l
l
0.1
–0.1
0.5
–0.5
%
%
V
REFLNREG
Reference Voltage Line Regulation V
IN
= 3.6V to 30V (Note 3) 0.002 0.02 %/V
V
OVL
Output Overvoltage Threshold Measured at V
EAIN
l
0.84 0.86 0.88 V
UVLO Undervoltage Lockout V
IN
Ramping Down 3 3.5 4 V
g
m
Transconductance Amplifier g
m
I
TH
= 1.2V; Sink/Source 5µA; (Note 3) 3 mmho
g
mOL
Transconductance Amplifier Gain I
TH
= 1.2V; (g
m
xZ
L
; No Ext Load); (Note 3) 1.5 V/mV
I
Q
Input DC Supply Current
Normal Mode
Shutdown
(Note 4)
EXTV
CC
Tied to V
OUT
; V
OUT
= 5V
V
RUN/SS
= 0V
580
20 40
µA
µA
I
RUN/SS
Soft‑Start Charge Current V
RUN/SS
= 1.9V –0.5 –1.2 µA
V
RUN/SS
RUN/SS Pin ON Threshold V
RUN/SS
Rising 1.0 1.5 1.9 V
V
RUN/SSLO
RUN/SS Pin Latchoff Arming V
RUN/SS
Rising from 3V 3.8 4.5 V
I
SCL
RUN/SS Discharge Current Soft Short Condition V
EAIN
= 0.5V; V
RUN/SS
= 4.5V 0.5 2 4 µA
I
SDLDO
Shutdown Latch Disable Current V
EAIN
= 0.5V 1.6 5 µA
I
SENSE
Total Sense Pins Source Current Each Channel; V
SENSE1
–
, 2
–
= V
SENSE1
+
, 2
+
= 0V –85 –60 µA
DF
MAX
Maximum Duty Factor In Dropout 98 99.5 %
TG1, 2 t
r
TG1, 2 t
f
Top Gate Transition Time:
Rise Time
Fall Time
C
LOAD
= 3300pF
C
LOAD
= 3300pF
30
40
90
90
ns
ns
BG1, 2 t
r
BG1, 2 t
f
Bottom Gate Transition Time:
Rise Time
Fall Time
C
LOAD
= 3300pF
C
LOAD
= 3300pF
30
20
90
90
ns
ns
TG/BG t
1D
Top Gate Off to Bottom Gate On Delay
Synchronous Switch‑On Delay Time
C
LOAD
= 3300pF Each Driver 90 ns
BG/TG t
2D
Bottom Gate Off to Top Gate On Delay
Top Switch‑On Delay Time
C
LOAD
= 3300pF Each Driver 90 ns
t
ON(MIN)
Minimum On‑Time Tested with a Square Wave (Note 5) 100 ns
Internal V
CC
Regulator
V
INTVCC
Internal V
CC
Voltage 6V < V
IN
< 30V; V
EXTVCC
= 4V 4.8 5.0 5.2 V
V
LDO
INT INTV
CC
Load Regulation I
CC
= 0 to 20mA; V
EXTVCC
= 4V 0.2 1.0 %
V
LDO
EXT EXTV
CC
Voltage Drop I
CC
= 20mA; V
EXTVCC
= 5V 80 160 mV
V
EXTVCC
EXTV
CC
Switchover Voltage I
CC
= 20mA, EXTV
CC
Ramping Positive
l
4.5 4.7 V
V
LDOHYS
EXTV
CC
Switchover Hysteresis I
CC
= 20mA, EXTV
CC
Ramping Negative 0.2 V
Oscillator and Phase-Locked Loop
f
NOM
Nominal Frequency V
PLLFLTR
= 1.2V 360 400 440 kHz
f
LOW
Lowest Frequency V
PLLFLTR
= 0V 230 260 290 kHz
f
HIGH
Highest Frequency V
PLLFLTR
≥ 2.4V 480 550 590 kHz
R
PLLIN
PLLIN Input Resistance 50 kΩ
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V, V
RUN/SS
= 5V unless otherwise noted.