Datasheet

LTC3727A-1
3
3727a1fa
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 15V, V
RUN/SS1, 2
= 5V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
g
m1, 2
Transconductance Amplifi er g
m
I
TH1, 2
= 1.2V; Sink/Source 5μA (Note 4) 1.3 mmho
g
mGBW1, 2
Transconductance Amplifi er GBW I
TH1, 2
= 1.2V (Note 4) 3 MHz
I
Q
Input DC Supply Current
Normal Mode
Shutdown
(Note 5)
V
IN
= 15V, EXTV
CC
Tied to V
OUT1
, V
OUT1
= 8.5V
V
RUN/SS1, 2
= 0V
670
20 35
μA
μA
V
FCB
Forced Continuous Threshold
l
0.76 0.800 0.84 V
I
FCB
Forced Continuous Pin Current V
FCB
= 0.85V –0.30 –0.18 –0.05 μA
V
BINHIBIT
Burst Inhibit (Constant Frequency)
Threshold
Measured at FCB pin 6.8 7.3 V
UVLO Undervoltage Lockout V
IN
Ramping Down
l
3.5 4 V
V
OVL
Feedback Overvoltage Lockout Measured at V
OSENSE1, 2
l
0.84 0.86 0.88 V
I
SENSE
Sense Pins Total Source Current (Each Channel) V
SENSE1
–
, 2
–
= V
SENSE1
+
, 2
+
= 0V –85 –60 μA
DF
MAX
Maximum Duty Factor In Dropout 98 99.4 %
I
RUN/SS1, 2
Soft-Start Charge Current V
RUN/SS1, 2
= 1.9V 0.5 1.2 μA
V
RUN/SS1, 2
ON RUN/SS Pin ON Threshold V
RUN/SS1
, V
RUN/SS2
Rising 1.0 1.5 1.9 V
V
SENSE(MAX)
Maximum Current Sense Threshold V
OSENSE1, 2
= 0.7V, V
SENSE1
–
, 2
–
= 12V
l
105 135 165 mV
TG1, 2 t
r
TG1, 2 t
f
TG Transition Time:
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
50
50
90
90
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
40
40
90
80
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 7) 120 ns
INTV
CC
Linear Regulator
V
INTVCC
Internal V
CC
Voltage 8.5V < V
IN
< 30V, V
EXTVCC
= 6V 7.2 7.5 7.8 V
V
LDO
INT INTV
CC
Load Regulation I
CC
= 0mA to 20mA, V
EXTVCC
= 6V 0.2 1.0 %
V
LDO
EXT EXTV
CC
Voltage Drop I
CC
= 20mA, V
EXTVCC
= 8.5V 70 160 mV
V
EXTVCC
EXTV
CC
Switchover Voltage I
CC
= 20mA, EXTV
CC
Ramping Positive
l
6.9 7.3 V
V
LDOHYS
EXTV
CC
Hysteresis 0.3 V
Oscillator and Phase-Locked Loop
f
NOM
Nominal Frequency V
PLLFLTR
= 1.2V 350 380 430 kHz
f
LOW
Lowest Frequency V
PLLFLTR
= 0V 220 255 290 kHz
f
HIGH
Highest Frequency V
PLLFLTR
≥ 2.4V 460 530 580 kHz
R
PLLIN
PLLIN Input Resistance 100 kΩ
I
PLLFLTR
Phase Detector Output Current
Sinking Capability
Sourcing Capability
f
PLLIN
< f
OSC
f
PLLIN
> f
OSC
–15
15
μA
μA