LTC3728 Linear Technology, LTC3728 Datasheet - Page 3

• Manufacturer Part Number: LTC3728
• Description: 2-Phase Synchronous Step-Down Switching Regulator
• Manufacturer: Linear Technology

ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are at T
g
g
V
I
V
UVLO
V
I
DF
I
V
V
I
I
V
TG1, 2 t
TG1, 2 t
BG1, 2 t
BG1, 2 t
TG/BG t
BG/TG t
t
INTV
V
V
V
V
V
Oscillator and Phase-Locked Loop
f
f
f
R
I
SYMBOL
FCB
SENSE
RUN/SS1, 2
SCL1, 2
SDLHO
ON(MIN)
NOM
LOW
HIGH
PLLFLTR
m1, 2
mGBW1, 2
FCB
BINHIBIT
OVL
RUN/SS1, 2
RUN/SS1, 2
SENSE(MAX)
INTVCC
LDO
LDO
EXTVCC
LDOHYS
PLLIN
MAX
CC
INT
EXT
1D
2D
Linear Regulator
r
f
r
f
ON RUN/SS Pin ON Threshold
LT RUN/SS Pin Latchoff Arming Threshold V
PARAMETER
Transconductance Amplifier g
Transconductance Amplifier GBW
Input DC Supply Current
Forced Continuous Threshold
Forced Continuous Pin Current
Burst Inhibit (Constant Frequency)
Threshold
Undervoltage Lockout
Feedback Overvoltage Lockout
Sense Pins Total Source Current
Maximum Duty Factor
Soft-Start Charge Current
RUN/SS Discharge Current
Shutdown Latch Disable Current
Maximum Current Sense Threshold
TG Transition Time:
Rise Time
Fall Time
BG Transition Time:
Rise Time
Fall Time
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
Minimum On-Time
Internal V
INTV
EXTV
EXTV
EXTV
Nominal Frequency
Lowest Frequency
Highest Frequency
PLLIN Input Resistance
Phase Detector Output Current
Sinking Capability
Sourcing Capability
Normal Mode
Shutdown
CC
CC
CC
CC
Load Regulation
Voltage Drop
Switchover Voltage
Hysteresis
CC
Voltage
m
CONDITIONS
I
I
(Note 4)
V
V
V
Measured at FCB pin
V
Measured at V
(Each Channel); V
In Dropout
V
V
Soft Short Condition V
V
V
V
V
(Note 5)
C
C
(Note 5)
C
C
C
C
Tested with a Square Wave (Note 6)
6V < V
I
I
I
V
V
V
f
f
TH1, 2
TH1, 2
CC
CC
CC
PLLIN
PLLIN
IN
RUN/SS1, 2
FCB
IN
RUN/SS1, 2
RUN/SS1,
RUN/SS1,
RUN/SS1, 2
OSENSE1, 2
OSENSE1, 2
OSENSE1, 2
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
PLLFLTR
PLLFLTR
PLLFLTR
A
= 15V; EXTV
= 0 to 20mA, V
= 20mA, V
= 20mA, EXTV
Ramping Down
= 25°C. V
= 0.85V
< f
> f
= 1.2V; Sink/Source 5uA; (Note 3)
= 1.2V; (Note 3)
IN
= 3300pF
= 3300pF
= 3300pF
= 3300pF
= 3300pF Each Driver
= 3300pF Each Driver
OSC
OSC
< 30V, V
= 1.2V
= 0V
≥ 2.4V
V
V
The
RUN/SS2
RUN/SS2
= 0V
= 4.5V
= 0.5V
= 0.7V,V
= 0.7V,V
= 1.9V
EXTVCC
OSENSE1, 2
IN
●
CC
denotes the specifications which apply over the full operating
EXTVCC
= 15V, V
SENSE1
CC
EXTVCC
Tied to V
Rising
Rising from 3V
SENSE1 – , 2 –
SENSE1 – , 2 –
Ramping Positive
= 5V
OSENSE1, 2
–
= 4V
, 2
= 4V
RUN/SS1, 2
– = V
OUT1
= 5V
= 5V
; V
= 0.5V;
SENSE1
OUT1
= 5V unless otherwise noted.
+
= 5V
, 2
+ = 0V
●
●
●
●
●
– 0.50
0.76
0.84
MIN
– 85
360
230
480
0.5
1.0
0.5
4.8
4.5
98
65
62
www.DataSheet4U.com
– 0.18
450
0.800
1.3
20
0.86
99.4
TYP
– 60
100
400
260
550
–15
3
4.3
3.5
1.2
1.5
3.8
1.6
5.0
0.2
4.7
0.2
75
75
50
50
40
40
90
90
80
50
15
2
LTC3728
MAX
0.84
– 0.1
0.88
35
160
440
290
590
4.8
1.9
4.5
5.2
1.0
85
88
90
90
90
80
4
4
5
UNITS
mmho
MHzI
3728fb
3
kHz
kHz
kHz
mV
mV
mV
kΩ
µA
µA
µA
µA
µA
µA
µA
µA
µA
ns
ns
ns
ns
ns
ns
ns
%
%
V
V
V
V
V
V
V
V
V
Q