ltc3728legn-trpbf Linear Technology Corporation, ltc3728legn-trpbf Datasheet - Page 3

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ltc3728legn-trpbf

Manufacturer Part Number
ltc3728legn-trpbf
Description
Dual, 550khz, 2-phase Synchronous Step-down Switching Regulator
Manufacturer
Linear Technology Corporation
Datasheet
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifi cations are at T
SYMBOL
Main Control Loops
V
I
V
V
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
OSENSE1, 2
FCB
SENSE
RUN/SS1, 2
SCL1, 2
SDLHO
ON(MIN)
m1, 2
mGBW1, 2
OSENSE1, 2
REFLNREG
LOADREG
FCB
BINHIBIT
OVL
RUN/SS1, 2
RUN/SS1, 2
SENSE(MAX)
INTVCC
LDO
LDO
MAX
CC
INT
EXT
Linear Regulator
1D
2D
r
f
r
f
ON
LT
PARAMETER
Regulated Feedback Voltage
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
Transconductance Amplifi er g
Transconductance Amplifi er 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 Pin ON Threshold
RUN/SS Pin Latchoff Arming
Threshold
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
Normal Mode
Shutdown
CC
CC
Load Regulation
Voltage Drop
CC
Voltage
m
CONDITIONS
(Note 3); I
(Note 3)
V
(Note 3)
Measured in Servo Loop; ΔI
Measured in Servo Loop; ΔI
I
I
(Note 4)
V
V
V
Measured at FCB Pin
V
Measured at V
(Each Channel); V
In Dropout
V
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
TH1, 2
TH1, 2
CC
CC
A
IN
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
= 25°C. V
= 0 to 20mA, V
= 20mA, V
= 3.6V to 30V (Note 3)
= 15V; EXTV
Ramping Down
= 0.85V
= 1.2V; Sink/Source 5μA; (Note 3)
= 1.2V; (Note 3)
= 3300pF
= 3300pF
= 3300pF
= 3300pF
= 3300pF Each Driver
= 3300pF Each Driver
IN
The
< 30V, V
TH1, 2
V
V
RUN/SS2
RUN/SS2
= 0V
= 1.9V
= 4.5V
= 0.5V
= 0.7V, V
= 0.7V, V
l
IN
EXTVCC
OSENSE1, 2
denotes the specifi cations which apply over the full operating
Voltage = 1.2V
CC
= 15V, V
EXTVCC
SENSE1
EXTVCC
Tied to V
Rising
Rising from 3V
OSENSE1
OSENSE1
= 5V
OSENSE1, 2
= 4V
, 2
RUN/SS1, 2
= 4V
– = V
OUT1
TH
TH
, 2
, 2
Voltage = 1.2V to 0.7V
Voltage = 1.2V to 2.0V
– = 5V
– = 5V
; V
SENSE1
= 0.5V;
OUT1
= 5V unless otherwise noted.
+
= 5V
, 2
+ = 0V
l
l
l
l
l
l
l
0.792
–0.50
0.76
0.84
MIN
–85
0.5
1.0
0.5
98
65
62
48
0.800
0.002
0.800
–0.18
LTC3728
–0.1
0.86
99.4
TYP
450
–60
100
0.1
1.3
4.3
3.5
1.2
1.5
3.8
1.6
5.0
0.2
–5
20
75
75
50
50
40
40
90
90
80
3
2
0.808
MAX UNITS
0.02
–0.5
0.84
–0.1
0.88
–50
160
0.5
4.8
1.9
4.5
5.2
1.0
35
85
88
90
90
90
80
4
4
5
mmho
MHzI
3728fd
3
%/V
mV
mV
mV
nA
μA
μA
μA
μA
μA
μA
μA
ns
ns
ns
ns
ns
ns
ns
%
%
%
%
V
V
V
V
V
V
V
V
Q

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