LTC1735
The
q
denotes 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.
SYMBOL
V
OVL
I
Q
PARAMETER
Feedback Overvoltage Lockout
Input DC Supply Current
Normal Mode
Shutdown
Run Pin Start Threshold
Run Pin Begin Latchoff Threshold
Soft-Start Charge Current
RUN/SS Discharge Current
Undervoltage Lockout
Maximum Current Sense Threshold
Sense Pins Total Source Current
Minimum On-Time
TG Transition Time:
Rise Time
Fall Time
BG Transition Time:
Rise Time
Fall Time
Top Gate Off to Synchronous
Gate On Delay Time
Synchronous Gate Off to Top
Gate On Delay Time
Internal V
CC
Voltage
Internal V
CC
Load Regulation
EXTV
CC
Drop Voltage
EXTV
CC
Switchover Voltage
EXTV
CC
Hysteresis
Oscillator Frequency
Maximum Sync Frequency Ratio
FCB Pin Threshold For Sync
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
Ramping Negative
I
PGOOD
= 2mA
V
PGOOD
= 5V
V
OSENSE
with Respect to Set Output Voltage
V
OSENSE
Ramping Negative
V
OSENSE
Ramping Positive
– 6.0
6.0
– 7.5
7.5
0.9
C
OSC
= 43pF (Note 5)
265
(Note 4)
V
RUN/SS
= 0V
V
RUN/SS
, Ramping Positive
V
RUN/SS
, Ramping Positive
V
RUN/SS
= 0V
Soft Short Condition, V
OSENSE
= 0.5V,
V
RUN/SS
= 4.5V
Measured at V
IN
Pin (V
IN
Ramping Down)
V
OSENSE
= 0.7V
V
SENSE–
= V
SENSE+
= 0V
Tested with a Square Wave (Note 6)
(Note 7)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
(Note 7)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
C
LOAD
= 3300pF Each Driver
C
LOAD
= 3300pF Each Driver
q
q
ELECTRICAL CHARACTERISTICS
CONDITIONS
q
MIN
0.84
TYP
0.86
450
15
MAX
0.88
UNITS
V
µA
µA
V
V
µA
µA
V
mV
µA
ns
ns
ns
ns
ns
ns
ns
25
1.9
4.5
4
3.9
85
80
200
90
90
90
80
V
RUN/SS
V
RUN/SS
I
RUN/SS
I
SCL
UVLO
∆V
SENSE(MAX)
I
SENSE
t
ON(MIN)
TG t
r
TG t
f
BG t
r
BG t
f
TG/BG t
1D
TG/BG t
2D
1.0
– 0.7
0.5
1.5
4.1
– 1.2
2
3.5
60
75
60
160
50
50
50
40
100
70
Internal V
CC
Regulator
V
INTVCC
V
LDO(INT)
V
LDO(EXT)
V
EXTVCC
V
EXTVCC(HYS)
Oscillator
f
OSC
f
H
/f
OSC
f
FCB(SYNC)
V
PGL
I
PGOOD
V
PG
300
1.3
1.2
110
200
±1
– 9.5
9.5
V
mV
µA
%
%
335
kHz
6V < V
IN
< 30V, V
EXTVCC
= 4V
I
CC
= 0 to 20mA, V
EXTVCC
= 4V
I
CC
= 20mA, V
EXTVCC
= 5V
I
CC
= 20mA, EXTV
CC
Ramping Positive
q
5.0
5.2
0.2
130
5.4
1
200
V
%
mV
V
V
4.5
4.7
0.2
PGOOD Output (LTC1735F Only)
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LTC1735CS, LTC1735IS: T
J
= T
A
+ (P
D
• 110
°C/W)
LTC1735CGN, LTC1735IGN, LTC1735EGN: T
J
= T
A
+ (P
D
• 130°C/W)
LTC1735CF, LTC1735IF: T
J
= T
A
+ (P
D
• 110°C/W)
1735fc
3
LINER [ LINEAR TECHNOLOGY ]
