LTC1735I-1 Linear Technology, LTC1735I-1 Datasheet - Page 3

• Manufacturer Part Number: LTC1735I-1
• Description: High Efficiency Synchronous Step-Down Switching Regulator
• Manufacturer: Linear Technology

ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are at T
SYMBOL
TG t
TG t
BG t
BG t
TG/BG T1D
TG/BG T2D
Internal V
V
V
V
V
V
Oscillator
f
f
PGOOD Pin
V
V
V
I
V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: T
dissipation P
Note 3: The LTC1735-1 is tested in a feedback loop that servos V
to the balance point for the error amplifier (V
Note 4: The minimum on-time condition corresponds to an inductor
peak-to-peak ripple current > 40% of I
Considerations in the Applications Information section).
OSC
H
PGOOD
INTVCC
LDO(INT)
LDO(EXT)
EXTVCC
EXTVCC(HYS)
PG(SYNC)
PG(FC)
PGL
PG
/f
OSC
LTC1735CS-1, LTC1735IS-1: T
LTC1735CGN-1, LTC1735IGN-1: T
r
f
r
f
J
CC
is calculated from the ambient temperature T
Regulator
D
according to the following formulas:
PARAMETER
TG Transition Time:
BG Transition Time:
Top Gate Off to Synchronous
Gate-On Delay Time
Synchronous Gate Off to Top
Gate-On Delay Time
Internal V
INTV
EXTV
EXTV
EXTV
Oscillator Frequency
Maximum Sync Frequency Ratio
PGOOD Threshold for Sync
PGOOD Threshold for Force Cont.
PGOOD Voltage Low
PGOOD Pull-Up Current
PGOOD Trip Level
Rise Time
Fall Time
Rise Time
Fall Time
CC
CC
CC
CC
Load Regulation
Drop Voltage
Switchover Voltage
Hysteresis
CC
Voltage
J
= T
J
MAX
A
= T
+ (P
(see Minimum On-Time
A
+ (P
ITH
D
• 110 C/W)
= 1.2V).
D
• 130 C/W)
A
and power
CONDITIONS
(Note 7)
C
C
(Note 7)
C
C
C
C
6V < V
I
I
I
(Note 6), C
Ramping Negative
I
V
V
CC
CC
CC
PGOOD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
PGOOD
OSENSE
A
V
V
OSENSE
OSENSE
= 25 C. V
= 0mA to 20mA, V
= 20mA, V
= 20mA, EXTV
OSENSE
= 3300pF
= 3300pF
= 3300pF
= 3300pF
= 3300pF Each Driver
= 3300pF Each Driver
IN
= 2mA
= 0.85V
The
With Respect to Set Output Voltage
< 30V, V
Ramping Negative
Ramping Positive
OSC
EXTVCC
IN
= 43pF
denotes specifications which apply over the full operating
= 15V, V
EXTVCC
CC
Ramping Positive
= 5V
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 6: Oscillator frequency is tested by measuring the C
current (I
Note 7: Rise and fall times are measured using 10% to 90% levels.
Delay times are measured using 50% levels.
EXTVCC
= 4V
f
OSC
RUN/SS
= 4V
(
kHz
OSC
) and applying the formula:
)
= 5V unless otherwise noted.
C
8 477 10
OSC
.
( )
pF
(
8
11
)
I
CHG
– 6.0
1
0.76
MIN
265
5.0
4.5
0.9
6.0
I
DIS
1
– 0.17
LTC1735-1
–7.5
–
TYP
100
130
300
110
5.2
0.2
4.7
0.2
1.3
1.2
0.8
50
50
50
40
70
1
7.5
OSC
MAX
0.84
–9.5
200
335
200
5.4
90
90
90
80
9.5
1
charge
UNITS
3
kHz
mV
mV
ns
ns
ns
ns
ns
ns
%
%
%
V
V
V
V
V
A