4
LTC3729
sn3729 3729fas
ELECTRICAL CHARACTERISTICS
The
●
denotes the 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.
Note 4:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 5:
The minimum on-time condition corresponds to the on inductor
peak-to-peak ripple current
≥
40% of I
MAX
(see Minimum On-Time
Considerations in the Applications Information section).
Note 6:
The LTC3729E is guaranteed to meet performance specifications
from 0
°
C to 70
°
C. Specifications over the – 40
°
C to 85
°
C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
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:
LTC3729EG: T
J
= T
A
+ (P
D
• 95
°
C/W)
LTC3729EUH: T
J
= T
A
+ (P
D
• 34
°
C/W)
Note 3:
The LTC3729 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
EAIN
.
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
Efficiency vs Output Current
(Figure 12)
Efficiency vs Output Current
(Figure 12)
Efficiency vs Input Voltage
(Figure 12)
OUTPUT CURRENT (A)
0.1
EFFICIENCY (%)
100
80
60
40
20
0
3729
G01
1
10
100
V
OUT
= 3.3V
V
EXTVCC
= 5V
I
OUT
= 20A
f = 250kHz
V
IN
= 5V
V
IN
= 8V
V
IN
= 12V
V
IN
= 20V
OUTPUT CURRENT (A)
1
EFFICIENCY (%)
70
80
3729
G02
60
50
10
100
100
90
V
EXTVCC
= 0V
V
OUT
= 3.3V
f = 250kHz
V
EXTVCC
= 5V
V
IN
(V)
5
EFFICIENCY (%)
100
90
80
70
3729
G03
10
15
20
V
OUT
= 3.3V
V
EXTVCC
= 5V
I
OUT
= 20A
f = 250kHz
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
CLKOUT
Phase (Relative to Controller 1)
V
PHASMD
= 0V
60
Deg
V
PHASMD
= Open
90
Deg
V
PHASMD
= 5V
120
Deg
CLK
HIGH
Clock High Output Voltage
4
V
CLK
LOW
Clock Low Output Voltage
0.2
V
PGOOD Output
V
PGL
PGOOD Voltage Low
I
PGOOD
= 2mA
0.1
0.3
V
I
PGOOD
PGOOD Leakage Current
V
PGOOD
= 5V
±
1
µ
A
V
PG
PGOOD Trip Level, Either Controller
V
EAIN
with Respect to Set Output Voltage
V
EAIN
Ramping Negative
– 6
– 7.5
– 9.5
%
V
EAIN
Ramping Positive
6
7.5
9.5
%
Differential Amplifier
A
DA
Gain
0.995
1
1.005
V/V
CMRR
DA
Common Mode Rejection Ratio
0V < V
CM
< 5V
46
55
dB
R
IN
Input Resistance
Measured at V
OS
+ Input
80
k
Ω
