Linear Technology LTC3729, Руководство пользователя

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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