LTC3858 Linear Technology, LTC3858 Datasheet - Page 4

• Manufacturer Part Number: LTC3858
• Description: Synchronous Step-Down Controller
• Manufacturer: Linear Technology

elecTrical characTerisTics
LTC3858
SYMBOL
TG/BG t
BG/TG t
t
INTV
V
V
V
V
V
V
Oscillator and Phase-Locked Loop
f
f
f
f
f
f
PGOOD1 and PGOOD2 Outputs
V
I
V
t
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Ratings for extended periods may affect device reliability and
lifetime.
Note 2: The LTC3858E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 125°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3858I is guaranteed
over the full –40°C to 125°C operating junction temperature range.
Note 3: T
dissipation P
junction temperature range, otherwise specifications are at T

ON(MIN)
25kΩ
65kΩ
105kΩ
LOW
HIGH
SYNC
PGOOD
PG
INTVCCVIN
LDOVIN
INTVCCEXT
LDOEXT
EXTVCC
LDOHYS
PGL
PG
T
CC
J
= T
Linear Regulator
1D
1D
J
A
is calculated from the ambient temperature T
+ (P
D
according to the following formula:
PARAMETER
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
Internal V
INTV
EXTV
EXTV
Programmable Frequency
Programmable Frequency
Programmable Frequency
Low Fixed Frequency
High Fixed Frequency
Synchronizable Frequency
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
Delay for Reporting a Fault (PGOOD Low)
D
• 34°C/W)
CC
CC
CC
CC
Load Regulation
Load Regulation
Switchover Voltage
Hysteresis Voltage
CC
CC
Voltage
Voltage
A
and power
CONDITIONS
C
C
(Note 7)
6V < V
I
6V < V
I
EXTV
R
R
R
V
V
PLLIN/MODE = External Clock
I
V
V
V
Hysteresis
V
V
Hysteresis
CC
CC
PGOOD
LOAD
LOAD
FREQ
FREQ
PGOOD
FB
FB
FREQ
FREQ
FREQ
FB
FB
= 0mA to 50mA, V
= 0mA to 50mA, V
with Respect to Set Regulated Voltage
with Respect to Set Regulated Voltage
Ramping Negative
Ramping Positive
CC
= 0V, PLLIN/MODE = DC Voltage
= INTV
= 3300pF Each Driver
= 3300pF Each Driver
= 25k, PLLIN/MODE = DC Voltage
= 65k, PLLIN/MODE = DC Voltage
= 105k, PLLIN/MODE = DC Voltage
IN
EXTVCC
= 2mA
The
= 5V
Ramping Positive
< 38V, V
A
= 25°C. V
l
< 13V
CC
denotes the specifications which apply over the full operating
, PLLIN/MODE = DC Voltage
EXTVCC
Note 4: The LTC3858 is tested in a feedback loop that servos V
specified voltage and measures the resultant V
85°C is not tested in production. This specification is assured by design,
characterization and correlation to production testing at 125°C.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications information.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels
Note 7: The minimum on-time condition is specified for an inductor
peak-to-peak ripple current ≥ of 40% I
Considerations in the Applications Information section).
EXTVCC
EXTVCC
IN
= 0V
= 12V, V
= 0V
= 8.5V
RUN1,2
= 5V, EXTV
l
CC
= 0V unless otherwise noted.
MAX
MIN
4.85
4.85
375
320
485
–13
4.5
75
7
(See Minimum On-Time
www.DataSheet4U.com
FB1,2
TYP
250
105
440
835
350
535
–10
5.1
0.7
5.1
0.6
4.7
0.2
2.5
2.5
30
30
95
10
25
. The specification at
MAX
5.35
5.35
505
380
585
850
1.1
1.1
4.9
0.4
±1
–7
13
ITH1,2
to a
UNITS
3858fa
kHz
kHz
kHz
kHz
kHz
kHz
mV
µA
ns
ns
ns
µs
%
%
%
%
%
%
V
V
V
V