LTC3890-2
4
38902f
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
RUN1,2
= 5V, EXTV
CC
= 0V unless otherwise noted.
(Note 2)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Gate Driver
TG1,2 Pull-Up On-Resistance
TG1,2 Pull-Down On-Resistance
2.5
1.5
BG1,2 Pull-Up On-Resistance
BG1,2 Pull-Down On-Resistance
2.4
1.1
TG1,2 t
r
TG1,2 t
f
TG Transition Time:
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
25
16
ns
ns
BG1,2 t
r
BG1,2 t
f
BG Transition Time:
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
28
13
ns
ns
TG/BG t
1D
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 30 ns
BG/TG t
1D
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 30 ns
t
ON(MIN)
Minimum On-Time (Note 7) 95 ns
INTV
CC
Linear Regulator
V
INTVCCVIN
Internal V
CC
Voltage 6V < V
IN
< 60V, V
EXTVCC
= 0V 4.85 5.1 5.35 V
V
LDOVIN
INTV
CC
Load Regulation I
CC
= 0mA to 50mA, V
EXTVCC
= 0V 0.7 1.1 %
V
INTVCCEXT
Internal V
CC
Voltage 6V < V
EXTVCC
< 13V 4.85 5.1 5.35 V
V
LDOEXT
INTV
CC
Load Regulation I
CC
= 0mA to 50mA, V
EXTVCC
= 8.5V 0.6 1.1 %
V
EXTVCC
EXTV
CC
Switchover Voltage EXTV
CC
Ramping Positive 4.5 4.7 4.9 V
V
LDOHYS
EXTV
CC
Hysteresis 250 mV
Oscillator and Phase-Locked Loop
f
25k
Programmable Frequency R
FREQ
= 25k, PLLIN/MODE = DC Voltage 105 kHz
f
65k
Programmable Frequency R
FREQ
= 65k, PLLIN/MODE = DC Voltage 375 440 505 kHz
f
105k
Programmable Frequency R
FREQ
= 105k, PLLIN/MODE = DC Voltage 835 kHz
f
LOW
Low Fixed Frequency V
FREQ
= 0V, PLLIN/MODE = DC Voltage 320 350 380 kHz
f
HIGH
High Fixed Frequency V
FREQ
= INTV
CC
, PLLIN/MODE = DC Voltage 485 535 585 kHz
f
SYNC
Synchronizable Frequency PLLIN/MODE = External Clock
l
75 850 kHz
LTC3890-2
5
38902f
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
RUN1,2
= 5V, EXTV
CC
= 0V unless otherwise noted.
(Note 2)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
PGOOD1 and PGOOD2 Outputs
V
PGL
PGOOD Voltage Low I
PGOOD
= 2mA 0.2 0.4 V
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 5V ±1 µA
V
PG
PGOOD Trip Level V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Negative
Hysteresis
–13 –10
2.5
–7 %
%
V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Positive
Hysteresis
710
2.5
13 %
%
t
PG
Delay for Reporting a Fault 25 µs
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 LTC3890-2 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3890E-2 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 LTC3890I-2 is guaranteed
over the –40°C to 125°C operating junction temperature range, the
LTC3890H-2 is guaranteed over the –40°C to 150°C operating junction
temperature range and the LTC3890MP-2 is tested and guaranteed over
the –55°C to 150°C operating junction temperature range.
High junction temperatures degrade operating lifetimes; operating lifetime
is derated for junction temperatures greater than 125°C. Note that the
maximum ambient temperature consistent with these specifications is
determined by specific operating conditions in conjunction with board layout,
the rated package thermal impedance and other environmental factors.
Note 3: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
• 34°C/W)
Note 4: The LTC3890-2 is tested in a feedback loop that servos V
ITH1,2
to a
specified voltage and measures the resultant V
FB
. The specification at 85°C is not
tested in production and is assured by design, characterization and correlation
to production testing at other temperatures (125°C for the LTC3890E-2/
LTC3890I-2, 150°C for the LTC3890H-2/LTC3890MP-2). For the LTC3890MP-2,
the specification at –40°C is not tested in production and is assured by design,
characterization and correlation to production testing at –55°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 ≥ 40% of I
MAX
(See Minimum On-Time
Considerations in the Applications Information section).
LTC3890-2
6
38902f
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency and Power Loss
vs Output Current
Efficiency vs Output Current
Load Step
Burst Mode Operation
Load Step
Forced Continuous Mode
Load Step
Pulse-Skipping Mode
Inductor Current at Light Load Soft Start-Up Tracking Start-Up
Efficiency vs Input Voltage
OUTPUT CURRENT (A)
FIGURE 13 CIRCUIT
0
EFFICIENCY (%)
POWER LOSS (mW)
70
100
10.10.010.0010.0001 10
38902 G01
50
40
30
20 1
10
100
1000
10000
0.1
10
60
80
90
V
IN
= 12V
V
OUT
= 3.3V
BURST EFFICIENCY
FCM LOSS
PULSE-SKIPPING
LOSS
BURST LOSS
FCM EFFICIENCY
PULSE-SKIPPING
EFFICIENCY
OUTPUT CURRENT (A)
0
EFFICIENCY (%)
70
100
10.10.010.0010.0001 10
38902 G02
50
40
30
20
10
60
80
90
V
OUT
= 8.5V
V
OUT
= 3.3V
V
IN
= 12V
Burst Mode OPERATION
FIGURE 13 CIRCUIT
INPUT VOLTAGE (V)
80
EFFICIENCY (%)
94
100
20 30 35 40 45 50 55 6015105025
38902 G03
90
88
86
84
82
92
96
98
V
OUT1
= 3.3V
V
OUT2
= 8.5V
I
LOAD
= 2A
FIGURE 13 CIRCUIT
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 13 CIRCUIT
50µs/DIV
38902 G04
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 13 CIRCUIT
50µs/DIV
38902 G05
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 13 CIRCUIT
50µs/DIV
38902 G06
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV
V
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 200µA
5µs/DIV
38902 G07
FORCED
CONTINUOUS
MODE
PULSE-SKIPPING
MODE
Burst Mode
OPERATION
1A/DIV
FIGURE 13 CIRCUIT
2ms/DIV
38902 G08
V
OUT2
2V/DIV
V
OUT1
2V/DIV
FIGURE 13 CIRCUIT
2ms/DIV
38902 G09
V
OUT2
2V/DIV
V
OUT1
2V/DIV

LTC3890HUH-2#PBF

Mfr. #:
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 60V Low IQ, Dual Output Synchronous Step-Down Controller
Lifecycle:
New from this manufacturer.
Delivery:
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