LTC3812-5
4
38125fc
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3812-5 is tested under pulsed load conditions such that
T
J
T
A
.The LTC3812E-5 is guaranteed to meet performance specifi cations
from 0°C to 85°C. Specifi cations over the –40°C to 125°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC3812I-5 is guaranteed
to meet performance specifi cations over the full –40°C to 125°C operating
junction temperature range.
Note 3: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC3812-5: T
J
= T
A
+ (P
D
• 38°C/W)
Note 4: The LTC3812-5 is tested in a feedback loop that servos V
FB
to the
reference voltage with the I
TH
pin forced to a voltage between 1V and 2V.
Note 5: The dynamic input supply current is higher due to the power
MOSFET gate charging being delivered at the switching frequency
(Q
G
• f
OSC
).
Note 6: Guaranteed by design. Not subject to test.
Note 7: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specifi ed maximum operating junction
temperature may impair device reliability.
Note 8: I
CC
is the sum of current into NDRV and INTV
CC
.
The l denotes specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C (Note 2), INTV
CC
= V
BOOST
= V
RNG
= V
EXTVCC
= V
NDRV
= 5V, V
FCB
= V
SW
=
0V, unless otherwise specifi ed.
ELECTRICAL CHARACTERISTICS
PARAMETER LTC3810 LTC3810-5 LTC3812-5
Maximum V
IN
100V 60V 60V
MOSFET Gate Drive 6.35V to 14V 4.5V to 14V 4.5V to 14V
INTV
CC
UV
+
6.2V 4.2V 4.2V
INTV
CC
UV
6V 4V 4V
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 5V 0 2 μA
PG Delay PGOOD Delay V
FB
Falling 120 μs
V
CC
Regulators
V
EXTVCC
EXTV
CC
Switchover Voltage
EXTV
CC
Rising
EXTV
CC
Hysterisis
l
4.5
0.1
4.7
0.25 0.4
V
V
V
INTVCC,1
INTV
CC
Voltage from EXTV
CC
6V < V
EXTVCC
< 15V 5.2 5.5 5.8 V
V
EXTVCC,1
V
EXTVCC
- V
INTVCC
at Dropout I
CC
= 20mA, V
EXTVCC
= 5V 75 150 mV
V
LOADREG,1
INTV
CC
Load Regulation from EXTV
CC
I
CC
= 0mA to 20mA, V
EXTVCC
= 10V 0.01 %
V
INTVCC,2
INTV
CC
Voltage from NDRV Regulator Linear Regulator in Operation 5.2 5.5 5.8 V
V
LOADREG,2
INTV
CC
Load Regulation from NDRV I
CC
= 0mA to 20mA, V
EXTVCC
= 0 0.01 %
I
NDRV
Current into NDRV Pin V
NDRV
– V
INTVCC
= 3V 20 40 60 μA
I
NDRVTO
Linear Regulator Timeout Enable
Threshold
210 270 350 μA
V
CCSR
Maximum Supply Voltage Trickle Charger Shunt Regulator 15 V
I
CCSR
Maximum Current into NDRV/INTV
CC
Trickle Charger Shunt Regulator,
INTV
CC
≤ 16.7V (Note 8)
10 mA
LTC3812-5
5
38125fc
Short-Circuit/Foldback Operation Pulse-Skipping Mode Operation
Effi ciency vs Input Voltage
Effi ciency vs Load Current Frequency vs Input Voltage
Frequency vs Load Current
Load Transient Response
Start-Up
Short-Circuit/Fault Timeout
Operation
TYPICAL PERFORMANCE CHARACTERISTICS
V
OUT
50mV/DIV
10μs/DIV
FRONT PAGE CIRCUIT
V
IN
= 25V
0A TO 5A LOAD STEP
38125 G01
I
OUT
5A/DIV
V
IN
20V/DIV
2ms/DIV
FRONT PAGE CIRCUIT
V
IN
= 30V
I
LOAD
= 0.5A
FCB = 0V
38125 G02
INTV
CC
,
V
OUT
2V/DIV
I
L
2A/DIV
INTV
CC
V
OUT
V
OUT
5V/DIV
5ms/DIV
FRONT PAGE CIRCUIT
V
IN
= 25V
R
SHORT
= 0.1Ω
38125 G03
SS/TRACK
2V/DIV
I
L
5A/DIV
V
OUT
5V/DIV
200μs/DIV
FRONT PAGE CIRCUIT
V
IN
= 25V
38125 G04
I
L
5A/DIV
V
OUT
100mV/DIV
I
TH
0.5A/DIV
20μs/DIV
FRONT PAGE CIRCUIT
V
IN
= 25V
I
OUT
= 100mA
FCB = INTV
CC
38125 G05
I
L
2A/DIV
INPUT VOLTAGE (V)
0
80
EFFICIENCY (%)
85
90
95
100
10 20 30 40
38125 G06
50 60
I
LOAD
= 5A
FORCED
CONTINUOUS
I
LOAD
= 0.5A
FORCED
CONTINUOUS
I
LOAD
= 0.5A
PULSE-SKIPPING
FRONT PAGE CIRCUIT
f = 250kHz
LOAD CURRENT (A)
0
85
EFFICIENCY (%)
90
95
100
1
234
38125 G07
56
V
IN
= 24V
V
IN
= 42V
V
OUT
= 12V
FCB = INTV
CC
f = 250kHz
INPUT VOLTAGE (V)
0
200
FREQUENCY (kHz)
220
240
260
10
20
30 40
LT1108 • TPC12
50
280
300
210
230
250
270
290
60
LOAD = 0A
LOAD = 5A
FRONT PAGE CIRCUIT
FCB = 0V
LOAD CURRENT (A)
0
250
300
350
4
38125 G09
200
150
123 5
100
50
0
FREQUENCY (kHz)
FORCED
CONTINUOUS
PULSE SKIPPING
FRONT PAGE CIRCUIT
LTC3812-5
6
38125fc
TYPICAL PERFORMANCE CHARACTERISTICS
On-Time vs Temperature Current Limit Foldback
Maximum Current Sense
Threshold vs V
RNG
Voltage
Maximum Current Sense
Threshold vs Temperature
Reference Voltage
vs Temperature
Driver Peak Source Current
vs Temperature
TEMPERATURE (°C)
–50
ON-TIME (ns)
640
660
680
25 75
38125 G13
620
600
–25 0
50 100 125
580
560
I
ON
= 300μA
V
FB
(V)
0
MAXIMUM CURRENT SENSE THRESHOLD (mV)
100
150
0.8
38125 G14
50
0
0.2
0.4
0.6
250
200
V
RNG
= INTV
CC
V
RNG
VOLTAGE (V)
0.5
MAXIMUM CURRENT SENSE THRESHOLD (mV)
200
38125 G15
100
0
1 1.5
300
400
2
TEMPERATURE (°C)
–50 –25
180
MAXIMUM CURRENT SENSE THRESHOLD (mV)
200
230
0
50
75
38125 G16
190
220
210
25
100
125
V
RNG
= INTV
CC
TEMPERATURE (°C)
–50 –25
0.797
REFERENCE VOLTAGE (V)
0.799
0.803
0.802
0
50
75
38125 G17
0.798
0.801
0.800
25
100
125
TEMPERATURE (°C)
–50
0.5
PEAK SOURCE CURRENT (A)
1.0
1.5
–25 0 25 50
38125 G18
75 100 125
V
BOOST
= V
INTVCC
= 5V
Current Sense Threshold
vs I
TH
Voltage
On-Time vs I
ON
CurrentI
TH
Voltage vs Load Current
LOAD CURRENT (A)
01
0
I
TH
VOLTAGE (V)
1.0
3.0
2.5
2
4
5
38125 G10
0.5
2.0
1.5
3
6
7
V
RNG
= 1V
FRONT PAGE CIRCUIT
I
TH
VOLTAGE (V)
0
–400
CURRENT SENSE THRESHOLD (mV)
–200
–300
–100
0
100
200
400
0.5
1 1.5 2
38125 G11
2.5 3
300
V
RNG
= 2V
1.4V
1V
0.7V
0.5V
I
ON
CURRENT (μA)
10
10
ON-TIME (ns)
100
1000
10000
100 1000 10000
38125 G12
V
ON
= INTV
CC

LTC3812IFE-5#TRPBF

Mfr. #:
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 60V Current Mode Buck Controller
Lifecycle:
New from this manufacturer.
Delivery:
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