Maximum Junction Temperature........................... 125°C
Operating Temperature Range (Note 2).. –40°C to 125°C
Storage Temperature Range
TSSOP ............................................... –65°C to 150°C
QFN.................................................... –65°C to 125°C
Lead Temperature (Soldering, 10 sec)
TSSOP Only ...................................................... 300°C
PIN CONFIGURATION
TOP VIEW
NPN_DRV
TOP VIEW
FB3
FB2
FB1
SHDN1
18 V
C2
17 SS2
25
16 GND
15 R
T
14 SYNC
13
SHDN3
7
V
IN1
8
SS1
9 10 11 12
FB1
V
C1
SHDN1
SHDN2
SHDN2
SHDN3
SYNC
R
T
SS2
V
C2
FB2
1
2
3
4
5
6
7
8
9
21
20 V
C1
19 SS1
18 V
IN1
17 GND
16 SW1
15 SW2
14 V
IN2
13 BOOST
12 V
IN3
11 NPN_DRV
BOOST
BIAS
V
IN3
24 23 22 21 20 19
V
IN2
1
V
IN2
2
SW2 3
SW1 4
GND 5
GND 6
FB3 10
UF PACKAGE
24-LEAD (4mm 4mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 37°C/W
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
FE PACKAGE
20-LEAD PLASTIC TSSOP
T
JMAX
= 125°C,
θ
JA
= 38°C/W
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT3570EUF#PBF
LT3570IUF#PBF
LT3570EFE#PBF
LT3570IFE#PBF
TAPE AND REEL
LT3570EUF#TRPBF
LT3570IUF#TRPBF
LT3570EFE#TRPBF
LT3570IFE#TRPBF
PART MARKING*
3570
3570
LT3570FE
LT3570FE
PACKAGE DESCRIPTION
24-Lead (4mm
×
4mm) Plastic QFN
24-Lead (4mm
×
4mm) Plastic QFN
20-Lead Plastic TSSOP
20-Lead Plastic TSSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
3570fb
2
LT3570
ELECTRICAL CHARACTERISTICS
PARAMETER
Minimum Operating Voltage (V
IN1
)
Minimum Operating Voltage (V
IN2
)
Shutdown Current (Note 4)
V
IN1
Quiescent Current
V
IN2
Quiescent Current
V
IN3
Quiescent Current
Bias Quiescent Current
V
SHDN1,2,3
Pin Threshold
V
SHDN1,2,3
Pin UVLO
V
SHDNX
Pin Current
Switching Frequency
Maximum Duty Cycle
Synchronous Frequency Threshold
Synchronous Frequency Range
Synchronous Frequency Minimum On/Off
Time
FB1,2,3 Pin Voltage
FB1,2,3 Pin Voltage Line Regulation
FB1,2 Pin Bias Current
FB3 Pin Bias Current
SS1,2 Pin Source Current
V
C1,2
Pin Source Current
V
C1,2
Pin Sink Current
SW1
Error Amplifier 1 Transconductance
Error Amplifier 1 Voltage Gain
V
C1
Pin Switching Threshold
V
C1
to SW1 Current Gain
SW1 Current Limit
SW1 V
CESAT
SW1 Leakage Current
(Note 7)
I
SW1
= 1A (Note 7)
SW1 = 40V, V
SHDN1
= 0V
1.5
190
100
750
5.9
2.4
240
0.2
5
3.1
μMho
V/V
mV
A/V
A
mV
μA
V
VIN1,2,3
= 2.5V to 36V, V
C1,2
= 1V
V
FB1,2
= 800mV, V
C1,2
= 1V (Note 6)
V
FB3
= 800mV (Note 6)
V
SS1,2
= 500mV
V
FB1,2
= 600mV
V
FB1,2
= 1V
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN1,2,3
= 12V, V
SHDN1,2,3
= 12V unless otherwise noted.
CONDITIONS
(Note 3)
(Note 3)
V
SHDN1,2,3
= 0V
V
SHDN1
= 12V, V
SHDN2,3
= 0V, V
C1
= 0.4V (Not Switching)
V
SHDN1
= 0V, V
SHDN2,3
= 12V
V
SHDN1,3
= 0V, V
SHDN2
= 12V, V
C2
= 0.4V (Not Switching)
V
SHDN1,3
= 12V, V
SHDN2
= 0V
V
SHDN1,2
= 0V, V
SHDN3
= 12V
V
SHDN1,2
= 12V, V
SHDN3
= 0V
V
BIAS
= 2.5V
I
VIN2
> 100μA
l
l
l
MIN
TYP
2.1
2.1
0
3.2
65
3.5
3.5
700
0
2.3
MAX
2.5
2.5
1.5
4.5
150
4.5
4.5
950
1.5
3.1
1.4
1.4
50
1.5
550
2300
UNITS
V
V
μA
mA
μA
mA
mA
μA
μA
mA
V
V
μA
μA
kHz
kHz
%
%
0.3
1.1
1.25
30
0.1
450
1900
95
80
0.3
650
50
772
788
0.01
30
30
4.5
12
12
500
2100
V
SHDNX
= 12V, V
SHDNY,Z
= 0V (Note 5)
V
SHDN1,2,3
= 0V
R
T
= 44.2k
R
T
= 7.87k
R
T
= 44.2k
R
T
= 7.87k
1.5
2750
V
kHz
ns
804
200
200
mV
%/V
nA
nA
μA
μA
μA
3570fb
3
LT3570
ELECTRICAL CHARACTERISTICS
PARAMETER
SW2
Error Amplifier 2 Transconductance
Error Amplifier 2 Voltage Gain
V
C2
Pin Switching Threshold
V
C2
to SW2 Current Gain
SW2 Current Limit
SW2 V
CESAT
SW2 Leakage Current
BOOST Pin Current
LDO
LDO Maximum Output Current
V
FB3
= 600mV
10
20
mA
(Note 7)
I
SW2
= 1A (Note 7)
SW2 = 0V, V
IN2
= 40V, V
SHDN2
= 0V
I
SW2
= 0.5A
I
SW2
= 1.5A
1.5
195
100
700
5.4
2.4
240
0.2
15
30
5
3.1
μMho
V/V
mV
A/V
A
mV
μA
mA
mA
CONDITIONS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN1,2,3
= 12V, V
SHDN1,2,3
= 12V unless otherwise noted.
MIN
TYP
MAX
UNITS
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 LT3570E is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT3570I is guaranteed over the full –40°C to 125°C operating junction
temperature range.
Note 3:
V
IN2
supplies power for the part. V
IN1
supplies power only to the
boost converter. V
IN3
supplies power only to the LDO Controller.
Note 4:
Shutdown current is for each individual input current.
Note 5:
Current flows into the pin.
Note 6:
Current flows out of the pin.
Note 7:
Switch current limit and switch V
CESAT
guaranteed by design
and/or correlation to static test.
Note 8:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed the maximum operating junction temperature
range when overtemperature protection is active. Continuous operation
above the specified maximum operating junction temperature may impair
