Datasheet

LTC3857
2
3857fd
PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS
(Note 1)
32 31 30 29 28 27 26 25
9 10 11 12 13 14 15 16
17
18
19
20
21
22
23
24
8
7
6
5
4
3
2
1
TOP VIEW
SENSE1
–
FREQ
PHASMD
CLKOUT
PLLIN/MODE
SGND
RUN1
RUN2
BOOST1
BG1
V
IN
PGND
EXTV
CC
INTV
CC
BG2
BOOST2
SENSE1
+
V
FB1
I
TH1
TRACK/SS1 I
LIM
PGOOD1 TG1 SW1
SENSE2
–
SENSE2
+
V
FB2
I
TH2
TRACK/SS2
PGOOD2
TG2
SW2
UH PACKAGE
32-LEAD (5mm s 5mm) PLASTIC QFN
33
SGND
T
JMAX
= 125°C, θ
JA
= 34°C/W
EXPOSED PAD (PIN 33) IS SGND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3857EUH#PBF LTC3857EUH#TRPBF 3857
32-Lead (5mm × 5mm) Plastic QFN
–40°C to 125°C
LTC3857IUH#PBF LTC3857IUH#TRPBF 3857
32-Lead (5mm × 5mm) Plastic QFN
–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/
Input Supply Voltage (V
IN
) ......................... –0.3V to 40V
Topside Driver Voltages
BOOST1, BOOST2 ................................. –0.3V to 46V
Switch Voltage (SW1, SW2) ........................ –5V to 40V
PLLIN/MODE, (BOOST1-SW1), (BOOST2-SW2),
INTV
CC
........................................................ –0.3V to 6V
RUN1, RUN2 ................................................ –0.3V to 8V
Maximum Current Sourced into Pin
from Source >8V...............................................100µA
SENSE1
+
, SENSE2
+
, SENSE1
–
SENSE2
–
Voltages ...................................... –0.3V to 28V
FREQ Voltages ..................................... –0.3V to INTV
CC
I
LIM
, PHASMD Voltages ....................... –0.3V to INTV
CC
EXTV
CC
...................................................... –0.3V to 14V
I
TH1
, I
TH2
,V
FB1
, V
FB2
Voltages ...................... –0.3V to 6V
PGOOD1, PGOOD2 Voltages ....................... –0.3V to 6V
TRACK/SS1, TRACK/SS2 Voltages .............. –0.3V to 6V
Operating Junction Temperature Range
(Note 2) .................................................. –40°C to 125°C
Maximum Junction Temperature (Note 3) ............ 125°C
Storage Temperature Range ................... –65°C to 150°C
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Input Supply Operating Voltage Range 4 38 V
V
FB1,2
Regulated Feedback Voltage (Note 4) I
TH1,2
Voltage = 1.2V
–40°C to 125°C
–40°C to 85°C
l
0.788
0.792
0.800
0.800
0.812
0.808
V
V
I
FB1,2
Feedback Current (Note 4) ±5 ±50 nA
V
REFLNREG
Reference Voltage Line Regulation (Note 4) V
IN
= 4.5V to 38V 0.002 0.02 %/V
The l denotes the specifications which apply over the full operating junction
temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 12V, V
RUN1,2
= 5V, EXTV
CC
= 0V, unless otherwise noted.