LTC3857 Datasheet, PDF (2/38 Pages) Linear Technology – Low IQ, Dual, 2-Phase Synchronous Step-Down Controller

LTC3857
Absolute Maximum Ratings
(Note 1)
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
(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
PLLIN/MODE, 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
Pin Configuration
TOP VIEW
32 31 30 29 28 27 26 25
SENSE1^– 1
24 BOOST1
FREQ 2
23 BG1
PHASMD 3
CLKOUT 4
PLLIN/MODE 5
SGND 6
RUN1 7
33
SGND
22 V_IN
21 PGND
20 EXTV_CC
19 INTV_CC
18 BG2
RUN2 8
17 BOOST2
9 10 11 12 13 14 15 16
UH PACKAGE
32-LEAD (5mm s 5mm) PLASTIC QFN
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/
Electrical Characteristics The l denotes the specifications which apply over the full 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.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
V_IN
V_FB1,2
Input Supply Operating Voltage Range
Regulated Feedback Voltage
(Note 4) I_TH1,2 Voltage = 1.2V
–40°C to 125°C
–40°C to 85°C
4
38
V
l 0.788 0.800 0.812
V
0.792 0.800 0.808
V
I_FB1,2
V_REFLNREG
Feedback Current
Reference Voltage Line Regulation
(Note 4)
(Note 4) V_IN = 4.5V to 38V
±5
±50
nA
0.002 0.02
%/V
3857fa