Slave Controller. LTC3870 Datasheet

LTC3870 Controller. Datasheet pdf. Equivalent

LTC3870 Datasheet
Recommendation LTC3870 Datasheet
Part LTC3870
Description PolyPhase Step-Down Slave Controller
Feature LTC3870; Features LTC3870 PolyPhase Step-Down Slave Controller for Digital Power System Management Descripti.
Manufacture Linear Technology
Datasheet
Download LTC3870 Datasheet




Linear Technology LTC3870
Features
LTC3870
PolyPhase Step-Down
Slave Controller for Digital
Power System Management
Description
n LTC3880 Family Phase Extender Supporting
LTC3880/3880-1, LTC3883/3883-1, LTC3886,
LTC3887 Master Controllers
n Cascade with Multiple Chips for Very Large Current
Applications
n Accurate PolyPhase Current Sharing
n EXTVCC Capable of 5V to 14V Input
n Wide VIN Range: 4.5V to 60V
n Wide Output Voltage Range : 0.5V to 14V
n Wide SYNC Frequency Range: 100kHz to 1MHz
n Pin Programmable of CCM/DCM Operation
n Pin Programmable of Phase-Shift Control
n Integrated Powerful N-Channel MOSFET Gate Drivers
n Available in a 28-Pin (4mm × 5mm) QFN Package
Applications
n High Power Distributed Power Systems
n Telecom Systems
n Industrial Applications
The LTC®3870 is a PolyPhase® step-down slave control-
ler specially designed for multiphase operation with the
LTC3880 family digital power system management DC/DC
controllers. It provides a small and cost effective solution
for supplying very large currents by cascading it with a
master controller. A peak current mode architecture pro-
vides the LTC3870 with excellent current sharing from
phase to phase and from chip to chip.
Coherently working with the LTC3880 family, the LTC3870
does not require additional I2C addresses, and it supports
all programmable features as well as fault protection.
The constant switching frequency can be synchronized
to an external clock from the master controller from
100kHz to 1MHz.
L, LT, LTC, LTM, PolyPhase, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6144194, 6177787,
6580258, 5408150
Typical Application
VIN
4.7µF
VOUT0
30A
1.0µH
+ 530µF
2.15k
0.2µF
0.1µF
LTC3880*
RUN0
3.3V
VSENSE0+
RUN1
GPIO0
GPIO1
1.8V VSENSE1
ITH0
ITH1
SYNC
* REFER TO LTC3880 DATA SHEET
FOR MASTER SETUP
VIN INTVCC
TG0 TG1
BOOST0 BOOST1
SW0 SW1
BG0 BG1
PGND
EXTVCC
LTC3870
IISSEENNSSEE00+– IISSEENNSSEE11+–
0.1µF
RUN0
RUN1
FAULT0
FAULT1
ITH0
ITH1
SYNC
FREQ
PHASMD
ILIM
MODE0
MODE1
SGND
100k
0.56µH
VOUT1
40A
1.74k
0.2µF
+ 530µF
Load Transient Response of a
2-Phase Master (3880)/Slave
(3870) Converter
ILOAD
10A/DIV
0A TO 10A TO 0A
IL_3880(CH1)
10A/DIV
IL_3870(CH1)
10A/DIV
VOUT1
100mV/DIV
AC-COUPLED
VIN = 12V
VOUT1 = 1.8V
50µs/DIV
3870 TA01b
3870 TA01a
3870fb
For more information www.linear.com/LTC3870
1



Linear Technology LTC3870
LTC3870
Absolute Maximum Ratings
(Note 1)
VIN.............................................................. –0.3V to 65V
BOOST0, BOOST1........................................–0.3V to 71V
SW0, SW1..................................................... –5V to 65V
ISENSE0+, ISENSE0−, ISENSE1+, ISENSE1–..........–0.3V to 15V
(BOOST0-SW0), (BOOST1-SW1).................. –0.3V to 6V
INTVCC, RUN0/RUN1.................................... –0.3V to 6V
EXTVCC....................................................... –0.3V to 14V
MODE0/MODE1, FREQ, PHASMD, ILIM....–0.3V to INTVCC
FAULT0/FAULT1, ITH0/ITH1, SYNC............... –0.3V to 3.6V
INTVCC, EXTVCC Peak Current (Note 9)................100mA
Operating Junction Temperature Range
........................................................... –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Pin Configuration
TOP VIEW
28 27 26 25 24 23
MODE0 1
ISENSE0+ 2
ISENSE0– 3
RUN0 4
RUN1 5
ISENSE1– 6
ISENSE1+ 7
MODE1 8
29
SGND
22 BOOST0
21 BG0
20 VIN
19 PGND
18 EXTVCC
17 INTVCC
16 BG1
15 BOOST1
9 10 11 12 13 14
UFD PACKAGE
28-LEAD (4mm × 5mm) PLASTIC QFN
TJMAX = 125°C, θJA = 43°C/W, θJC_BOT = 3.4°C/W
EXPOSED PAD (PIN 29) IS SGND, MUST BE SOLDERED TO PCB
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC3870EUFD#PBF
LTC3870EUFD#TRPBF 3870
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 125°C
LTC3870IUFD#PBF
LTC3870IUFD#TRPBF 3870
28-Lead (4mm × 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 nonstandard 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/
E lectrical Characteristics The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications
(externally driven) unless otherwise specified.
are
at
TA
=
25°C.
(Note
2)
VIN
=
15V,
VRUN0,VRUN1
=
3.3V,
fSYNC = 350kHz
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
VIN
VOUT
IQ
VUVLO
Input Voltage Range
Output Voltage Range
Input Voltage Supply Current
Normal Operation
Undervoltage Lockout Threshold
When VIN > 4.2V
(Note 3)
(Note 4)
VVRRUUNN00,,VVRRUUNN11
=
=
0V (Note
3.3V, No
5)
Caps
on
TG
and
BG
VVIINNTTVVCCCC
Falling
Rising
4.5 60
0.5 14
1.1
2.6
3.7
4.0
V
V
mA
mA
V
V
3870fb
2 For more information www.linear.com/LTC3870



Linear Technology LTC3870
LTC3870
E lectrical Characteristics The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications
(externally driven) unless otherwise specified.
are
at
TA
=
25°C.
(Note
2)
VIN
=
15V,
VRUN0,VRUN1
=
3.3V,
fSYNC = 350kHz
SYMBOL
Control Loop
IIIISSEENNSSEE01++,
IIIISSEENNSSEE01––,
VIILIMIT
Gate Drivers
TG RUP
TG RDOWN
BG RUP
BG RDOWN
TG0, TG1
tr
tf
BG0, BG1
ttrf
TG/BG t1D
PARAMETER
Current Sense + Pin Current
Current Sense − Pin Current
Maximum Current Sense threshold
(High Range)
Maximum Current Sense threshold
(Low Range)
Pull-Up On-Resistance
Pull-down On-Resistance
Pull-Up On-Resistance
Pull-down On-Resistance
TG Transition Time:
Rise Time
Fall Time
BG Transition Time:
Rise Time
Fall Time
Top Gate Off to Bottom Gate On Delay Time
BG/TG t2D
Bottom Gate Off to Top Gate On Delay Time
tON(MIN)
Minimum On-Time
INTVCC Regulator
VINTVCC_VIN
Internal VCC Voltage No Load
VLDO INT
INTVCC Load Regulation
VINTVCC_EXT
Internal VCC Voltage No Load
VLDO EXT
INTVCC Load Regulation with EXTVCC
VEXTVCC
EXTVCC Switchover Voltage
VHYS_EXTVCC EXTVCC HYSTERESIS
Oscillator and Phase-Locked Loop
fSNYC
VTH,SYNC
Oscillator SYNC Range
SYNC Input Threshold
fNOM
IFREQ
θ SYNC-θ0
Nominal Frequency
FREQ setting current
SYNC to Ch0 Phase Relationship Based on
the Falling Edge of Sync and Rising Edge of
TG0
θ SYNC-θ1
SYNC to Ch1 Phase Relationship Based on
the Falling Edge of Sync and Rising Edge of
TG1
CONDITIONS
VISENSE0,1+ = 3.3V
VISENSE0,1– = 3.3V
VITH = 2.22V, ILIM = INTVCC
VITH = 2.22V, ILIM = GND
TG High
TG Low
BG High
BG Low
(Note 6)
CLOAD = 3300pF
CLOAD = 3300pF
(Note 6)
CCLLOOAADD
=
=
3300pF
3300pF
(Note 6)
CLOAD = 3300pF Each Driver
(Note 6)
CLOAD = 3300pF Each Driver
(Note 7)
6.0V <VIN <60V, VEXTVCC = 0 V
ICC = 0mA to 50mA, VEXTVCC = 0V
VEXTVCC = 8.5V (Note 8)
ICC = 0 to 20mA, VEXTVCC = 8.5V
VEXTVCC Ramping Positive (Note 8)
VTH,sync Falling (Note 9)
VTH,sync Rising
VFREQ = 1.0V
PHASMD = 0
PHASMD = 1/3 INTVCC
PHASMD = 2/3 INTVCC
PHASMD = INTVCC
PHASMD = 0
PHASMD
PHASMD
=
=
1/3
2/3
IINNTTVVCCCC
PHASMD = INTVCC
MIN TYP MAX UNITS
l ±0.1 ±1
l ±0.1 ±1
l 70 75 80
l 45 50 55
µA
µA
mV
mV
2.5
1.5
2.4
1.1
30
30
30
30
30
30
90
4.85 5.1 5.35
0.8 ±2
4.85 5.1 5.35
0.5 ±2
4.7 4.8 4.9
200
l 100
9
1000
0.4
2.0
500
10 11
180
60
120
90
0
300
240
270
Ω
Ω
Ω
Ω
ns
ns
ns
ns
ns
ns
ns
V
%
V
%
V
mV
kHz
V
V
kHz
µA
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
3870fb
For more information www.linear.com/LTC3870
3







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