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LTC3828EUH#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P32
LTC3828
1
3828fc
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
Dual, 2-Phase Step-Down
Controller with Tracking
The LTC
®
3828 is a dual high performance step-down
switching regulator controller that drives all N-channel
synchronous power MOSFET stages. A constant frequency
current mode architecture allows for a phase-lockable
frequency of up to 550kHz. The TRCKSS pin provides both
soft-start and tracking functions. Multiple LTC3828s can
be daisy-chained in applications requiring more than two
voltages to be tracked.
OPTI-LOOP compensation allows the transient response
to be optimized over a wide range of output capacitance
and ESR values. The precision 0.8V reference and power
good output indicator are compatible with a wide 4.5V to
28V (30V maximum) input supply range, encompassing
all battery chemistries.
The RUN pins control their respective channels indepen-
dently. The FCB/PLLIN pin selects among Burst Mode
®
operation, skip-cycle mode and continuous current mode.
Current foldback limits MOSFET dissipation during short-
circuit conditions. Reverse current and current foldback
functions are disabled during soft-start.
High Effi ciency Dual 2.5V/3.3V Step-Down Converter with Tracking
n
Telecom Infrastructure
n
ASIC Power Supply
n
Industry Equipment
L, LT, LTC, LTM, Burst Mode and OPTI-LOOP 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,
6304066, 6580258
n
Dual, 180° Phased Controllers Reduce Required
Input Capacitance and Power Supply Induced Noise
n
Tracking for Both Outputs
n
Constant Frequency Current Mode Control
n
Wide V
IN
Range: 4.5V to 28V Operation
n
Power Good Output Voltage Indicator
n
Adjustable Soft-Start Current Ramping
n
Foldback Output Current Limiting–
Disabled at Start-Up
n
No Reverse Current During Soft-Start Interval
n
Clock Output for 3-, 4-, 6-Phase Operation
n
Dual N-Channel MOSFET Synchronous Drive
n
±1% Output Voltage Accuracy
n
Phase-Lockable Fixed Frequency 260kHz to 550kHz
n
OPTI-LOOP
®
Compensation Minimizes C
OUT
n
Very Low Dropout Operation: 99% Duty Cycle
n
Output Overvoltage Protection
n
Small 28-Lead SSOP and 5mm × 5mm QFN
Packages
+
4.7µF
0.1µF
63.4k 1%
1000pF
3.2µH
220pF
1µF
CERAMIC
22µF
50V
CERAMIC
+
47µF
4V
SP
0.01
20k
1%
20k
1%
15k
3.3V
5A
0.1µF
0.1µF
42.5k
1%
3.2µH
220pF
1000pF
+
56µF
4V
SP
0.01
20k
1%
15k
2.5V
5A
TG1 TG2
BOOST1 BOOST2
SW1 SW2
BG1 BG2
SGND
PGND
SENSE1
+
SENSE2
+
SENSE1
–
SENSE2
–
V
OSENSE1
V
OSENSE2
I
TH1
I
TH2
V
IN
PGOOD INTV
CC
RUN1 RUN2
4.5V TO 28V
3828 TA01
LTC3828
FCB/PLLIN
500kHz
TRCKSS1TRCKSS1TRCKSS2
63.4k 1%
LTC3828
2
3828fc
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage (V
IN
) ........................ 30V to –0.3V
Top Side Driver Voltages
BOOST1, BOOST2 ................................. 36V to –0.3V
Switch Voltage (SW1, SW2) ........................ 30V to –5V
INTV
CC
, DRV
CC
, RUN1, RUN2, (BOOST1-SW1),
(BOOST2-SW2) ........................................... 7V to –0.3V
SENSE1
+
, SENSE2
+
, SENSE1
–
,
SENSE2
–
Voltages ........................ (1.1)INTV
CC
to –0.3V
FCB/PLLIN, PLLFLTR, CLKOUT,
PHSMD Voltage .................................. INTV
CC
to –0.3V
TRCKSS1, TRCKSS2 ............................. INTV
CC
to –0.3V
(Note 1)
PGOOD ...................................................... 5.5V to –0.3V
I
TH1
, I
TH2
, V
OSENSE1
, V
OSENSE2
Voltages ... 2.7V to –0.3V
Peak Output Current <10µs (TG1, TG2, BG1, BG2) .... 3A
INTV
CC
Peak Output Current (Note 8) ................... 50mA
Operating Temperature Range (Note 7)
LTC3828E ............................................ –40°C to 85°C
Junction Temperature (Note 2) ............................ 125°C
Storage Temperature Range .................. –65°C to 125°C
Refl ow Peak Body Temperature (UH Package) ..... 260°C
Lead Temperature (Soldering, 10 sec)
G Package ......................................................... 300°C
1
2
3
4
5
6
7
8
9
10
11
12
13
14
TOP VIEW
G PACKAGE
28-LEAD PLASTIC SSOP
28
27
26
25
24
23
22
21
20
19
18
17
16
15
CLKOUT
PGOOD
BOOST1
TG1
SW1
V
IN
INTV
CC
PGND
BG1
BG2
SW2
TG2
BOOST2
RUN2
TRCKSS1
I
TH1
SENSE1+
SENSE1–
V
OSENSE1
PLLFLTR
RUN1
FCB/PLLIN
SGND
TRCKSS2
SENSE2
–
SENSE2
+
I
TH2
V
OSENSE2
T
JMAX
= 125°C, θ
JA
= 95°C/W
32 31 30 29 28 27 26 25
9 10 11 12 13
TOP VIEW
33
14 15 16
17
18
19
20
21
22
23
24
8
7
6
5
4
3
2
1V
OSENSE1
PLLFLTR
RUN1
PHSMD
FCB/PLLIN
SGND
TRCKSS2
NC
SW1
V
IN
INTV
CC
DRV
CC
PGND
BG1
BG2
SW2
SENSE1
–
SENSE1
+
I
TH1
TRCKSS1
CLKOUT
PGOOD
BOOST1
TG1
NC
SENSE2
–
SENSE2
+
I
TH2
V
OSENSE2
RUN2
BOOST2
TG2
UH PACKAGE
32-LEAD (5mm s 5mm) PLASTIC QFN
T
JMAX
= 125°C, θ
JA
= 34°C/W
EXPOSED PAD (PIN 33) IS GND, MUST BE SOLDERED TO PCB
PIN CONFIGURATION
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3828EG#PBF LTC3828EG#TRPBF LTC3828EG 28-Lead Plastic SSOP –40°C to 85°C
LTC3828EUH#PBF LTC3828EUH#TRPBF 3828
32-Lead (5mm × 5mm) Plastic QFN
–40°C to 85°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based fi nish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to:
http://www.linear.com/tapeandreel/
LTC3828
3
3828fc
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 15V, V
RUN1, 2
= 5V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loops
V
OSENSE1, 2
Regulated Feedback Voltage (Note 3); I
TH1, 2
Voltage = 1.2V
l
0.792 0.800 0.808 V
I
VOSENSE1, 2
Feedback Current (Note 3) ±5 ±50 nA
V
REFLNREG
Reference Voltage Line Regulation V
IN
= 4.6V to 28V (Note 3) 0.002 0.02 %/V
V
LOADREG
Output Voltage Load Regulation (Note 3)
Measured in Servo Loop; ΔI
TH
Voltage = 1.2V to 0.7V
Measured in Servo Loop; ΔI
TH
Voltage = 1.2V to 2.0V
l
l
0.1
–0.1
0.5
–0.5
%
%
g
m1, 2
Transconductance Amplifi er g
m
I
TH1, 2
= 1.2V; Sink/Source 5µA; (Note 3) 1.3 mmho
g
mGBW1, 2
Transconductance Amplifi er GBW I
TH1, 2
= 1.2V; (Note 3) 3 MHz
I
Q
Input DC Supply Current
Normal Mode
Shutdown
(Note 4)
V
OUT1
= 5V
V
RUN/SS1, 2
= 0V
2
20
3
100
mA
µA
V
FCB
Forced Continuous Threshold
l
0.76 0.800 0.84 V
I
FCB
Forced Continuous Pin Current V
FCB
= 0.85V –0.50 –0.18 –0.1 µA
V
BINHIBIT
Burst Inhibit (Constant Frequency)
Threshold
Measured at FCB pin 4.3 4.8 V
UVLO Undervoltage Lockout V
IN
Ramping Down
l
3.5 4 V
V
OVL
Feedback Overvoltage Lockout Measured at V
OSENSE1, 2
l
0.84 0.86 0.88 V
I
SENSE
Sense Pins Total Source Current (Each Channel); V
SENSE1
–
, 2
–
= V
SENSE1
+
, 2
+
= 0V –90 –65 µA
DF
MAX
Maximum Duty Factor In Dropout 98 99.4 %
I
TRCKSS1,2
Soft-Start Charge Current V
TRCKSS1, 2
= 0.2V 0.5 1.2 µA
V
RUN1, 2
ON RUN Pin ON Threshold V
RUN1
, V
RUN2
Rising 1.0 1.5 2.0 V
V
SENSE(MAX)
Maximum Current Sense Threshold V
OSENSE1, 2
= 0.7V,V
SENSE1
–
, 2
–
= 5V
V
OSENSE1, 2
= 0.7V,V
SENSE1
–
, 2
–
= 5V
l
62
60
75
75
85
88
mV
mV
TG1, 2 tr
TG1, 2 tf
TG Transition Time:
Rise Time
Fall Time
(Note 5)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
55
55
100
100
ns
ns
BG1, 2 tr
BG1, 2 tf
BG Transition Time:
Rise Time
Fall Time
(Note 5)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
65
55
120
100
ns
ns
TG/BG t
1D
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 60 ns
BG/TG t
2D
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
C
LOAD
= 3300pF Each Driver 80 ns
t
ON(MIN)
Minimum On-Time Tested with a Square Wave (Note 6) 120 ns
INTV
CC
Linear Regulator
V
INTVCC
Internal V
CC
Voltage 6V < V
IN
< 30V 4.8 5.0 5.2 V
V
LDO
INT INTV
CC
Load Regulation I
CC
= 0mA to 20mA 0.2 2.0 %
Oscillator and Phase-Locked Loop
f
NOM
Nominal Frequency V
PLLFLTR
= 1.2V 360 400 440 kHz
f
LOW
Lowest Frequency V
PLLFLTR
= 0V 230 260 290 kHz
f
HIGH
Highest Frequency V
PLLFLTR
≥ 2.4V 480 550 590 kHz
I
PLLFLTR
Phase Detector Output Current
Sinking Capability
Sourcing Capability
V
PLLFLTR
= 1.2V
f
PLLIN
< f
NOM
f
PLLIN
> f
NOM
–17
17
µA
µA
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LTC3828EUH#PBF

Mfr. #:
Buy LTC3828EUH#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators Dual, 2-Phase Controller, w/ Tracking PLL
Lifecycle:
New from this manufacturer.
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