LTC3892/
LTC3892-1/LTC3892-2
60V Low I , Dual, 2-Phase
Q
Synchronous Step-Down
DC/DC Controller
FEATURES DESCRIPTION
n
Wide V Range: 4.5V to 60V (65V Abs Max) The LTC 3892/LTC3892-1/LTC3892-2 is a high perfor-
IN
n
Wide Output Voltage Range: 0.8V V 99% V mance dual step-down DC/DC switching regulator control-
OUT IN
n
Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE) ler that drives all N-channel synchronous power MOSFET
n
No External Bootstrap Diodes Required stages. Power loss and noise are minimized by operating
n
Low Operating I : 29A (One Channel On) the two controller output stages out-of-phase.
Q
n
Selectable Gate Drive UVLO Thresholds
The gate drive voltage can be programmed from 5V to
n
Out-of-Phase Operation Reduces Required Input
10V to allow the use of logic or standard-level FETs and
Capacitance and Power Supply Induced Noise
to maximize efficiency. Internal switches in the top gate
n
Phase-Lockable Frequency: 75kHz to 850kHz
drivers eliminate the need for external bootstrap diodes.
n
Selectable Continuous, Pulse Skipping or Low Ripple
A wide 4.5V to 60V input supply range encompasses a wide
Burst Mode Operation at Light Loads
n range of intermediate bus voltages and battery chemistries.
Selectable Current Limit (LTC3892/LTC3892-2)
n Output voltages up to 99% of V can be regulated. OPTI-
Very Low Dropout Operation: 99% Duty Cycle IN
n LOOP compensation allows the transient response and
Power Good Output Voltage Monitors (LTC3892/LTC3892-2)
n loop stability to be optimized over a wide range of output
Low Shutdown I : 3.6A
Q
n capacitance and ESR values.
Small 32-Lead 5mm 5mm QFN Package (LTC3892/
LTC3892-2) or TSSOP Package (LTC3892-1)
The 29A no-load quiescent current extends operating run
time in battery powered systems. For a comparison of the
LTC3892 to the LTC3892-1 and LTC3892-2, see Table 1
APPLICATIONS
in the Pin Functions section of this data sheet.
n
Automotive and Industrial Power Systems
L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, Linear Technology and the Linear logo are
n
Distributed DC Power Systems
registered trademarks of Analog Devices, Inc. All other trademarks are the property of their
respective owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6144194,
n
High Voltage Battery Operated Systems
6177787, 6580258.
TYPICAL APPLICATION
High Efficiency Dual 5V/12V Output Step-Down Converter
VIN
12.5V TO 60V
RUN1 VIN RUN2
47F
Efficiency vs Output Current
TG1 TG2 Efciency vs Output Current
BOOST1 BOOST2 96
0.1F 0.1F
V = 12V
IN
5.6H 8m
V 5m 15H V
OUT1 OUT2
V = 5V
95
OUT
5V 12V
SW1 SW2 Burst Mode OPERATION
8A 5A
94
BG1 BG2
220F 150F
LTC3892 93
+ +
92
SENSE1 SENSE2
100k
1nF 1nF
SENSE1 SENSE2 GATE DRIVE
91
V V DRV =5V
FB1 FB2 CC
90
DRV =6V
CC
ITH1 ITH2
DRV =8V
CC
TRACK/SS1 TRACK/SS2
89
DRV =10V
CC
7.15k
VPRG1 DRVSET
88
7.5k 34.8k
0.01 0.1 1 10
DRVUV
LOAD CURRENT (A)
100pF 0.1F 100pF
0.1F
3892 F01b
INTV GND DRV
CC CC
2.2nF 1nF
0.1F 4.7F
3892 TA01
38921fc
1
For more information www.linear.com/LTC3892
EFFICIENCY (%)LTC3892/
LTC3892-1/LTC3892-2
ABSOLUTE MAXIMUM RATINGS (Notes 1, 3)
TRACK/SS1, TRACK/SS2 Voltages .............. 0.3V to 6V
Input Supply Voltage (V ) ......................... 0.3V to 65V
IN
PGOOD1, PGOOD2 Voltages
Top Side Driver Voltages
(LTC3892/LTC3892-2) ............................. 0.3V to 6V
(BOOST1, BOOST2) ............................... 0.3V to 76V
VPRG1, ILIM Voltages
Switch Voltage (SW1, SW2) .......................... 5V to 70V
(LTC3892/LTC3892-2) ............................. 0.3V to 6V
DRV , (BOOST1-SW1),
CC
Operating Junction Temperature Range (Note 2)
(BOOST2-SW2) .......................................0.3V to 11V
LTC3892E, LTC3892I,
BG1, BG2, TG1, TG2 ........................................... (Note 8)
LTC3892E-1, LTC3892I-1,
RUN1, RUN2 Voltages ................................ 0.3V to 65V
+ +
LTC3892E-2, LTC3892I-2 ................... 40C to 125C
SENSE1 , SENSE2 , SENSE1
LTC3892H,
SENSE2 Voltages ................................. 0.3V to 65V
LTC3892H-1, LTC3892H-2 ................. 40C to 150C
PLLIN/MODE, FREQ Voltages ...................... 0.3V to 6V
LTC3892MP, LTC3892MP-1,
EXTV Voltage ......................................... 0.3V to 14V
CC
LTC3892MP-2 .................................... 55C to 150C
I , I , V , V Voltages ..................... 0.3V to 6V
TH1 TH2 FB1 FB2
Storage Temperature Range .................. 65C to 150C
DRVSET, DRVUV Voltages ........................... 0.3V to 6V
PIN CONFIGURATION
LTC3892/LTC3892-2 LTC3892-1
TOP VIEW TOP VIEW
ITH1 1 28 TRACK/SS1
V 2 27 TG1
FB1
+
SENSE1 3 26 SW1
32 31 30 29 28 27 26 25
SENSE1 4 25 BOOST1
FREQ 1 24 BOOST1
FREQ 5 24 BG1
PLLIN/MODE 2 23 BG1
PLLIN/MODE 6 23 V
IN
PGOOD1 3 22 V
IN
INTV 7 22 EXTV
CC
PGOOD2 EXTV CC 29
4 21
CC
33
GND
GND RUN1 8 21 DRV
INTV DRV CC
5 20
CC CC
RUN2 9 20 BG2
RUN1 6 19 BG2
RUN2 7 18 BOOST2 SENSE2 10 19 BOOST2
+
ILIM 8 17 SW2
SENSE2 11 18 SW2
9 10 11 12 13 14 15 16 V 12 17 TG2
FB2
ITH2 13 16 TRACK/SS2
DRVUV 14 15 DRVSET
FE PACKAGE
UH PACKAGE
28-LEAD PLASTIC TSSOP
32-LEAD (5mm 5mm) PLASTIC QFN
T = 150C, = 30C/W
JMAX JA
T = 150C, = 44C/W
JMAX JA
EXPOSED PAD (PIN 29) IS GND, MUST BE CONNECTED TO GND
EXPOSED PAD (PIN 33) IS GND, MUST BE CONNECTED TO GND
38921fc
2
For more information www.linear.com/LTC3892
SENSE2 SENSE1
+ +
SENSE2 SENSE1
V V
FB2 FB1
ITH2 ITH1
DRVUV VPRG1
DRVSET TRACK/SS1
TRACK/SS2 TG1
TG2 SW1