LTC3864
60V Low I Step-Down
Q
DC/DC Controller with
100% Duty Cycle Capability
Descrip T
Fea T
n
Wide Operating V Range: 3.5V to 60V
The LTC 3864 is a robust, high voltage step-down DC/DC
IN
n
Wide V Range: 0.8V to V
OUT IN controller optimized for automotive and industrial applica-
n
Low Operating I = 40A
Q tions. It drives a P-channel power MOSFET switch allowing
n
Very Low Dropout Operation: 100% Duty Cycle
100% duty cycle operation. The wide input and output volt-
n
Strong High Voltage MOSFET Gate Driver
age ranges cover a multitude of applications. This device
n
Constant Frequency Current Mode Architecture
has been verified with the failure mode and effects analysis
n
Verified FMEA for Adjacent Pin Open/Short
(FMEA) procedure for operation during failure conditions.
n
Selectable High Efficiency Burst Mode Operation or
The LTC3864 offers excellent light load efficiency, draw-
Pulse-Skipping Mode at Light Loads
ing only 40A quiescent current in a user programmable
n
Programmable Fixed Frequency: 50kHz to 850kHz
n Burst Mode operation. Its peak current mode, constant
Phase-Lockable Frequency: 75kHz to 750kHz
n frequency PWM architecture provides for good control of
Accurate Current Limit
n
switching frequency and output current limit. The switch-
Programmable Soft-Start or Voltage Tracking
n ing frequency can be programmed from 50kHz to 850kHz
Internal Soft-Start Guarantees Smooth Start-Up
n
with an external resistor and can be synchronized to an
Power Good Output Voltage Monitor
n
external clock from 75kHz to 750kHz.
Low Shutdown I = 7A
Q
n
Available in Small 12-Pin Thermally Enhanced MSOP
The LTC3864 offers programmable soft-start or output
and DFN Packages
tracking. Safety features include overvoltage protection,
overcurrent and short-circuit protection including fre-
a T quency foldback and a power good output signal.
n The LTC3864 is available in thermally enhanced 12-Pin
Industrial and Automotive Power Supplies
n MSOP and 3mm 4mm DFN packages.
Telecom Power Supplies
n L, LT, LTC, LTM, OPTI-LOOP, Linear Technology, Burst Mode and the Linear logo are registered
Distributed Power Systems
trademarks and Hot Swap is a trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners. Protected by U.S. Patents including 5731694.
Typical a T
5.2V to 60V Input, 5V/2A Output, 350kHz Step-Down Converter Efficiency
V *
IN 100
5.2V TO 60V
0.47F 10F
Burst Mode
OPERATION
90
CAP
RUN V
IN
350kHz
25m
PLLIN/MODE
80
SENSE
SS PULSE-SKIPPING
LTC3864
3.3nF
GATE
9.09k
70
10H
V *
OUT
ITH
5V
2A
60
FREQ
100k 422k
47F
V = 12V
IN
2
SGND
V = 5V
OUT
PGOOD 50
0.01 0.1 1
V
FB
LOAD CURRENT (A)
PGND
*V FOLLOWS V 80.6k 3864 TA01b
OUT IN
WHEN 3.5V V 5.2V
IN
3864 TA01a
3864fa
1
For more information www.linear.com/LTC3864
EFFICIENCY (%)
ion pplica
ions pplica
ures
ionLTC3864
a Te Maxi Mu M r a T
(Note 1)
Operating Junction Temperature Range (Notes 2, 3, 4)
Input Supply Voltage (V ) ......................... 0.3V to 65V
IN LTC3864E,I ....................................... 40C to 125C
V -V Voltage ...................................... 0.3V to 6V
IN SENSE LTC3864H .......................................... 40C to 150C
V -V Voltage ........................................ 0.3V to 10V
IN CAP LTC3864MP ....................................... 55C to 150C
RUN Voltage............................................... 0.3V to 65V
Storage Temperature Range .................. 65C to 150C
PGOOD, PLLIN/MODE Voltages ................... 0.3V to 6V
Lead Temperature (Soldering, 10 sec)
SS, ITH, FREQ, V Voltages ........................ 0.3V to 5V
FB MSOP Package .................................................300C
p in c F T
TOP VIEW
TOP VIEW
PLLIN/MODE 1 12 GATE
PLLIN/MODE 1 12 GATE
FREQ 2 11 V
IN
FREQ 2 11 V
IN
SGND 3 10 SENSE
3
13 SGND 13 10 SENSE
PGND 4 PGND
SS 9 CAP
SS 4 9 CAP
V 5 8 RUN
FB
V 5 8 RUN
FB ITH 6 7 PGOOD
ITH 6 7 PGOOD
MSE PACKAGE
12-LEAD PLASTIC MSOP
DE PACKAGE
T = 150C, = 40C/W, = 10C/W
JMAX JA JC
12-LEAD (4mm 3mm) PLASTIC DFN
EXPOSED PAD (PIN 13) IS PGND, MUST BE SOLDERED TO PCB FOR OPTIMAL
T = 150C, = 43C/W, = 5.5C/W
JMAX JA JC THERMAL PERFORMANCE
EXPOSED PAD (PIN 13) IS PGND, MUST BE SOLDERED TO PCB FOR OPTIMAL
THERMAL PERFORMANCE
o r Der i n F Ma T
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3864EMSE#PBF LTC3864EMSE#TRPBF 3864 12-Lead Plastic MSOP 40C to 125C
LTC3864IMSE#PBF LTC3864IMSE#TRPBF 3864 12-Lead Plastic MSOP 40C to 125C
LTC3864HMSE#PBF LTC3864HMSE#TRPBF 3864 12-Lead Plastic MSOP 40C to 150C
LTC3864MPMSE#PBF LTC3864MPMSE#TRPBF 3864 12-Lead Plastic MSOP 55C to 150C
LTC3864EDE#PBF LTC3864EDE#TRPBF 3864 12-Lead (4mm 3mm) Plastic DFN 40C to 125C
LTC3864IDE#PBF LTC3864IDE#TRPBF 3864 12-Lead (4mm 3mm) Plastic DFN 40C to 125C
LTC3864HDE#PBF LTC3864HDE#TRPBF 3864 12-Lead (4mm 3mm) Plastic DFN 40C to 150C
LTC3864MPDE#PBF LTC3864MPDE#TRPBF 3864 12-Lead (4mm 3mm) Plastic DFN 55C to 150C
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: