Linear Technology LTC3810-5 Datasheet

FeaTures
High Voltage Operation: Up to 60V
n
Large 1Ω Gate Drivers
n
No Current Sense Resistor Required
n
Dual N-Channel MOSFET Synchronous Drive
n
Extremely Fast Transient Response
n
±0.5% 0.8V Voltage Reference
n
Programmable Output Voltage Tracking/Soft-Start
n
Generates 5.5V Driver Supply from Input Supply
n
Synchronizable to External Clock
n
Selectable Pulse Skip Mode Operation
n
Power Good Output Voltage Monitor
n
Adjustable On-Time/Frequency: t
n
Adjustable Cycle-by-Cycle Current Limit
n
Programmable Undervoltage Lockout
n
Output Overvoltage Protection
n
5mm × 5mm QFN Package
n
applicaTions
48V Telecom and Base Station Power Supplies
n
Networking Equipment, Servers
n
Automotive and Industrial Control Systems
n
L, LT, LTC, LTM, Linear Technology, the Linear logo and No R
of Linear Technology Corporation. All other trademarks are the property of their respective
owners. Protected by U.S. Patents including 5481178, 5847554, 6304066, 6476589, 6580258,
6677210, 6774611.
Typical applicaTion
High Efficiency High Voltage Step-Down Converter
274k
I
ON
PGOOD
LTC3810-5
V
RNG
MODE/SYNC
1000pF
SS/TRACK
SHDN
I
TH
47pF
200k
V
FB
5pF
SGND BGRTN
< 100ns
ON(MIN)
are registered trademarks
SENSE
+
100k
NDRV ZXMN10A07F
BOOST
Si7450DP
TG
0.1µF
SW
EXTV
CC
DRV
CC
INTV
CC
+
SENSE
Si7450DP
BG
–
SENSE
1µF
Synchronous Switching
Regulator Controller
DescripTion
The LTC 3810-5 is a synchronous step-down switching
®
regulator controller that can directly step-down voltages
from up to 60V, making it ideal for telecom and automo-
tive applications. The LTC3810-5 uses a constant on-time
valley current control architecture to deliver very low duty
cycles with accurate cycle-by-cycle current limit, without
requiring a sense resistor.
A precise internal reference provides 0.5% DC accuracy. A
high bandwidth (25MHz) error amplifier provides very fast
line and load transient response. Large 1Ω gate drivers
allow the LTC3810-5 to drive multiple MOSFETs for higher
current applications. The operating frequency is selected
by an external resistor and is compensated for variations
in V and can also be synchronized to an external clock
IN
for switching-noise sensitive applications. A shutdown
pin allows the LTC3810-5 to be turned off, reducing the
supply current to 240µA.
Integrated bias control generates gate drive power from
the input supply during start-up or when an output short-
circuit occurs, with the addition of a small external SOT23
MOSFET. When in regulation, power is derived from the
output for higher efficiency.
V
IN
13V TO 60V
22µF
10µH
V
OUT
12V/6A
14k
+
MBR1100 270µF
1k
38105 TA01
LTC3810-5
60V Current Mode
Efficiency vs Load Current
100
V = 24V
IN
95
V = 42V
IN
90
85
0 1 2 3 4 5
LOAD CURRENT (A)
38105 TA01b
6
38105fd
1