LT3510_12 Datasheet, PDF (1/30 Pages) Linear Technology – Monolithic Dual Tracking 2A Step-Down Switching

FEATURES
n _{Wide Input Range: 3.1V to 25V}
n _{Two Switching Regulators with 2A Output Capability}
n _{Independent Supply to Each Regulator}
n _{Adjustable/Synchronizable Fixed Frequency}
Operation from 250kHz to 1.5MHz
n _{Antiphase Switching}
n _{Outputs Can be Paralleled}
n _{Independent, Sequential, Ratiometric or Absolute}
Tracking Between Outputs
n _{Independent Soft-Start and Power Good Pins}
n _{Enhanced Short-Circuit Protection}
n _{Low Dropout: 95% Maximum Duty Cycle}
n _{Low Shutdown Current: <10μA}
n _{20-Lead TSSOP Package with Exposed Leadframe}
APPLICATIONS
n _{DSP Power Supplies}
n _{Disc Drives}
n _{DSL/Cable Modems}
n _{Wall Transformer Regulation}
n _{Distributed Power Regulation}
n _{PCI Cards}
L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
LT3510
Monolithic Dual Tracking
2A Step-Down Switching
Regulator
DESCRIPTION
The LT^®3510 is a dual current mode PWM step-down
DC/DC converter with two internal 2.5A switches. Inde-
pendent input voltage, feedback, soft-start and power
good pins for each channel simplify complex power
supply tracking/sequencing requirements.
Both converters are synchronized to either a common
external clock input or a resistor programmable fixed
250kHz to 1.5MHz internal oscillator. At all frequencies, a
180° phase relationship between channels is maintained,
reducing voltage ripple and component size. Programmable
frequency allows for optimization between efficiency and
external component size.
Minimum input-to-output voltage ratios are improved
by allowing the switch to stay on through multiple clock
cycles, only switching off when the boost capacitor needs
recharging, resulting in ~95% maximum duty cycle.
Each output can be independently disabled using its own
soft-start pin, or by using the SHDN pin the entire part can
be placed in a low quiescent current shutdown mode.
The LT3510 is available in a 20-lead TSSOP package with
exposed leadframe for low thermal resistance.
TYPICAL APPLICATION
V_IN
12V
4.7μF
PMEG4005
V_OUT1
3.3V
2A
3.3V and 1.8V Dual 2A Step-Down Converter with Output Tracking
PMEG4005
4.7μH
V_IN1
SHDN
V_IN2
R_T/SYNC
61.9k
BST1
0.47μF
SW1
BST2
0.47μF
SW2
B360A
LT3510
3.3μH
B360A
47μF
24.9k
8.06k
470pF
10pF 40.2k
IND1
V_OUT1
IND2
V_OUT2
PG1
PG2
FB1
FB2
V_C1
V_C2
SS/TRACK1 SS/TRACK2
GND
0.1μF
V_OUT2
1.8V
10k
100μF 2A
470pF
40.2k
47pF 8.06k
3510 TA01a
100
90
80
70
60
50
40
30
20
10
0
0
Efficiency
V_OUT = 5V
V_OUT = 3.3V
V_OUT = 1.8V V_OUT = 2.5V
V_IN = 12V
I_OUT2 = 0A
FREQUENCY = 500kHz
0.5
1
1.5
LOAD CURRENT (A)
2
3510 TA01b
3510fe
1