Switching Regulator. LT3501 Datasheet

LT3501 Regulator. Datasheet pdf. Equivalent

Part LT3501
Description Monolithic Dual Tracking 3A Step-Down Switching Regulator
Feature www.DataSheet4U.com FEATURES ■ ■ ■ ■ LT3501 Monolithic Dual Tracking 3A Step-Down Switching Regula.
Manufacture Linear Technology
Total Page 28 Pages
Datasheet
Download LT3501 Datasheet



LT3501
www.DataSheet4U.com
FEATURES
Wide Input Range: 3.1V to 25V
Two Switching Regulators with 3A Output Capability
Independent Supply to Each Regulator
Adjustable/Synchronizable Fixed Frequency
Operation from 250kHz to 1.5MHz
Antiphase Switching
Outputs Can be Paralleled
Independent, Sequential, Ratiometric or Absolute
Tracking Between Outputs
Independent Soft-Start and Power Good Pins
Enhanced Short-Circuit Protection
Low Dropout: 95% Maximum Duty Cycle
Low Shutdown Current: <10µA
20-Lead TSSOP Package with Exposed Leadframe
APPLICATIONS
DSP Power Supplies
Disc Drives
DSL/Cable Modems
Wall Transformer Regulation
Distributed Power Regulation
LT3501
Monolithic Dual Tracking
3A Step-Down Switching
Regulator
DESCRIPTION
The LT®3501 is a dual current mode PWM step-down
DC/DC converter with two internal 3.5A 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 LT3501 is available in a 20-lead TSSOP package with
exposed leadframe for low thermal resistance.
, LT, LTC, and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
VIN
12V
4.7µF
PMEG4005
3.3V and 1.8V Dual 3A Step-Down Converter with Output Tracking
4.7µH
PMEG4005
VIN1
SHDN
VIN2
RT/SYNC
61.9k
BST1
0.47µF
SW1
BST2
0.47µF
SW2
B360A
LT3501
3.3µH
B360A
VOUT1
3.3V
3A
47µF
24.9k
8.06k
470pF
10pF 40.2k
IND1
VOUT1
IND2
VOUT2
PG1 PG2
FB1 FB2
VC1 VC2
SS/TRACK1 SS/TRACK2
GND
0.1µF
VOUT2
1.8V
10k 100µF 3A
470pF
40.2k
47pF 8.06k
3501 TA01a
100
90
80
70
60
50
40
30
20
10
0
0
Efficiency
VOUT1 = 5V
VOUT1 = 3.3V
VOUT1 = 1.8V VOUT1 = 2.5V
VIN = 12V
IOUT2 = 0A
FREQUENCY = 500kHz
0.5 1 1.5 2
LOAD CURRENT (A)
2.5 3
3501 TA01b
3501fb
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LT3501
LT3501www.DataSheet4U.com
ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN1/2, SHDN, PG1/2 ...................................... 25V/–0.3V
SW1/2 .................................................................... VIN1/2
BST1/2 ........................................................... 35V/–0.3V
BST1/2 Pins Above SW1/2........................................25V
IND1/2 .....................................................................±5A
VOUT1/2........................................................ VIN1/2/–0.3V
FB1/2, SS1/2, RT/SYNC............................................5.5V
VC1/2 ......................................................................±1mA
Operating Junction Temperature Range
LT3501EFE (Notes 2, 8) ..................... –40°C to 125°C
LT3501IFE (Notes 2, 8) ...................... –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
VIN1 1
SW1 2
20 BST1
19 SS/TRACK1
IND1 3
VOUT1 4
PG1 5
PG2 6
18 VC1
17 FB1
21 16 RT/SYNC
15 SHDN
VOUT2 7
IND2 8
SW2 9
14 FB2
13 VC2
12 SS/TRACK2
VIN2 10
11 BST2
FE PACKAGE
20-LEAD PLASTIC TSSOP
TJMAX = 125°C, θJA = 45°C/W, θJC(PAD) = 10°C/W
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER
LT3501EFE
LT3501IFE
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TJ = 25°C. VVIN1/2 = 15V, VBST1/2 = open, VRT/SYNC = 2V, VVOUT1/2 = open,
unless otherwise specified.
PARAMETER
SHDN Threshold
SHDN Input Current
Minimum Input Voltage Ch 1 (Note 3)
Minimum Input Voltage Ch 2
Supply Shutdown Current Ch 1
Supply Shutdown Current Ch 2
Supply Quiescent Current Ch 1
Supply Quiescent Current Ch 2
Feedback Voltage Ch 1/2
Feedback Voltage Line Regulation
Feedback Voltage Offset Ch 1 to Ch 2
Feedback Bias Current Ch 1/2
Error Amplifier gm Ch 1/2
Error Amplifier Gain Ch 1/2
Error Amplifier to Switch Gain Ch 1/2
CONDITIONS
MIN
VOUT1/2 = 0V, RT/SYNC = 133k
VSHDN = 1.375V
VSHDN = 1.225V
VFB1/2 = 0V, VVOUT1/2 = 0V, VIND1/2 = 0V, RT/SYNC = 133k
1.23
7
2
VFB1/2 = 0V, VVOUT1/2 = 0V, VIND1/2 = 0V
VSHDN = 0V
VSHDN = 0V
VFB1/2 = 0.9V
VFB1/2 = 0.9V
VVC1/2 = 1V
VVIN1/2 = 3V to 25V
VVC1/2 = 1V
VFB1/2 = 0.8V, VVC1/2 = 1V
VVC1/2 = 1V, IVC1/2 = ±5µA
0.784
–1
–16
–250
150
TYP
1.28
10
3
2.8
2.8
9
0
3.5
200
0.8
0
0
75
275
1000
3.3
MAX
1.37
13
5
3
3
30
5
5
500
0.816
1
16
250
450
UNITS
V
µA
µA
V
V
µA
µA
mA
µA
V
%
mV
nA
µmho
V/V
A/V
3501fb
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