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LT3070
1
3070fb
For more information www.linear.com/LT3070
APPLICATIONS
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FPGA and DSP Supplies
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ASIC and Microprocessor Supplies
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Servers and Storage Devices
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Post Buck Regulation and Supply Isolation
TYPICAL APPLICATION
DESCRIPTION
5A, Low Noise,
Programmable Output,
85mV Dropout
Linear Regulator
The LT
®
3070 is a low voltage, UltraFast™ transient re-
sponse linear regulator. The device supplies up to 5A of
output current with a typical dropout voltage of 85mV.
A 0.01µF reference bypass capacitor decreases output
voltage noise to 25µV
RMS
. The LT3070’s high bandwidth
permits the use of low ESR ceramic capacitors, saving
bulk capacitance and cost. The LT3070’s features make
it ideal for high performance FPGAs, microprocessors or
sensitive communication supply applications.
Output voltage is digitally selectable in 50mV increments
over a 0.8V to 1.8V range. A margining function allows
the user to adjust system output voltage in increments of
±1%, ±3% or ±5%. The IC incorporates a unique tracking
function to control a buck regulator powering the LT3070’s
input. This tracking function drives the buck regulator to
maintain the LT3070’s input voltage to V
OUT
+ 300mV,
minimizing power dissipation.
Internal protection includes UVLO, reverse-current protec-
tion, precision current limiting with power foldback and
thermal shutdown. The LT3070 regulator is available in a
thermally enhanced 28-lead, 4mm × 5mm QFN package.
0.9V, 5A Regulator
FEATURES
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Output Current: 5A
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Dropout Voltage: 85mV Typical
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Digitally Programmable V
OUT
: 0.8V to 1.8V
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Digital Output Margining: ±1%, ±3% or ±5%
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Low Output Noise: 25µV
RMS
(10Hz to 100kHz)
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Parallel Multiple Devices for 10A or More
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Precision Current Limit: ±20%
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±1% Accuracy Over Line, Load and Temperature
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Stable with Low ESR Ceramic Output Capacitors
(15µF Minimum)
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High Frequency PSRR: 30dB at 1MHz
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Enable Function Turns Output On/Off
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VIOC Pin Controls Buck Converter to Maintain Low
Power Dissipation and Optimize Efficiency
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PWRGD/UVLO/Thermal Shutdown Flag
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Current Limit with Foldback Protection
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Thermal Shutdown
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28-Lead (4mm × 5mm × 0.75mm) QFN Package
Dropout Voltage
BIAS
50k
LT3070
IN
EN
V
O0
V
O1
330µF
2.2µF
2.2µF*
0.01µF1nF
4.7µF*
*X5R OR X7R CAPACITORS
3070 TA01a
10µF*
PWRGD
V
OUT
0.9V
5A
V
O2
MARGSEL
MARGTOL
VIOC
SENSE
OUT
V
BIAS
2.2V TO 3.6V
V
IN
1.2V
PWRGD
REF/BYP
GND
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
UltraFast and VLDO are trademarks of Linear Technology Corporation. All other trademarks are
the property of their respective owners. Patents pending.
OUTPUT CURRENT (A)
0
DROPOUT VOLTAGE (mV)
90
120
150
4
3070 TA01b
60
30
0
1
2
3
5
V
OUT
= 1.8V
V
BIAS
= 3.3V
V
OUT
= 0.8V
V
BIAS
= 2.5V
V
IN
= V
OUT(NOMINAL)
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