Download FWE-Exec Template

Linear Technology
Corporation
LT3070 Backgrounder
Steve Knoth
Senior Product Marketing Engineer
2
Agenda
Background
•
Past Limitations for LDOs Powering FPGAs/ASICs
•
Advantages of Next Gen Linear Tech LDOs
LT3070
•
Definition
•
Features & Benefits
•
Application Circuits
•
Target Markets
•
Target Applications
© 2006 Linear Technology
3
Power Business Unit
• Products:
– Switching Regulators, DC/DC Controllers, ChargePumps, Linear Regulators, Battery Chargers,
PMICs, LED Drivers, DC Power Switches
• Markets:
 Handheld Battery Powered Products – Cell Phones,
Digital Still Cameras, PDAs, MP3 Players, PNDs, etc.
 Industrial Control and Instrumentation
 Automotive – Navigation and Infotainment
 Telecommunications – Infrastructure
 Computer – Servers, Workstations and Notebook PC
© 2006 Linear Technology
4
Traditional Limitations for in Powering
FPGAs/DSPs/ASICs/µPs
For high-performance digital ICs such as FPGAs, DSPs, µP’s, µC’s
and ASICs, the trend is for higher currents and lower voltages.
More efficient, switching regulators have traditionally been used to
power these devices but there are noise and layout limitations, so
LDOs have come into play.
•
•
•
•
•
•
•
•
The LDO must have:
Operation over a wide input/output voltage range
High output current capability
Low output noise
Low dropout operation
Excellent thermal performance
Fast response time
High PSRR
System debugging features a “+” plus
© 2006 Linear Technology
X
X
X
X
X
X
X
X
5
LT3070: What is It? UltraFast™ 5A LDO
© 2006 Linear Technology
6
LT3070: What is It? UltraFast 5A LDO
5A, Low Noise,
Programmable Output,
85mV Dropout
Linear Regulator
• New NMOS LDO Family:
Low Noise, Programmable Output, High BW
• Wide VIN Range: 0.95V to 3V
• Ultra-Low Output Voltage Noise: 25µVRMS (10Hz to 100kHz)
• Wide VOUT Range: 0.8V to 1.8V in 50mV increments
• Fast Transient Response
• Digital Margining for System Debug
© 2006 Linear Technology
7
LT3070: Block Diagram
The LT3070’s architecture drives an internal N-channel power MOSFET as a source
follower. This configuration permits a user to realize an extremely low dropout, ultrafast transient response regulator with excellent high frequency PSRR performance.
© 2006 Linear Technology
8
LT3070: Key Technical Features *
•
•
•
•
•
•
•
•
Output Current: 5A
Dropout Voltage: 85mV Typical
Digitally Programmable VOUT: 0.8V to 1.8V in 50mV steps
Digital Output Margining: ±1%, ±3% or ±5%
±1% Accuracy Over Line, Load and Temperature (Initial = 0.2%)
Low Output Noise: 25μVRMS (10Hz to 100kHz)
Parallelable: Use Two for a 10A Output
28-Lead (4mm × 5mm) QFN Package
* Specifications subject to change
© 2006 Linear Technology
9
LT3070: Other Features *
• Stable with Low ESR Ceramic Output Capacitors (15μF Min)
• High Frequency PSRR: 30dB at 1MHz
• VIOC Pin Controls Upstream Buck Converter to Maintain Low
Power Dissipation and Optimize Efficiency
• PWRGD/UVLO Flag
• REF/BYP Pin: Single Cap provides programmable soft-start
and lowers output noise
• Enable Function Turns Output On/Off
• Current Limit Foldback Protection
• Thermal Shutdown
* Specifications subject to change
© 2006 Linear Technology
10
LT3070: Features & Benefits
FEATURES
BENEFITS
Ultra-Low Dropout Voltage: 85mV
High efficiency, low Vin to low Vout conversion, reduces
power dissipation
Ultra-Low Noise: 25µVRMS
(10Hz to 100kHz)
Great for powering noise-sensitive supply rails or for postregulating switchers
Digitally Programmable Vout: 0.8V to 1.8V in 50mV
increments
Precision output voltage set capability
Digital Margining: ±1%, ±3%, ±5%
Helpful to determine system tolerance during debug phase
Wide Input Voltage Range: 1V to 3V
Flexibility, penetration into a wide variety of end
markets/applications
2 Devices May be Paralleled (10A)
Higher-current capability than a single LDO can provide;
spreads heat across a PCB
Fast Transient Response
Maintains output voltage stability during fast events
Reverse Current Protection, Current Limit with Power
Foldback, Thermal Shutdown, UVLO
Bulletproof protection for the IC and the load
Thermally Efficient Package:
4mmx5mm QFN-28, ThetaJA=30°C/W
Small package provides plenty of current in a small footprint
with great thermal performance
© 2006 Linear Technology
11
LT3070: Package/Pinout
© 2006 Linear Technology
12
LT3070 Typical Application Circuit
Power Good Indicator
Pin-selectable VOUT
Small Output Caps!!!
Soft Start Control
Digital Margining Select
© 2006 Linear Technology
13
LT3070 Post-Buck Regulator Application
VBIAS 3.3V
SGND
1W
47µF
6.3V
(x3)
2.2µF
100pF
50K
50K
0.1µF
PGOOD
CLKOUTRUN PVIN PVIN SVIN ITHM ITH
NC
NC
100pF
10pF
IN
47µF
VFB
VO2
PVIN
PVIN
NC VO1
PVIN
PVIN
PLLLPF
SENSE
EN
15K
TRACK
SGND
15K
BIAS
20K
LT3070
NC MARGTOL
SW
NC MARGSEL
SW
SW
VIOC
SW
SW
MODE
PGND
PGOOD
CLKIN
BSEL
PHMODE
MGN
0.2µH
Optimal Efficiency
across LDO
1.3V / 7A
Notes:
LTC3415 Switcher 2MHz internal oscillator
Maintain a constant “VIN – VOUT” across the LDO
by adjusting the VITH / VC pin regulation point
© 2006 Linear Technology
0.01µF
X7R
4.7nF
PGNDPGNDPGNDPGNDPGNDPGNDPGND
100µF, 6.3V
(x3)
REF/BYP
GND
2K
LOAD
2.2 + 4.7 + 10µF
X7R, 0805
NC VO0
SW
T
LC3415EUHF
VOUT 1.0V / 5A
PWRGD
SW
SW
OUT
14
LT3070 Current Sharing Application
Achieve 10A load current capability…or more!
© 2006 Linear Technology
15
LT3070: Typical Applications/Target End Markets
• FPGA and DSP Supplies
• ASIC and Microprocessor Supplies
• Servers and Storage Devices
• Sensitive Communication Supplies
• Supply Isolation
• Post Buck Regulation
© 2006 Linear Technology
16
© 2006 Linear Technology
17
LT3070: Conclusion
• Requirements for LDOs Powering High Performance Digital ICs:
• Operation over a wide input/output voltage range with high output current capability
• Low output noise
• Low dropout operation
• Excellent thermal performance
• Fast response time and high PSRR
• System debugging features a “+” plus
LT3070 UltraFast 5A Ultra-Low Dropout, Low Noise LDO:
• Dropout Voltage: 85mV Typical
• Digitally Programmable VOUT: 0.8V to 1.8V
• Digital Output Margining: ±1%, ±3% or ±5%
• ±1% Accuracy Over Line, Load and Temperature
• Low Output Noise: 25μVRMS (10Hz to 100kHz)
• Parallelable: Use Two for a 10A Output
• 28-Lead (4mm × 5mm) QFN Package
© 2006 Linear Technology