Linear Technology Corporation

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Linear Technology Corporation

• LT3070 Backgrounder
• Steve KnothSenior Product Marketing Engineer

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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

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Power Business Unit

• Products
• Switching Regulators, DC/DC Controllers,
  Charge-Pumps, 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

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Traditional Limitations for in Powering
FPGAs/DSPs/ASICs/µPs

• For high-performance digital ICs such as FPGAs,
  DSPs, µPs, µCs 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

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LT3070 What is It? UltraFast 5A LDO
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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

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LT3070 Block Diagram

The LT3070s architecture drives an internal
N-channel power MOSFET as a source follower. This
configuration permits a user to realize an
extremely low dropout, ultra- fast transient
response regulator with excellent high frequency
PSRR performance.
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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

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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

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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 post-regulating 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, ThetaJA30C/W Small package provides plenty of current in a small footprint with great thermal performance
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LT3070 Package/Pinout
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LT3070 Typical Application Circuit
Power Good Indicator
Pin-selectable VOUT
Small Output Caps!!!
Soft Start Control
Digital Margining Select
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LT3070 Post-Buck Regulator Application
Optimal Efficiency across LDO
Maintain a constant VIN VOUT across the LDO
by adjusting the VITH / VC pin regulation point
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LT3070 Current Sharing Application
Achieve 10A load current capabilityor more!
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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

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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