Linear Technology Corporation LT3070 Backgrounder Steve Knoth Senior Product Marketing Engineer.
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Transcript of Linear Technology Corporation LT3070 Backgrounder Steve Knoth Senior Product Marketing Engineer.
Linear Technology CorporationLT3070 Backgrounder
Steve KnothSenior Product Marketing Engineer
© 2006 Linear Technology
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,
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 InstrumentationAutomotive – Navigation and InfotainmentTelecommunications – InfrastructureComputer – 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
XXXXXXX
X
© 2006 Linear Technology
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, ultra- fast 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
LowPower 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 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, 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
Pin-selectable VOUT
Digital Margining SelectSoft Start Control
Small Output Caps!!!
Power Good Indicator
© 2006 Linear Technology
13
LT3070 Post-Buck Regulator Application
Maintain a constant “VIN – VOUT” across the LDO by adjusting the VITH / VC pin regulation point
1.3V / 7A
VBIAS 3.3V
PGOOD
0.01µFX7R
VOUT
2.2µF
47µF
50K
LOAD
1
50K
2.2 + 4.7 + 10µFX7R, 0805
100µF, 6.3V(x3)
PLLLPF
MODE
PHMODE
TRACK
V
PGOOD
BSEL
MGN
LTC3415EUHF
RUN PVCLKOUT SV
SW
SW
PGND
SGND
IN IN ITHITHM
CLKIN
PVIN
SW
SW
NC
SW
SW
SW
SW
PGND PGNDPGNDPGNDPGND PGND
PVIN
PVIN
FB
PVIN
PVIN
NC
PGND
0.2µH
47µF
(x3)6.3V
15K
20K
0.1µF
10pF100pF
15K
1.0V / 5A
NC
NC
NC
NC
Notes:LTC3415 Switcher 2MHz internal oscillator
PWRGD
VIOC
OUTIN
GND
BIAS
REF/BYP
VO2
VO1
VO0
EN SENSE
LT3070
MARGTOL
MARGSEL
100pF
4.7nF
SGND
2K
Optimal Efficiency across LDO
© 2006 Linear Technology
14
LT3070 Current Sharing Application
1.32V / 7A
VBIAS 3.3V
PGOOD
0.01µFX7R
VOUT
2.2µF
47µF
50K
0.01µFX7R
2.2µF
P.O.L. 1
VOUTP.O.L. 2
1 50K
2.2 + 4.7 + 10µFX7R, 0805
2.2 + 4.7 + 10µFX7R, 0805
R2mΩ
TRACE
1V POW
ER PLAN
E
controlled
R2mΩ
TRACE
controlled
100µF, 6.3V(x3)
PLLLPF
MODE
PHMODE
TRACK
V
PGOOD
BSEL
MGN
LTC3415EUHF
RUN PVCLKOUT SV
SW
SW
PGND
SGND
IN IN ITHITHM
CLKIN
PVIN
SW
SW
NC
SW
SW
SW
SW
PGND PGNDPGNDPGNDPGND PGND
PVIN
PVIN
FB
PVIN
PVIN
NC
PGND
0.2µH
47µF
(x3)6.3V
47µF
50K
15K
18K
0.1µF
10pF100pF
15K
1.0V / 5A
1.0V / 5A
SGND
NC
NC
NC
NC
NC
NC
NC
NC
Notes:LTC3415 Switcher 2MHz internal oscillator
PWRGD
VIOC
OUTIN
GND
BIAS
REF/BYP
VO2
VO1
VO0
EN SENSE
LT3070(2)
MARGTOL
MARGSEL
PWRGD
VIOC
OUTIN
GND
BIAS
REF/BYP
VO2
VO1
VO0
EN SENSE
LT3070(1)
MARGTOL
MARGSEL
4.7nF
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