AAT1147 SwitchReg member AnalogicTech's Total Power Management IC(TPMI

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

AAT1147 SwitchReg member AnalogicTech's Total Power Management IC(TPMI

Datasheet Thumbnail

Top Searches for this datasheet

High Efficiency, Noise, Fast Transient 400mA Step-Down Converter General Description
AAT1147 SwitchReg member AnalogicTech's Total Power Management IC(TPMICTM) product family. fixed frequency 1.4MHz step-down converter with input voltage range 2.7V 5.5V output voltage 0.6V. AAT1147 optimized noise portable applications, reacts quickly load variations, reaches peak efficiency heavy load. AAT1147 output voltage programmable with external feedback resistors. deliver 400mA load current while maintaining high power efficiency. 1.4MHz switching frequency minimizes size external components while keeping switching losses low. AAT1147 available Pb-free, space-saving 2.0x2.1mm SC70JW-8 package rated over -40°C +85°C temperature range.
AAT1147
SwitchReg
Range: 2.7V 5.5V VOUT Adjustable from 0.6V 400mA Output Current Efficiency Noise, 1.4MHz Fixed Frequency Operation Fast Load Transient 150µs Soft Start Over-Temperature Current Limit Protection 100% Duty Cycle Dropout Operation <1µA Shutdown Current 8-Pin SC70JW Package Temperature Range: -40°C +85°C
Applications
Cellular Phones Digital Cameras Handheld Instruments Microprocessor/DSP Core Power PDAs Handheld Computers devices
Typical Application
AAT1147 AGND PGND PGND PGND
1.8V 4.7H 118k 4.7F
4.7F
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Descriptions
AAT1147
Symbol
AGND PGND
Function
Enable pin. Feedback input pin. This connected external resistive divider adjustable output. Input supply voltage converter. Switching node. Connect inductor this pin. connected internally drain both high- low-side MOSFETs. Non-power signal ground pin. Main power ground return pins. Connect output input capacitor return.
Configuration
SC70JW-8 (Top View)
PGND PGND PGND AGND
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Absolute Maximum Ratings1
Symbol
VOUT TLEAD
AAT1147
Description
Input Voltage Operating Junction Temperature Range Maximum Soldering Temperature leads, sec)
Value
-0.3 -0.3 -0.3
Units
Thermal Information2
Symbol
Description
Maximum Power Dissipation Thermal Resistance
Value
0.625
Units
°C/W
Stresses above those listed Absolute Maximum Ratings cause permanent damage device. Functional operation conditions other than operating conditions specified implied. Only Absolute Maximum Rating should applied time. Mounted board. Derate 6.25mW/°C above 25°C. 1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Electrical Characteristics1
-40°C +85°C, unless otherwise noted. Typical values 25°C, 3.6V. Symbol Description Conditions
Rising Hysteresis Falling IOUT 400mA, 2.7V 5.5V Load AGND PGND 0.45 0.40 5.5V, VIN, 2.7V 5.5V 0.6V Output, Load, 25°C 0.6V Output From Enable Output Regulation -3.0
AAT1147
Units
Step-Down Converter Input Voltage VUVLO VOUT VOUT ISHDN ILIM RDS(ON)H RDS(ON)L ILXLEAK VLINEREG VOUT IOUT FOSC THYS VEN(L) VEN(H) Enable Threshold Enable Threshold High Input Current UVLO Threshold Output Voltage Tolerance Output Voltage Range Quiescent Current Shutdown Current P-Channel Current Limit High Side Switch Resistance Side Switch Resistance Leakage Current Line Regulation Threshold Voltage Accuracy Leakage Current Start-Up Time Oscillator Frequency Over-Temperature Shutdown Threshold Over-Temperature Shutdown Hysteresis
VOUT 5.5V -1.0
AAT1147 guaranteed meet performance specifications over -40°C +85°C operating temperature range assured design, characterization, correlation with statistical process controls.
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Typical Characteristics
Efficiency Load
(VOUT 3.3V; 6.8µH)
AAT1147
Regulation
(VOUT 3.3V)
3.6V
Output Error
Efficiency
-0.5 -1.0 -1.5
4.2V
4.2V
1000
5.0V
3.6V
5.0V
-2.0
1000
Output Current (mA)
Output Current (mA)
Efficiency Load
(VOUT 2.5V; 6.8µH)
Regulation
(VOUT 2.5V)
Output Error
Efficiency
3.6V
-0.5 -1.0 -1.5
4.2V
4.2V 5.0V
5.0V
3.6V
1000
1000
-2.0
Output Current (mA)
Output Current (mA)
Efficiency Load
(VOUT 1.8V; 4.7µH)
Regulation
(VOUT 1.8V)
Output Error
3.0V
3.6V
Efficiency
-0.5 -1.0 -1.5
1000
4.2V
4.2V
3.6V
3.0V
-2.0
1000
Output Current (mA)
Output Current (mA)
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Typical Characteristics
Line Regulation
(VOUT 3.3V)
AAT1147
Line Regulation
(VOUT 2.5V)
Accuracy
-0.1 -0.2 -0.3 -0.4 -0.5
Accuracy
IOUT 10mA IOUT
-0.1 -0.2 -0.3 -0.4 -0.5
IOUT 10mA IOUT
IOUT 400mA
IOUT 400mA
Input Voltage
Input Voltage
Line Regulation
(VOUT 1.8V)
Frequency Input Voltage
Frequency Variation
-1.0 -2.0 -3.0 -4.0
Accuracy
-0.1 -0.2 -0.3 -0.4 -0.5
IOUT 10mA
IOUT
VOUT 1.8V
IOUT 400mA
VOUT 2.5V
VOUT 3.3V
Input Voltage
Input Voltage
Output Voltage Error Temperature
(VIN 3.6V; VOUT 1.8V; IOUT 400mA)
Switching Frequency Temperature
(VIN 3.6V; VOUT 1.8V)
Output Error
-0.5 -1.0 -1.5 -2.0
Variation
Temperature (°C)
Temperature (°C)
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Typical Characteristics
No-Load Quiescent Current Input Voltage
AAT1147
Line Transient Response
(40mA 400mA; 3.6V; VOUT 1.8V; 4.7µF; 100pF)
-0.2 -0.4 -0.6
Load Inductor Current (bottom) (200mA/div)
Supply Current (µA)
85°C
Output Voltage (top)
25°C
-40°C
Input Voltage
Time (25µs/div)
Line Transient Response
(40mA 400mA; 3.6V; VOUT 1.8V; 4.7µF)
Soft Start
(VIN 3.6V; VOUT 1.8V; IOUT 400mA)
Enable Output Voltage (top)
400mA 40mA
-0.2 -0.4 -0.6
-0.8 -1.6 -2.4
-0.4
Load Inductor Current (bottom) (200mA/div)
Inductor Current (bottom)
Output Voltage (top)
Time (25µs/div)
Time (25µs/div)
Line Response
(VOUT 1.8V 400mA)
1.90 1.85 1.80 1.75 1.70 1.65 1.60 1.55 1.50 1.45 1.40
Output Ripple
(VIN 3.6V; VOUT 1.8V; IOUT 400mA)
Output Voltage Coupled) (top) (mV)
-100 -120
Inductor Current (bottom)
Output Voltage (top)
Input Voltage (bottom)
Time (25µs/div)
Time (500ns/div)
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Functional Block Diagram
AAT1147
Voltage Reference
Logic
INPUT
PGND
AGND
Functional Description
AAT1147 high performance 400mA 1.4MHz monolithic step-down converter. been designed with goal minimizing external component size optimizing efficiency heavy load. Apart from small bypass input capacitor, only small filter required output. Typically, 4.7µH inductor 4.7µF ceramic capacitor recommended (see table values). Only three external power components (CIN, COUT, required. Output voltage programmed with external resistors ranges from 0.6V input voltage. additional feed-forward capacitor also added external feedback pro-
vide improved transient response (see Figure dropout, converter duty cycle increases 100% output voltage tracks input voltage minus RDS(ON) drop P-channel highside MOSFET. input voltage range 2.7V 5.5V. converter efficiency been optimized heavy load conditions 400mA. internal error amplifier compensation provide excellent transient response, load, line regulation. Soft start eliminates output voltage overshoot when enable input voltage applied.
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter
AAT1147
Enable
100pF
AAT1147
PGND PGND PGND AGND
VOUT =1.8V
118k 4.7H
4.7F
GND2 AAT1147 SC70JW-8 CDRH3D16-4R7 4.7F 0805 6.3V 0805
Figure Enhanced Transient Response Schematic.
Control Loop
AAT1147 peak current mode step-down converter. current through P-channel MOSFET (high side) sensed current loop control, well short circuit overload protection. fixed slope compensation signal added sensed current maintain stability duty cycles greater than 50%. peak current mode loop appears voltage-programmed current source parallel with output capacitor. output voltage error amplifier programs current mode loop necessary peak switch current force constant output voltage load line conditions. Internal loop compensation terminates transconductance voltage error amplifier output. error amplifier reference 0.6V.
Current Limit Over-Temperature Protection
overload conditions, peak input current limited. minimize power dissipation stresses under current limit short-circuit conditions, switching terminated after entering current limit series pulses. Switching terminated seven consecutive clock cycles after current limit been sensed series four consecutive clock cycles. Thermal protection completely disables switching when internal dissipation becomes excessive. junction over-temperature threshold 140°C with 15°C hysteresis. Once over-temperature over-current fault conditions removed, output voltage automatically recovers.
Soft Start Enable
Soft start limits current surge seen input eliminates output voltage overshoot. When pulled low, enable input forces AAT1147 into low-power, non-switching state. total input current during shutdown less than 1µA.
Under-Voltage Lockout
Internal bias circuits controlled input. Under-voltage lockout (UVLO) guarantees sufficient bias proper operation internal circuitry prior activation.
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Applications Information
Inductor Selection
step-down converter uses peak current mode control with slope compensation maintain stability duty cycles greater than 50%. output inductor value must selected inductor current down slope meets internal slope compensation requirements. internal slope compensation AAT1147 0.24A/µsec. This equates slope compensation that inductor current down slope 1.5V output 4.7µH inductor. average current ratings result excessive losses high DCR. Always consider losses associated with effect total converter efficiency when selecting inductor. 4.7µH CDRH3D16 series inductor selected from Sumida 105m 900mA current rating. full load, inductor loss 17mW which gives 2.8% loss efficiency 400mA, 1.5V output.
AAT1147
Input Capacitor
Select 4.7µF 10µF ceramic capacitor input. estimate required input capacitor size, determine acceptable input ripple level (VPP) solve calculated value varies with input voltage maximum when double output voltage.
0.75 0.75 1.5V 0.24 4.7H
This internal slope compensation. When externally programming 0.6V version 2.5V, calculated inductance 7.5µH.
0.75
0.75 0.24A
2.5V 7.5H
this case, standard 6.8µH value selected. Table displays inductor values AAT1147. Manufacturer's specifications list both inductor current rating, which thermal limitation, peak current rating, which determined saturation characteristics. inductor should show appreciable saturation under normal load conditions. Some inductors meet peak
CIN(MIN)
Always examine ceramic capacitor voltage coefficient characteristics when selecting proper value. example, capacitance 10µF, 6.3V, ceramic capacitor with 5.0V applied actually about 6µF.
Configuration
0.6V Adjustable With External Feedback
Output Voltage
1.2V 1.5V, 1.8V 2.5V, 3.3V Table Inductor Values.
Inductor
2.2µH 4.7µH 6.8µH
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter
maximum input capacitor current Since inductance short trace feeding input voltage significantly lower than power leads from bench power supply, most applications exhibit this problem. applications where input power source lead inductance cannot reduced level that does affect converter performance, high tantalum aluminum electrolytic should placed parallel with ESR, bypass ceramic. This dampens high network stabilizes system.
AAT1147
IRMS
input capacitor ripple current varies with input output voltage will always less than equal half total load current.
0.52
Output Capacitor
output capacitor limits output ripple provides holdup during large load transitions. 4.7µF 10µF ceramic capacitor typically provides sufficient bulk capacitance stabilize output during large load transitions characteristics necessary output ripple. output voltage droop load transient dominated capacitance ceramic output capacitor. During step increase load current, ceramic output capacitor alone supplies load current until loop responds. Within three switching cycles, loop responds inductor current increases match load current demand. relationship output voltage droop during three switching cycles output capacitance estimated
ILOAD VDROOP
IRMS(MAX)
term appears both input voltage ripple input capacitor current equations maximum when twice VIN. This input voltage ripple input capacitor current ripple maximum duty cycle. input capacitor provides impedance loop edges pulsed current drawn AAT1147. ESR/ESL ceramic capacitors ideal this function. minimize stray inductance, capacitor should placed closely possible This keeps high frequency content input current localized, minimizing input voltage ripple. proper placement input capacitor (C2) seen evaluation board layout Figure laboratory test set-up typically consists long wires running from bench power supply evaluation board input voltage pins. inductance these wires, along with low-ESR ceramic input capacitor, create high network that affect converter performance. This problem often becomes apparent form excessive ringing output voltage during load transients. Errors loop phase gain measurements also result.
COUT
Once average inductor current increases load level, output voltage recovers. above equation establishes limit minimum value output capacitor with respect load transients. internal voltage loop compensation also limits minimum output capacitor value 4.7µF. This effect loop crossover frequency (bandwidth), phase margin, gain margin. Increased output capacitance will reduce crossover frequency with greater phase margin.
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter
AAT1147
Figure AAT1147 Evaluation Board Side.
Figure Exploded View Evaluation Board Side Layout.
Figure AAT1147 Evaluation Board Bottom Side.
maximum output capacitor ripple current given
VOUT (VIN(MAX) VOUT) VIN(MAX)
IRMS(MAX)
Dissipation current ceramic output capacitor typically minimal, resulting less than degrees rise hot-spot temperature.
higher than 0.6V. limit bias current required external feedback resistor string while maintaining good noise immunity, minimum suggested value 59k. Although larger value will further reduce quiescent current, will also increase impedance feedback node, making more sensitive external noise interference. Table summarizes resistor values various output voltages with either good noise immunity 221k reduced load input current.
VOUT 1.5V 0.6V 88.5k
Output Resistor Selection
output voltage AAT1147 0.6V version externally programmed. Resistors Figure program output regulate voltage
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter
AAT1147, combined with external feedforward capacitor Figure delivers enhanced transient response extreme pulsed load applications. addition feedforward capacitor typically requires larger output capacitor stability. VOUT
1.85
AAT1147
Thermal Calculations
There three types losses associated with AAT1147 step-down converter: switching losses, conduction losses, quiescent current losses. Conduction losses associated with RDS(ON) characteristics power output switching devices. Switching losses dominated gate charge power output switching devices. full load, assuming continuous conduction mode (CCM), simplified form losses given
(RDSON(H) RDSON(L) [VIN VO])
221k
1000
19.6 29.4 39.2 49.9 59.0 68.1 78.7 88.7
PTOTAL
(tsw
step-down converter quiescent current. term used estimate full load stepdown converter switching losses.
Table Resistor Values With 0.6V Step-Down Converter.
Enable
AAT1147
PGND PGND PGND AGND
VOUT 118k 4.7H
4.7F
GND2
AAT1147 SC70JW-8 CDRH3D16-4R7 0805 4.7F 0805
Figure AAT1147 Evaluation Board Schematic.
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter
condition where step-down converter dropout 100% duty cycle, total device dissipation reduces
PTOTAL RDSON(H)
AAT1147
Since RDS(ON), quiescent current, switching losses vary with input voltage, total losses should investigated over complete input voltage range. Given total losses, maximum junction temperature derived from SC70JW-8 package which 160°C/W.
feedback trace (Pin should separate from power trace connect closely possible load point. Sensing along high-current load trace will degrade load regulation. External feedback resistors should placed closely possible (Pin minimize length high impedance feedback trace. resistance trace from load return PGND (Pins 6-8) should kept minimum. This will help minimize error regulation differences potential internal signal ground power ground. high density, small footprint layout achieved using inexpensive, miniature, nonshielded, high inductor. evaluation board available with this inductor shown Figure total solution footprint area 40mm2.
TJ(MAX) PTOTAL TAMB
Layout
suggested layout AAT1147 shown Figures following guidelines should used help ensure proper layout. input capacitor (C2) should connect closely possible (Pin PGND (Pins 6-8). should connected closely possible. connection should short possible. Figure Minimum Footprint Evaluation Board Using 2.0mm 1.6mm 0.95mm Inductor.
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Step-Down Converter Design Example
Specifications
TAMB 1.8V 400mA (adjustable using 0.6V version), Pulsed Load ILOAD 300mA 2.7V 4.2V (3.6V nominal) 1.4MHz 85°C
AAT1147
1.8V Output Inductor
1.8V 5.4H
(use 4.7µH; Table
Sumida inductor CDRH3D16, 4.7µH, 105m.
1.8V 1.8V 156mA 4.2V 4.7H 1.4MHz
IPKL1
0.4A 0.068A 0.468A
0.4A2 105m 17mW
1.8V Output Capacitor
VDROOP 0.1V
ILOAD 0.3A 6.4F; 10µF 0.1V 1.4MHz VDROOP (VO) (VIN(MAX) 1.8V (4.2V 1.8V) 45mArms 4.7H 1.4MHz 4.2V VIN(MAX)
COUT IRMS
Pesr IRMS2 (45mA)2
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter
Input Capacitor
Input Ripple 25mV
AAT1147
3.11F; 4.7F 25mV 1.4MHz 0.4A
IRMS
0.2Arms
IRMS2 (0.2A)2 0.2mW
AAT1147 Losses
PTOTAL (RDSON(H) RDSON(L) [VIN -VO])
(tsw
0.42 (0.725 1.8V [4.2V 1.8V])
4.2V
(5ns 1.4MHz 0.4A 70A) 4.2V 126mW
TJ(MAX) TAMB PLOSS 85°C (160°C/W) 126mW 105.1°C
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter
Adjustable Version (0.6V device) VOUT
1.85
AAT1147
19.6 29.4 39.2 49.9 59.0 68.1 78.7 88.7
221k1
75.0 1000
(µH)
Table Evaluation Board Component Values.
Manufacturer
Sumida Sumida Sumida MuRata MuRata Coilcraft Coiltronics Coiltronics Coiltronics
Part Number
CDRH3D16-2R2 CDRH3D16-4R7 CDRH3D16-6R8 LQH2MCN4R7M02 LQH32CN4R7M23 LPO3310-472 SD3118-4R7 SD3118-6R8 SDRC10-4R7
Inductance (µH)
Current
1.20 0.90 0.73 0.40 0.45 0.80 0.98 0.82 1.30
0.072 0.105 0.170 0.80 0.20 0.27 0.122 0.175 0.122
Size (mm) LxWxH
3.8x3.8x1.8 3.8x3.8x1.8 3.8x3.8x1.8 2.0x1.6x0.95 2.5x3.2x2.0 3.2x3.2x1.0 3.1x3.1x1.85 3.1x3.1x1.85 5.7x4.4x1.0
Type
Shielded Shielded Shielded Non-Shielded Non-Shielded Shielded Shielded Shielded
Table Typical Surface Mount Inductors.
reduced quiescent current, 221k. 1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter
Manufacturer
MuRata MuRata MuRata
AAT1147
Part Number
GRM219R61A475KE19 GRM21BR60J106KE19 GRM21BR60J226ME39
Value
4.7µF 10µF 22µF
Voltage
6.3V 6.3V
Temp.
Case
0805 0805 0805
Table Surface Mount Capacitors.
1147.2006.05.1.0
High Efficiency, Noise, Fast Transient 400mA Step-Down Converter Ordering Information
Package
SC70JW-8
AAT1147
Marking1
SCXYY
Part Number (Tape Reel)2
AAT1147IJS-0.6-T1
AnalogicTech products offered Pb-free packaging. term "Pb-free" means semiconductor products that compliance with current RoHS standards, including requirement that lead exceed 0.1% weight homogeneous materials. more information, please visit website
Package Information
SC70JW-8
0.50 0.50 0.50
1.75 0.10
0.225 0.075 2.00 0.20
2.20 0.20
0.048REF
0.85 0.15
1.10
0.15 0.05
0.100
0.45 0.10 2.10 0.30
dimensions millimeters.
assembly date code. Sample stock generally held part numbers listed BOLD.
Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility circuitry other than circuitry entirely embodied AnalogicTech product. circuit patent licenses, copyrights, mask work rights, other intellectual property rights implied. AnalogicTech reserves right make changes their products specifications discontinue product service without notice. Customers advised obtain latest version relevant information verify, before placing orders, that information being relied current complete. products sold subject terms conditions sale supplied time order acknowledgement, including those pertaining warranty, patent infringement, limitation liability. AnalogicTech warrants performance semiconductor products specifications applicable time sale accordance with AnalogicTech's standard warranty. Testing other quality control techniques utilized extent AnalogicTech deems necessary support this warranty. Specific testing parameters each device necessarily performed. AnalogicTech AnalogicTech logo trademarks Advanced Analogic Technologies Incorporated. other brand product names appearing this document registered trademarks trademarks their respective holders.
Advanced Analogic Technologies, Inc.
Arques Avenue, Sunnyvale, 94085 Phone (408) 737-4600 (408) 737-4611
1147.2006.05.1.0
0.05 0.05

AAT1147 SwitchReg member AnalogicTech's Total Power Management IC(TPMI

Top Searches for this datasheet

Other recent searches