MicroPowerRegulated Charge Pump General Description AAT3111 Charg

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MicroPowerRegulated Charge Pump General Description AAT3111 Charg

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AAT3111
MicroPowerRegulated Charge Pump General Description
AAT3111 ChargePumpis MicroPower switched-capacitor voltage converter that delivers regulated output. external inductor required operation. Using three small capacitors, AAT3111 deliver 150mA voltage regulated output. AAT3111 features very quiescent current high efficiency over large portion load range making this device ideal battery-powered applications. Furthermore, combination external components small package size keeps total converter board area minimum space restricted applications. AAT3111 operates output-regulated voltage doubling mode. regulator uses pulse-skipping technique provide regulated output from varying input supply. AAT3111 contains thermal management circuit protect device under continuous output short circuit conditions. AAT3111 available surface mount 6-pin SOT23 8-pin SC70JW package rated from 85°C. AAT3111 ChargePumpis member AnalogicTech's Total Power Management product family.
ChargePump
Step-up type voltage converter Input Range AAT3111-3.6: 1.8V 3.6V AAT3111-3.3: 1.8V 3.3V MicroPower consumption: 13µA 3.6V, 3.3V Regulated output 3.6V Output Current 100mA with 3.0V 20mA with 2.0V 3.3V Output Current 100mA with 2.5V 20mA with 1.8V High Frequency operation Shutdown mode draws less than Short-circuit/over-temperature protection Rating SC70JW-8 SOT23-6 package
Advanced Information
Applications
Handheld Electronics Digital Cameras PDAs Battery Back Supplies Players
Typical Operating Circuits
AAT3111
VOUT
COUT VOUT
10uF
CCIN
ON/OFF
SHDN
10uF
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
Descriptions
SOT-23-6 SC70JW-8
Symbol
VOUT SHDN CVIN
Function
Regulated output pin. Bypass this ground with least 6.8µF capacitor Ground connection Shutdown input. Active signal disables converter. Flying capacitor negative terminal Input supply pin. Bypass this ground with least 6.8µF capacitor Flying capacitor positive terminal
Configuration
SOT23-6 SC70JW-8
VOUT SHDN
VOUT
CSHDN
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
Absolute Maximum Ratings
Symbol
VOUT VSHDN TLEAD VESD
(TA=25°C unless otherwise noted) Value
-0.3 -0.3 -0.3 Indefinite 2000
Description
VOUT SHDN Output Short-Circuit Duration Operating Junction Temperature Range Maximum Soldering Temperature leads, sec) Rating1
Units
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. Note Human body model 100pF capacitor discharged through 1.5k resistor into each pin.
Thermal Information
Symbol
Description
Maximum Thermal Resistance (SOT23-6 SC70JW-8) Maximum Power Dissipation (SOT23-6 SC70JW-8)
Rating
Units
°C/W
Note Mounted board.
Electrical Characteristics 85°C unless otherwise noted.
CFLY=1µF, CIN=10µF, COUT=10µF) AAT3111-3.6 Symbol
VOUT ISHDN VRIPPLE fOSC
Typical values TA=25°C,
Description
Input Voltage Load Supply Current Output Voltage Shutdown Supply Current Ripple Voltage Efficiency Frequency SHDN Input Threshold High SHDN Input Threshold SHDN Input Current High SHDN Input Current VOUT Turn-on time Short-circuit current3
Conditions
VOUT=3.6V 1.8V 3.6V, IOUT=0mA, SHDN=VIN 2.0V 3.6V, IOUT 20mA 3.0V 3.6V, IOUT 100mA 1.8V 3.6V, IOUT =0mA, VSHDN=0 2.0V, IOUT 20mA IOUT 100mA 2.0V, IOUT 20mA Oscillator Free Running
3.46 3.46
0.01
VOUT 3.74 3.74
Units
mVP-P
SHDN SHDN 1.8V, IOUT 1.8V, VOUT GND, SHDN
Note Under short-circuit conditions, device enter overtemperature protection mode.
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
Electrical Characteristics 85°C unless otherwise noted.
CFLY=1µF, CIN=10µF, COUT=10µF) AAT3111-3.3 Symbol
VOUT ISHDN VRIPPLE fOSC
Typical values TA=25°C,
Description
Input Voltage Load Supply Current Output Voltage Shutdown Supply Current Ripple Voltage Efficiency Frequency SHDN Input Threshold High SHDN Input Threshold SHDN Input Current High SHDN Input Current VOUT Turn-on time Short-circuit current
Conditions
VOUT=3.3V 1.8V 3.3V, IOUT=0mA 1.8V 3.3V, IOUT=20mA 2.5V 3.3V, IOUT=100mA 1.8V 3.3V, IOUT =0mA, VSHDN=0 2.0V, IOUT 50mA 1.8V, IOUT 25mA Oscillator Free Running
3.17 3.17
3.30 3.30 0.01
VOUT 3.43 3.43
Units
mVP-P
SHDN SHDN 1.8V, IOUT 1.8V, VOUT GND, SHDN
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
Functional Block Diagram
SHDN
CONTROL
VREF
VOUT
Functional Description
Operation (Refer block diagram)
AAT3111 uses switched capacitor charge pump boost input voltage regulated output voltage. Regulation achieved sensing charge pump output voltage through internal resistor divider network. switched doubling circuit enabled when divided output drops below preset trip point controlled internal comparator. charge pump switch cycling enables four internal switches non-overlapping phases. During first phase, switches switched (short) switches (open). flying capacitor CFLY charged level approximately equal input voltage VIN. second phase, switches turned (open), turned (short). side flying capacitor CFLY connected during first phase. During second phase, flying capacitor CFLY switched that side connected VIN. voltage high side flying capacitor CFLY bootstrapped connected output through switch. each cycle phase, charge from input node transported from lower voltage higher voltage. This cycle repeats itself until output node voltage high enough exceed preset input threshold control comparator. When output voltage exceeds internal trip point level, switching cycle stops charge pump circuit tem3111.2001.11.0.6
porarily placed idle state. When idle, AAT3111 quiescent current 13µA less. closed loop feed back system containing voltage sense circuit control comparator allows AAT3111 provide regulated output voltage limits input voltage output load current. switching signal, which drives charge pump created integrated oscillator within control circuit block. free running charge pump switching frequency approximately 750kHz. switching frequency under active load function VIN, VOUT, COUT IOUT. each phase switching cycle, charge transported from VOUT approximated following formula: VPHASE CFLY VOUT) relative average current that charge pump supply output approximated following expression: IOUT(AVG) CFLY VOUT) AAT3111 complete output short circuit thermal protection safeguard device under extreme operating conditions. internal thermal protection circuit senses temperature will shut down device internal junction temperature exceeds approximately 145°C. charge pump will remain disabled until fault condition relieved.
AAT3111
MicroPowerRegulated Charge Pump
Applications Information
External Capacitor Selection
Careful selection three external capacitors CIN, COUT CFLY very important because they will affect turn time, output ripple transient performance. Optimum performance will obtained when (<100m) ceramic capacitors used COUT CFLY. general, defined less than 100m. desired particular application, Tantalum capacitors substituted; however optimum output ripple performance realized. Aluminum Electrolytic capacitors recommended with AAT3111 their inherent high characteristic. Typically starting point, capacitor value 10µF should used COUT with CFLY when AAT3111 used under maximum output load conditions. Lower values CIN, COUT CFLY utilized light load current applications. Applications drawing load current 10mA less COUT capacitor value CFLY value 0.1µF. COUT range from light loads 10µF more heavy output load conditions. CFLY range from 0.01µF 2.2µF more. CFLY increased, COUT should also increased same ratio minimize output ripple. basic rule, ratio between CIN, COUT CFLY should approximately compromise lowering value CIN, COUT flying capacitor CFLY output ripple voltage increased. case, external capacitor values deviate greatly from recommendation COUT 10µF CFLY 1µF, AAT3111 output performance should evaluated assure device meets application requirements. applications where input voltage source very impedance, possible omit capacitor. However, used, circuit performance should evaluated assure desired operation achieved. Under high peak current operating conditions that typically experienced during circuit start when load demands create large inrush current, poor output voltage regulation result input supply source impedance
high, value low. This situation remedied increasing value CIN.
Capacitor Characteristics
Ceramic composition capacitors highly recommended over other types capacitors with AAT3111. Ceramic capacitors offer many advantages over their tantalum aluminum electrolytic counterparts. ceramic capacitor typically very ESR, lower cost, smaller footprint non-polarized. ceramic capacitors help maximize charge pump transient response. Since ceramic capacitors non-polarized, they prone incorrect connection damage. Equivalent Series Resistance (ESR): very important characteristic consider when selecting capacitor. resistance internal capacitor, which caused leads, internal connections, size area, material composition ambient temperature. Typically capacitor measured milliohms ceramic capacitors range more then several ohms tantalum aluminum electrolytic capacitors. Ceramic Capacitor Materials: Ceramic capacitors less then 0.1µF typically made from materials. materials typically have tight tolerance very stable over temperature. Large capacitor values typically composed X7R, X5R, dielectric materials. Large ceramic capacitors, typically greater than 2.2µF often available cost dielectrics. these types capacitors selected with charge pump, nominal value should doubled compensate capacitor tolerance which vary more than ±50% over operating temperature range device. 10µF capacitor could reduced less than over temperature, this could cause problems circuit operation. dielectrics much more desirable. temperature tolerance dielectric better than ±15%. Capacitor area another contributor ESR. Capacitors that physically large will have lower when compared equivalent material smaller capacitor. These larger devices improve circuit transient response when compared equal value capacitor smaller package size.
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
Applications Information
Charge Pump Efficiency
AAT3111 regulated output voltage doubling charge pump. efficiency simply defined linear voltage regulator with effective output voltage that equal times input voltage. Efficiency ideal voltage doubler typically expressed output power divided input power. POUT addition, with ideal voltage doubling charge pump output current expressed half input current. expression define ideal efficiency rewritten POUT (VOUT IOUT) (VIN 2IOUT) VOUT 2VIN 100(VOUT 2VIN) charge pump with output volts nominal input volts, theoretical efficiency 91.6%. internal switching losses quiescent current consumption, actual efficiency measured 91%. These figures close agreement output load conditions from 100mA. Efficiency will decrease load current drops below 0.05mA when level approaches VOUT. Refer Typical Characteristics section measured plots efficiency versus input voltage output load current given charge pump output voltage options.
charge pump will then become active again. thermal protection system will cycle output short circuit condition persists. This will allow AAT3111 operate indefinitely short circuit condition without damage device.
Output Ripple Ripple Reduction
There several factors that determine amplitude frequency charge pump output ripple, values COUT CFLY, load current IOUT level VIN. Ripple observed VOUT typically sawtooth waveform shape. ripple frequency will vary depending load current IOUT level VIN. increases ability charge pump transfer charge from input output becomes greater, does, peak-to-peak output ripple voltage will also increase. size type capacitors used CIN, COUT CFLY have effect output ripple. Since output ripple associated with charge time constant these capacitors, capacitor value will contribute resulting charge pump output ripple. This capacitors recommended charge pump applications. Typically, output ripple greater than 35mVP-P when 2.0V, VOUT 3.3V, COUT 10µF CFLY 1µF. When AAT3111 used light output load applications where IOUT 10mA, flying capacitor CFLY value reduced. reason this effect when charge pump under very light load conditions, transfer charge across CFLY greater during each phase switching cycle. result higher ripple seen charge pump output. This effect will reduced decreasing value CFLY. Caution should observed when decreasing flying capacitor. output load current rises above nominal level reduced CFLY value, charge pump efficiency compromised. There several methods that employed reduce output ripple depending upon requirements given application. most simple straightforward technique increase value COUT capacitor. nominal 10µF COUT capacitor increased 22µF more. Larger values COUT capacitor (22µF greater) will nature have lower improve both high
Short Circuit Thermal Protection
event short circuit condition, charge pump draw much 100mA 400mA current from VIN. This excessive current consumption output short circuit condition will cause rise internal junction temperature. AAT3111 thermal protection shutdown circuit that continuously monitors junction temperature. thermal protection circuit senses temperature exceeding approximately 145°C, thermal shutdown will disable charge pump switching cycle operation. thermal limit system 10°C system hysteresis before charge pump reset. Once over current event removed from output junction temperature drops below 135°C,
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
Applications Information
frequency components charge pump output ripple response. higher value tantalum capacitor used COUT reduce frequency ripple elements, small ceramic capacitor should added parallel tantalum capacitor (see Figure reason this tantalum capacitors typically have higher than equivalent value ceramic capacitors less able reduce high frequency components output ripple. only disadvantage using large values COUT capacitor AAT3111 device turn-on time in-rush current increased. additional ripple reduction desired, filter added charge pump output addition COUT capacitor (see Figure filter will reduce output ripple primarily attenuating high frequency components output ripple waveform. frequency break point filter will significantly depend capacitor value selected.
Layout Considerations
High charge pump switching frequencies large peak transient currents mandate careful printed circuit board layout. general rule charge pump boost converters, external capacitors should located close possible device package with minimum length trace connections. Maximize ground plane around AAT3111 charge pump make sure external capacitors connected immediate ground plane. local component side ground plane recommended. this possible layout design limitations, assure good ground connections large multiple via's. Refer following AAT3111 evaluation board example good charge pump layout design (Figures through
VOUT (3.3V)
COUT2
COUT1 22µF
VOUT
CFLY
AAT3111
10µF
(1.8V 3.3V)
ON/OFF
SHDN
Figure Application using tantalum capacitor
VOUT (3.3V)
RFILTER ohms
VOUT
CFILTER 33µF
CFLY 10µF
COUT 10µF
AAT3111
(1.8V 3.3V)
ON/OFF
SHDN
Figure Application with output ripple reduction filter
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
Figure Evaluation board side silk screen layout assembly drawing
Figure Evaluation board component side layout
Figure Evaluation board component side layout
Typical Application Circuits
VOUT
COUT 10µF
VOUT
CFLY
AAT3111
10µF
ON/OFF
SHDN
Figure Typical charge pump boost converter circuit
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
Ordering Information
Output Voltage 3.3V 3.6V 3.3V 3.6V Package SOT-23-6 SOT-23-6 SC70JW-8 SC70JW-8 Marking Part Number Bulk Tape Reel AAT3111IGU-3.3-T1 AAT3111IGU-3.6-T1 AAT3111IJS-3.3-T1 AAT3111IJS-3.6-T1
Package Information
SOT-23-6
GAUGE PLANE
Millimeters 0.95 1.45 0.05 0.15 0.90 1.30 0.35 0.50 0.08 0.20 2.84 3.00 1.50 1.70 2.60 3.00 0.95 1.90 0.50 0.23 0.40 0.10 0.60
Inches 0.037 0.057 0.002 0.006 0.035 0.051 0.0137 0.019 0.0031 0.0078 0.1118 0.118 0.059 0.0669 0.102 0.118 0.0374 0.0748 0.0197 0.009 0.016 0.039 0.0236
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
SC70JW-8
0.048REF
Millimeters 2.10 1.75 2.00 0.23 0.40 1.10 0.10 0.70 1.00 2.00 0.50 0.15 0.30 0.10 0.20
Inches 0.083 0.069 0.079 0.009 0.016 0.043 0.004 0.028 0.039 0.079 0.020 0.006 0.012 0.004 0.008
3111.2001.11.0.6
AAT3111
MicroPowerRegulated Charge Pump
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Advanced Analogic Technologies, Inc.
1250 Oakmead Parkway, Suite 310, Sunnyvale, 94086 Phone (408) 524-9684 (408) 524-9689
3111.2001.11.0.6

MicroPowerRegulated Charge Pump General Description AAT3111 Charg

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