AAT3110 MicroPower™ Regulated Charge Pump General Description Features The AAT3110 ChargePump is a member of AnalogicTech's Total Power Management IC™ (TPMIC™) product family. It is a MicroPower switched capacitor voltage converter that delivers a regulated output. No external inductor is required for operation. Using three small capacitors, the AAT3110 can deliver up to 100mA to the voltage regulated output. The AAT3110 features very low quiescent current and high efficiency over a large portion of its load range, making this device ideal for battery-powered applications. Furthermore, the combination of few external components and small package size keeps the total converter board area to a minimum in space-restricted applications. The AAT3110 operates in an output regulated voltage doubling mode. The regulator uses a pulse skipping technique to provide a regulated output from a varying input supply. The AAT3110 contains a thermal management circuit to protect the device under continuous output short-circuit conditions. • • • • • • • • • • • • The AAT3110 is available in a Pb-free, surfacemount 6-pin SOT23 or 8-pin SC70JW package and is rated over the -40°C to +85°C temperature range. ChargePump SmartSwitch™ Step-Up Voltage Converter Input Voltage Range: — AAT3110-5: 2.7V to 5V — AAT3110-4.5: 2.7V to 4.5V MicroPower Consumption: 13µA Regulated 5V, 4.5V ±4% Output 5V Output Current: — 100mA with VIN ≥ 3.0V — 50mA with VIN ≥ 2.7V 4.5V Output Current: — 100mA with VIN ≥ 3.0V — 50mA with VIN ≥ 2.7V Peak Current 250mA for 100ms High Frequency 750kHz Operation Shutdown Mode Draws Less Than 1µA Short-Circuit/Over-Temperature Protection 2kV ESD Rating SC70JW-8 or SOT23-6 Package Applications • • • • • • • Cellular Phones Digital Cameras Handheld Electronics LED/Display Backlight Driver LEDs for Camera Flash PDAs Portable Communication Devices Typical Application AAT3110 VOUT VOUT C+ 1µF COUT 10µF ON/OFF GND SHDN VIN VIN C- CIN 10µF 3110.2005.11.1.4 1 AAT3110 MicroPower™ Regulated Charge Pump Pin Descriptions Pin # SOT23-6 SC70JW-8 Symbol Function 1 1 VOUT Regulated output pin. Bypass this pin to ground with a 6.8µF (min) low equivalent series resistance (ESR) capacitor. 2 2, 3, 4 GND Ground connection. 3 5 SHDN 4 6 C- 5 7 VIN Input supply pin. Bypass this pin to ground with a 6.8µF (min) low-ESR capacitor. 6 8 C+ Flying capacitor positive terminal. Shutdown input. Logic low signal disables the converter. Flying capacitor negative terminal. Pin Configuration SOT23-6 VOUT GND SHDN 2 1 2 3 SC70JW-8 6 5 4 C+ VIN C- VOUT GND GND GND 1 8 2 7 3 6 4 5 C+ VIN CSHDN 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Symbol VIN VOUT VSHDN tSC TJ TLEAD VESD Description VIN to GND VOUT to GND SHDN to GND Output to GND Short-Circuit Duration Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) ESD Rating2 — HBM Value Units -0.3 to 6 -0.3 to 6 -0.3 to 6 Indefinite -40 to 150 300 2000 V V V s °C °C V Rating Units 150 667 °C/W mW Thermal Information3 Symbol ΘJA PD Description Maximum Thermal Resistance Maximum Power Dissipation 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. 3. Mounted on an FR4 board. 3110.2005.11.1.4 3 AAT3110 MicroPower™ Regulated Charge Pump Electrical Characteristics TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C, CFLY = 1µF, CIN = 10µF, COUT = 10µF. Symbol Description AAT3110-5 VIN Input Voltage IQ No Load Supply Current1 VOUT Output Voltage ISHDN Shutdown Supply Current VRIPPLE Ripple Voltage η Efficiency fOSC Frequency VIH SHDN Input Threshold High VIL SHDN Input Threshold Low IIH SHDN Input Current High IIL SHDN Input Current Low tON VOUT Turn-On Time ISC Short-Circuit Current2 AAT3110-4.5 VIN Input Voltage IQ No Load Supply Current3 VOUT Output Voltage ISHDN Shutdown Supply Current VRIPPLE η fOSC VIH VIL IIH IIL tON ISC Ripple Voltage Efficiency Frequency SHDN Input Threshold High SHDN Input Threshold Low SHDN Input Current High SHDN Input Current Low VOUT Turn-On Time Short-Circuit Current2 Conditions Min VOUT = 5.0V 2.7V < VIN < 5V, IOUT = 0mA, SHDN = VIN 2.7V < VIN < 5V, IOUT ≤ 50mA 3.0V < VIN < 5V, IOUT ≤ 100mA 2.7V < VIN < 3.6V, IOUT = 0mA, VSHDN = 0 3.6V < VIN < 5V, IOUT = 0mA, VSHDN = 0 VIN = 2.7V, IOUT = 50mA VIN = 3V, IOUT = 100mA VIN = 2.7V, IOUT = 50mA Oscillator Free Running 2.7 4.8 4.8 Typ Max Units 13 5.0 5.0 0.01 VOUT 30 5.2 5.2 1 2.5 V µA 25 30 92 750 -1 -1 VOUT = 4.5V 2.7V < VIN < 4.5V, IOUT = 0mA, SHDN = VIN 2.7V < VIN < 4.5V, IOUT ≤ 50mA 3.0V < VIN < 4.5V, IOUT ≤ 100mA 2.7V < VIN < 3.6V, IOUT = 0mA, VSHDN = 0 3.6V < VIN < 4.5V, IOUT = 0mA, VSHDN = 0 VIN = 2.7V, IOUT = 50mA VIN = 3V, IOUT = 100mA VIN = 2.7V, IOUT = 50mA Oscillator Free Running 2.7 0.3 1 1 0.2 300 4.32 4.32 13 4.5 4.5 0.01 VOUT 30 4.68 4.68 1 2.5 25 30 83 750 0.3 1 1 -1 -1 0.2 300 % kHz V V µA µA ms mA V µA V µA mVP-P 1.4 SHDN = VIN SHDN = GND VIN = 3V, IOUT = 0mA VIN = 3V, VOUT = GND, SHDN = 3V µA mVP-P 1.4 SHDN = VIN SHDN = GND VIN = 3V, IOUT = 0mA VIN = 3V, VOUT = GND, SHDN = 3V V % kHz V V µA µA ms mA 1. VOUT is pulled up to 5.5V to prevent switching. 2. Under short-circuit conditions, the device may enter over-temperature protection mode. 3. VOUT is pulled up to 5.0V to prevent switching. 4 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump Typical Characteristics — AAT3110-5V Unless otherwise noted, VIN = 3V, CIN = COUT = 10µF, CFLY = 1µF, TA = 25°C. Output Voltage vs. Output Current Supply Current vs. Supply Voltage 22 5.1 Supply Current (µA) Output Voltage (V) 5.15 VIN = 3.6V 5.05 5 VIN = 3.0V 4.95 VIN = 2.7V VIN = 3.3V 4.9 4.85 50 100 18 16 14 12 10 8 2.5 4.8 0 IOUT = 0µA CFLY = 1µF VSHDN = VIN 20 150 3 Supply Current vs. VSHDN 95 IOUT = 0µA 5 5.5 20 VIN = 5.5V 15 VIN = 3.3V 25mA 90 25 Efficiency (%) Supply Current (µA) 4.5 Efficiency vs. Supply Voltage 30 VIN = 2.8V 4 Supply Voltage (V) Output Current (mA) 10 3.5 85 80 75 50mA 70 65 100mA 60 55 50 5 45 2.70 0 0 1 2 3 4 3.00 5 3.50 4.00 4.50 5.00 Supply Voltage (V) VSHDN Control Voltage (V) Efficiency vs. Load Current 100 VIN = 2.7V 90 Efficiency (%) 80 70 60 VIN = 3.0V VIN = 3.6V 50 40 VIN = 3.3V 30 20 10 0 0.01 0.1 1 10 Load Current (mA) 3110.2005.11.1.4 100 1000 Oscillator Frequency (kHz) Oscillator Frequency vs. Supply Voltage 1200 1100 1000 - 40°C 900 800 700 25°C 600 500 400 2.7 85°C 3.0 3.5 4.0 4.5 5.0 Supply Voltage (V) 5 AAT3110 MicroPower™ Regulated Charge Pump Typical Characteristics — AAT3110-5V Unless otherwise noted, VIN = 3V, CIN = COUT = 10µF, CFLY = 1µF, TA = 25°C. Startup Time with 100mA Load Startup Time with 50mA Load SHDN (2V/div) SHDN (2V/div) VOUT (1V/div) VOUT (1V/div) Time (50µs/div) Time (50µs/div) Load Transient Response for 50mA IOUT 0mA to 50mA (20mA/div) Load Transient Response for 100mA IOUT 0mA to 100 mA (50mA/div) VIN = 3.0V VIN = 3.0V VOUT AC Coupled (20mV/div) VOUT AC Coupled (20mV/div) Time (50µs/div) Time (50µs/div) Output Ripple with IOUT = 50mA VOUT AC Coupled (10 mV/div) VOUT AC Coupled (10 mV/div) VIN = 3.0V VIN = 3.0V Time (2µs/div) 6 Output Ripple with IOUT = 100mA Time (2µs/div) 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump Typical Characteristics — AAT3110-5V Unless otherwise noted, VIN = 3V, CIN = COUT = 10µF, CFLY = 1µF, TA = 25°C. Output Voltage vs. Input Voltage (IOUT = 250mA) Output Voltage (V) 5.2 -20°C 4.8 20°C 4.4 55°C one shot pulse t = 100ms 4 3.6 3.2 3.2 3.4 3.6 3.8 4 4.2 Input Voltage (V) 3110.2005.11.1.4 7 AAT3110 MicroPower™ Regulated Charge Pump Typical Characteristics — AAT3110-4.5V Unless otherwise noted, VIN = 3V, CIN = COUT = 10µF, CFLY = 1µF, TA = 25°C. Output Voltage vs. Output Current Supply Current vs. Supply Voltage 4.54 18 Supply Current (µA) Output Voltage (V) 3.6V 4.53 4.52 2.7V 3.0V 4.51 3.3V 4.5 4.49 0.1 1 10 100 17 16 No Load, Switching 15 14 13 12 No Load, No Switching 11 10 1000 2.5 Output Current (mA) 3 3.5 4 4.5 Supply Voltage (V) Supply Current vs. VSHDN Efficiency vs. Supply Voltage 30 85 80 25 Efficiency (%) Supply Current (µA) IOUT = 0µA 20 VIN = 5.5V 15 10 VIN = 2.8V VIN = 3.3V 75 100mA 70 50mA 65 60 5mA 55 5 50 2.7 0 0 1 2 3 4 2.9 3.1 5 3.3 3.5 3.7 3.9 4.1 4.3 4.5 Supply Voltage (V) VSHDN Control Voltage (V) Oscillator Frequency vs. Supply Voltage Oscillator Frequency (kHz) Efficiency vs. Load Current 85 VIN = 2.7V Efficiency (%) 80 75 VIN = 3.0V 70 VIN = 3.3V 65 60 0.1 1 10 Load Current (mA) 8 100 1000 1200 1100 1000 - 40°C 900 800 700 25°C 600 500 400 2.7 85°C 3.0 3.5 4.0 4.5 5.0 Supply Voltage (V) 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump Typical Characteristics — AAT3110-4.5V Unless otherwise noted, VIN = 3V, CIN = COUT = 10µF, CFLY = 1µF, TA = 25°C. Load Transient Response Load Transient Response (VIN = 2.7V) (VIN = 3.0V) IOUT (100mA/div) IOUT (100mA/div) VOUT (20mV/div) VOUT (20mV/div) Time (50µs/div) Time (50µs/div) Output Ripple Output Ripple (IOUT = 50mA @ VIN = 2.7V) (IOUT = 100mA @ VIN = 3.0V) VOUT AC Coupled (5mV/div) VOUT AC Coupled (5mV/div) Time (5µs/div) Time (5µs/div) Output Voltage vs. Input Voltage for Pulsed High Current Maximum Current Pulse (mA) Maximum Current Pulse vs. Input Voltage Output Voltage (V) 4.6 4.5 4.4 4.3 One-shot pulse duration = 50ms IOUT = 250mA 4.2 4.1 4 3 3.2 3.4 3.6 3.8 Input Voltage (V) 3110.2005.11.1.4 4 4.2 600 500 400 300 200 One-shot pulse duration = 50ms VOUT > 4.0V 100 0 3 3.2 3.4 3.6 3.8 4 4.2 Input Voltage (V) 9 AAT3110 MicroPower™ Regulated Charge Pump Typical Characteristics — AAT3110-4.5V Unless otherwise noted, VIN = 3V, CIN = COUT = 10µF, CFLY = 1µF, TA = 25°C. Startup SHDN (1V/div) ILOAD = 150mA @ VIN = 3.3V ILOAD = 100mA @ VIN = 3.0V VOUT (2V/div) ILOAD = 50mA @ VIN = 2.7V Time (100µs/div) 10 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump Typical Characteristics — AAT3110 SHDN Input Threshold (high) vs. Input Voltage SHDN Input Threshold (low) vs. Input Voltage 1.00 0.95 0.90 -40°C 0.85 25°C 0.80 0.75 0.70 85°C 0.65 0.60 0.55 0.50 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 1.00 SHDN Input Threshold (low) (V) SHDN Input Threshold (high) (V) Unless otherwise noted, VIN = 3V, CIN = COUT = 10µF, CFLY = 1µF, TA = 25°C. 0.95 0.90 -40°C 0.85 0.80 25°C 0.75 0.70 0.65 85°C 0.60 0.55 0.50 2.0 Input Voltage (V) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Input Voltage (V) VSHDN Threshold vs. Input Voltage Normalized Output Voltage (%) Normalized Output Voltage vs. Temperature 1.00 VSHDN Threshold (V) 0.95 0.90 VIH 0.85 0.80 0.75 0.70 VIL 0.65 0.60 0.55 0.50 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 1.20 IOUT = 25mA 1.00 0.80 0.60 0.40 0.20 0.00 -0.20 -0.40 -0.60 -50 -25 0 25 50 75 100 125 Temperature (°C) Input Voltage (V) 3110.2005.11.1.4 11 AAT3110 MicroPower™ Regulated Charge Pump Functional Block Diagram VIN S1 S2 SHDN CONTROL C+ CVREF S4 S3 VOUT + GND Functional Description Operation (Refer to block diagram) The AAT3110 uses a switched capacitor charge pump to boost an input voltage to a regulated output voltage. Regulation is achieved by sensing the charge pump output voltage through an internal resistor divider network. A switched doubling circuit is enabled when the divided output drops below a preset trip point controlled by an internal comparator. The charge pump switch cycling enables four internal switches at two non-overlapping phases. During the first phase, switches S1 and S4 are switched on (short) and switches S2 and S3 are off (open). The flying capacitor CFLY is charged to a level approximately equal to input voltage VIN. During the second phase, switches S1 and S4 are turned off (open) and switches S2 and S3 are turned on (short). The low side of the flying capacitor CFLY is connected to GND during the first phase. During the second phase, the flying capacitor CFLY is switched so that the low side is connected to VIN. The voltage at the high side of the flying capacitor CFLY is bootstrapped to 2 × VIN and is connected to output through a switch. For each cycle phase, charge from input node VIN is transported from a lower voltage to a higher voltage. This cycle repeats itself until the output node voltage is high enough to exceed the preset input threshold of the control comparator. When the output voltage exceeds the internal trip point level, the switching 12 cycle stops and the charge pump circuit is temporarily placed in an idle state. When idle, the AAT3110 has a quiescent current of 13µA or less. The closed loop feedback system containing the voltage sense circuit and control comparator allows the AAT3110 to provide a regulated output voltage to the limits of the input voltage and output load current. The switching signal, which drives the charge pump, is created by an integrated oscillator within the control circuit block. The free-running charge pump switching frequency is approximately 750kHz. The switching frequency under an active load is a function of VIN, VOUT, COUT, and IOUT. For each phase of the switching cycle, the charge transported from VIN to VOUT can be approximated by the following formula: VPHASE ≈ CFLY × (2 × VIN - VOUT) The relative average current that the charge pump can supply to the output may be approximated by the following expression: IOUT(AVG) α CFLY × (2 × VIN - VOUT) × FSW The AAT3110 has complete output short-circuit and thermal protection to safeguard the device under extreme operating conditions. An internal thermal protection circuit senses die temperature and will shut down the device if the internal junction temperature exceeds approximately 145°C. The charge pump will remain disabled until the fault condition is relieved. 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump Applications Information External Capacitor Selection Careful selection of the three external capacitors CIN, COUT, and CFLY is very important because they will affect turn-on time, output ripple, and transient performance. Optimum performance will be obtained when low ESR ceramic capacitors are used. In general, low ESR may be defined as less than 100mΩ. If desired for a particular application, low ESR tantalum capacitors may be substituted; however, optimum output ripple performance may not be realized. Aluminum electrolytic capacitors are not recommended for use with the AAT3110 due to their inherent high ESR characteristic. Typically as a starting point, a capacitor value of 10µF should be used for CIN and COUT with 1µF for CFLY when the AAT3110 is used under maximum output load conditions. Lower values for CIN, COUT, and CFLY may be utilized for light load current applications. Applications drawing a load current of 10mA or less may use a CIN and COUT capacitor value as low as 1µF and a CFLY value of 0.1µF. CIN and COUT may range from 1µF for light loads to 10µF or more for heavy output load conditions. CFLY may range from 0.01µF to 2.2µF or more. If CFLY is increased, COUT should also be increased by the same ratio to minimize output ripple. As a basic rule, the ratio between CIN, COUT, and CFLY should be approximately 10 to 1. The compromise for lowering the value of CIN, COUT, and the flying capacitor CFLY is that the output ripple voltage may be increased. In any case, if the external capacitor values deviate greatly from the recommendation of CIN = COUT = 10µF and CFLY = 1µF, the AAT3110 output performance should be evaluated to assure the device meets application requirements. In applications where the input voltage source has very low impedance, it is possible to omit the CIN capacitor. However, if CIN is not used, circuit performance should be evaluated to assure desired operation is achieved. Under high peak current operating conditions that are typically experienced during circuit start-up or when load demands create a large inrush current, poor output voltage regulation can result if the input supply source impedance is high or if the value of CIN is too low. This situation can be remedied by increasing the value of CIN. 3110.2005.11.1.4 Capacitor Characteristics Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the AAT3110. Ceramic capacitors offer many advantages over their tantalum and aluminum electrolytic counterparts. A ceramic capacitor typically has very low ESR, is lower cost, has a smaller PCB footprint, and is non-polarized. Low ESR ceramic capacitors help maximize charge pump transient response. Since ceramic capacitors are non-polarized, they are not prone to incorrect connection damage. Equivalent Series Resistance: ESR is a very important characteristic to consider when selecting a capacitor. ESR is a resistance internal to a capacitor that is caused by the leads, internal connections, size or area, material composition, and ambient temperature. Typically, capacitor ESR is measured in milliohms for ceramic capacitors and can range to more then several ohms for tantalum or aluminum electrolytic capacitors. Ceramic Capacitor Materials: Ceramic capacitors less than 0.1µF are typically made from NPO or C0G materials. NPO and C0G materials typically have tight tolerance and are very stable over temperature. Large capacitor values are typically composed of X7R, X5R, Z5U, or Y5V dielectric materials. Large ceramic capacitors, typically greater than 2.2µF, are often available in low-cost Y5V and Z5U dielectrics. If these types of capacitors are selected for use with the charge pump, the nominal value should be doubled to compensate for the capacitor tolerance which can vary more than ±50% over the operating temperature range of the device. A 10µF Y5V capacitor could be reduced to less than 5µF over temperature; this could cause problems for circuit operation. X7R and X5R dielectrics are much more desirable. The temperature tolerance of X7R dielectric is better than ±15%. Capacitor area is another contributor to ESR. Capacitors that are physically large will have a lower ESR when compared to an equivalent material smaller capacitor. These larger devices can improve circuit transient response when compared to an equal value capacitor in a smaller package size. Charge Pump Efficiency The AAT3110 is a regulated output voltage doubling charge pump. The efficiency (η) can simply 13 AAT3110 MicroPower™ Regulated Charge Pump be defined as a linear voltage regulator with an effective output voltage that is equal to two times the input voltage. Efficiency (η) for an ideal voltage doubler can typically be expressed as the output power divided by the input power. η= POUT PIN In addition, with an ideal voltage doubling charge pump, the output current may be expressed as half the input current. The expression to define the ideal efficiency (η) can be rewritten as: η= POUT VOUT × IOUT V = = OUT PIN VIN × 2IOUT 2VIN -or- η(%) = 100 ⎛ VOUT ⎞ ⎝ 2VIN ⎠ For a charge pump with an output of 5.0V and a nominal input of 3.0V, the theoretical efficiency is 83.3%. Due to internal switching losses and IC quiescent current consumption, the actual efficiency can be measured at 82.7%. These figures are in close agreement for output load conditions from 1mA to 100mA. Efficiency will decrease as load current drops below 0.05mA or when the level of VIN approaches VOUT. Refer to the Typical Characteristics section of this datasheet for measured plots of efficiency versus input voltage and output load current for the given charge pump output voltage options. Short-Circuit and Thermal Protection In the event of a short-circuit condition, the charge pump can draw a much as 100mA to 400mA of current from VIN. This excessive current consumption due to an output short-circuit condition will cause a rise in the internal IC junction temperature. The AAT3110 has a thermal protection and shutdown circuit that continuously monitors the IC junction temperature. If the thermal protection circuit senses the die temperature exceeding approximately 145°C, the thermal shutdown will disable the 14 charge pump switching cycle operation. The thermal limit system has 10°C of system hysteresis before the charge pump can reset. Once the overcurrent event is removed from the output and the junction temperature drops below 135°C, the charge pump will become active again. The thermal protection system will cycle on and off if an output short-circuit condition persists. This will allow the AAT3110 to operate indefinitely under short-circuit conditions without damaging the device. Output Ripple and Ripple Reduction There are several factors that determine the amplitude and frequency of the charge pump output ripple, the values of COUT and CFLY, the load current IOUT, and the level of VIN. Ripple observed at VOUT is typically a sawtooth waveform in shape. The ripple frequency will vary depending on the load current IOUT and the level of VIN. As VIN increases, the ability of the charge pump to transfer charge from the input to the output becomes greater. As it does, the peak-to-peak output ripple voltage will also increase. The size and type of capacitors used for CIN, COUT, and CFLY have an effect on output ripple. Since output ripple is associated with the R/C charge time constant of these two capacitors, the capacitor value and ESR will contribute to the resulting charge pump output ripple. This is why low ESR capacitors are recommended for use in charge pump applications. Typically, output ripple is not greater than 30mVP-P when VIN = 3.0V, VOUT = 5.0V, COUT = 10µF, and CFLY = 1µF. When the AAT3110 is used in light output load applications where IOUT < 10mA, the flying capacitor CFLY value can be reduced. The reason for this effect is when the charge pump is under very light load conditions, the transfer of charge across CFLY is greater during each phase of the switching cycle. The result is higher ripple seen at the charge pump output. This effect will be reduced by decreasing the value of CFLY. Caution should be observed when decreasing the flying capacitor. If the output load current rises above the nominal level for the reduced CFLY value, charge pump efficiency can be compromised. There are several methods that can be employed to reduce output ripple depending upon the requirements of a given application. The most simple and straightforward technique is to increase the value of 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump the COUT capacitor. The nominal 10µF COUT capacitor can be increased to 22µF or more. Larger values for the COUT capacitor (22µF and greater) will by nature have lower ESR and can improve both high and low frequency components of the charge pump output ripple response. If a higher value tantalum capacitor is used for COUT to reduce low frequency ripple elements, a small 1µF low ESR ceramic capacitor should be added in parallel to the tantalum capacitor (see Figure 1). The reason for this is tantalum capacitors typically have higher ESR than equivalent value ceramic capacitors and are less able to reduce high frequency components of the output ripple. The only disadvantage to using large values for the COUT capacitor is the AAT3110 device turn-on time and inrush current may be increased. If additional ripple reduction is desired, an R/C filter can be added to the charge pump output in addition to the COUT capacitor (see Figure 2). An R/C filter will reduce output ripple by primarily attenuating high frequency components of the output ripple VOUT (5V) COUT2 1 µF COUT1 22µF + VOUT waveform. The low frequency break point for the R/C filter will significantly depend on the capacitor value selected. Layout Considerations High charge pump switching frequencies and large peak transient currents mandate careful printed circuit board layout. As a general rule for charge pump boost converters, all external capacitors should be located as closely as possible to the device package with minimum length trace connections. Maximize the ground plane around the AAT3110 charge pump and make sure all external capacitors are connected to the immediate ground plane. A local component side ground plane is recommended. If this is not possible due to layout design limitations, assure good ground connections by the use of large or multiple PCB vias. Refer to the AAT3110 evaluation board for an example of good charge pump layout design (Figures 3 through 5). C+ AAT3110-5 GND CFLY 1µF VIN (2.7V to 5V) VIN + ON/OFF SHDN C- CIN 10µF Figure 1: Application Using Tantalum Capacitor. VOUT (5V) RFILTER 1.5Ω VOUT CFILTER 33µF COUT 10µF ON/OFF C+ AAT3110-5 GND SHDN CFLY 1 µF VIN (2.7V to 5V) VIN C- CIN 10µF Figure 2: Application With Output Ripple Reduction Filter. 3110.2005.11.1.4 15 AAT3110 MicroPower™ Regulated Charge Pump Figure 3: Evaluation Board Top Side Silk Screen Layout / Assembly Drawing. Figure 4: Evaluation Board Component Side Layout. Figure 5: Evaluation Board Solder Side Layout. Typical Application Circuits VOUT (5V) VOUT COUT 10µF C+ CFLY 1µF AAT3110-5 GND ON/OFF SHDN VIN (2.7V to 5V) VIN CIN 10µF C- Figure 6: Typical Charge Pump Boost Converter Circuit. CFLY 1µF C- VIN (USB Port VOUT) C+ VOUT 5V 100mA VOUT VIN SHDN CIN 10µF AAT3110-5 COUT 10µF GND GND (USB Port Return) GND Figure 7: 5V, 100mA Supply Powered From a USB Port. 16 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump VIN VOUT C+ Li-Ion Battery 2.7V to 4.2V 10µF SHDN ON/OFF 10µF AAT3110-5 120 120 120 120 1µF C- Figure 8: 5V LED or Display Driver from a Li-Ion Battery Source. VIN = 3.0V to 5V VIN CIN 10µF SHDN VOUT = 5V IOUT = 200mA VOUT C+ AAT3110-5 (A) SHDN C- CFLY 1µF GND VIN VOUT C+ AAT3110-5 (B) SHDN C- CFLY 1µF COUT 10µF GND Figure 9: 5V, 200mA Step-Up Supply from a 3V to 5V Source. 3110.2005.11.1.4 17 AAT3110 MicroPower™ Regulated Charge Pump Ordering Information Output Voltage Package Marking1 Part Number (Tape and Reel)2 4.5V SOT23-6 EEXYY AAT3110IGU-4.5-T1 5.0V SOT23-6 ASXYY AAT3110IGU-5.0-T1 4.5V SC70JW-8 EEXYY AAT3110IJS-4.5-T1 5.0V SC70JW-8 ASXYY AAT3110IJS-5.0-T1 All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. Package Information SOT23-6 2.85 ± 0.15 1.90 BSC 2.80 ± 0.20 1.20 ± 0.25 0.15 ± 0.07 4° ± 4° 1.10 ± 0.20 0.075 ± 0.075 1.575 ± 0.125 0.95 BSC 10° ± 5° 0.40 ± 0.10 × 6 0.60 REF 0.45 ± 0.15 GAUGE PLANE 0.10 BSC All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on all part numbers listed in BOLD. 18 3110.2005.11.1.4 AAT3110 MicroPower™ Regulated Charge Pump SC70JW-8 2.20 ± 0.20 1.75 ± 0.10 0.50 BSC 0.50 BSC 0.50 BSC 0.225 ± 0.075 2.00 ± 0.20 0.100 7° ± 3° 0.45 ± 0.10 4° ± 4° 0.05 ± 0.05 0.15 ± 0.05 1.10 MAX 0.85 ± 0.15 0.048REF 2.10 ± 0.30 All dimensions in millimeters. 3110.2005.11.1.4 19 AAT3110 MicroPower™ Regulated Charge Pump © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 20 3110.2005.11.1.4