AIC1848 Regulated 5V Charge Pump In SOT-23 DESCRIPTION FEATURES Regulated ±4% Output Voltage The AIC1848 charge pump is a micropower Output Current: 100mA at VIN =3.1V Input Range: 2.7V to 4.5V No Inductors Required charge pump DC/DC converter that produces a regulated output voltage from 2.7V to 4.5V input voltage. Low external-part count (one flying Very Low Shutdown Current: <1µA 1.8MHz Switching Frequency Short-Circuit and Over Temperature Protection Low Profile Package: SOT-23-6 capacitor and two small bypass capacitors) makes the AIC1848 ideal for small, batterypowered applications. The AIC1848 operates as a constant frequency mode switched capacitor voltage doubler to APPLICATIONS produce a regulated output and features with thermal shutdown capability and short circuit White LEDs Backlighting SIM Interface Supplies for Cellular Telephones Li-Ion Battery Backup Supplies Local 3V to 5V Conversion Smart Card Readers PCMCIA Local 5V Supplies protection. The AIC1848 is available in a space-saving SOT-23-6 package. TYPICAL APPLICATION CIRCUIT VOUT U1 1-Cell CIN 1µF Li-ion Battery 1 VOUT 2 3 GND SHDN C+ 6 VIN C- COUT 1µF R1 R2 R3 5 4 CFLY 1µF AIC1848 Regulated 5V Output from 2.7V to 4.5V Input WLED series number: NSPW310BS, VF=3.6V, IF=20mA R= VOUT − V F IF CIN, CFLY, COUT: JMK107BJ105KA, TAIYO YUDEN Analog Integrations Corporation Si-Soft Research Center DS-1848P-03 102406 3A1, No.1, Li-Hsin Rd. I , Science Park , Hsinchu 300, Taiwan , R.O.C. TEL: 886-3-5772500 FAX: 886-3-5772510 www.analog.com.tw 1 AIC1848 ORDERING INFORMATION AIC1848XXXX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL BG: BAG SOT-23-6 TOP VIEW C+ VIN 6 5 C4 BP50/BP50P PACKAGE TYPE G: SOT-23-6 1 2 3 VOUT GND SHDN C: COMMERCIAL P: LEAD FREE COMMERCIAL Note: Pin1 is determined by orienting the package marking as shown. Example: AIC1848CGTR in SOT-23-6 Package & Taping & Reel Packing Type AIC1848PGTR in Lead Free SOT-23-6 Package & Taping & Reel Packing Type SOT-23-6 Marking Part No. Marking Part No. Marking AIC1848CG BP50 AIC1848PG BP50P ABSOLUATE MAXIMUM RATINGS VIN to GND 6V VOUT to GND 6V All Other Pins to GND 6V VOUT Short-Circuit Duration Operating Temperature Range Maximum Junction Temperature Storage Temperature Range Lead Temperature (Soldering 10 Sec.) Continuous -40°C to 85 °C 125°C -65°C to 150 °C 260°C Thermal Resistance Junction to Case 130°C/W Thermal Resistance Junction to Ambient 220°C/W (Assume no Ambient Airflow, no Heatsink) Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. 2 AIC1848 TEST CIRCUIT VOUT VIN U1 CIN 1µF 1 VOUT 2 3 GND SHDN COUT 1µF C+ 6 5 VIN C- 4 CFLY 1µF AIC1848 ELECTRICAL CHARACTERISTICS (TA=25°C, CFLY=1µF, CIN=1µF, COUT=1µF, unless otherwise specified.) (Note 1) PARAMETER TEST CONDITIONS Input Voltage Output Voltage Supply Current 2.7V≤ VIN< 4.5V, IOUT≤ 40mA 3.1V≤ VIN≤ 4.5V, IOUT≤ 100mA 2.7V≤ VIN≤ 5.0V, IOUT=0 , SHDN =VIN 2.7V≤ VIN≤ 5.0V, SYMBOL MIN. VIN 2.7 4.8 TYP. 5 MAX. UNIT 4.5 V 5.2 VOUT V 4.8 5 5.2 1 3 5 mA I SHDN 0.01 1.0 µA ICC Shutdown Current IOUT=0 , SHDN =0V Efficiency VIN =2.7V , IOUT=30mA η 85 % Switching Frequency Oscillator Free Running fOSC 1.8 MHz Output Ripple VIN =3.7V, Cout = 2.2uF Iout= 60mA Cout = 1uF 30 mV 40 High VIH Low VIL SHDN =VIN IIH SHDN = 0V IIL Vout Turn On Time VIN =3V, IOUT = 1mA tON 50 µS Output Short Circuit Current VIN=3V, VOUT= 0V, SHDN = VIN ISC 300 mA Shutdown Input Threshold Shutdown Input Current 1.4 V 0.3 V -1 1 µA -1 1 µA Note 1: Specifications are production tested at TA=25°C. Specifications over the -40°C to 85°C operating temperature range are assured by design, characterization and correlation with Statistical Quality Controls (SQC). 3 AIC1848 TYPICAL PERFORMANCE CHARACTERISTICS 5.2 5.15 CIN= COUT=CFLY=1µF TA = -40°C TA=25°C TA =85°C Output Voltage (V) Output Voltage (V) 5.10 5.05 5.00 TA =25°C 4.95 IOUT=20mA 4.90 VIN=3.2V 5.1 VIN=3V 5.0 4.9 VIN=2.7V CIN=COUT=CFLY=1µF 4.85 4.8 2.7 3.0 3.3 3.6 3.9 4.2 0 4.5 50 Fig. 2 Fig. 1 Output Voltage vs. Supply Voltage 3.0 Oscillator Frequency (MHz) Supply Current (mA) 150 200 Output Voltage vs. Load Current 2.0 TA=25°C 2.5 TA=-40°C 2.0 TA=85°C 1.5 CIN= COUT=CFLY=1µF VSHDN=VIN 2.7 1.9 1.8 TA = -40°C 1.7 TA =25°C 1.6 TA =85°C 1.0 1.5 3.0 3.3 3.6 3.9 4.2 4.5 2.7 Supply Voltage (V) 3.6 3.9 4.2 4.5 800 Output Short Circuit Current (mA) 2.5 TA=-40°C TA=25°C 2.0 TA=85°C 1.5 1.0 CIN= COUT=CFLY=1µF TA=25°C VOUT=0V 600 400 200 3.0 3.3 3.6 3.9 4.2 4.5 2.7 Supply Voltage (V) Fig. 5 3.3 Fig. 4 Oscillator Frequency vs. Supply Voltage 3.0 2.7 3.0 Supply Voltage (V) Fig. 3 No Load Supply Current vs. Supply Voltage Shutdown Threshold Voltage (V) 100 Load Current (mA) Supply Voltage (V) VSHDN Threshold Voltage vs. Supply Voltage 3.0 3.3 3.6 3.9 4.2 4.5 Supply Voltage (V) Fig. 6 Short Circuit Current vs. Supply Voltage 4 AIC1848 TYPICAL PERFORMANCE CHARACTERISTICS (Continued) 90 90 Vin=2.7V Vin=2.7 80 Vin=3.4V Vin=3.7V 60 Vin=4.2V 50 40 CIN= COUT=1uF CFLY=1uF Vin=3.7V 60 Vin=4.2V 50 CIN= COUT=1uF CFLY=0.1uF 30 20 20 1 10 100 1000 1 10 100 1000 Load Current (mA) Load Current (mA) Fig.7 Efficiency vs. Load Current Fig.8 Efficiency vs. Load Current 140 80 CIN=COUT=1µF 120 VIN=4.2V CFLY=0.1µF Output Ripple Voltage (mV) Output Ripple Voltage (mV) Vin=3.4V 40 30 VIN=3.6V 100 80 VIN=3.0V 60 40 VIN=2.7V 20 0 Vin=3.0V 70 Efficiency (%) 70 Efficiency (%) 80 Vin=3.0V 0 50 100 150 200 250 VIN=3V 70 CFLY=0.1µF COUT=1uF 60 50 40 COUT=2.2uF 30 20 10 0 0 20 40 60 80 100 120 Output Current (mA) Output Current (mA) Fig. 9 Output Ripple Voltage vs. Output Current Fig. 10 Output Ripple Voltage vs. Output Current 5 AIC1848 BLOCK DIAGRAM VOUT 2 COUT 1µF C+ 1 VIN CFLY 2 Control 1µF CIN 1µF COMP CVREF SHDN 1 PIN DESCRIPTIONS PIN 1:VOUT - PIN 2: GND - Regulated output voltage. For the best performance, VOUT should be bypassed a 1µF (min.) low ESR capacitor with the shortest distance in between. Ground. Should be tied to ground plane direct for best performance. PIN 3: SHDN - Active low shutdown input. Tie to higher than 1.4V to enable device, 0.3V or less to disable device. SHDN pin is not allowed to float. PIN 4: C- - Flying capacitor negative terminal. PIN 5: VIN - Input supply voltage. VIN should be bypassed a 1µF (min.) low ESR capacitor with the shortest distance in between. PIN 6: C+ Flying capacitor positive terminal. - APPLICATION INFORMATION Introduction AIC1848 is a micropower charge pump DC/DC converter that produces a regulated 5V output charge pump switches. Operation with an input voltage range from 2.7V to 4.5V. It This kind of converter uses capacitors to store utilizes the charge pump topology to boost VIN to and transfer energy. Since the capacitors can’t a regulated output voltage. Regulation is obtained change to the voltage level abruptly, the voltage by sensing the output voltage through an internal ratio of VOUT to VIN is limited. Capacitive voltage resistor divider. A switched doubling circuit conversion is obtained by switching a capacitor enables the charge pump when the feedback periodically. Refer to Fig. 11, during the on state voltage is lower than the internal comparator point, of internal clock, Q1 and Q4 are closed, which and vice versa. When the charge pump is enabled, charges CFLY to VIN level. During the off state, Q3 a two-phase non-overlapping clock activates the and Q2 are closed. The output voltage is VIN plus 6 AIC1848 VCFLY, that is, 2VIN. VIN during on state and off state, respectively. Q2 VOUT Q1 CIN COUT CFLY Q3 Q4 D is the duty cycle, which means the proportion the on state takes. Let’s take advantage of conversation of charge for capacitor CFLY. Assume that the capacitor CFLY has reached its steady state. The amount of Fig. 11 The circuit of charge pump charge flowing into CFLY during on state is equal to that flowing out of CFLY at off state. Short Circuit/Thermal Protection ION− AVE × DT = IOFF − AVE × (1 − D)T (1) AIC1848 obtains built-in short circuit current ION- AVE × D = IOFF - AVE × (1 − D) (2) limiting and over temperature protection. During IIN = ION- AVE × D + IOFF- AVE × (1 − D) the short circuit condition, the output current is automatically constrained at = 2 × ION- AVE × D approximately (3) = 2 × IOFF- AVE × (1 - D) 300mA. Continued current limit will cause internal IC junction temperature increased. When the IOUT = IOFF- AVE × (1 − D) temperature of device exceeds 150°C, the IIN = 2 × IOUT thermal protection will shut the switching down (4) and the temperature will reduce afterwards. Once the temperature drops below 135°C, the charge For AIC1848, the controller takes the PWM (Pulse pump switching circuit will re-start. If the fault Width Modulation) control strategy. When the duty doesn’t eliminate, the above protecting operation cycle is limited to 0.5, there will be: will repeat again and again. It allows AIC1848 to ION- AVE × 0.5 × T = IOFF- AVE × (1 − 0.5) × T continuously work at short circuit condition without ION- AVE = IOFF- AVE damaging the device. Shutdown According to the equation (4), we know that as long as the flying capacitor CFLY is at steady state, In shutdown mode, the output is disconnected input current is double of output current. The from input. The input current gets extremely low efficiency of charge pump is given below: since most of the circuitry is turned off. Due to η = high impedance, shutdown pin can’t be floated. Efficiency VIN Refer to Fig. 12 and Fig. 13, they shows the circuit of charge pump at different operation states. RDS-ON is the resistance of the switching element VOUT × IOUT V ×I V = OUT OUT = OUT VIN × IIN VIN × 2IOUT 2VIN ION RDS-ON-Q1 CIN VOUT ESR Q2 COUT CFLY at conduction. ESR is the equivalent series resistance of the flying capacitor CFLY. ION-AVE and IOFF-AVE are the average current Q3 RDS-ON-Q4 Fig. 12 The on state of charge pump circuit 7 AIC1848 VIN RDS-ON-Q2 VOUT ESR COUT Q1 CIN CFLY is, the larger output current and smaller ripple voltage obtain. However, large CIN and COUT are required when large CFLY applies. The CFLY RDS-ON-Q3 IOFF CFLY is critical for the charge pump. The larger ratio of CIN (as well as COUT) to CFLY should be approximately 10:1. Q4 Fig. 13 The off state of charge pump circuit Layout Considerations External Capacitor Selection Three external capacitors, CIN, COUT and CFLY, Due to the switching frequency and high transient determine Optimum current of AIC1848, careful consideration of PCB performance can be obtained by using low ESR layout is necessary. To achieve the best ceramic capacitors. Due to high ESR, tantalum performance of AIC1848, minimize the distance and aluminum capacitors are not recommended between every for charge pump application. minimize every AIC1848 performances. two components connection length and also with a maximum trace width. Make sure each device To reduce noise and ripple, low ESR ceramic connects to immediate ground plane. Fig. 14 to capacitor is recommended for CIN and COUT. The Fig. 16 show the recommended layout. value of COUT determines the amount of output ripple voltage. An output capacitor with larger value results in smaller ripple. Fig. 14 Top layer Fig. 15 Bottom layer Fig. 16 Top-over layer 8 AIC1848 APPLICATION EXAMPLES VIN CIN 1µF 1 VOUT 2 CAP+ GND 3 U1 CAP- CAP+ 2 GND 0.1µF 6 CFLY2 0.1µF 5 VIN 3 SHDN U2 4 CFLY1 VOUT COUT 1µF AIC1848 1 VOUT VSHDN 5 VIN SHDN 6 CAP- 4 AIC1848 Fig. 17 Parallel Two AIC1848 to Obtain the Regulated 5V Output with large output current. 5Vout Vin 1 CIN 1µF U1 2 3 Enable VOUT C+ GND VIN SHDN COUT 1µF 6 5 CFLY 0.1µF 4 C- R1 27 R2 9.1 Q1 Si2302 AIC1848 Flash Control Fig. 18 Flash WLED Application 5Vout Vin Cin 1µF Enable 1 2 3 U1 VOUT C+ GND VIN SHDN C- Cout 1µF 6 5 4 CFLY1 0.1µF R1 27 R2 2.7 AIC1848 R3 Q1 Si2302 1k 1 2 3 U2 VOUT GND SHDN C+ VIN C- 6 5 4 CFLY2 0.1µF C1 0.1µF AIC1848 Flash R4 1M Fig. 19 Flash WLED Application with Parallel Two AIC1848 9 AIC1848 PHYSICAL DIMENSIONS (unit: mm) SOT-23-6 D A e e1 SEE VIEW B WITH PLATING c A A2 b SECTION A-A MILLIMETERS MIN. MAX. 0.95 1.45 A1 0.05 0.15 A2 0.90 1.30 b 0.30 0.50 c 0.08 0.22 D 2.80 3.00 E 2.60 3.00 E1 1.50 1.70 e 0.95 BSC e1 1.90 BSC L A1 BASE METAL SOT-23-6 0.30 0° 8° 0.25 θ 0.60 0.42 REF L1 GAUGE PLANE SEATING PLANE L L1 θ A A E E1 S Y M B O L VIEW B Note : 1. Refer to JEDEC MO-178AB. 2. Dimension "D" does not include mold flash, protrusions or gate burrs. Mold flash, protrusion or gate burrs shall not exceed 10 mil per side. 3. Dimension "E1" does not include inter-lead flash or protrusions. 4. Controlling dimension is millimeter, converted inch dimensions are not necessarily exact. Note: Information provided by AIC is believed to be accurate and reliable. However, we cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AIC product; nor for any infringement of patents or other rights of third parties that may result from its use. We reserve the right to change the circuitry and specifications without notice. Life Support Policy: AIC does not authorize any AIC product for use in life support devices and/or systems. Life support devices or systems are devices or systems which, (I) are intended for surgical implant into the body or (ii) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 10