MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 SC1517-5 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION FEATURES The SC1517-5 is pin compatible with LTC1517-5. This versatile charge pump produces a regulated 5V output from an input voltage ranging from 2.7V to 5V. The Extremely low operating current (typically 10µA with no load) prolongs battery usage time. The small device footprint and the low external parts count (one 0.1µF flying capacitor and two small bypass capacitors at VIN and VOUT) make the part ideally suited for compact circuit design. •= •= •= •= •= •= The SC1517-5 charge pump can be used for applications that require up to 20mA (3V < VIN < 5V) of output current, while providing a regulated 5V output voltage. During short circuit a current limit circuitry provides protection, while the thermal shutdown capability cycles VOUT to prevent device failure. The SC1517-5 is available in a 5 lead SOT-23 package. •= •= •= •= •= Ultra low power: ICC = 10µA typ Soft start / Short circuit Current limit Thermal protected 5V+4% Regulated output VIN Range: 2.7V to 5V Output current: 10mA (VIN > 2.7V) 20mA (VIN > 3V) No inductors Ultra small application circuit 800kHz switching frequency Surface mount packaging (5 pin SOT-23) All specifications rated over full temperature range (-40°C to 85°C) APPLICATIONS •= Cellular telephones •= Battery-operated equipment •= Local power supplies •= Handheld instruments •= PCMCIA supplies ORDERING INFORMATION (1) TYPICAL APPLICATION SCHEMATIC Device Package Temp. Range (TA) SC1517ISK-5.TR SOT-23-5 -40° to 85°C Notes: (1) Only available in tape and reel packaging. A reel contains 3000 devices C1 = CIN = = COUT Note : Ceramic capacitors used for improved performance, Low ESR Tantalum with ESR < 0.5 Ohms could also be used. 1 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 ABSOLUTE MAXIMUM RATINGS Parameter Symbol Maximum Units Input Supply Voltage Vin -0.3 to 6 V Output Supply Voltage Vout -0.3 to 6 V Power Dissipation Pd 391 mW Thermal Resistance θ JA 256 °C/W Operating Ambient Temperature Range TA -40 to +85 °C Operating Junction Temperature Range TJ -40 to +125 °C Storage Temperature Range TSTG -65 to +150 °C Lead Temperature (Soldering) 10 Sec TLEAD +300 °C ESD Rating (Human Body Model) ESD 2 kV ELECTRICAL CHARACTERISTICS Unless specified: TA = -40°C to 85°C, VIN = 2.7V to 5V, C1 = 0.1µF, CIN = 3.3µF, COUT = 6.8µF. Parameter Symbol Operating Input Voltage Output Voltage VOUT Ripple (pk-pk) (1)(2) (1)(2) Oscillator Frequency Typ Max Units 5 V 2.7V < VIN < 5V, IOUT < 10mA 4.8 5.0 5.2 V 3V < VIN < 5V, IOUT < 20mA 4.8 5.0 5.2 V 15 µA ICC 2.7V < VIN < 5V, IOUT = 0 10 VR VIN = 3V, IOUT = 20mA, COUT = 6.8µF 75 mVP-P 800 kHz 1 ms 65 mA fOSC (1)(2) tON VIN = 3V, IOUT = 0mA Soft start / Short circuit Current limit(1)(2)(3) Ilimit Short circuit applied at Vout to GND VOUT Turn-On Time Min 2.7 VIN VOUT Input Supply Current Conditions 35 NOTES: (1) All electrical characteristics are for the application circuit on page 1. (2) Guaranteed by design. (3) Indefinite duration. 2 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 BLOCK DIAGRAM PIN CONFIGURATION Top View SOT-23-5L PIN DESCRIPTION Pin # Pin Name Description 1 VIN Charge pump input voltage. May be between 2.7V and 5V. VIN should be bypassed with a >3.3µF low ESR capacitor as close as possible to the pin for best performance. 2 GND Ground pin. 3 VOUT Regulated output voltage. VOUT should be bypassed with a >3.3µF low ESR capacitor as close as possible to the pin for best performance. 4 C1+ Charge pump flying capacitor positive terminal. 5 C1- Charge pump flying capacitor negative terminal. 3 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 Typical Output ripple vs Vin ( Ta = 25 Deg. C.) Typical Eff. vs Iout (Ta = 25 Deg. C.) 100% 150.0E-3 90% 130.0E-3 70% 110.0E-3 Vout (V) Efficiency (%) 80% 60% 50% 40% 90.0E-3 70.0E-3 Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 30% 20% Iout = 10mA 10% 30.0E-3 2.50 0% 10.0E-6 100.0E-6 1.0E-3 Iout (A) 10.0E-3 Cout Cout Cout Cout 50.0E-3 100.0E-3 3.00 3.50 4.00 4.50 = = = = 3.3uF 6.8uF 10uF 22uF 5.00 5.50 Vin (V) Typical Eff. vs Vin (Ta = 25 Deg. C.) 100% 90% Efficiency (%) 80% 70% 60% 50% 40% Iout Iout Iout Iout Iout 30% 20% 10% 0% 2.50 3.00 = = = = = 20mA 10mA 5mA 200uA 10uA 3.50 4.00 4.50 5.00 5.50 Vin (V) Typical Iin vs Iout (Ta = 25 Deg. C.) 50.0E-3 45.0E-3 40.0E-3 Iin (A) 35.0E-3 30.0E-3 25.0E-3 20.0E-3 15.0E-3 Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 10.0E-3 5.0E-3 000.0E+0 000.0E+ 0 5.0E-3 10.0E-3 15.0E-3 20.0E-3 25.0E-3 Iout (A) 4 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 Typical Iin vs Ta (Iout = 0 A) Typical Eff. vs Ta (Iout = 5 mA) 100% 14.0E-6 90% 13.0E-6 Efficiency (%) 80% Iin (A) 12.0E-6 11.0E-6 10.0E-6 Vin = 5.00 V Vin = 3.85 V Vin = 2.75 V 9.0E-6 70% 60% 50% 40% 30% Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 20% 10% 8.0E-6 0% 0 10 20 30 40 50 60 70 0 10 20 Ta (Deg. C.) 50 60 70 100% 70% 90% 60% 80% 50% Efficiency (%) Efficiency (%) 40 Typical Eff. vs Ta (Iout = 10 mA) Typical Eff. vs Ta (Iout = 10 uA) 40% 30% 20% Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 10% 70% 60% 50% 40% 30% Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 20% 10% 0% 0% 0 10 20 30 40 50 60 0 70 10 20 Ta (Deg. C.) 100% 80% 90% 70% 80% Efficiency (%) 60% 50% 40% 30% Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 10% 40 50 60 70 Typical Eff. vs Ta (Iout = 20 mA) 90% 20% 30 Ta (Deg. C.) Typical Eff. vs Ta (Iout = 200 uA) Efficiency (%) 30 Ta (Deg. C.) 70% 60% 50% 40% 30% Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 20% 10% 0% 0% 0 10 20 30 40 Ta (Deg. C.) 50 60 70 0 10 20 30 40 50 60 70 Ta (Deg. C.) 5 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 Typical Vout vs Vin (Iout = 10mA) 5.00 Vout (V) 4.95 4.90 Ta = 70 Deg. C. Ta = 25 Deg. C. Ta = 0 Deg. C. 4.85 4.80 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Vin (V) 6 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 Vout 2V/div. Vin = 3V 2V/div. Turn on Regulation time(Ta = 25 Deg. C.) Vout 50mV/div. Iout Step 0 -10 ma Vin = 3.0V Load Transient Response(Ta = 25 Deg. C.) 7 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 APPLICATION NOTES THEORY OF OPERATION The SC1517-5 utilizes a switched capacitor charge pump, to generate an output voltage regulated to 5V+/4%. and disable the charge pump once an upper threshold is reached. As the output voltage drops below the lower threshold, the comparator enables the charge pump and hence regulation is achieved. SHORT CIRCUIT / SOFT START An internal current limit and soft start circuit provides protection against output short circuit and limits large current spikes generated during the initial start up to charge output capacitor. Current Limit & As the over current condition is applied at the output, a comparator senses the output voltage and compares it to a signal approximating VIN - 500mV. If VOUT < VIN - 500mV, the comparator enables a 65mA typical limited current source and the charge pump is disabled. Once the over current is removed and VOUT > VIN - 500mV, the current source is disconnected from output and the charge pump circuitry is enabled again. Soft Start An internal oscillator generates two out of phase clock signals which turn on and off internal MOSFET switches. During phase1 of clock, the flying charge Charge transfer from Cin to C_charge ON S1,S2 OFF ON S3,S4 OFF Charge transfer from (Cin,and C_charge) to Cout pump capacitor is charged to Vin through switches S1, and S2. During phase2 the flying charge pump capacitor is connected in series with the input voltage via S3, and S4, producing an output voltage. An integrated comparator senses the output voltage S1 C_charge The thermal shutdown circuit provides added protection to the SC1517-5. During a VOUT short circuit condition or if the load is excessive (IOUT > = 20mA), the thermal shut down circuit is active and if the junction temperature exceeds approximately 160°C, the charge pump is disabled. The charge pump is enabled only if the junction temperature drops to approximately 145°C. The SC1517-5 will cycle in and out of thermal shut down until the short circuit or the excessive load condition on VOUT is removed, thereby improving device reliability. VOUT RIPPLE & CAPACITOR SELECTION The peak to peak output ripple voltage is dependent on the following factors: 1- Oscillator Frequency 2- Hysteresis window of the comparator 3- ESR of CCharge , and Cout 4- Capacitance value of Cout , and CCharge S4 C1+ THERMAL SHUTDOWN Cout C1- Vout S3 Vin S2 Cin Item 1, and 2 are fixed and depend on the charge pump device used. Item 3, and 4 can be optimized for best performance and reduction of the output ripple. Gnd Gnd 8 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 The following formula could approximation for Vout_ripple. Vout_ripple = be used for an Iout + Iout x ESR_ C out 2 x Fosc x C out Capacitor Manufacturers Manufacturer Figure below shows the effect of output capacitance value on the ripple voltage. Capacitors used were multilayer ceramic with low ESR < 0.1 Ohms . Typical Output ripple vs Vin (Iout = 10mA) 150.0E-3 130.0E-3 Phone AVX Corp. (803)-448-9411 VISHAY (207)-324-4140 Nichicon Corp. (708)-843-7500 muRata (800)-831-9172 TOKIN (408)-432-8020 Taiyo Yuden (800)-348-2496 Sanyo (619)-661-6835 Vout (V) 110.0E-3 90.0E-3 70.0E-3 Cout = 3.3uF Cout = 6.8uF Cout = 10uF Cout = 22uF 50.0E-3 30.0E-3 2.50 3.00 3.50 4.00 4.50 5.00 LAYOUT CONSIDERATION 5.50 Vin (V) Following table shows typical capacitor characteristics : Component ESR (Ohms) 0.1 uF Ceramic 0603 package 0.100 1.60 1.0 uF Ceramic 1206 package 0.120 0.47 10 uF Ceramic 1206 package 0.075 0.5 47 uF, 16V Tantalum D case 0.100 0.60 330 uF, 6.3V “OSCON” 0.025 2.5 330 uF, 16V Al Electrolytic 0.143 2.37 820 uF, 4.0V “OSCON” 0.012 2.5 1000 uF, 10V Al Electrolytic 0.053 5 Standard power board layout should followed to ensure proper operation. Any stray inductance should be minimized, this can be achieved by using large power planes or traces, and reducing the distances between input, output and the load. All components should be placed as close as possible to the SC1517-5. ESL (nH) 9 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP SC1517-5 October 3, 2000 DEVICE OUTLINE SOT23-5L LAND PATTERN SOT23-5L ECN00-1360 10 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320