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| MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 SC1517-5 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION 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 10A with no load) prolongs battery usage time. The small device footprint and the low external parts count (one 0.1F 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. FEATURES *= *= *= *= *= *= *= *= *= *= *= Ultra low power: ICC = 10A 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 (-40C to 85C) APPLICATIONS *= Cellular telephones *= Battery-operated equipment *= Local power supplies *= Handheld instruments *= PCMCIA supplies ORDERING INFORMATION Device (1) Package SOT-23-5 Temp. Range (TA) -40 to 85C SC1517ISK-5.TR TYPICAL APPLICATION SCHEMATIC C1 = Notes: (1) Only available in tape and reel packaging. A reel contains 3000 devices CIN = = COUT Note : Ceramic capacitors used for improved performance, Low ESR Tantalum with ESR < 0.5 Ohms could also be used. 1 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 SC1517-5 ABSOLUTE MAXIMUM RATINGS Parameter Input Supply Voltage Output Supply Voltage Power Dissipation Thermal Resistance Operating Ambient Temperature Range Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering) 10 Sec ESD Rating (Human Body Model) Symbol Vin Vout Pd JA TA TJ TSTG TLEAD ESD Maximum -0.3 to 6 -0.3 to 6 391 256 -40 to +85 -40 to +125 -65 to +150 +300 2 Units V V mW C/W C C C C kV ELECTRICAL CHARACTERISTICS Unless specified: TA = -40C to 85C, VIN = 2.7V to 5V, C1 = 0.1F, CIN = 3.3F, COUT = 6.8F. Parameter Operating Input Voltage Output Voltage Symbol VIN VOUT ICC VR fOSC tON Ilimit VIN = 3V, IOUT = 0mA Short circuit applied at Vout to GND 35 (1)(2) Conditions Min 2.7 Typ Max 5 Units V V V A mVP-P kHz ms mA 2.7V < VIN < 5V, IOUT < 10mA 3V < VIN < 5V, IOUT < 20mA 2.7V < VIN < 5V, IOUT = 0 VIN = 3V, IOUT = 20mA, COUT = 6.8F 4.8 4.8 5.0 5.0 10 75 800 1 65 5.2 5.2 15 Input Supply Current VOUT Ripple (pk-pk) (1)(2) Oscillator Frequency VOUT Turn-On Time (1)(2) Soft start / Short circuit Current limit(1)(2)(3) NOTES: (1) All electrical characteristics are for the application circuit on page 1. (2) Guaranteed by design. (3) Indefinite duration. 2 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 SC1517-5 BLOCK DIAGRAM PIN CONFIGURATION Top View SOT-23-5L PIN DESCRIPTION Pin # 1 Pin Name VIN Description Charge pump input voltage. May be between 2.7V and 5V. VIN should be bypassed with a >3.3F low ESR capacitor as close as possible to the pin for best performance. Ground pin. Regulated output voltage. VOUT should be bypassed with a >3.3F low ESR capacitor as close as possible to the pin for best performance. Charge pump flying capacitor positive terminal. Charge pump flying capacitor negative terminal. 2 3 4 5 GND VOUT C1+ C1- 3 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 SC1517-5 Typical Eff. vs Iout (Ta = 25 Deg. C.) 100% 90% 80% Efficiency (%) 70% 60% 50% 40% 30% 20% 10% 0% 10.0E-6 100.0E-6 1.0E-3 Iout (A) 10.0E-3 100.0E-3 Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V Vout (V) Typical Output ripple vs Vin ( Ta = 25 Deg. C.) 150.0E-3 130.0E-3 110.0E-3 90.0E-3 70.0E-3 50.0E-3 Iout = 10mA Cout Cout Cout Cout 4.00 4.50 = = = = 3.3uF 6.8uF 10uF 22uF 5.50 30.0E-3 2.50 3.00 3.50 5.00 Vin (V) Typical Eff. vs Vin (Ta = 25 Deg. C.) 100% 90% 80% Efficiency (%) 70% 60% 50% 40% 30% 20% 10% 0% 2.50 Iout Iout Iout Iout Iout 3.00 = = = = = 20mA 10mA 5mA 200uA 10uA 3.50 4.00 Vin (V) 4.50 5.00 5.50 Typical Iin vs Iout (Ta = 25 Deg. C.) 50.0E-3 45.0E-3 40.0E-3 35.0E-3 Iin (A) 30.0E-3 25.0E-3 20.0E-3 15.0E-3 10.0E-3 5.0E-3 000.0E+0 000.0E+ 0 5.0E-3 10.0E-3 15.0E-3 Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 20.0E-3 25.0E-3 Iout (A) 4 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 Typical Iin vs Ta (Iout = 0 A) Typical Eff. vs Ta (Iout = 5 mA) SC1517-5 14.0E-6 13.0E-6 12.0E-6 Iin (A) Efficiency (%) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 0 10 20 30 40 50 60 70 11.0E-6 10.0E-6 9.0E-6 8.0E-6 0 10 20 30 40 50 60 70 Ta (Deg. C.) Vin = 5.00 V Vin = 3.85 V Vin = 2.75 V Ta (Deg. C.) Typical Eff. vs Ta (Iout = 10 uA) Typical Eff. vs Ta (Iout = 10 mA) 70% 60% Efficiency (%) 100% 90% 80% Efficiency (%) 50% 40% 30% 20% 10% 0% 0 10 20 30 40 50 60 70 Ta (Deg. C.) 70% 60% 50% 40% 30% 20% 10% 0% 0 10 20 30 40 50 60 70 Ta (Deg. C.) Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V Typical Eff. vs Ta (Iout = 200 uA) Typical Eff. vs Ta (Iout = 20 mA) 90% 80% 70% Efficiency (%) Efficiency (%) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V 0 10 20 30 40 50 60 70 60% 50% 40% 30% 20% 10% 0% 0 10 20 30 40 50 60 70 Ta (Deg. C.) Vin = 2.75 V Vin = 3.85 V Vin = 5.00 V Ta (Deg. C.) 5 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 Typical Vout vs Vin (Iout = 10mA) SC1517-5 5.00 4.95 Vout (V) 4.90 4.85 Ta = 70 Deg. C. Ta = 25 Deg. C. Ta = 0 Deg. C. 3.00 3.50 4.00 Vin (V) 4.80 2.50 4.50 5.00 5.50 6 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 SC1517-5 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 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 SC1517-5 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 & Soft Start 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. 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 THERMAL SHUTDOWN 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 160C, the charge pump is disabled. The charge pump is enabled only if the junction temperature drops to approximately 145C. 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. 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 S4 C_charge Cout 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 C1+ C1- Vout S3 Vin Gnd Cin S2 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 8 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 The following formula could approximation for Vout_ripple. be used for an Capacitor Manufacturers SC1517-5 Vout_ripple = Iout + Iout x ESR_ C out 2 x Fosc x C out Manufacturer AVX Corp. VISHAY Nichicon Corp. Phone (803)-448-9411 (207)-324-4140 (708)-843-7500 (800)-831-9172 (408)-432-8020 (800)-348-2496 (619)-661-6835 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-3 110.0E-3 Vout (V) muRata TOKIN Taiyo Yuden Sanyo 90.0E-3 70.0E-3 50.0E-3 30.0E-3 2.50 Cout = 3.3uF Cout = 6.8uF Cout = 10uF Cout = 22uF 3.00 3.50 4.00 Vin (V) LAYOUT CONSIDERATION 5.50 4.50 5.00 Following table shows typical capacitor characteristics : 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. Component 0.1 uF Ceramic 0603 package 1.0 uF Ceramic 1206 package 10 uF Ceramic 1206 package 47 uF, 16V Tantalum D case 330 uF, 6.3V "OSCON" 330 uF, 16V Al Electrolytic 820 uF, 4.0V "OSCON" 1000 uF, 10V Al Electrolytic ESR (Ohms) 0.100 0.120 0.075 0.100 0.025 0.143 0.012 0.053 ESL (nH) 1.60 0.47 0.5 0.60 2.5 2.37 2.5 5 9 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 MICROPOWER, REGULATED 5V CHARGE PUMP October 3, 2000 SC1517-5 DEVICE OUTLINE SOT23-5L LAND PATTERN SOT23-5L ECN00-1360 10 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 |
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