TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 features applications D Inverts Input Supply Voltage D Up to 60-mA Output Current D Only Three Small 1-µF Ceramic Capacitors D D D D D D Needed D Input Voltage Range From 1.6 V to 5.5 V D PowerSave-Mode for Improved Efficiency D D D D at Low Output Currents (TPS60400) Device Quiescent Current Typical 100 µA Integrated Active Schottky-Diode for Start-Up Into Load Small 5-Pin SOT23 Package Evaluation Module Available TPS60400EVM–178 LCD Bias GaAs Bias for RF Power Amps Sensor Supply in Portable Instruments Bipolar Amplifier Supply Medical Instruments Battery-Operated Equipment DBV PACKAGE (TOP VIEW) OUT 1 IN 2 CFLY– 3 5 CFLY+ 4 GND description The TPS6040x is a family of devices that generate an unregulated negative output voltage from an input voltage ranging from 1.6 V to 5.5 V. The devices are typically supplied by a preregulated supply rail of 5 V or 3.3 V. Due to its wide input voltage range, two or three NiCd, NiMH, or alkaline battery cells, as well as one Li-Ion cell can also power them. Only three external 1-µF capacitors are required to build a complete dc/dc charge pump inverter. Assembled in a 5-pin SOT23 package, the complete converter can be built on a 50 mm2 board area. Additional board area and component count reduction is achieved by replacing the Schottky diode that is typically needed for start-up into load by integrated circuitry. The TPS6040x can deliver a maximum output current of 60 mA with a typical conversion efficiency of greater than 90% over a wide output current range. Three device options with 20-kHz, 50-kHz, and 250-kHz fixed frequency operation are available. One device comes with a variable switching frequency to reduce operating current in applications with a wide load range and enables the design with low-value capacitors. typical application circuit TPS60400 C(fly) 1 µF CI 1 µF IO = 60 mA 5 CFLY– 2 0 TPS60400 IN OUT GND 4 IO = 30 mA –1 CFLY+ 1 CO 1 µF Output –1.6 V to –5 V, Max 60 mA V O – Output Voltage – V 3 Input 1.6 V to 5.5 V OUTPUT VOLTAGE vs INPUT VOLTAGE IO = 1 mA –2 –3 –4 TA = 25°C –5 0 1 2 3 4 VI – Input Voltage – V 5 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright 2001, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 AVAILABLE OPTIONS PART NUMBER† MARKING DBV PACKAGE TYPICAL FLYING CAPACITOR [µF] FEATURE TPS60400DBV PFKI 1 Variable switching frequency 50 kHz–250 kHz TPS60401DBV PFLI 10 Fixed frequency 20 kHz TPS60402DBV PFMI 3.3 Fixed frequency 50 kHz TPS60403DBV PFNI 1 Fixed frequency 250 kHz † The DBV package is available taped and reeled. Add R suffix to device type (e.g. TPS60400DBVR) to order quantities of 3000 devices per reel. Add T suffix to device type (e.g. TPS60400DBVT) to order quantities of 250 devices per reel. TPS60400 functional block diagram VI VI – VCFLY+ < 0.5 V VI MEAS VI < 1 V VO > Vbe R Start FF Q DC_ Startup VO Q1 OSC CHG OSC VO MEAS 50 kHz Q Phase Generator + Q Q2 VO Q4 C(fly) VO > –1 V VI VI S B Q3 Q5 GND VO VCO_CONT VI / VO MEAS DC_ Startup VO < –VI – Vbe Terminal Functions TERMINAL I/O DESCRIPTION NAME NO. CFLY+ 5 Positive terminal of the flying capacitor C(fly) CFLY– 3 Negative terminal of the flying capacitor C(fly) GND 4 IN 2 I Supply input. Connect to an input supply in the 1.6-V to 5.5-V range. Bypass IN to GND with a capacitor that has the same value as the flying capacitor. OUT 1 O Power output with VO = –VI Bypass OUT to GND with the output filter capacitor CO. 2 Ground POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 detailed description operating principle The TPS60400, TPS60401 charge pumps invert the voltage applied to their input. For the highest performance, use low equivalent series resistance (ESR) capacitors (e.g., ceramic). During the first half-cycle, switches S2 and S4 open, switches S1 and S3 close, and capacitor (C(fly)) charges to the voltage at VI. During the second half-cycle, S1 and S3 open, S2 and S4 close. This connects the positive terminal of C(fly) to GND and the negative to VO. By connecting C(fly) in parallel, CO is charged negative. The actual voltage at the output is more positive than –VI, since switches S1–S4 have resistance and the load drains charge from CO. VI S1 C(fly) S4 VO (–VI) 1 µF S2 CO 1 µF S3 GND GND Figure 1. Operating Principle charge-pump output resistance The TPS6040x devices are not voltage regulators. The charge pumps output source resistance is approximately 15 Ω at room temperature (with VI = 5 V), and VO approaches –5 V when lightly loaded. VO will droop toward GND as load current increases. VO = –(VI – RO × IO) R O [ ƒosc 1 C ǒ ) 4 2R SWITCH ) ESR (fly) RO = output resistance of the converter Ǔ ) ESRCO (1) CFLY efficiency considerations The power efficiency of a switched-capacitor voltage converter is affected by three factors: the internal losses in the converter IC, the resistive losses of the capacitors, and the conversion losses during charge transfer between the capacitors. The internal losses are associated with the IC’s internal functions, such as driving the switches, oscillator, etc. These losses are affected by operating conditions such as input voltage, temperature, and frequency. The next two losses are associated with the voltage converter circuit’s output resistance. Switch losses occur because of the on-resistance of the MOSFET switches in the IC. Charge-pump capacitor losses occur because of their ESR. The relationship between these losses and the output resistance is as follows: PCAPACITOR LOSSES + PCONVERSION LOSSES = IO2 × RO RSWITCH = resistance of a single MOSFET-switch inside the converter fOSC = oscillator frequency The first term is the effective resistance from an ideal switched-capacitor circuit. Conversion losses occur during the charge transfer between C(fly) and CO when there is a voltage difference between them. The power loss is: ƪ P CONV.LOSS + 1 2 ǒ Ǔ ǒ C (fly) V I2 * V O 2 ) 1 C O V RIPPLE2 * 2V OV RIPPLE 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 Ǔƫ ƒ osc (2) 3 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 efficiency considerations (continued) The efficiency of the TPS6040x devices is dominated by their quiescent supply current at low output current and by their output impedance at higher current. h^ IO IO ) IQ ǒ I 1* O RO VI Ǔ Where, IQ = quiescent current. capacitor selection To maintain the lowest output resistance, use capacitors with low ESR (see Table 1). The charge-pump output resistance is a function of C(fly)’s and CO’s ESR. Therefore, minimizing the charge-pump capacitor’s ESR minimizes the total output resistance. The capacitor values are closely linked to the required output current and the output noise and ripple requirements. It is possible to only use 1-µF capacitors of the same type. input capacitor (CI) Bypass the incoming supply to reduce its ac impedance and the impact of the TPS6040x switching noise. The recommended bypassing depends on the circuit configuration and where the load is connected. When the inverter is loaded from OUT to GND, current from the supply switches between 2 x IO and zero. Therefore, use a large bypass capacitor (e.g., equal to the value of C(fly)) if the supply has high ac impedance. When the inverter is loaded from IN to OUT, the circuit draws 2 × IO constantly, except for short switching spikes. A 0.1-µF bypass capacitor is sufficient. flying capacitor (C(fly)) Increasing the flying capacitor’s size reduces the output resistance. Small values increases the output resistance. Above a certain point, increasing C(fly)’s capacitance has a negligible effect, because the output resistance becomes dominated by the internal switch resistance and capacitor ESR. output capacitor (CO) Increasing the output capacitor’s size reduces the output ripple voltage. Decreasing its ESR reduces both output resistance and ripple. Smaller capacitance values can be used with light loads if higher output ripple can be tolerated. Use the following equation to calculate the peak-to-peak ripple. V O(ripple) + I f osc O Co )2 I O ESR CO Table 1. Recommended Capacitor Values 4 DEVICE VI [V] IO [mA] CI [µF] C(fly) [µF] CO [µF] TPS60400 1.8…5.5 60 1 1 1 TPS60401 1.8…5.5 60 10 10 10 TPS60402 1.8…5.5 60 3.3 3.3 3.3 TPS60403 1.8…5.5 60 1 1 1 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 detailed description (continued) Table 2. Recommended Capacitors MANUFACTURER PART NUMBER SIZE CAPACITANCE TYPE Taiyo Yuden EMK212BJ474MG LMK212BJ105KG LMK212BJ225MG EMK316BJ225KL LMK316BJ475KL JMK316BJ106KL 0805 0805 0805 1206 1206 1206 0.47 µF 1 µF 2.2 µF 2.2 µF 4.7 µF 10 µF Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic TDK C2012X5R1C105M C2012X5R1A225M C2012X5R1A335M 0805 0805 0805 1 µF 2.2 µF 3.3 µF Ceramic Ceramic Ceramic Table 3 contains a list of manufacturers of the recommended capacitors. Ceramic capacitors will provide the lowest output voltage ripple because they typically have the lowest ESR-rating. Table 3. Recommended Capacitor Manufacturers MANUFACTURER CAPACITOR TYPE INTERNET Taiyo Yuden X7R/X5R ceramic www.t-yuden.com TDK X7R/X5R ceramic www.component.tdk.com Vishay X7R/X5R ceramic www.vishay.com Kemet X7R/X5R ceramic www.kemet.com absolute maximum ratings over operating free-air temperature (unless otherwise noted)† Voltage range: IN to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 5.5 V OUT to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –5.0 V to 0.3 V CFLY– to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to (VO – 0.3 V) CFLY+ to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to (VI + 0.3 V) Continuous power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Dissipation Rating Table Continuous output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 mA Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to 150°C Maximum junction temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. DISSIPATION RATING TABLE PACKAGE TA < 25°C POWER RATING DERATING FACTOR ABOVE TA = 25°C TA = 70°C POWER RATING TA = 85°C POWER RATING DBV 437 mW 3.5 mW/°C 280 mW 227 mW POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 recommended operating conditions MIN Input voltage range, VI NOM 1.8 Output current range at OUT, IO MAX UNIT 5.25 V 60 Input capacitor, CI 0 Flying capacitor, C(fly) 1 Output capacitor, CO 1 Operating junction temperature, TJ –40 mA µF C(fly) µF 100 µF 125 °C electrical characteristics at CI = C(fly) = CO (according to Table 1), TC = –40°C to 85°C, VI = 5 V over recommended operating free-air temperature range (unless otherwise noted) PARAMETER VI Supply voltage range IO VO Maximum output current at VO TEST CONDITIONS At TC = –40°C to 85°C, At TC ≥ 0°C, 1.8 RL = 5 kΩ 1.6 Output voltage Output voltage ripple TPS60402 IO = 5 mA TPS60403 V mA C(fly) = CO = 10 µF 20 C(fly) = CO = 3.3 µF 20 C(fly) = CO = 1 µF 15 270 65 190 120 270 425 700 TPS60403 60°C At T ≤ 60°C, 135 VI = 5 V 210 TPS60403 TPS60400 6 A µA 640 VCO version 30 50–250 350 TPS60401 13 20 28 TPS60402 30 50 70 150 TPS60403 Impedance at 25°C 25°C, VI = 5 V µA A 210 TPS60400 TPS60402 Internal switching frequency mVP–P 125 TPS60401 fOSC V TPS60401 At VI = 5 V UNIT 5.25 TPS60400 TPS60402 Quiescent current (no-load in input ut current) MAX –VI 35 C(fly) = 1 µF, CO = 2.2 µF TPS60401 IQ RL = 5 kΩ TYP 60 TPS60400 VP–P MIN 250 300 TPS60400 CI = C(fly) = CO = 1 µF 12 15 TPS60401 CI = C(fly) = CO = 10 µF 12 15 TPS60402 CI = C(fly) = CO = 3.3 µF 12 15 TPS60403 CI = C(fly) = CO = 1 µF 12 15 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 kHz Ω TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 TYPICAL CHARACTERISTICS Table of Graphs FIGURE η Efficiency vs Output current at 3.3 V, 5 V TPS60400, TPS60401, TPS60402, TPS60403 2, 3 II Input current vs Output current TPS60400, TPS60401, TPS60402, TPS60403 4, 5 IS Supply current vs Input voltage TPS60400, TPS60401, TPS60402, TPS60403 6, 7 Output resistance vs Input voltage at –40°C, 0°C, 25°C, 85°C TPS60400, CI = C(fly) = CO = 1 µF TPS60401, CI = C(fly) = CO = 10 µF TPS60402 , CI = C(fly) = CO = 3.3 µF TPS60403, CI = C(fly) = CO = 1 µF 8, 9, 10, 11 VO Output voltage vs Output current at 25°C, VIN=1.8 V, 2.5 V, 3.3 V, 5 V TPS60400, CI = C(fly) = CO = 1 µF TPS60401, CI = C(fly) = CO = 10 µF TPS60402 , CI = C(fly) = CO = 3.3 µF TPS60403, CI = C(fly) = CO = 1 µF 12, 13, 14, 15 fOSC Oscillator frequency vs Temperature at VI = 1.8 V, 2.5 V, 3.3 V, 5 V TPS60400, TPS60401, TPS60402, TPS60403 16, 17, 18, 19 fOSC Oscillator frequency vs Output current TPS60400 at 2 V, 3.3 V, 5.0 V Output ripple and noise VI = 5 V, IO = 30 mA, CI = C(fly) = CO = 1 µF (TPS60400) VI = 5 V, IO = 30 mA, CI = C(fly) = CO = 10 µF (TPS60401) VI = 5 V, IO = 30 mA, CI = C(fly) = CO = 3.3 µF (TPS60402) VI = 5 V, IO = 30 mA, CI = C(fly) = CO = 1 µF (TPS60403) TPS60400, TPS60401 TPS60402, TPS60403 EFFICIENCY vs OUTPUT CURRENT EFFICIENCY vs OUTPUT CURRENT 100 100 TPS60400 VI = 5 V 95 TPS60403 VI = 5 V 95 TPS60401 VI = 5 V TPS60402 VI = 5 V 90 85 Efficiency – % 90 Efficiency – % 20 21, 22 TPS60401 VI = 3.3 V 80 75 TPS60400 VI = 3.3 V 70 85 80 TPS60403 VI = 3.3 V 75 TPS60402 VI = 3.3 V 70 65 65 TA = 25°C 60 TA = 25°C 60 0 10 20 30 40 50 60 70 80 IO – Output Current – mA 90 100 0 10 Figure 2 20 30 40 50 60 70 80 IO – Output Current – mA 90 100 Figure 3 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 TYPICAL CHARACTERISTICS TPS60400, TPS60401 INPUT CURRENT vs OUTPUT CURRENT TPS60402, TPS60403 INPUT CURRENT vs OUTPUT CURRENT 100 100 TA = 25°C TPS60400 VI = 5 V I I – Input Current – mA I I – Input Current – mA TA = 25°C 10 TPS60401 VI = 5 V TPS60401 VI = 2 V 1 TPS60403 VI = 5 V 10 TPS60403 VI = 2 V 1 TPS60402 VI = 5 V TPS60400 VI = 2 V 0.1 0.1 TPS60402 VI = 2 V 1 10 IO – Output Current – mA 0.1 0.1 100 1 10 IO – Output Current – mA Figure 4 Figure 5 TPS60400, TPS60401 TPS60402, TPS60403 SUPPLY CURRENT vs INPUT VOLTAGE SUPPLY CURRENT vs INPUT VOLTAGE 0.6 0.6 IO = 0 mA TA = 25°C I DD – Supply Current – mA IO = 0 mA TA = 25°C I DD – Supply Current – mA 100 0.4 0.2 0.4 TPS60403 0.2 TPS60400 TPS60402 TPS60401 0 0 1 2 3 VI – Input Voltage – V 4 0 5 0 Figure 6 8 1 2 3 VI – Input Voltage – V Figure 7 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 4 5 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 TYPICAL CHARACTERISTICS TPS60400 TPS60401 OUTPUT RESISTANCE vs INPUT VOLTAGE OUTPUT RESISTANCE vs INPUT VOLTAGE 40 40 IO = 30 mA CI = C(fly) = CO = 1 µF 30 30 ro – Output Resistance – Ω ro – Output Resistance – Ω 35 IO = 30 mA CI = C(fly) = CO = 10 µF 35 25 TA = 85°C 20 TA = 25°C 15 10 25 20 TA = 25°C 15 10 5 5 TA = –40°C TA = –40°C 0 0 1 2 3 4 VI – Input Voltage – V 5 6 1 2 3 4 VI – Input Voltage – V Figure 8 5 6 Figure 9 TPS60402 TPS60403 OUTPUT RESISTANCE vs INPUT VOLTAGE OUTPUT RESISTANCE vs INPUT VOLTAGE 40 40 IO = 30 mA CI = C(fly) = CO = 3.3 µF 30 25 TA = 25°C 20 TA = 85°C 15 10 TA = –40°C 5 IO = 30 mA CI = C(fly) = CO = 1 µF 35 ro – Output Resistance – Ω 35 ro – Output Resistance – Ω TA = 85°C 30 25 20 TA = 25°C TA = 85°C 15 10 5 0 TA = –40°C 0 1 2 3 4 VI – Input Voltage – V 5 6 1 Figure 10 2 3 4 VI – Input Voltage – V 5 6 Figure 11 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 TYPICAL CHARACTERISTICS TPS60400 TPS60401 OUTPUT VOLTAGE vs OUTPUT CURRENT OUTPUT VOLTAGE vs OUTPUT CURRENT 0 0 TA = 25°C –1 VI = 1.8 V VI = 1.8 V VO – Output Voltage – V VO – Output Voltage – V –1 TA = 25°C VI = 2.5 V –2 –3 VI = 3.3 V –4 VI = 5 V –5 –6 VI = 2.5 V –2 VI = 3.3 V –3 –4 VI = 5 V –5 0 10 20 30 40 50 –6 60 0 10 IO – Output Current – mA 20 Figure 12 TPS60402 TPS60403 OUTPUT VOLTAGE vs OUTPUT CURRENT OUTPUT VOLTAGE vs OUTPUT CURRENT 60 50 60 TA = 25°C –1 –1 VI = 1.8 V VO – Output Voltage – V VI = 1.8 V VO – Output Voltage – V 50 0 TA = 25°C VI = 2.5 V –2 VI = 3.3 V –3 –4 VI = 5 V VI = 2.5 V –2 VI = 3.3 V –3 –4 VI = 5 V –5 –5 –6 0 10 20 30 40 50 60 0 10 20 30 Figure 14 Figure 15 POST OFFICE BOX 655303 40 IO – Output Current – mA IO – Output Current – mA 10 40 Figure 13 0 –6 30 IO – Output Current – mA • DALLAS, TEXAS 75265 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 TYPICAL CHARACTERISTICS TPS60400 TPS60401 OSCILLATOR FREQUENCY vs FREE-AIR TEMPERATURE OSCILLATOR FREQUENCY vs FREE-AIR TEMPERATURE 24 250 23.8 VI = 1.8 V 200 150 VI = 2.5 V VI = 3.3 V 100 VI = 5 V 50 f osc– Oscillator Frequency – kHz f osc– Oscillator Frequency – kHz IO = 10 mA IO = 10 mA 23.6 VI = 3.3 V 23.4 VI = 5 V 23.2 23 VI = 2.5 V 22.8 22.6 VI = 1.8 V 22.4 22.2 0 –40 –30 –20 –10 0 22 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90 TA – Free-Air Temperature – °C Figure 16 Figure 17 TPS60402 TPS60403 OSCILLATOR FREQUENCY vs FREE-AIR TEMPERATURE OSCILLATOR FREQUENCY vs FREE-AIR TEMPERATURE 250 57 IO = 10 mA VI = 5 V 240 VI = 5 V VI = 3.3 V 55 54 VI = 2.5 V 53 52 VI = 1.8 V 51 50 f osc– Oscillator Frequency – kHz 56 f osc– Oscillator Frequency – kHz 10 20 30 40 50 60 70 80 90 TA – Free-Air Temperature – °C VI = 3.3 V 230 VI = 2.5 V 220 210 VI = 1.8 V 200 190 180 170 IO = 10 mA 160 49 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90 150 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90 TA – Free-Air Temperature – °C TA – Free-Air Temperature – °C Figure 18 Figure 19 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 11 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 TYPICAL CHARACTERISTICS TPS60400 TPS60401, TPS60402 OSCILLATOR FREQUENCY vs OUTPUT CURRENT OUTPUT VOLTAGE vs TIME 300 VI = 5 V IO = 30 mA TPS60401 VI = 3.3 V 250 VI = 1.8 V VO – Output Voltage – mV f osc– Oscillator Frequency – kHz TA = 25°C 200 VI = 5 V 150 100 50 mV/DIV TPS60402 50 50 mV/DIV 0 0 10 20 30 40 50 60 70 80 90 100 20 µs/DIV t – Time – µs IO – Output Current – mA Figure 20 Figure 21 TPS60400, TPS60403 OUTPUT VOLTAGE vs TIME VO – Output Voltage – mV VI = 5 V IO = 30 mA TPS60400 100 mV/DIV TPS60403 50 mV/DIV 4 µs/DIV t – Time – µs Figure 22 12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION voltage inverter The most common application for these devices is a charge-pump voltage inverter (see Figure 23). This application requires only two external components; capacitors C(fly) and CO, plus a bypass capacitor, if necessary. Refer to the capacitor selection section for suggested capacitor types. C(fly) 2 Input 5 V CI 1 µF 1 µF 3 5 C1– C1+ TPS60400 IN OUT GND 4 1 CO 1 µF –5 V, Max 60 mA Figure 23. Typical Operating Circuit For the maximum output current and best performance, three ceramic capacitors of 1 µF (TPS60400, TPS60403) are recommended. For lower currents or higher allowed output voltage ripple, other capacitors can also be used. It is recommended that the output capacitors has a minimum value of 1 µF. With flying capacitors lower than 1 µF, the maximum output power will decrease. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION RC-post filter VI C(fly) 1 2 3 1 µF OUT C1+ TPS60400 IN C1– GND 5 RP 4 VO (–VI) CI 1 µF CO 1 µF CP GND GND Figure 24. TPS60400 and TPS60401 With RC-Post Filter An output filter can easily be formed with a resistor (RP) and a capacitor (CP). Cutoff frequency is given by: ƒc + 1 2pR PC P (1) and ratio VO/VOUT is: Ť Ť VO V OUT + 1 Ǹ1 ) ǒ2pƒR C Ǔ (2) 2 P P with RP = 50 Ω, CP = 0.1 µF and f = 250 kHz: Ť Ť VO V OUT + 0.125 The formula refers only to the relation between output and input of the ac ripple voltages of the filter. LC-post filter VI C(fly) 1 2 3 1 µF OUT C1+ TPS60400 IN C1– GND 5 VOUT LP 4 CI 1 µF VO (–VI) CO 1 µF GND CP GND Figure 25. LC-Post Filter Figure 25 shows a configuration with a LC-post filter to further reduce output ripple and noise. 14 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION Table 4. Measurement Results on the TPS60400 (Typical) CI [µF] C(fly) [µF] CO [µF] CERAMIC CERAMIC CERAMIC 1 1 60 1 5 60 5 60 5 5 CP [µF] BW = 500 MHz VPOUT VP–P[mV] BW = 20 MHz VPOUT VP–P[mV] VPOUT VACeff [mV] 1 320 240 65 1 2.2 120 240 32 1 1 1 0.1 (X7R) 260 200 58 1 1 1 0.1 0.1 (X7R) 220 200 60 60 1 1 2.2 0.1 0.1 (X7R) 120 100 30 60 1 1 10 0.1 0.1 (X7R) 50 28 8 VI [V] IO(2) ( ) [mA] 5 60 5 LP [µH] CERAMIC rail splitter VI C(fly) 1 2 3 1 µF OUT C1+ TPS60400 IN C1– GND CI 1 µF 5 C3 1 µF VO (–VI) 4 CO 1 µF GND GND Figure 26. TPS60400 as a High-Efficiency Rail Splitter A switched-capacitor voltage inverter can be configured as a high efficiency rail-splitter. This circuit provides a bipolar power supply that is useful in battery powered systems to supply dual-rail ICs, like operational amplifiers. Moreover, the SOT23-5 package and associated components require very little board space. After power is applied, the flying capacitor (C(fly)) connects alternately across the output capacitors C3 and CO. This equalizes the voltage on those capacitors and draws current from VI to VO as required to maintain the output at 1/2 VI. The maximum input voltage between VI and GND in the schematic (or between IN and OUT at the device itself) must not exceed 6.5 V. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 15 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION combined doubler/inverter In the circuit of Figure 27, capacitors CI, C(fly), and CO form the inverter, while C1 and C2 form the doubler. C1 and C(fly) are the flying capacitors; CO and C2 are the output capacitors. Because both the inverter and doubler use part of the charge-pump circuit, loading either output causes both outputs to decline toward GND. Make sure the sum of the currents drawn from the two outputs does not exceed 60 mA. The maximum output current at V(pos) must not exceed 30 mA. If the negative output is loaded, this current must be further reduced. II ≈ –IO + 2 × IO(POS) VI C(fly) 1 2 3 + 1 µF + C1 OUT C1+ TPS60400 IN C1– D2 5 V(pos) + –VI 4 GND CI 1 µF + + CO 1 µF C2 GND GND Figure 27. TPS60400 as Doubler/Inverter cascading devices Two devices can be cascaded to produce an even larger negative voltage (see Figure 28). The unloaded output voltage is normally –2 × VI, but this is reduced slightly by the output resistance of the first device multiplied by the quiescent current of the second. When cascading more than two devices, the output resistance rises dramatically. VI VO (–2 VI) C(fly) 1 2 3 + CI 1 µF 1 µF C(fly) OUT C1+ TPS60400 IN C1– GND 1 5 2 4 3 + 1 µF OUT C1+ TPS60400 IN C1– GND CO 1 µF 4 + GND CO 1 µF GND GND Figure 28. Doubling Inverter 16 5 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION paralleling devices Paralleling multiple TPS6040xs reduces the output resistance. Each device requires its own flying capacitor (C(fly)), but the output capacitor (CO) serves all devices (see Figure 29). Increase CO’s value by a factor of n, where n is the number of parallel devices. Equation 1 shows the equation for calculating output resistance. VI C(fly) 1 2 3 1 µF OUT C1+ TPS60400 IN C1– GND C(fly) 5 1 2 4 3 1 µF OUT C1+ TPS60400 IN C1– GND 5 VO (–VI) 4 CI 1 µF + GND CO 2.2 µF GND Figure 29. Paralleling Devices active-Schottky diode For a short period of time, when the input voltage is applied, but the inverter is not yet working, the output capacitor is charged positive by the load. To prevent the output being pulled above GND, a Schottky diode must be added in parallel to the output. The function of this diode is integrated into the TPS6040x devices, which gives a defined startup performance and saves board space. A current sink and a diode in series can approximate the behavior of a typical, modern operational amplifier. Figure 30 shows the current into this typical load at a given voltage. The TPS6040x devices are optimized to start into these loads. VI C(fly) 5 1 µF C1+ +V Load Current Typical Load 3 –V C1– 60 mA TPS60400 2 CI 1 µF GND OUT VO (–VI) 1 IO IN 0.4 V 25 mA CO 1 µF GND 4 0.4 V 1.25 V Figure 30. Typical Load POST OFFICE BOX 655303 5V Voltage at the Load Figure 31. Maximum Start-Up Current • DALLAS, TEXAS 75265 17 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION shutting down the TPS6040x If shutdown is necessary, use the circuit in Figure 32. The output resistance of the TPS6040x will typically be 15 Ω plus two times the output resistance of the buffer. Connecting multiple buffers in parallel can reduce the output resistance of the buffer driving the IN pin. VI C(fly) 1 2 SDN 3 VO (–VI) 1 µF OUT C1+ TPS60400 IN C1– GND 5 CO 1 µF 4 CI 1 µF GND GND Figure 32. Shutdown Control GaAs supply A solution for a –2.7-V/3-mA GaAs bias supply is proposed in Figure 33. The input voltage of 3.3 V is first inverted with a TPS60403 and stabilized using a TLV431 low-voltage shunt regulator. Resistor RP with capacitor CP is used for filtering the output voltage. RP VI (3.3 V) C(fly) VO (–2.7 V/3 mA) 0.1 µF R2 1 2 3 OUT C1+ TPS60400 IN C1– GND 5 CO 1 µF CP TLV431 R1 4 CI 0.1 µF GND GND Figure 33. GaAs Supply ǒ V O + * 1 ) R1 R2 Ǔ V ref * R1 I I(ref) A 0.1-µF capacitor was selected for C(fly). By this, the output resistance of the inverter is about 52 Ω. 18 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION GaAs supply (continued) RPMAX can be calculated using the following equation: R PMAX + ǒ V CO * V O IO * RO Ǔ With: VCO = –3.3 V; VO = –2.7 V; IO = –3 mA RPMAX = 200 Ω – 52 Ω = 148 Ω A 100-Ω resistor was selected for RP. The reference voltage across R2 is 1.24 V typical. With 5-µA current for the voltage divider, R2 gets: R2 + 1.24 V [ 250 kW 5 mA R1 + 2.7 * 1.24 V [ 300 kW 5 mA With CP = 1 µF the ratio VO/VI of the RC post filter is: Ť Ť VO VI + 1 Ǹ1 ) (2p125000Hz 100W 1 mF) 2 [ 0.01 step-down charge pump By exchanging GND with OUT (connecting the GND pin with OUT and the OUT pin with GND), a step-down charge pump can easily be formed. In the first cycle S1 and S3 are closed, and C(fly) with CO in series are charged. Assuming the same capacitance, the voltage across C(fly) and CO is split equally between the capacitors. In the second cycle, S2 and S4 close and both capacitors with VI/2 across are connected in parallel. VI C(fly) VI S1 1 C(fly) + S4 GND 2 1 µF S2 CO 1 µF S3 VO (VI/2) VO (VI/2) Figure 34. Step-Down Principle 3 CI 1 µF GND 1 µF OUT C1+ TPS60400 IN C1– GND 5 4 VO (VI/2) CO 1 µF GND Figure 35. Step-Down Charge Pump Connection The maximum input voltage between VI and GND in the schematic (or between IN and OUT at the device itself) must not exceed 6.5 V. For input voltages in the range of 6.5 V to 11 V, an additional Zener-diode is recommended (see Figure 36). POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 19 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION 5V6 VI C(fly) 1 µF 1 OUT 2 3 C1+ 5 TPS60400 IN C1– GND 4 CI 1 µF VO – VI CO 1 µF GND GND Figure 36. power dissipation As given in the data sheet, the thermal resistance of the unsoldered package is RθJA = 347°C/W. Soldered on the EVM, a typical thermal resistance of RθJA(EVM) = 180°C/W was measured. The terminal resistance can be calculated using the following equation: R T *T A + J qJA P D Where: TJ is the junction temperature. TA is the ambient temperature. PD is the power that needs to be dissipated by the device. R T *T A + J qJA P D The maximum power dissipation can be calculated using the following equation: PD = VI × II – VO × IO = VI(max) × (IO + I(SUPPLY)) – VO × IO The maximum power dissipation happens with maximum input voltage and maximum output current. At maximum load the supply current is 0.7 mA maximum. PD = 5 V × (60 mA + 0.7 mA) – 4.4 V × 60 mA = 40 mW With this maximum rating and the thermal resistance of the device on the EVM, the maximum temperature rise above ambient temperature can be calculated using the following equation: ∆TJ = RθJA × PD = 180°C/W × 40 mW = 7.2°C This means that the internal dissipation increases TJ by <10°C. The junction temperature of the device shall not exceed 125°C. This means the IC can easily be used at ambient temperatures up to: TA = TJ(max) – ∆TJ = 125°C/W – 10°C = 115°C 20 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 APPLICATION INFORMATION layout and board space All capacitors should be soldered as close as possible to the IC. A PCB layout proposal for a single-layer board is shown in Figure 37. Care has been taken to connect all capacitors as close as possible to the circuit to achieve optimized output voltage ripple performance. CFLY IN CIN COUT OUT GND U1 TPS60400 Figure 37. Recommended PCB Layout for TPS6040x (top layer) device family products Other inverting dc-dc converters from Texas Instruments are listed in Table 5. Table 5. Product Identification PART NUMBER DESCRIPTION TPS6735 Fixed negative 5-V, 200-mA inverting dc-dc converter TPS6755 Adjustable 1-W inverting dc-dc converter POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 21 TPS60400, TPS60401, TPS60402, TPS60403 UNREGULATED 60-mA CHARGE PUMP VOLTAGE INVERTER SLVS324 – JULY 2001 MECHANICAL DATA DBV (R-PDSO-G5) PLASTIC SMALL-OUTLINE 0,50 0,30 0,95 5 0,20 M 4 1,70 1,50 1 0,15 NOM 3,00 2,60 3 Gage Plane 3,00 2,80 0,25 0°–8° 0,55 0,35 Seating Plane 1,45 0,95 0,05 MIN 0,10 4073253-4/F 10/00 NOTES: A. B. C. D. 22 All linear dimensions are in millimeters. This drawing is subject to change without notice. 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