TK715xxAS LOW DROPOUT VOLTAGE REGULATOR FEATURES n n n n n n n n APPLICATIONS High Voltage Precision at 2.0% or 60 mV Very Low Quiescent Current Very Low Dropout Voltage Reverse Voltage Protection Miniature Package (SOT23-3) Short Circuit Protection High Ripple Rejection Can use Multilayer Ceramic Capacitors n n n n n n n n n Battery Powered Systems Cellular Telephones Pagers Personal Communications Equipment Portable Instrumentation Portable Consumer Equipment Radio Control Systems Toys Low Voltage Systems DESCRIPTION The TK715xx is a low dropout linear regulator housed in a small SOT23-3 package, rated at 400 mW. An internal PNP transistor is used to achieve a low dropout voltage of 105 mV (typ.) at 50 mA load current. This device offers high precision output voltage of 2.0 % or 60 mV. The TK715xx has a very low quiescent current of 25 A (typ.) at no load. The low quiescent current and dropout voltage make this part ideal for battery powered applications. The internal reverse bias protection eliminates the requirement for a reverse voltage protection diode, saving cost and board space. The high 60 dB ripple rejection and low noise provide enhanced performance for critical applications. TK715xxAS VOUT VIN 30T 20P GND ORDERING INFORMATION TK715 ASCL Tape/ Reel Code Temp. Code Package Code Voltage Code VOLTAGE CODE TEMPERATURE CODE TAPE/REEL CODE 15 = 1.5 V 16 = 1.6 V 17 = 1.7 V 18 = 1.8 V 19 = 1.9 V 20 = 2.0 V 21 = 2.1 V 22 = 2.2 V 23 = 2.3 V 24 = 2.4 V 25 = 2.5 V 26 = 2.6 V 27 = 2.7 V 28 = 2.8 V 29 = 2.9 V 30 = 3.0 V 31 = 3.1 V 32 = 3.2 V 33 = 3.3 V 34 = 3.4 V C -30 to +80 C L: Tape Left 35 = 3.5 V 36 = 3.6 V 37 = 3.7 V 38 = 3.8 V 39 = 3.9 V 40 = 4.0 V 41 = 4.1 V 42 = 4.2 V 43 = 4.3 V 44 = 4.4 V 45 = 4.5 V 46 = 4.6 V 47 = 4.7 V 48 = 4.8 V 49 = 4.9 V 50 = 5.0 V 60 = 6.0 V 70 = 7.0 V 80 = 8.0 V 90 = 9.0 V BLOCK DIAGRAM VIN PACKAGE CODE S : SOT-23-3 March 2001 TOKO, Inc. VOUT THERMAL PROTECTION + + BANDGAP REFERENCE GND Page 1 TK715xxAS ABSOLUTE MAXIMUM RATINGS (VOUT 5.0 V) Supply Voltage ............................................. -0.4 to 19 V Power Dissipation (Note 1) ................................ 400 mW Reverse Bias ............................................................. 8 V Short Circuit Current ........................................... 170 mA Storage Temperature (Ambient) .............. -55 to +150 C Operating Temperature (Ambient) ............ -30 to +80 C Max. Operating Temperature (Junction) ............. 125 C Operating Voltage Range ........................... 1.8 to 18.0 V Junction Temperature ......................................... 150 C Lead Soldering Temperature (10 s) ..................... 235 C TK715xx ELECTRICAL CHARACTERISTICS (VOUT 5.0 V) Test conditions: VIN = VOUT(TYP) + 1V, TA = 25 C, unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS MIN TYP MAX UNITS IQ Quiescent Current IOUT = 0 mA 25 45 A IGND Ground Pin Current IOUT = 15 mA 300 500 A VOUT Output Voltage IOUT = 5 mA See Table 1 Line Reg Line Regulation VIN = VOUT(TYP) + 1 V to VOUT(TYP) + 6 V 3 12 mV Load Reg Load Regulation IOUT = 5 to 100 mA, (Note 2) 18 36 mV IOUT = 50 mA 0.105 0.18 V IOUT = 100 mA, 2.4 V VOUT 5.0 V 0.16 0.28 V IOUT = 100 mA, 2.1 V VOUT 2.4 V 0.16 0.30 V VDROP Dropout Voltage (Note 5) IOUT(MAX) Continuous Output Current RR Ripple Rejection VOUT / T Temperature Coefficient 1.8 V Vin 2.1 V (Note 3) 115 155 70 90 V mA (Note 4) 60 dB IOUT = 5 mA 30 ppm/C Note 1: Power dissipation is 400 mW when mounted as recommended. Derate at 3.2 mW/C for operation above 25 C. Note 2: Refer to "Definition of Terms." Note 3: Please refer to the Applications Section for more information. Note 4: Ripple rejection is measured at VR = 200 mVrms, VIN = VOUT(TYP) + 2 V, IOUT = 10 mA, CL = 2.2 F, f = 100 Hz. Note 5: The minimum operating voltage for VIN can be 1.8 V. Also, the minimum voltage required for VIN is VIN = VDROP + VOUT. As a result, operating at VOUT 2.0 V at the minimum input operating voltage is not preferred. Gen. Note: Parameters with min. or max. values are 100% tested at TA = 25 C. Page 2 March 2001 TOKO, Inc. TK715xxAS ABSOLUTE MAXIMUM RATINGS (VOUT 5.1 V) Supply Voltage ............................................. -0.4 to 19 V Power Dissipation (Note 1) ................................ 400 mW Reverse Bias ............................................................. 8 V Short Circuit Current ........................................... 170 mA Storage Temperature (Ambient) .............. -55 to +150 C Operating Temperature (Ambient) ............ -30 to +80 C Max. Operating Temperature (Junction) ............. 125 C Operating Voltage Range .............................. 1.8 to 18 V Junction Temperature ......................................... 150 C Lead Soldering Temperature (10 s) ..................... 235 C TK715xx ELECTRICAL CHARACTERISTICS (VOUT 5.1 V) Test conditions: VIN = VOUT(TYP) + 1V, TA = 25 C, unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS MIN TYP MAX UNITS IQ Quiescent Current IOUT = 0 mA 32 60 A IGND Ground Pin Current IOUT = 15 mA 300 500 A VOUT Output Voltage IOUT = 5 mA See Table 1 Line Reg Line Regulation VIN = VOUT(TYP) + 1 V to VOUT(TYP) + 6 V or Max 18 V 3 12 mV Load Reg Load Regulation IOUT = 5 to 100 mA, (Note 2) 35 80 mV 0.18 V Dropout Voltage IOUT = 50 mA 0.105 VDROP IOUT = 100 mA 0.160 0.28 V IOUT(MAX) Continuous Output Current RR Ripple Rejection VOUT / T Temperature Coefficient 115 V 155 mA (Note 3) 60 dB IOUT = 5 mA 30 ppm/C Note 1: Power dissipation is 400 mW when mounted as recommended. Derate at 3.2 mW/C for operation above 25 C. Note 2: Refer to "Definition of Terms." Note 3: Ripple rejection is measured at VR = 200 mVrms, VIN = VOUT(TYP) + 2 V, IOUT = 10 mA, CL = 2.2 F, f = 100 Hz. Gen. Note: Parameters with min. or max. values are 100% tested at TA = 25 C. March 2001 TOKO, Inc. Page 3 TK715xxAS TK715xxAS ELECTRICAL CHARACTERISTICS TABLE 1 Output Voltage 1.5 V 1.6 V 1.7 V 1.8 V 1.9 V 2.0 V 2.1 V 2.2 V 2.3 V 2.4 V 2.5 V 2.6 V 2.7 V 2.8 V 2.9 V 3.0 V 3.1 V 3.2 V 3.3 V 3.4 V Page 4 Voltage Code 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 VOUT(MIN) VOUT(MAX) 1.440 1.540 1.640 1.740 1.840 1.940 2.040 2.140 2.240 2.340 2.440 2.540 2.640 2.740 2.840 2.940 3.040 3.140 3.240 3.340 1.560 1.660 1.760 1.860 1.960 2.060 2.160 2.260 2.360 2.460 2.560 2.660 2.760 2.860 2.960 3.060 3.160 3.260 3.360 3.460 V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V Test Voltage 2.5 V 2.6 V 2.7 V 2.8 V 2.9 V 3.0 V 3.1 V 3.2 V 3.3 V 3.4 V 3.5 V 3.6 V 3.7 V 3.8 V 3.9 V 4.0 V 4.1 V 4.2 V 4.3 V 4.4 V Output Voltage 3.5 V 3.6 V 3.7 V 3.8 V 3.9 V 4.0 V 4.1 V 4.2 V 4.3 V 4.4 V 4.5 V 4.6 V 4.7 V 4.8 V 4.9 V 5.0 V 6.0 V 7.0 V 8.0 V 9.0 V Voltage Code 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 60 70 80 90 VOUT(MIN) VOUT(MAX) 3.440 3.530 3.630 3.730 3.830 3.930 4.030 4.130 4.230 4.330 4.430 4.530 4.630 4.730 4.830 4.930 5.880 6.860 7.840 8.820 3.560 3.670 3.770 3.870 3.970 4.070 4.170 4.270 4.370 4.470 4.570 4.670 4.770 4.870 4.970 5.070 6.120 7.140 8.160 9.180 V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V Test Voltage 4.5 V 4.6 V 4.7 V 4.8 V 4.9 V 5.0 V 5.1 V 5.2 V 5.3 V 5.4 V 5.5 V 5.6 V 5.7 V 5.8 V 5.9 V 6.0 V 7.0 V 8.0 V 9.0 V 10.0 V March 2001 TOKO, Inc. TK715xxAS TEST CIRCUIT IIN VOUT VIN VIN CL 1.0 F TANTALUM CIN 0.1 F VOUT IOUT GND TYPICAL PERFORMANCE CHARACTERISTICS TA = 25 C, unless otherwise specified. LOAD REGULATION OUTPUT VOLTAGE vs. INPUT VOLTAGE SHORT CIRCUIT CURRENT VOUT TYPICAL 5 VOUT (25 mV/ DIV) VOUT (10 mV/ DIV) VOUT TYPICAL VOUT (V) 4 3 2 IOUT = 0 mA IOUT = 50 mA IOUT = 100 mA 50 mV/DIV 1 VIN = VOUT 50 IOUT (mA) 100 0 100 IOUT (mA) 0 200 VIN (V) INPUT CURRENT VS. INPUT VOLTAGE REVERSE BIAS CURRENT RANGE LINE REGULATION (VIN = 0 V) 100 VOUT (50 mV/ DIV) VOUT TYPICAL 80 IREV (A) I OUT = 0 mA 2 Because the output voltage is different, the reverse current will change this area. VOUT = 2.0 V I Q (mA) 0 0 60 1 40 VOUT = 3 V 20 VOUT = 8.0 V 0 0 10 VIN (V) March 2001 TOKO, Inc. 20 0 5 VREV (V) 10 0 0 5 VIN (V) 10 Page 5 TK715xxAS TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. 500 250 -100 400 200 IOUT = 100 mA IGND (A) VDROP(mV) 0 VDROP (mV) GROUND PIN CURRENT vs. OUTPUT CURRENT DROPOUT VOLTAGE VS. TEMPERATURE DROPOUT VOLTAGE VS. OUTPUT CURRENT 150 100 IOUT = 50 mA 0 50 IOUT (mA) 0 -50 100 GROUND PIN CURRENT vs. OUTPUT CURRENT 5 200 100 50 -200 300 0 50 0 100 TA (C) 0 5 10 IOUT (mA) OUTPUT VOLTAGE VS. TEMPERATURE MAX OUTPUT CURRENT 15 20 180 3 2 IOUT (mA) 10 VOUT (mV) IGND (mA) 4 3.0 V 0 3.0 V 160 140 -10 120 1 -20 100 0 0 20 40 60 IOUT (mA) 80 100 -30 -50 0 50 100 0 -50 0 TA (C) 50 100 TA (C) Ripple Rejection RIPPLE REJECTION 0 -10 -20 VIN ----TANTALUM 1.0 F : 4.7 F -30 dB -40 VOUT 715xxA CL 1.0 F 2.2 F 4.7 F 0.1 F IOUT = 10 mA -50 (TANTALUM OR CERAMIC) -60 -70 -80 GND CERAMIC 2.2 F : 4.7 F RIPPLE REJECTION CIRCUIT -90 -100 0.01 0.1 Page 6 1 10 F (kHz) 100 1000 March 2001 TOKO, Inc. TK715xxAS TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. Output Noise NOISE LEVEL (TK71530A) VS. OUTPUT CURRENT VIN VOUT 715xxA CL = 1 F 250 NOISE (V) CL = 2.2 F CL = 4.7 F 200 CL 1.0 F 2.2 F 4.7 F 10 F 0.1 F CL = 10 F 150 (TANTALUM) GND 100 OUTPUT NOISE CIRCUIT 50 BW = 400 Hz~80 KHz 0 1.0 5.0 IOUT (mA) 10 Load & Line Response LOAD CURRENT STEP RESPONSE LINE VOLTAGE STEP RESPONSE VIN VOUT + 2V CL = 1.0 F 50 mA IOUT 5 mA VOUT + 1V 25 S/DIV CL = 1.0 F 25 S/DIV VOUT VOUT 50 mV/DIV 50 mV/DIV IOUT = 10mA Note: To improve the load and line transient response, increase the value of the output capacitor. March 2001 TOKO, Inc. Page 7 TK715xxAS DEFINITION AND EXPLANATION OF TECHNICAL TERMS OUTPUT VOLTAGE (VOUT) RIPPLE REJECTION RATIO (RR) The output voltage is specified with VIN = (VOUT(TYP) + 1 V) and IOUT = 5 mA. Ripple rejection is the ability of the regulator to attenuate the ripple content of the input voltage at the output. It is specified with 200 mVrms, 100 Hz superimposed on the input voltage, where VIN = VOUT(TYP) + 2.0 V. The output decoupling capacitor is set to 2.2 F and the load current is set to 10 mA. Ripple rejection is the ratio of the ripple content of the output vs. the input and is expressed in dB. DROPOUT VOLTAGE (VDROP) The dropout voltage is the difference between the input voltage and the output voltage at which point the regulator starts to fall out of regulation. Below this value, the output voltage will fall as the input voltage is reduced. It is dependent upon the load current and the junction temperature. REVERSE VOLTAGE PROTECTION Normal operating output current. This is limited by package power dissipation. Reverse voltage protection prevents damage due to the output voltage being higher than the input voltage. This fault condition can occur when the output capacitor remains charged and the input is reduced to zero, or when an external voltage higher than the input voltage is applied to the output side. LINE REGULATION (Line Reg) REDUCTION OF OUTPUT NOISE Line regulation is the ability of the regulator to maintain a constant output voltage as the input voltage changes. The line regulation is specified as the input voltage is changed from VIN = VOUT(TYP) + 1 V to VIN = VOUT(TYP) + 6 V or VIN = max 18 V. Although the architecture of the Toko regulators are designed to minimize semiconductor noise, further reduction can be achieved by the selection of external components. The obvious solution is to increase the size of the output capacitor. Please note that several parameters are affected by the value of the capacitors and bench testing is recommended when deviating from standard values. CONTINUOUS OUTPUT CURRENT (IOUT) LOAD REGULATION (Load Reg) Load regulation is the ability of the regulator to maintain a constant output voltage as the load current changes. It is a pulsed measurement to minimize temperature effects with the input voltage set to VIN = VOUT(TYP) +1 V. The load regulation is specified under the output current step condition 5 mA to 100 mA. QUIESCENT CURRENT (IQ) The quiescent current is the current which flows through the ground terminal under no load conditions (IOUT = 0 mA). GROUND CURRENT (IGND) Ground current is the current which flows through the ground pin(s). It is defined as IIN - IOUT, excluding control current. Page 8 PACKAGE POWER DISSIPATION (PD) This is the power dissipation level at which the thermal sensor is activated. The IC contains an internal thermal sensor which monitors the junction temperature. When the junction temperature exceeds the monitor threshold of 150 C, the IC is shut down. The junction temperature rises as the difference between the input power (VIN x IIN) and the output power (VOUT x IOUT) increases. The rate of temperature rise is greatly affected by the mounting pad configuration on the PCB, the board material, and the ambient temperature. When the IC mounting has good thermal conductivity, the junction temperature will be low even if the power dissipation is great. When mounted on the recommended mounting pad, the power dissipation of the SOT23-3 is increased to 400 mW. For operation at ambient temperatures over 25 C, the power dissipation of the SOT23-3 device should be derated at 3.2 mW/C. To March 2001 TOKO, Inc. TK715xxAS DEFINITION AND EXPLANATION OF TECHNICAL TERMS (CONT.) determine the power dissipation for shutdown when mounted, attach the device on the actual PCB and deliberately increase the output current (or raise the input voltage) until the thermal protection circuit is activated. Calculate the power dissipation of the device by subtracting the output power from the input power. These measurements should allow for the ambient temperature of the PCB. The value obtained from PD /(150 C - TA) is the derating factor. The PCB mounting pad should provide maximum thermal conductivity in order to maintain low device temperatures. As a general rule, the lower the temperature, the better the reliability of the device. The thermal resistance when mounted is expressed as follows: 2) PD1 is taken to be PD x (~ 0.8 - 0.9) 3) Plot PD1 against 25 C 4) Connect PD1 to the point corresponding to the 150 C with a straight line. 5) In design, take a vertical line from the maximum operating temperature (e.g., 75 C) to the derating curve. 6) Read off the value of PD against the point at which the vertical line intersects the derating curve. This is taken as the maximum power dissipation, DPD. The maximum operating current is: IOUT = (DPD / (VIN(MAX) - VOUT) 500 Tj = 0jA x PD + TA MOUNTED AS SHOWN For Toko ICs, the internal limit for junction temperature is 150 C. If the ambient temperature (TA) is 25 C, then: 150 C = 0jA x PD + 25 C 0jA = 125 C/ PD PD (mW) 400 300 FREE AIR 200 100 PD is the value when the thermal sensor is activated. A simple way to determine PD is to calculate VIN x IIN when the output side is shorted. Input current gradually falls as temperature rises. You should use the value when thermal equilibrium is reached. 0 0 50 100 150 TA (C) SOT23-3 POWER DISSIPATION CURVE The range of usable currents can also be found from the graph below. (mW) 3 PD 6 DPD 4 5 25 50 75 TA (C) 150 Procedure: 1) Find PD March 2001 TOKO, Inc. Page 9 TK715xxAS APPLICATION INFORMATION INPUT-OUTPUT CAPACITORS Linear regulators require input and output capacitors in order to maintain regulator loop stability. The output capacitor should be selected within the Equivalent Series Resistance (ESR) range as shown in the graphs below for stable operation. The output capacitor CL can be reduced as the output voltage is increased. However, the output noise will increase as CL is reduced, so the largest value of CL possilbe is recommended (CL = 4.7 mF or more). Note: It is very important to check the selected manufacturers electrical characteristics (capacitance and ESR) over temperature. MULTI LAYER CERAMIC CAP 5.0 0.68 F CL 4.7 F or More C = 0.1 F IN 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.5 0 CL = 0.68 F MLCC CL = 4.7 F MLCC or More Stable area is above the line ESR 0.01 1.0 F 2.2 F 3.3 F 20 40 60 IOUT (mA) 80 100 UNSTABLE AREA UNDER AND TO THE LEFT Range which can be used: VOUT 2.8V VOUT 2.0V VOUT 1.5V IOUT = 1 mA ~ Max, MULTI LAYER CERAMIC CAP. 0.68 mF IOUT = 1 mA ~ Max, MULTI LAYER CERAMIC CAP. 1.0 mF IOUT = 1 mA ~ Max, MULTI LAYER CERAMIC CAP. 4.7 mF TANTALUM CAP VOUT (V) 5.0 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.5 0 CIN = 0.1 F 0.1 F CL 0.22 F or More CL = 0.1 F TANTALUM CL = 0.22 F (TANTALUM) or More Stable area is above the line ESR 1.0 0.1 F 20 40 60 IOUT (mA) 80 100 UNSTABLE AREA UNDER AND TO THE LEFT Range which can be used: VOUT 1.9V IOUT = 1 mA ~ Max, TANTALUM CAP. 0.1 mF (CERAMIC CAP 0.22 mF + 2.2W Capacitor used for evaluation: VOUT 1.5V IOUT = 1 mA ~ Max, TANTALUM CAP. 0.22 mF (CERAMIC CAP 0.22 mF + 2.2W Page 10 March 2001 TOKO, Inc. TK715xxAS APPLICATION INFORMATION (CONT) INPUT-OUTPUT CAPACITORS (CONT) OUTPUT NOISE IMPROVEMENT An RC filter can be added to the output stage of the regulator to reduce output noise when the input voltage is high and the output current only makes small changes. Select a regulator with a slightly higher output voltage because the final output voltage will be reduced by the RC filter. If the output current does make a large change, the output voltage will change. The following table shows output noise, and output voltage for various values of ROUT and COUT using a 3.5 V device. VIN = 4.0 V, CIN = 10 mF (aluminum electrolytic), COUT = (see table), ROUT = (see table) VOUT VIN ROUT TK715xxA COUT CL = 2.2 F MEASUREMENT CONDITION LOAD ADJ. IOUT = 20, 30, 40 mA OUTPUT SIDE CAPACITOR (COUT) UNITS IOUT ROUT VOUT 10 F 47 F 100 F F IOUT = 20 - 40 mA 0 3.500 V 210 V 150 V 130 V RMS 20 mA 10 W 3.296 V 76 V 50 V 40 V RMS 30 mA 6.8 W 3.287 V 88 V 55 V 48 V RMS 40 mA 5.1 W 3.266 V 100 V 60 V 48 V RMS COUT NOISE RIPPLE REJECTION RATIO An RC filter can be added to the input stage of the regulator to increase the ripple rejection when the input voltage is high. Even if the resulting difference between VIN at the regulator (after the RC filter) and VOUT is small the TK71533AS will output a stable voltage. The voltage dropped across the RC filter depends on the value of the input ripple noise. Select the value of RIN such that the lowest value of VIN plus the ripple noise after the RC filter (peak to peak) is the output voltage plus 0.2 V. RIN VOUT VIN TK715xxA CIN March 2001 TOKO, Inc. CL LOAD ADJ. IOUT = 20, 30, 40 mA Page 11 TK715xxAS APPLICATION INFORMATION (CONT) R(*) MAG -17.98 dB B(*) B -41.05 dB 10 dB/ 10 dB/ -50.00 dB -50.00 dB R(*) MAG -57.78 dB B(*) B -41.05 dB 10 dB/ 10 dB/ -50.00 dB -50.00 dB TK71533 FILTER RIN = 27 CIN = 47 F FILTER + TK71533 RIN = 27 CIN = 47 F CL = 10 F START: 100 Hz STOP: 1 MHz OUT (B): -20.00 dBm ST: AUTO x1 1 M IRG: 26 dBm RBW: 30 kHZ VBW: 38 kHz START: 100 Hz STOP: 1 MHz OUT (B): -20.00 dBm ST: AUTO x1 1 M IRG: 26 dBm RBW: 30 kHZ VBW: 38 kHz TEMPERATURE DEPENDENCY VOLTAGE DEPENDENCY 100 90 B CURVE CAPACITANCE (%) CAPACITANCE (%) 100 80 70 F CURVE 60 50 40 0 2 4 6 8 BIAS V (V) 10 90 B CURVE 80 70 F CURVE 60 50 -50 -25 0 25 TA (C) 50 75 100 In general, a ceramic capacitor has a voltage and temperature dependence. Parts should be selected with consideration of the voltage and temperature used. The "B" characteristic curves are recommended. Page 12 March 2001 TOKO, Inc. TK715xxAS APPLICATION INFORMATION (CONT.) BOARD LAYOUT The copper pattern should be as large as possible. Power dissipation is 400 mW for the SOT23-3, derated at 3.2 mW/C for operation above TA = 25C (qja = 312C/W) The internal reverse bias protection eliminates the requirement for a reverse voltage protection diode. This saves both cost and board space. SOT23-3 BOARD LAYOUT VIN GND + VOUT + 500 P D(mW) 400 300 200 RECOMMENDED AS SHOWN FREE AIR 100 March 2001 TOKO, Inc. Page 13 TK715xxAS APPLICATION INFORMATION (CONT.) REVERSE VOLTAGE PROTECTION SWITCHING OPERATION The internal reverse bias protection eliminates the requirement for a reverse voltage protection diode. This saves both cost and board space. Even though the input voltages or the output voltages are different, the outputs of the TK715xxA regulators can be connected together, and the output voltages switched. If two or more TK715xxA regulators are turned ON simultaneously, the highest output voltage will be present. VIN VIN VOUT 715xxAS TK71530A VIN Another reverse voltage protection technique is illustrated below. The extra diode and extra capacitor are not necessary with the TK715xxA. The high output voltage accuracy is maintained because the diode forward voltage variations over temperature and load current have been eliminated. VIN VOUT TK715xxAS VOUT 3.0 OR 2.8 V TK71528A GND CURRENT BOOST OPERATION The output current can be increased by connecting an external PNP transistor as shown below. The output current capability depends upon the Hfe of the external transistor. Note: The TK715xxA internal short circuit protection and thermal sensor do not protect the external transistor. VIN VIN PARALLEL OPERATION TK715xxA 150 VOUT 3.3 F 0.22 F The series resistor R is put in the input line of the low output voltage regulator in order to prevent overdissipation. The voltage dropped across the resistor reduces the large input-to-output voltage across the regulator, reducing the power dissipation in the device. VIN TK71550A TK71530A 5V 3V R TK71520A Page 14 2V March 2001 TOKO, Inc. TK715xxAS PACKAGE OUTLINE Marking Information SOT23-3 Product Code T Voltage Code 0.8 1.0 3 e1 2.4 Marking e 0.95 VOLTAGE CODE e 0.95 PRODUCT CODE e1 1.90 0.4 e 1 e 0.95 0.95 Recommended Mounting Pad + 0.15 0.05 C1 0.1 2 1.6 15max 0.1 1.1 0.15 + 0.15 0.05 0.1 0 ~ 0.1 1.3 max 2.9 0.4 2.8 0.3 Dimensions are shown in millimeters Tolerance: x.x = 0.2 mm (unless otherwise specified) TK71515S TK71516S TK71517S TK71518S TK71519S TK71520S TK71521S TK71522S TK71523S TK71524S TK71525S TK71526S TK71527S TK71528S TK71529S TK71530S TK71531S TK71532S TK71533S TK71534S TK71535S TK71536S TK71537S TK71538S TK71539S TK71540S TK71541S TK71542S TK71543S TK71544S TK71545S TK71546S TK71547S TK71548S TK71549S TK71550S TK71560S TK71570S TK71580S TK71590S 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 60 70 80 90 Toko America, Inc. Headquarters 1250 Feehanville Drive, Mount Prospect, Illinois 60056 Tel: (847) 297-0070 Fax: (847) 699-7864 TOKO AMERICA REGIONAL OFFICES Midwest Regional Office Toko America, Inc. 1250 Feehanville Drive Mount Prospect, IL 60056 Tel: (847) 297-0070 Fax: (847) 699-7864 Western Regional Office Toko America, Inc. 2480 North First Street , Suite 260 San Jose, CA 95131 Tel: (408) 432-8281 Fax: (408) 943-9790 Semiconductor Technical Support Toko Design Center 4755 Forge Road Colorado Springs, CO 80907 Tel: (719) 528-2200 Fax: (719) 528-2375 Visit our Internet site at http://www.tokoam.com The information furnished by TOKO, Inc. is believed to be accurate and reliable. However, TOKO reserves the right to make changes or improvements in the design, specification or manufacture of its products without further notice. TOKO does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc. March 2001 TOKO, Inc. (c) 1999 Toko, Inc. All Rights Reserved Page 15 IC-xxx-TK715xx 0798O0.0K Printed in the USA