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| TK712xx LOW DROPOUT REGULATOR FEATURES s s s s s Low Dropout Voltage Low Quiescent Current Very Stable Output Low Noise (35 Vrms) Miniature Package (SOT-25) APPLICATIONS s s s s s s s Battery Powered Systems Portable Consumer Equipment Cordless Telephones Personal Communications Equipment Radio Control Systems Toys Low Voltage Systems DESCRIPTION TK712xx is a low dropout, linear regulator. Since a PNP power transistor is used, dropout voltage is very low, making it possible to maintain stable output voltage even as the battery decreases. This allows longer battery life. The TK712xx has a noise bypass pin available for noise reduction. The TK712xx is available in a miniature SOT-25 surface mount package. 20 P TK712xx NOISE BYPASS GND VIN GND VOUT ORDERING INFORMATION TK712 VoltageCode M Tape/Reel Code VIN BLOCK DIAGRAM VOUT VOLTAGE CODE 20 = 2.0 V 25 = 2.5 V 28 = 2.8 V 30 = 3.0 V 33 = 3.3 V 35 = 3.5 V 40 = 4.0 V 45 = 4.5 V 50 = 5.0 V TAPE/REEL CODE TL: Tape Left NOISE BYPASS THERMAL PROTECTION BANDGAP REFERENCE GND GND January 1999 TOKO, Inc. Page 1 TK712xx ABSOLUTE MAXIMUM RATINGS Input Voltage ............................................................ 15 V Power Dissipation (Note 1) ................................ 350 mW Operating Voltage Range ............................... 1.4 to 14 V Junction Temperature ........................................... 150 C Storage Temperature Range ................... -55 to +150 C Operating Temperature Range ................... -30 to +80 C Lead Soldering Temperature (10 s) ...................... 235 C TK71220 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 3 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass Terminal Voltage Temperature Coefficient TEST CONDITIONS VIN = 3.0 V, IOUT = 0 mA VIN = 1.8 V, IOUT = 0 mA VIN = 3.0 V, IOUT = 10 mA IOUT = 30 mA MIN TYP 13 0 1.4 MAX 300 3.0 2.1 200 UNITS A mA V mV mA 1.9 2.0 100 100 VIN = 3.0 V, IOUT = 30 mA VIN = 3.0 to 13.0 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA 160 1. 5 10 20 63 1.27 0.15 3.5 30 40 mA mV mV dB V mV/ C Note 1: Power dissipation is 350 mW when mounted as recommended. Derate at 2.8 mW/C for operation above 25 C. Page 2 January 1999 TOKO, Inc. TK712xx TK71225 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 3.5 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass Terminal Voltage Temperature Coefficient TEST CONDITIONS VIN = 3.5 V, IOUT = 0 mA VIN = 2.0 V, IOUT = 0 mA VIN = 3.5 V, IOUT = 10 mA IOUT = 30 mA MIN TYP 13 0 1.4 MAX 300 3.0 2.6 200 UNITS A mA V mV mA 2.4 2.5 100 100 VIN = 3.5 V, IOUT = 30 mA VIN = 3.5 to 13.5 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA 160 1. 5 10 20 63 1.27 0.15 3.5 30 40 mA mV mV dB V mV/ C TK71228 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 3.8 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass terminal Voltage Temperature Coefficient TEST CONDITIONS VIN = 3.8 V, IOUT = 0 mA VIN = 2.5 V, IOUT = 0 mA VIN = 3.8 V, IOUT = 10 mA IOUT = 30 mA MIN TYP 13 0 1.4 MAX 300 3.0 2.9 200 UNITS A mA V mV mA 2.7 2.8 100 100 VIN = 3.8 V, IOUT = 30 mA VIN = 3.8 to 13.8 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA 160 1. 5 10 20 63 1.27 0.18 3.5 30 40 mA mV mV dB V mV/ C January 1999 TOKO, Inc. Page 3 TK712xx TK71230 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 4.0 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass Terminal Voltage Temperature Coefficient VIN = 4.0 V, IOUT = 30 mA VIN = 4.0 to 14.0 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA TEST CONDITIONS VIN = 4.0 V, IOUT = 0 mA VIN = 2.5 V, IOUT = 0 mA VIN = 4.0 V, IOUT = 10 mA IOUT = 30 mA 100 2.9 MIN TYP 13 0 1.4 3.0 100 160 1. 5 10 20 63 1.27 0.18 3.5 30 40 MAX 300 3.0 3.1 200 UNITS A mA V mV mA mA mV mV dB V mV/ C TK71233 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 3.9 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass Terminal Voltage Temperature Coefficient VIN = 3.9 V, IOUT = 30 mA VIN = 3.9 to 14.0 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA TEST CONDITIONS VIN = 3.9 V, IOUT = 0 mA VIN = 2.8 V, IOUT = 0 mA VIN = 3.9 V, IOUT = 10 mA IOUT = 30 mA 100 3.2 MIN TYP 13 0 1.4 3.3 100 160 1. 5 10 20 63 1.27 0.18 3.5 30 40 MAX 300 3.0 3.4 200 UNITS A mA V mV mA mA mV mV dB V mV/ C Page 4 January 1999 TOKO, Inc. TK712xx TK71235 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 4.1 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass Terminal Voltage Temperature Coefficient TEST CONDITIONS VIN = 4.1 V, IOUT = 0 mA VIN = 3.0 V, IOUT = 0 mA VIN = 4.1 V, IOUT = 10 mA IOUT = 30 mA MIN TYP 13 0 1.4 MAX 300 3.0 3.61 200 UNITS A mA V mV mA 3.39 3.50 100 100 VIN = 4.1 V, IOUT = 30 mA VIN = 4.1 to 14.0 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA 160 1. 5 10 20 63 1.27 0.2 3.5 30 40 mA mV mV dB V mV/ C TK71240 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 4.6 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass Terminal Voltage Temperature Coefficient VIN = 4.6 V, IOUT = 30 mA VIN = 4.6 to 14.0 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA TEST CONDITIONS VIN = 4.6 V, IOUT = 0 mA VIN = 3.5 V, IOUT = 0 mA VIN = 4.6 V, IOUT = 10 mA IOUT = 30 mA 100 3.88 MIN TYP 13 0 1.4 4.00 100 160 1. 5 10 20 63 1.27 0.2 3.5 30 40 MAX 300 3.0 4.12 200 UNITS A mA V mV mA mA mV mV dB V mV/ C January 1999 TOKO, Inc. Page 5 TK712xx TK71245 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 5.1 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass Terminal Voltage Temperature Coefficient VIN = 5.1 V, IOUT = 30 mA VIN = 5.1 to 14.0 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA TEST CONDITIONS VIN = 5.1 V, IOUT = 0 mA VIN = 4.0 V, IOUT = 0 mA VIN = 5.1 V, IOUT = 10 mA IOUT = 30 mA 100 4.36 MIN TYP 13 0 1.4 4.50 100 160 1. 5 10 20 63 1.27 0.25 3.5 30 40 MAX 300 3.0 4.64 200 UNITS A mA V mV mA mA mV mV dB V mV/ C TK71250 ELECTRICAL CHARACTERISTICS Test Conditions: VIN = 5.6 V, TA = 25 C, unless otherwise specified. SYMBOL IQ VOUT VDROP IOUT IGND Line Reg Load Reg RR Vref VOUT /T PARAMETER Quiescent Current Regulated Output Voltage Dropout Voltage Output Current Ground Current Line Regulation Load Regulation Ripple Rejection Noise Bypass Terminal Voltage Temperature Coefficient TEST CONDITIONS VIN = 5.6 V, IOUT = 0 mA VIN = 4.0 V, IOUT = 0 mA VIN = 5.6 V, IOUT = 10 mA IOUT = 30 mA MIN TYP 13 0 1.4 MAX 300 3.0 5.15 200 UNITS A mA V mV mA 4.85 5.00 100 100 VIN = 5.6 V, IOUT = 30 mA VIN = 5.6 to 14.0 V IOUT = 1 to 60 mA CL = 3.3 F, f = 400 Hz, IOUT = 10 mA 160 1. 5 10 20 63 1.27 0.25 3.5 30 40 mA mV mV dB V mV/ C Page 6 January 1999 TOKO, Inc. TK712xx TEST CIRCUIT IIN VIN VOUT + VIN NOISE BYPASS GND + CL IOUT VOUT CN TYPICAL PERFORMANCE CHARACTERISTICS TA = 25 C, unless otherwise specified. GROUND CURRENT VS. AMBIENT TEMPERATURE 5 4 IOUT = 60 mA VDROP (mV) 500 400 300 IOUT = 60 mA 200 100 0 -50 OUTPUT VOLTAGE VS. INPUT VOLTAGE 50 30 VOUT (mV) DROPOUT VOLTAGE VS. AMBIENT TEMPERATURE 10 -10 -30 -50 0 10 VIN (V) NOISE VOLTAGE VS. BYPASS CAPACITOR 300 200 CL = 1.0 F CL = 3.3 F IOUT = 30 mA VOUT = 5 V IGND (mA) 3 2 1 0 -50 IOUT = 30 mA IOUT = 30 mA 0 TA (C) RIPPLE REJECTION VS. FREQUENCY 20 0 TA (C) 50 100 50 100 NOISE SPECTRUM -50 IOUT = 30 mA 0 CL = 1 F NOISE (V) 150 CL = 10 F 100 50 VOUT = 2 V -100 INSTRUMENT NOISE FLOOR RR (dB) CL = 10 F NOISE (dB) CN = 0.01 F CL = 1 F -50 CL = 10 F 0 1 pF 10 pF 100 pF 1000 pF 0.01 F.1 F CN -150 0 500 FREQUENCY (kHz) 1000 -100 100 1k 10 k 100 k FREQUENCY (Hz) January 1999 TOKO, Inc. Page 7 TK712xx TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. LINE TRANSIENT RESPONSE VOUT(TYP) + 2 V LOAD TRANSIENT RESPONSE GROUND CURRENT VS. OUTPUT CURRENT 10 IOUT = 30 mA IOUT VIN VOUT(TYP) + 1 V VOUT (400 mV / DIV) VOUT (20 mV / DIV) 8 0 mA IGND (mA) VOUT VOUT 6 4 2 CL = 3.3 F CL = 1.0 F 0 0 TIME (50 s / DIV) TIME (50 s / DIV) 50 IOUT (mA) 100 OUTPUT VOLTAGE VS. INPUT VOLTAGE VOUT (50 mV / DIV) VOUT(TYP) + 1 V 30 mA IOUT = 0 mA 60 mA VIN = VOUT VIN (100 mV / DIV) Page 8 January 1999 TOKO, Inc. TK712xx TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. QUIESCENT CURRENT VS. INPUT VOLTAGE 2 150 IOUT = 0 mA IOUT (mA) VOUT (V) TK71220 OUTPUT VOLTAGE VS. OUTPUT CURRENT 2.05 OUTPUT CURRENT VS. AMBIENT TEMPERATURE IQ (mA) 2.00 1 100 1.95 0 50 IOUT (mA) DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 400 100 0 0 5 VIN (V) 10 50 -50 0 TA (C) 50 100 SHORT CIRCUIT PROTECTION 5 4 2.05 OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE VDROP (mV) VOUT (V) 300 200 100 0 0 3 2 1 0 VOUT (V) 0 100 IOUT (mA) 200 2.00 50 IOUT (mA) 100 1.95 -50 0 TA (C) 50 100 TK71225 OUTPUT VOLTAGE VS. OUTPUT CURRENT 2.55 2 150 IOUT = 0 mA QUIESCENT CURRENT VS. INPUT VOLTAGE OUTPUT CURRENT VS. AMBIENT TEMPERATURE 2.50 1 IOUT (mA) 0 5 VIN (V) 10 VOUT (V) IQ (mA) 100 2.45 0 50 IOUT (mA) 100 0 50 -50 0 TA (C) 50 100 January 1999 TOKO, Inc. Page 9 TK712xx TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. TK71225 (CONT.) DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 400 VDROP (mV) VOUT (V) 300 200 100 0 0 5 4 3 2 1 0 VOUT (V) SHORT CIRCUIT PROTECTION OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE 2.55 2.50 50 IOUT (mA) 100 0 100 IOUT (mA) 200 2.45 -50 0 TA (C) 50 100 TK71228 OUTPUT VOLTAGE VS. OUTPUT CURRENT 2.85 QUIESCENT CURRENT VS. INPUT VOLTAGE 2 150 OUTPUT CURRENT VS. AMBIENT TEMPERATURE IOUT = 0 mA IOUT (mA) 0 5 VIN (V) 10 VOUT (V) IQ (mA) 2.80 1 100 2.75 0 50 IOUT (mA) DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 400 100 0 50 -50 0 TA (C) 50 100 SHORT CIRCUIT PROTECTION 5 4 2.85 OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE VDROP (mV) VOUT (V) 300 200 100 0 0 3 2 1 0 VOUT (V) 0 100 IOUT (mA) 200 2.80 50 IOUT (mA) 100 2.75 -50 0 TA (C) 50 100 Page 10 January 1999 TOKO, Inc. TK712xx TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. QUIESCENT CURRENT VS. INPUT VOLTAGE 2 150 IOUT = 0 mA IOUT (mA) VOUT (V) IQ (mA) TK71230 OUTPUT VOLTAGE VS. OUTPUT CURRENT 3.05 OUTPUT CURRENT VS. AMBIENT TEMPERATURE 3.00 1 100 2.95 0 50 IOUT (mA) DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 400 0 100 0 5 VIN (V) 10 50 -50 0 TA (C) 50 100 SHORT CIRCUIT PROTECTION 5 4 VOUT (V) 3.05 OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE VDROP (mV) 300 200 100 0 0 3 2 1 0 VOUT (V) 0 100 IOUT (mA) 200 3.00 50 IOUT (mA) 100 2.95 -50 0 TA (C) 50 100 TK71233 OUTPUT VOLTAGE VS. OUTPUT CURRENT 3.35 2 150 IOUT = 0 mA QUIESCENT CURRENT VS. INPUT VOLTAGE OUTPUT CURRENT VS. AMBIENT TEMPERATURE 3.30 1 IOUT (mA) 0 5 VIN (V) 10 VOUT (V) IQ (mA) 100 3.25 0 50 IOUT (mA) 100 0 50 -50 0 TA (C) 50 100 January 1999 TOKO, Inc. Page 11 TK712xx TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. TK71233 (CONT.) DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 400 VDROP (mV) VOUT (V) 300 200 100 0 0 5 4 3 2 1 0 VOUT (V) SHORT CIRCUIT PROTECTION OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE 3.35 3.30 50 IOUT (mA) 100 0 100 IOUT (mA) 200 3.25 -50 0 TA (C) 50 100 TK71235 OUTPUT VOLTAGE VS. OUTPUT CURRENT 3.55 2 150 IOUT = 0 mA IOUT (mA) VOUT (V) IQ (mA) QUIESCENT CURRENT VS. INPUT VOLTAGE OUTPUT CURRENT VS. AMBIENT TEMPERATURE 3.50 1 100 3.45 0 50 IOUT (mA) 100 0 0 5 VIN (V) 10 50 -50 0 TA (C) 50 100 DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 400 SHORT CIRCUIT PROTECTION 5 4 3.55 OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE VDROP (mV) VOUT (V) 300 200 100 0 0 3 2 1 0 VOUT (V) 0 100 IOUT (mA) 200 3.50 50 IOUT (mA) 100 3.45 -50 0 TA (C) 50 100 Page 12 January 1999 TOKO, Inc. TK712xx TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. QUIESCENT CURRENT VS. INPUT VOLTAGE 2 150 IOUT = 0 mA IOUT (mA) VOUT (V) TK71240 OUTPUT VOLTAGE VS. OUTPUT CURRENT 4.05 OUTPUT CURRENT VS. AMBIENT TEMPERATURE 4.00 IQ (mA) 1 100 3.95 0 50 IOUT (mA) 100 0 0 5 VIN (V) 10 50 -50 0 TA (C) 50 100 DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 400 VDROP (mV) SHORT CIRCUIT PROTECTION 5 4 OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE 4.05 300 200 100 0 0 VOUT (V) 3 2 1 0 VOUT (V) 4.00 50 IOUT (mA) 100 0 100 IOUT (mA) QUIESCENT CURRENT VS. INPUT VOLTAGE 200 3.95 -50 0 TA (C) 50 100 TK71245 OUTPUT VOLTAGE VS. OUTPUT CURRENT 4.55 2 150 IOUT = 0 mA OUTPUT CURRENT VS. AMBIENT TEMPERATURE 4.50 1 IOUT (mA) 0 5 VIN (V) 10 VOUT (V) IQ (mA) 100 4.45 0 50 IOUT (mA) 100 0 50 -50 0 TA (C) 50 100 January 1999 TOKO, Inc. Page 13 TK712xx TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 C, unless otherwise specified. TK71245 (CONT.) DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 400 VDROP (mV) 300 200 100 0 0 VOUT (V) 5 4 3 2 1 0 VOUT (V) SHORT CIRCUIT PROTECTION OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE 4.55 4.50 50 IOUT (mA) 100 0 100 IOUT (mA) 200 4.45 -50 0 TA (C) 50 100 TK71250 OUTPUT VOLTAGE VS. OUTPUT CURRENT 5.05 2 150 IOUT = 0 mA IOUT (mA) QUIESCENT CURRENT VS. INPUT VOLTAGE OUTPUT CURRENT VS. AMBIENT TEMPERATURE VOUT (V) 5.00 IQ (mA) 1 100 4.95 0 50 IOUT (mA) 100 0 0 5 VIN (V) 10 50 -50 0 TA (C) 50 100 DROPOUT VOLTAGE VS. OUTPUT CURRENT 500 SHORT CIRCUIT PROTECTION 5.05 OUTPUT VOLTAGE VS. AMBIENT TEMPERATURE 5 400 4 VDROP (mV) VOUT (V) 300 200 100 0 0 3 2 1 0 0 100 IOUT (mA) 200 VOUT (V) 5.00 50 IOUT (mA) 100 4.95 -50 0 TA (C) 50 100 Page 14 January 1999 TOKO, Inc. TK712xx DEFINITION AND EXPLANATION OF TECHNICAL TERMS LINE REGULATION (LINE REG) Line regulation is the ability of the regulator to maintain a constant output voltage as the input voltage changes. 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. The load regulation is specified an output current step condition of 1 mA to 60 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 ICONT. DROPOUT VOLTAGE (VDROP) This is a measure of how well the regulator performs as the input voltage decreases. The smaller the number, the further the input voltage can decrease before regulation problems occur. Nominal output voltage is first measured when VIN = VOUT + 1 at a chosen load current. When the output voltage has dropped 100 mV from the nominal, VIN - VO is the dropout voltage. This voltage is affected by load current and junction temperature. OUTPUT NOISE VOLTAGE This is the effective AC voltage that occurs on the output voltage under the condition where the input noise is low and with a given load, filter capacitor, and frequency range. THERMAL PROTECTION This is an internal feature which turns the regulator off when the junction temperature rises above 150 C. After the regulator turns off, the temperature drops and the regulator output turns back on. Under certain conditions, the output waveform may appear to be an oscillation as the output turns off and on and back again in succession. 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 mounting pad, the power dissipation of the SOT-25 is increased to 350 mW. For operation at ambient temperatures over 25 C, the power dissipation of the SOT-25 device should be derated at 2.8 mW/C. To 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: Tj = 0jA x PD + TA 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 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. January 1999 TOKO, Inc. Page 15 TK712xx DEFINITION AND EXPLANATION OF TECHNICAL TERMS (CONT.) The range of usable currents can also be found from the graph below. (mW) PD 3 DPD 6 4 5 25 50 75 TA (C) 150 Procedure: 1) 2) 3) 4) Find PD PD1 is taken to be PD x (~ 0.8 - 0.9) Plot PD1 against 25 C 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) 1000 800 PD (mW) 600 400 MOUNTED FREE AIR 200 0 0 50 TA (C) 100 150 SOT-25 POWER DISSIPATION CURVE Page 16 January 1999 TOKO, Inc. TK712xx APPLICATION INFORMATION INPUT/OUTPUT DECOUPLING CONSIDERATIONS CAPACITOR OPTIMUM PERFORMANCE Optimum performance can only be achieved when the IC is mounted on a PC board according to the diagram below. This is because of the extremely small package and limited power dissipation. Shape the metal portion of the PCB as shown in the following drawing. Voltage regulators require input and output decoupling capacitors. The required value of these capacitors vary with application. Capacitors made by different manufacturers can have different characteristics, particularly with regard to high frequencies and Equivalent Series Resistance (ESR) over temperature. The type of capacitor is also important. For example, a 4.7 F aluminum electrolytic may be required for a certain application. If a tantalum capacitor is used, a lower value of 2.2 F would be adequate. It is important to consider the temperature characteristics of the decoupling capacitors. While Toko regulators are designed to operate as low as -40 C, many capacitors will not operate properly at this temperature. The capacitance of aluminum electrolytic capacitors may decrease to 0 at low temperatures. This may cause oscillation on the output of the regulator since some capacitance is required to guarantee stability. Thus, it is important to consider the characteristics of the capacitor over temperature when selecting decoupling capacitors. The ESR is another important parameter. The ESR will increase with temperature but low ESR capacitors are often larger and more costly. In general, tantalum capacitors offer lower ESR than aluminum electrolytic, but new low ESR aluminum electrolytic capacitors are now available from several manufacturers. Usually a bench test is sufficient to determine the minimum capacitance required for a particular application. After taking thermal characteristics and tolerance into account, the minimum capacitance value should be approximately two times this value. The recommended minimum capacitance for the TK712xx is 2.2 F for a tantalum capacitor or 3.3 F for an aluminum electrolytic. Please note that linear regulators with a low dropout voltage have high internal loop gains which require care in guarding against oscillation caused by insufficient decoupling capacitance. The use of high quality decoupling capacitors suited for your application will guarantee proper operation of the circuit. Pay attention to temperature characteristics of the capacitor, especially the increase of ESR and decrease of capacitance in low temperatures. Oscillation, reduction of ripple rejection and increased noise may occur in some cases if the proper capacitor is not used. An output capacitor more than 1.0 F is required to maintain stability. The standard test condition is 3.3 F (TA = 25 C). VIN VOUT + + GND GND SOT-25 BOARD LAYOUT Use a large bypass capacitor and connect it in a place near GND of the IC. Pay attention to temperature characteristics of the capacitor, especially the increase of ESR and decrease of capacitance in low temperatures. Oscillation, reduction of ripple rejection and increased noise may occur in some cases if the proper capacitor is not used. An output capacitor more than 1.0 F is required to maintain stability. The standard test condition is 3.3 F (TA = 25 C). + CN January 1999 TOKO, Inc. Page 17 TK712xx PACKAGE OUTLINE Marking Information 0.7 SOT-25 (SOT-23-5) Marking (0.6) 1.0 5 4 (0.6) 1.6 TK71220 TK71225 TK71228 TK71230 TK71233 TK71235 TK71240 TK71245 TK71250 Marking J20 J25 J28 J30 J33 J35 J40 J45 J50 +0.2 - 0.3 e 0.95 e' e 0.95 1.90 1 2 3 0.4 +0.15 - 0.05 e 0.95 Recommended Mount Pad e 0.95 0.1 M 2.9 1.3 max +0.1 +0.15 - 0.05 (0.8) 1.1 e1 2.4 0 - 0.1 0.16 0.1 2.8 Dimensions are shown in millimeters Tolerance: x.x = 0.2 mm (unless otherwise specified) 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 Eastern Regional Office Toko America, Inc. 107 Mill Plain Road Danbury, CT 06811 Tel: (203) 748-6871 Fax: (203) 797-1223 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. Page 18 (c) 1999 Toko, Inc. All Rights Reserved IC-161-TK712xx 0798O0.0K 15 0.3 max January 1999 TOKO, Inc. Printed in the USA |
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