TK73200 ADJUSTABLE LOW DROPOUT REGULATOR FEATURES APPLICATIONS ■ Up to 5 A Output Current Capability with External PNP Transistor ■ Internal Short Circuit Protection ■ Excellent Load Regulation ■ CMOS/TTL-Compatible On/Off Switch ■ Internal Reverse Bias Current Protection Switch ■ Internal Thermal Shutdown ■ Wide Adjustable Output Voltage Range (2.0 V to 12.0 V) ■ Continuous and Pulsed Current Modes ■ ■ ■ ■ ■ ■ ■ ■ ■ Battery Powered Systems Cellular/Cordless Telephones Radio Control Systems Wireless Communications Systems Portable Instrumentations Portable Computers Personal Digital Assistants Local Area Network (LAN) Receivers Power Recovery for Microprocessors DESCRIPTION The TK73200 is a controller IC for an adjustable low dropout voltage regulator. The TK73200 and the external PNP power transistor provide adjustable output voltages from 2 to 12 V and output current from 100 mA to 5 A. By utilizing an external PNP power transistor, low dropout voltage at high current can be readily achieved. The internal electronic switch can be controlled by TTL or CMOS logic levels. The device is in the “on” state when the control pin is pulled to a high logic level. A pin for a bypass capacitor, which connects to the internal circuitry, is provided to lower the overall output noise level. TK73200 CONTROL BASE NOISE BYPASS VADJ CPULSE GND VIN IPK The current limit characteristics can be configured as continuous (constant current) or pulsed (cycling). An internal thermal shutdown circuit limits the junction temperatures to below 150 °C. BLOCK DIAGRAM VIN IPK CPULSE BASE VADJ ORDERING INFORMATION TK73200M L ON/OFF CIRCUIT Tape/Reel Code Temp. Code Package Code TAPE/REEL CODE PACKAGE CODE L: Tape Left M: SOT23L-8 THERMAL SENSOR CONTROL BANDGAP REFERENCE TEMP. RANGE C: -30 to 80 °C GND June 1999 TOKO, Inc. NOISE BYPASS Page 1 TK73200 ABSOLUTE MAXIMUM RATINGS (NOTE 5) Supply Voltage Range ............................................ 19 V Power Dissipation (Note 1) ................................ 600 mW Reverse Bias Voltage Range ..................................... 6 V Noise Bypass Pin Terminal Voltage Range ............... 5 V Control Pin Terminal Voltage Range ........................ 14 V Storage Temperature Range ................... -55 to +150 °C Operating Temperature Range ...................-30 to +80 °C Extended Temperature Range ................... -40 to +85 °C Operating Voltage Range ............................ 1.8 to 14.0 V Junction Temperature ........................................... 150 °C Lead Soldering Temperature (10 s) ...................... 235 °C TK73200 ELECTRICAL CHARACTERISTICS Test conditions: VIN = VOUT(TYP) + 1 V, TA = 25 °C, unless otherwise specified. SYMBOL PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 250 360 µA 0.1 µA IQ Quiescent Current IOUT = 0 mA, Excluding ICONT ISTBY Standby Current VIN = 8 V, Output OFF IOUT Output Current External Transistor Dependent N/ A A VDROP Dropout Voltage External Transistor Dependent N/A V VOUT Output Voltage Set by External Resistors Line Reg Line Regulation VIN = VOUT(TYP) + 1 V to VOUT(TYP) + 6 V (Note 2) 3.0 External Transistor Dependent 10 Load Reg Load Regulation 2 12 V 20 mV mV IBASE(L) Base Current LOW 1.8 V ≤ VIN ≤ 4 V 15 mA IBASE(H) Base Current HIGH 4.1 V ≤ VIN ≤ 12 V 40 mA Continuous Current Limit Mode 80 100 120 mV VSENSE Current Limit Detect Voltage Pulse Current Limit Mode 70 90 110 mV RR Ripple Rejection f = 400 Hz, CL = 10 µF, CN = 0.1 µF, VIN = VOUT(TYP) = 1.5 V, IOUT = 30 mA, VRIPPLE = 100 mVrms, (Note 3) VNO Output Noise f = 1 kHz, BPF = 400 Hz to 30 kHz, (Note 3) IPULSE CPULSE Pin Terminal Current (Note 4) 15 ∆VOUT /∆T Temperature Coefficient Vref 57 dB 0.13 µV/ Hz 25 45 20 Reference Voltage 1.22 µA ppm/° C 1.25 1.28 V 6.5 20 µA CONTROL TERMINAL SPECIFICATIONS ICONT Control Current VCONT = 1.8 V, Output ON VCONT(ON) Control Voltage (ON) Output ON VCONT(OFF) Control Voltage (OFF) Output OFF Page 2 1.8 V 0.6 V June 1999 TOKO, Inc. TK73200 TK73200 ELECTRICAL CHARACTERISTICS (STANDARD DEVICES) CONT. Note 1: Power dissipation is 600 mW when mounted as recommended. Derate at 4.8 mW/°C for operation above 25 °C. Note 2: Refer to: “Definition of Terms.” Note 3: Ripple rejection and noise voltage are affected by the value and characteristics of the capacitor used. Note 4: This pin is used for Pulse Current Limit Mode. When selecting Continuous Current Limit Mode, this pin is connected to GND. Note 5: The voltage applied to any pin must be greater than -0.4 V. Gen. Note: Parameters with min. or max. values are 100% tested at TA = 25 °C. June 1999 TOKO, Inc. Page 3 TK73200 TEST CIRCUIT CP CN RP VIN CIN Note:Transistor: 2SB1115 CN = 0.1 µF CP = 0.1 µF CIN = 1 µF CL = 4.7 µF RP = 330 k Continuous Current Limit Mode: ISET (mA) = 100 mV / RIPK (Ω) Pulse Current Limit Mode: ISET (mA) = 90 mV / RIPK (Ω) TK73200 RIPK VOUT = 1.25 ( 1 + R2 / R1) 20 kΩ ≤ R1 ≤ 68 kΩ 2.0 V ≤ VOUT ≤12 V VOUT CONT BASE R1 EMITTER CL EXTERNAL TRANSISTOR R2 COLLECTOR VOUT TYPICAL PERFORMANCE CHARACTERISTICS TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified. 0 10 VOUT (5 mV/ DIV) 20 0 10 20 0 IOUT (mA) QUIESCENT CURRENT VS. INPUT VOLTAGE DROPOUT VOLTAGE VS. OUTPUT CURRENT AND EXTERNAL TRANSISTORS GROUND CURRENT VS. OUTPUT CURRENT 2SB799 VOUT = 5.0 V 2 1 2SB1115 -200 2SB1114 2SB1302 -300 0 VIN (V) Page 4 20 3 2 1 -400 10 4 IGND (mA) VDROP (mV) 3 1000 5 -100 VOUT = 3.0 V 0 500 VIN (V) 0 4 VOUT TYPICAL VIN (V) 5 IQ (mA) LOAD REGULATION VOUT (10 mV/ DIV) LINE REGULATION 2 VOUT (50 mV/ DIV) LINE REGULATION 1 0 500 IOUT (mA) 1000 0 0 500 1000 IOUT (mA) June 1999 TOKO, Inc. TK73200 TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified. CURRENT LIMIT DETECTOR VOLTAGE VS. INPUT VOLTAGE BASE CURRENT DRIVE VS. INPUT VOLTAGE REVERSE BIAS CURRENT (VIN = 0 TO 6 V) 1E-6 100 IREV (A) 100 IB (mA) ∆V (mV) CONTINUOUS CURRENT LIMIT MODE PULSE CURRENT LIMIT MODE VIN = 0 V 1E-9 50 VIN = 6 V 50 VIN = 4 V VIN = 2 V 1E-12 0 5 10 15 0 5 VIN (V) 10 0 15 5 QUIESCENT CURRENT VS. INPUT VOLTAGE (OFF MODE) 10 VREV (V) VIN (V) RIPPLE REJECTION 0 CN = NONE -20 VIN VOUT 73200 IQ (A) RR (dB) 1E-6 -40 VCONT CN = 0.01 µF CL 4.7 µF CN RCONT -60 1E-9 CN = 0.1 µF RIPPLE REJECTION CIRCUIT -80 -100 0.01 1E-12 0 10 20 100 CONTROL VOLTAGE (OUTPUT ON POINT) VS. TEMPERATURE 2.0 OUTPUT VOLTAGE VARIATION VS. TEMPERATURE 50 RCONT = 0 Ω VCONT = 5 V 30 20 VOUT (mV) 30 VCONT (V) ICONT (µA) 10 CONTROL CURRENT VS. TEMPERATURE 40 0 -50 1 f (kHz) 50 10 0.1 VIN (V) 1.0 VCONT = 2 V 0 June 1999 TOKO, Inc. 10 -10 -30 50 TA (°C) VOUT TYPICAL 100 -50 0 50 TA (°C) 100 -50 -50 0 50 100 TA (°C) Page 5 TK73200 TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) TA = 25 °C, external transistor is 2SB1115(NEC), unless otherwise specified. CONTROL PIN VOLTAGE VS. CONTROL CURRENT ON/OFF STEP RESPONSE ON/OFF TRANSIENT 5000 50 VOUT 30 RISE TIME (µs) 40 VCONT (V) CL = 100 µF ON/OFF CONTROL RCONT = 0 k RCONT = 100 k 20 1000 CL = 4.7 µF CL = 4.7 µF OR 10 µF CL = 22 µF 100 RCONT = 200 k 0 50 10 0.001 100 VOUT 10 0 -50 CL = 4.7 µF CN = NONE IOUT = 30 mA 0.01 0.1 10 10 20 30 TIME (µs) CN (µF) ICONT (µA) 0 LINE VOLTAGE STEP RESPONSE LOAD CURRENT STEP RESPONSE CL = 22 µF CL = 10 µF 5 10 TIME (µs) Page 6 VIN VOUT + 1 V CN = NONE CN = 0.1 µF IOUT = 50 mA CL = 4.7 µF 0 VOUT CL = 47 OR 100 µF VOUT (20 mV/ DIV) VOUT (200 mV/ DIV) VOUT + 2 V IOUT = 0 TO 300 mA 15 20 TIME (µs) June 1999 TOKO, Inc. TK73200 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 = 30 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 100 mVrms, 400 Hz superimposed on the input voltage, where VIN = VOUT(TYP) + 1.5 V. The output decoupling capacitor is set to 10 µF, the noise bypass capacitor is set to 0.1 µF, and the load current is set to 30 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, the external transistor and the junction temperature. BASE CONTROL CURRENT (IBASE) STANDBY CURRENT (ISTBY) Standby current is the current which flows into the regulator when the output is turned off by the control function (VCONT = 0 V). It is measured with VIN = 8 V. The base control current is the drive current for the base of the external transistor. SENSOR CIRCUITS OUTPUT CURRENT (IOUT) Overcurrent Sensor The output current depends on the characteristics of the external transistor and current limit setting. The overcurrent sensor protects the device if the output is shorted to ground. LINE REGULATION (Line Reg) Thermal Sensor 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. 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. Load regulation depends on the external transistor. The thermal sensor protects the device if the junction temperature exceeds the safe value (Tj = 150 °C). This temperature rise can be caused by extreme heat, excessive power dissipation caused by large output voltage drops, or excessive output current. The regulator will shut off when the temperature exceeds the safe value. As the junction temperature decreases, the regulator will begin to operate again. Under sustained fault conditions, the regulator output will oscillate as the device turns off then resets. Damage may occur to the device under extreme fault conditions. QUIESCENT CURRENT (IQ) Reverse Voltage Protection The quiescent current is the current which flows through the ground terminal under no load conditions (IOUT = 0 mA) and excludes the control pin current. 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. LOAD REGULATION (Load Reg) GROUND CURRENT (IGND) Ground current is the current which flows through the ground pin(s). It is defined as IIN - IOUT, excluding control current. June 1999 TOKO, Inc. Page 7 TK73200 DEFINITION AND EXPLANATION OF TECHNICAL TERMS (CONT.) 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 SOT23L-8 is increased to 600 mW. For operation at ambient temperatures over 25 °C, the power dissipation of the SOT23L-8 device should be derated at 4.8 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: 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 2) PD1 is taken to be PD x (Note: It is not necessary to connect a ceramic capacitor in parallel with an aluminum or tantalum output capacitor. (~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) Tj = 0jA x PD + TA 750 For Toko ICs, the internal limit for junction temperature is 150 °C. If the ambient temperature (TA) is 25 °C, then: PD (mW) 150 °C = 0jA x PD + 25 °C 0jA = 125 °C / PD MOUNTED AS SHOWN 600 450 FREE AIR 300 150 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) SOT23L-8 POWER DISSIPATION CURVE Page 8 June 1999 TOKO, Inc. TK73200 APPLICATION INFORMATION INPUT-OUTPUT CAPACITORS PULSE CURRENT LIMIT MODE The output capacitor is necessary for stable operation. The regulator may oscillate if the output capacitor is too small or missing. The output capacitor size is determined by load, transient response and external transistor used. Evaluation in the circuit is recommended to ensure performance requirements are satisfied. A minimum of 4.7 µF is necessary for stability, with twice that value recommended. The minimum recommended input capacitor is 1 µF. Problems do not occur with larger values of capacitance. However, extremely low ESR may result in unstable operation. Thus, the use of large value ceramic capacitors is not recommended on the output. CP CN RP 330 k VIN CIN TK73200 RIPK VCONT BASE GND R1 EMITTER CL EXTERNAL TRANSISTOR R2 COLLECTOR VOUT EVALUATION BOARD TOKO VOUT R2 External Transistor R1 CL 1 The equation for the pulse output current limit is as follows: ISET (mA) = 90 (mV) / RIPK (Ω) 4.7 µF TK73200 RIPK CIN GND 1 µF 0.1 µF RP 330k VIN CON SOT23L-8 BOARD LAYOUT GND CON VIN AP008-99 TOKO VOUT VOUT IOUT During the initial turn-on, charge (surge) current flows to the output capacitor. This IC has a possibility for the current limit to operate and to turn off the output by the charge current of the output capacitor. Therefore, the relationship between CL and CP is set as shown in the graph below: 1000 100 CL (µF) CN 0.1 µF CP AP008-99 1 10 1 0.01 STABLE REGION 0.1 1 10 CP (µF) June 1999 TOKO, Inc. Page 9 TK73200 APPLICATION INFORMATION (CONT.) CONTINUOUS CURRENT LIMIT MODE VIN CN VOUT TK73200 µ PRO R VCONT R CONT VIN 2 1 CIN RIPK TK73200 VCONT GND BASE R1 EMITTER The high output voltage accuracy and low dropout voltage are maintained when the IC is turned ON/OFF by using the control pin as illustrated above. CL EXTERNAL TRANSISTOR R2 COLLECTOR VOUT In the continuous current limit mode, the CPULSE pin (pin 3) is directly connected to ground. The output current limit is set by RIPK according to the following equation: ISET (mA) = 100 (mV) / RIPK (Ω) If the continuous current limit mode is also used for output short circuit protection, the ISET value is set 50% to 100% more than the maximum operating current. The current transistor is selected from the ISET value. The output voltage drops when the output current exceeds the ISET value. However, the output voltage returns to normal once the output current decreases below the ISET value. HIGH-SIDE SWITCHING VDROP VOLTAGE REGULATOR VOUT ON/OFF CONTROL High-side switching should not be implemented by an external transistor as shown above. This results in additional voltage drop and loss of accuracy. Page 10 June 1999 TOKO, Inc. TK73200 APPLICATION INFORMATION (CONT.) EXTERNAL PNP POWER TRANSISTOR This IC can use any kind of external transistor. The external transistor selection is a function of the load current, Hfe and power dissipation. See following chart: LOAD CURRENT RECOMMENDED EXTERNAL TRANSISTOR RECOMMENDED RIPK (Ω) 0 ~ 180 mA 2SB624, 2SB1115, 2SB799 (NEC), 2SB970 (Matsushita) 0.33 ~ 0.39 0 ~ 300 mA 2SB1115, 2SB799 (NEC) 0.22 ~ 0.27 0 ~ 500 mA 2SB1114, 2SB1115 (NEC), 2SB1302 (Sanyo), 2SA1203, 2SA1213, 2SA1734 (Toshiba) 0.12 ~ 0.15 0~1A 2SA1242, 2SA1736 (Toshiba), 2SB1302, 2SA1896 (Sanyo) 0.056 ~ 0.068 0~2A 2SA1451, 2SA1242 (Toshiba) 0.033 ~ 0.039 0~3A 2SA1451 (Toshiba), 2SA1645 (NEC) 0.022 ~ 0.027 0~4A 2SA1451 (Toshiba), 2SB904 (Sanyo), 2SA1645 (NEC) 0.012 ~ 0.015 VOLTAGE BACKUP OPERATION (HOLDUP TIME) PARALLEL ON/OFF CONTROL OPERATION VOUT VIN VOLTAGE DETECTOR IC µ PRO 73200 R 2 VCONT OFF VIN TK73200 RESET R 5V 5A 2 CL R R 1 1 3V 100 mA TK11230B R TK11220B 2V 100 mA ON/OFF CONTROL C L becomes the backup power supply when the microprocessor is reset with the voltage detector IC simultaneously with turning OFF the TK73200. CL provides the holdup time necessary to do an orderly shutdown of the microprocessor. June 1999 TOKO, Inc. The figure above illustrates multiple regulators being controlled by a single ON/OFF control signal. 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-tooutput voltage across the regulator, reducing the power dissipation in the device. Page 11 TK73200 PACKAGE OUTLINE Marking Information SOT23L-8 TK73200 C00 0.45 5 1.0 8 e1 3.0 marking Product Code Voltage Code 1 e 0.8 4 Recommended Mount Pad e 0.8 0.3 0.1 Çl +0.3 3.5 - 0.1 2.2 15 max 1.2 +0.15 - 0.15 0 - 0.1 0.1 0.4 + 0.3 0.15 1.4max (0.3) (3.4) 3.3 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 12 © 1999 Toko, Inc. All Rights Reserved June 1999 TOKO, Inc. IC-xxx-TK732xx 0798O0.0K Printed in the USA