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| 50mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT PRELIMINARY INFORMATION TC1054 TC1054 50mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT FEATURES s s s s s s s s s s Zero Ground Current for Longer Battery Life Very Low Dropout Voltage Guaranteed 50mA Output High Output Voltage Accuracy Standard or Custom Output Voltages Power-Saving Shutdown Mode ERROR Output can be Used as a Low Battery Detector, or Processor Reset Generator Over-Current and Over-Temperature Protection Space-Saving SOT-23A-5 Package Pin Compatible Upgrades for Bipolar Regulators GENERAL DESCRIPTION The TC1054 is a high accuracy (typically 0.5%) CMOS upgrade for older (bipolar) low dropout regulators. Designed specifically for battery-operated systems, the TC1054's CMOS construction eliminates wasted ground current, significantly extending battery life. Total supply current is typically 50A at full load (20 to 60 times lower than in bipolar regulators!). TC1054 key features include ultra low noise operation, very low dropout voltage (typically 100mV at full load) and internal feed-forward compensation for fast response to step changes in load. An error output (ERROR) is asserted when the TC1054 is out-of-regulation (due to a low input voltage or excessive output current). ERROR can be used as a low battery warning or as a processor RESET signal (with the addition of an external RC network). Supply current is reduced to less than 1A, and both VOUT and ERROR are disabled when the shutdown input is low. The TC1054 incorporates both over-temperature and over-current protection. The TC1054 is stable with an output capacitor of only 1F and has a maximum output current of 50mA. For higher output current regulators, please see the TC1055 (IOUT = 100mA) regulator and TC1107, TC1108 (IOUT = 300mA) data sheets. TYPICAL APPLICATION APPLICATIONS s s s s s s s Battery Operated Systems Portable Computers Medical Instruments Instrumentation Cellular/GSMS/PHS Phones Linear Post-Regulators for SMPS Pagers ORDERING INFORMATION Part No. Output Voltage **(V) Package 2.5 2.7 3.0 3.3 5.0 Junction Temp. Range TC1054-2.5VCT TC1054-2.7VCT TC1054-3.0VCT TC1054-3.3VCT TC1054-5.0VCT SOT-23A-5* - 40C to +125C SOT-23A-5* - 40C to +125C SOT-23A-5* - 40C to +125C SOT-23A-5* - 40C to +125C SOT-23A-5* - 40C to +125C VIN 1 VIN VOUT 5 1F VOUT NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A) ** Other output voltages available. Please contact TelCom Semiconductor for details 2 GND TC1054 1M PIN CONFIGURATION VOUT 5 ERROR 3 4 SHDN ERROR 4 ERROR TC1054 (SOT-23A-5*) 1 2 3 TOP VIEW Shutdown Control (from Power Control Logic) VIN GND SHDN NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A) TC1054-01 6/12/97 TelCom Semiconductor reserves the right to make changes in the circuitry and specifications of its devices 1 PRELIMINARY INFORMATION 50mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT TC1054 ABSOLUTE MAXIMUM RATINGS* Input Voltage .................................................................7V Output Voltage ............................. (- 0.3V) to (VIN + 0.3V) Power Dissipation .................... Internally Limited (Note 7) Operating Temperature Range ........ - 40C < TJ < 125C Storage Temperature ............................ - 65C to +150C Maximum Voltage on Any Pin ............ VIN +0.3V to - 0.3V Lead Temperature (Soldering, 10 Sec.) ................ +260C *Stresses above 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 above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS: VIN = VOUT + 1V, IL = 0.1mA, CL = 3.3F, SHDN > VIH, TA = 25C, unless otherwise noted. BOLDFACE type specifications apply for junction temperatures of - 40C to +125C. Symbol VIN IOUTMAX VOUT TC VOUT VOUT/VIN VOUT/VOUT VIN - VOUT Parameter Input Operating Voltage Maximum Output Current Output Voltage VOUT Temperature Coefficient Line Regulation Load Regulation Test Conditions Min -- 50 VR - 2.5% -- -- -- -- -- -- -- -- -- 100 x VR -- -- -- -- -- -- 45 -- Typ -- -- VR 0.5% -- 40 0.01 0.5 5 65 95 0 50 -- 160 x VR 64 200 0.04 160 10 160 -- -- Max 6.5 -- VR + 2.5% -- 0.05 -- -- Units V mA V ppm/C %/V % mV Note 1 Note 2 IGND IIN IINSD ROUT PSRR IOUTSC VOUT/PD TSD TSD eN (VR + 1V) < VIN < 6V IL = 0.1mA to IOUTMAX (Note 3) Dropout Voltage IL = 0.1mA IL = 20mA IL = 50mA (Note 4) Ground Pin Current IL = IOUTMAX, (Note 5) Supply Current SHDN = VIH, IL = 0 Shutdown Supply Current SHDN = 0V Output Resistance during Shutdown SHDN < VIL Power Supply Rejection Ratio FRE 1kHz Output Short Circuit Current VOUT = 0V Thermal Regulation Note 6 Thermal Shutdown Die Temperature Thermal Shutdown Hysteresis Output Noise IL = IOUTMAX SHDN Input High Threshold SHDN Input Low Threshold VIN = 2.5V to 6.5V VIN = 2.5V to 6.5V -- -- 0.05 -- -- 450 -- -- -- -- -- 15 A A A k dB mA %W C C V %VIN %VIN SHDN Input VIH VIL TC1054-01 6/12/97 2 50mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT PRELIMINARY INFORMATION TC1054 ELECTRICAL CHARACTERISTICS: VIN = VOUT + 1V, IL = 0.1mA, CL = 3.3F, SHDN > VIH, TA = 25C, unless otherwise noted. Symbol ERROR Output VMIN VOL VTH VHYS Minimum Operating Voltage Output Logic Low Voltage ERROR Threshold Voltage ERROR Positive Hysteresis 1mA Flows to ERROR See Figure 2 Note 8 1.0 -- -- -- -- -- 0.95 x VR 50 -- 400 -- -- V mV V mV Parameter Test Conditions Min Typ Max Units NOTES: 1. VR is the regulator output voltage setting. VR = 2.5V, 2.7V, 3.0V, 3.3V, 5.0V. 2. TC VOUT = VOUTMAX - VOUTMIN x 106 VOUT x T 3. Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested over a load range from 0.1mA to the maximum specified output current. Changes in output voltage due to heating effects are covered by the thermal regulation specification. 4. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value. 5. Ground pin current is the regulator pass transistor gate current. The total current drawn from the input supply is the sum of the load current, ground current and supply current (i.e. IIN = ISUPPLY + IGND + ILOAD). 6. Thermal Regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or line regulation effects. Specifications are for a current pulse equal to ILMAX at VIN = 6V for T = 10msec. 7. The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction temperature and the thermal resistance from junction-to-air (i.e. TA, TJ, qJA). Exceeding the maximum allowable power dissipation causes the device to initiate thermal shutdown. Please see Thermal Considerations section of this data sheet for more details. 8. Hysteresis voltage is referenced by VR. PIN DESCRIPTION Pin No. (SOT-23A-5) 1 2 3 Symbol VIN GND SHDN Description Unregulated supply input. Ground terminal. Shutdown control input. The regulator is fully enabled when a logic high is applied to this input. The regulator enters shutdown when a logic low is applied to this input. During shutdown, output voltage falls to zero, ERROR is open circuited and supply current is reduced to 0.05 microamp (typical). Out-of-Regulation Flag. (Open drain output). This output goes low when VOUT is out-of-tolerance by approximately - 5%. Regulated voltage output. 4 5 ERROR VOUT TC1054-01 6/12/97 3 PRELIMINARY INFORMATION 50mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT TC1054 DETAILED DESCRIPTION The TC1054 is a precision fixed output voltage regulator. (If an adjustable version is desired, please see the TC1070 or TC1071 data sheets.) Unlike the bipolar regulators, the TC1054 supply current does not increase with load current. In addition, VOUT remains stable and within regulation at very low load currents (an important consideration in RTC and CMOS RAM battery back-up applications). Figure 1 shows a typical application circuit. The regulator is enabled any time the shutdown input (SHDN) is at or above VIH, and shutdown (disabled) when SHDN is at or below VIL. SHDN may be controlled by a CMOS logic gate, or I/O port of a microcontroller. If the SHDN input is not required, it should be connected directly to the input supply. While in shutdown, supply current decreases to 0.05A (typical) and VOUT falls to zero volts and ERROR is open circuited. Pull-up resistor R1 can be tied to VOUT, VIN or any other voltage less than (VIN = 0.3V). VOUT VTH HYSTERESIS (VHYS) ERROR VIH VOL Figure 2. ERROR Output Operation Output Capacitor VIN 1F VOUT 1F C1 GND VOUT BATTERY TC1054VCT V+ SHDN Shutdown Control (to CMOS Logic or Tie to VIN if unused) ERROR R1 1M BATTLOW or RESET C2 Requires Only if ERROR is used as a Processor RESET Signal (See Text) 0.2F C2 Figure 1. Typical Application Circuit A 1F(min) capacitor from VOUT to ground is recommended. The output capacitor should have an effective series resistance of 5 or less, and a resonant frequency above 1MHz. A 1F capacitor should be connected from VIN to GND if there is more than 10 inches of wire between the regulator and the AC filter capacitor, or if a battery is used as the power source. Aluminum electrolytic or tantalum capacitor types can be used. (Since many aluminum electrolytic capacitors freeze at approximately - 30C, solid tantalums are recommended for applications operating below - 25C.) When operating from sources other than batteries, supply-noise rejection and transient response can be improved by increasing the value of the input and output capacitors and employing passive filtering techniques. ERROR Open Drain Output ERROR is driven low whenever VOUT falls out of regulation by more than - 5% (typical). This condition may be caused by low input voltage, output current limiting, or thermal limiting. The ERROR threshold is 5% below rated VOUT regardless of the programmed output voltage value (e.g. ERROR = VOL at 4.75 (typ.) for a 5.0V regulator and 2.85V (typ.) for a 3.0V regulator). ERROR output operation is shown in Figure 2. Note that ERROR is active when VOUT falls to VTH, and inactive when VOUT rises above VTH = VHYS. As shown in Figure 1, ERROR can be used as a battery low flag, or as a processor RESET signal (with the addition of timing capacitor C2). R1 x C2 should be chosen to maintain ERROR below VIH of the processor RESET input for at least 200msec to allow time for the system to stabilize. TC1054-01 6/12/97 Thermal Considerations Thermal Shutdown Integrated thermal protection circuitry shuts the regulator off when die temperature exceeds 160C. The regulator remains off until the die temperature drops to approximately 150C. Power Dissipation The amount of power the regulator dissipates is primarily a function of input and output voltage, and output current. The following equation is used to calculate worst case actual power dissipation: 4 50mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT PRELIMINARY INFORMATION TC1054 PD (VINMAX - VOUTMIN)ILOADMAX Where: PD VINMAX VOUTMIN ILOADMAX = Worst case actual power dissipation = Maximum voltage on VIN = Minimum regulator output voltage = Maximum output (load) current Equation 1. In this example, the TC1054 dissipates a maximum of only 18.5mW; far below the allowable limit of 318mW. In a similar manner, Equation 1 and Equation 2 can be used to calculate maximum current and/or input voltage limits. Layout Considerations The primary path of heat conduction out of the package is via the package leads. Therefore, layouts having a ground plane, wide traces at the pads, and wide power supply bus lines combine to lower JA and therefore increase the maximum allowable power dissipation limit. The maximum allowable power dissipation (Equation 2) is a function of the maximum ambient temperature (TAMAX), the maximum allowable die temperature (125C) and the thermal resistance from junction-to-air (JA). SOT-23A-5 package has a JA of approximately 220C/Watt when mounted on a single layer FR4 dielectric copper clad PC board. PD MAX = (TJMAX - TJMAX) JA Where all terms are previously defined. Equation 2. Equation 1 can be used in conjunction with Equation 2 to ensure regulator thermal operation is within limits. For example: Given: VINMAX = 3.0V 5% VOUTMIN = 2.7V 0.5V ILOAD = 40mA TAMAX = 55C 1. Actual power dissipation 2. Maximum allowable dissipation Find: Actual power dissipation: PD (VINMAX - VOUTMIN)ILOADMAX = [(3.0 x 1.05) - (2.7 x .995)]40 x 10-3 = 18.5mW Maximum allowable power dissipation: PDMAX = (TJMAX - TAMAX) JA = (125 - 55) 220 = 318mW TC1054-01 6/12/97 5 PRELIMINARY INFORMATION 50mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT TC1054 MARKINGS SOT-23A-5 & = part number code + temperature range and voltage TC1054 (V) 2.5 2.7 3.0 3.3 5.0 Code C1 C2 C3 C4 C6 represents year and quarter code represents lot ID number PACKAGE DIMENSIONS SOT-23A-5* 0.75 (1.90) REFERENCE .122 (3.10) .098 (2.50) .020 (0.50) .012 (0.30) .071 (1.80) .059 (1.50) .037 (0.95) REFERENCE .122 (3.10) .106 (2.70) .057 (1.45) .035 (0.90) .006 (0.15) .000 (0.00) 10 MAX. .022 (0.55) .008 (0.20) .010 (0.25) .004 (0.09) NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A) Dimensions: inches (mm) Sales Offices TelCom Semiconductor 1300 Terra Bella Avenue P.O. Box 7267 Mountain View, CA 94039-7267 TEL: 415-968-9241 FAX: 415-967-1590 E-Mail: liter@c2smtp.telcom-semi.com TC1054-01 6/12/97 TelCom Semiconductor Austin Product Center 9101 Burnet Rd. Suite 214 Austin, TX 78758 TEL: 512-873-7100 FAX: 512-873-8236 6 TelCom Semiconductor H.K. Ltd. 10 Sam Chuk Street, Ground Floor San Po Kong, Kowloon Hong Kong TEL: 852-2324-0122 FAX: 852-2354-9957 Printed in the U.S.A. 100mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT PRELIMINARY INFORMATION TC1055 TC1055 100mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT FEATURES s s s s s s s s s s Zero Ground Current for Longer Battery Life Very Low Dropout Voltage Guaranteed 100mA Output High Output Voltage Accuracy Standard or Custom Output Voltages Power-Saving Shutdown Mode ERROR Output can be Used as a Low Battery Detector, or Processor Reset Generator Over-Current and Over-Temperature Protection Space-Saving SOT-23A-5 Package Pin Compatible Upgrades for Bipolar Regulators GENERAL DESCRIPTION The TC1055 is a high accuracy (typically 0.5%) CMOS upgrade for older (bipolar) low dropout regulators. Designed specifically for battery-operated systems, the TC1055's CMOS construction eliminates wasted ground current, significantly extending battery life. Total supply current is typically 50A at full load (20 to 60 times lower than in bipolar regulators!). TC1055 key features include ultra low noise operation, very low dropout voltage (typically 200mV at full load) and internal feed-forward compensation for fast response to step changes in load. An error output (ERROR) is asserted when the TC1055 is out-of-regulation (due to a low input voltage or excessive output current). ERROR can be used as a low battery warning or as a processor RESET signal (with the addition of an external RC network). Supply current is reduced to less than 1A, and both VOUT and ERROR are disabled when the shutdown input is low. The TC1055 incorporates both over-temperature and over-current protection. The TC1055 is stable with an output capacitor of only 1F and has a maximum output current of 100mA. For higher output current regulators, please see the TC1107, TC1108 (IOUT = 300mA) data sheets. TYPICAL APPLICATION APPLICATIONS s s s s s s s Battery Operated Systems Portable Computers Medical Instruments Instrumentation Cellular/GSMS/PHS Phones Linear Post-Regulators for SMPS Pagers ORDERING INFORMATION Part No. Output Voltage **(V) Package 2.5 2.7 3.0 3.3 5.0 Junction Temp. Range TC1055-2.5VCT TC1055-2.7VCT TC1055-3.0VCT TC1055-3.3VCT TC1055-5.0VCT SOT-23A-5* - 40C to +125C SOT-23A-5* - 40C to +125C SOT-23A-5* - 40C to +125C SOT-23A-5* - 40C to +125C SOT-23A-5* - 40C to +125C VIN 1 VIN VOUT 5 1F VOUT NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A) ** Other output voltages available. Please contact TelCom Semiconductor for details 2 GND TC1055 1M PIN CONFIGURATION VOUT 5 ERROR 3 4 SHDN ERROR 4 ERROR TC1055 (SOT-23A-5*) 1 VIN 2 GND 3 SHDN TOP VIEW Shutdown Control (from Power Control Logic) NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A) TC1055-01 6/5/97 TelCom Semiconductor reserves the right to make changes in the circuitry and specifications of its devices 1 PRELIMINARY INFORMATION 100mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT TC1055 ABSOLUTE MAXIMUM RATINGS* Input Voltage .................................................................7V Output Voltage ............................. (- 0.3V) to (VIN + 0.3V) Power Dissipation .................... Internally Limited (Note 7) Operating Temperature Range ........ - 40C < TJ < 125C Storage Temperature ............................ - 65C to +150C Maximum Voltage on Any Pin ............ VIN +0.3V to - 0.3V *Stresses above 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 above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS: VIN = VOUT + 1V, IL = 0.1mA, CL = 3.3F, SHDN > VIH, TA = 25C, unless otherwise noted. Symbol VIN IOUTMAX VOUT TC VOUT VOUT/VIN VOUT/VOUT VIN - VOUT Parameter Input Operating Voltage Maximum Output Current Output Voltage VOUT Temperature Coefficient Line Regulation Load Regulation Test Conditions Note 9 Note 9 Notes 1, 9 Note 2, 9 Min -- 100 VR - 2.5% -- -- -- -- -- -- -- -- -- -- 100 x VR -- -- -- -- 45 -- Typ -- -- VR 0.5% 20 40 0.05 0.5 20 70 100 200 0 50 -- 160 x VR 64 300 0.04 160 -- -- Max 6.5 -- VR + 2.5% -- -- -- -- Units V mA V ppm/C % % mV IGND IIN IINSD ROUT PSRR IOUTSC VOUT/PD eN (VR + 1V) < VIN < 6V IL = 0.1mA to IOUTMAX (Note 3) Dropout Voltage IL = 0.1mA IL = 20mA IL = 50mA IL = 100mA (Note 4) Ground Pin Current IL = IOUTMAX, (Note 5, 9) Supply Current SHDN = VIH, IL = 0 Shutdown Supply Current SHDN = 0V Output Resistance during Shutdown SHDN < VIL Power Supply Rejection Ratio FRE 1kHz Output Short Circuit Current VOUT = 0V Thermal Regulation Note 6 Output Noise IL = IOUTMAX SHDN Input High Threshold SHDN Input Low Threshold VIN = 2.5V to 6.5V VIN = 2.5V to 6.5V -- 80 0.05 -- -- 500 -- -- -- 15 A A A k dB mA %W nV/Hz %VIN %VIN SHDN Input VIH VIL TC1055-01 6/5/97 2 100mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT PRELIMINARY INFORMATION TC1055 ELECTRICAL CHARACTERISTICS: VIN = VOUT + 1V, IL = 0.1A, CL = 3.3F, SHDN > VIH, TA = 25C, unless otherwise noted. Symbol VMIN VOL VTH VHYS Parameter Minimum Operating Voltage Output Logic Low Voltage ERROR Threshold Voltage ERROR Positive Hysteresis Test Conditions Min 1.0 -- -- -- Typ -- -- 0.95 x VR 50 Max -- 400 -- -- Units V mV V mV ERROR Open Drain Output 1mA Flows to ERROR See Figure 2 Note 8 NOTES: 1. VR is the regulator output voltage setting. VR = 2.5V, 2.7V, 3.0V, 3.3V, 5.0V. 2. TC VOUT = (VOUTMAX - VOUTMIN) x 106 VOUT x T 3. Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested over a load range from 0.1mA to the maximum specified output current. Changes in output voltage due to heating effects are covered by the thermal regulation specification. 4. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value. 5. Ground pin current is the regulator pass transistor gate current. The total current drawn from the input supply is the sum of the load current, ground current and supply current (i.e. IIN = ISUPPLY + IGND + ILOAD). 6. Thermal Regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or line regulation effects. Specifications are for a current pulse equal to ILMAX at VIN = 6V for T = 10msec. 7. The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction temperature and the thermal resistance from junction-to-air (i.e. TA, TJ, qJA). Exceeding the maximum allowable power dissipation causes the device to initiate thermal shutdown. Please see Thermal Considerations section of this data sheet for more details. 8. Hysteresis voltage is referenced by VR. 9. Boldface type specifications apply for junction temperatures of - 40C to +125C. PIN DESCRIPTION Pin No. (SOT-23A-5) 1 2 3 Symbol VIN GND SHDN Description Unregulated supply input. Ground terminal. Shutdown control input. The regulator is fully enabled when a logic high is applied to this input. The regulator enters shutdown when a logic low is applied to this input. During shutdown, output voltage falls to zero, ERROR is open circuited and supply current is reduced to 0.05 microamp (typical). Out-of-Regulation Flag. (Open drain output). This output goes low when VOUT is out-of-tolerance by approximately - 5%. Regulated voltage output. 4 5 ERROR VOUT TC1055-01 6/5/97 3 PRELIMINARY INFORMATION 100mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT TC1055 DETAILED DESCRIPTION The TC1055 is a precision fixed output voltage regulator. (If an adjustable version is desired, please see the TC1070 or TC1071 data sheets.) Unlike the bipolar regulators, the TC1055 supply current does not increase with load current. In addition, VOUT remains stable and within regulation at very low load currents (an important consideration in RTC and CMOS RAM battery back-up applications). Figure 1 shows a typical application circuit. The regulator is enabled any time the shutdown input (SHDN) is at or above VIH, and shutdown (disabled) when SHDN is at or below VIL. SHDN may be controlled by a CMOS logic gate, or I/O port of a microcontroller. If the SHDN input is not required, it should be connected directly to the input supply. While in shutdown, supply current decreases to 0.05A (typical) and VOUT falls to zero volts and ERROR is open circuited. Pull-up resistor R1 can be tied to VOUT, VIN or any other voltage less than (VIN + 0.3V). VOUT VTH HYSTERESIS (VHYS) ERROR VIH VOL Figure 2. ERROR Output Operation Output Capacitor VIN 1F VOUT 1F C1 GND VOUT BATTERY TC1055VCT V+ SHDN Shutdown Control (to CMOS Logic or Tie to VIN if unused) ERROR R1 1M BATTLOW or RESET C2 Requires Only if ERROR is used as a Processor RESET Signal (See Text) 0.2F C2 Figure 1. Typical Application Circuit A 1F(min) capacitor from VOUT to ground is recommended. The output capacitor should have an effective series resistance of 5 or less, and a resonant frequency above 1MHz. A 1F capacitor should be connected from VIN to GND if there is more than 10 inches of wire between the regulator and the AC filter capacitor, or if a battery is used as the power source. Aluminum electrolytic or tantalum capacitor types can be used. (Since many aluminum electrolytic capacitors freeze at approximately - 30C, solid tantalums are recommended for applications operating below - 25C.) When operating from sources other than batteries, supply-noise rejection and transient response can be improved by increasing the value of the input and output capacitors and employing passive filtering techniques. ERROR Open Drain Output ERROR is driven low whenever VOUT falls out of regulation by more than - 5% (typical). This condition may be caused by low input voltage, output current limiting, or thermal limiting. The ERROR threshold is 5% below rated VOUT regardless of the programmed output voltage value (e.g. ERROR = VOL at 4.75 (typ.) for a 5.0V regulator and 2.85V (typ.) for a 3.0V regulator). ERROR output operation is shown in Figure 2. Note that ERROR is active when VOUT falls to VTH, and inactive when VOUT rises above VTH by VHYS. As shown in Figure 1, ERROR can be used as a battery low flag, or as a processor RESET signal (with the addition of timing capacitor C2). R1 x C2 should be chosen to maintain ERROR below VIH of the processor RESET input for at least 200msec to allow time for the system to stabilize. TC1055-01 6/5/97 Thermal Considerations Thermal Shutdown Integrated thermal protection circuitry shuts the regulator off when die temperature exceeds 160C. The regulator remains off until the die temperature drops to approximately 150C. Power Dissipation The amount of power the regulator dissipates is primarily a function of input and output voltage, and output current. The following equation is used to calculate worst case actual power dissipation: 4 100mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT PRELIMINARY INFORMATION TC1055 PD (VINMAX - VOUTMIN)ILOADMAX Where: PD VINMAX VOUTMIN ILOADMAX = Worst case actual power dissipation = Maximum voltage on VIN = Minimum regulator output voltage = Maximum output (load) current Equation 1. In this example, the TC1055 dissipates a maximum of only 60mW; far below the allowable limit of 318mW. In a similar manner, Equation 1 and Equation 2 can be used to calculate maximum current and/or input voltage limits. For example, the maximum allowable VIN is found by substituting the maximum allowable power dissipation of 318mW into Equation 1, from which VINMAX = 5.9V. Layout Considerations The primary path of heat conduction out of the package is via the package leads. Therefore, layouts having a ground plane, wide traces at the pads, and wide power supply bus lines combine to lower JA and therefore increase the maximum allowable power dissipation limit. The maximum allowable power dissipation (Equation 2) is a function of the maximum ambient temperature (TAMAX), the maximum allowable die temperature (125C) and the thermal resistance from junction-to-air (JA). SOT-23A-5 package has a JA of approximately 220C/Watt when mounted on a single layer FR4 dielectric copper clad PC board. PD MAX = (TJMAX - TJMAX) JA Where all terms are previously defined. Equation 2. Equation 1 can be used in conjunction with Equation 2 to ensure regulator thermal operation is within limits. For example: Given: VINMAX = 3.0V 5% VOUTMIN = 2.7V 0.5V ILOAD = 40mA TAMAX = 55C 1. Actual power dissipation 2. Maximum allowable dissipation Find: Actual power dissipation: PD (VINMAX - VOUTMIN)ILOADMAX = [(3.0 x 1.05) - (2.7 x .995)]40 x 10-3 = 18.5mW Maximum allowable power dissipation: PDMAX = (TJMAX - TAMAX) JA = (125 - 55) 220 = 318mW TC1055-01 6/5/97 5 PRELIMINARY INFORMATION 100mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT TC1055 MARKINGS SOT-23A-5 & = part number code + temperature range and voltage TC1055 (V) 2.5 2.7 3.0 3.3 5.0 Code D1 D2 D3 D4 D6 represents year and quarter code represents lot ID number PACKAGE DIMENSIONS SOT-23A-5* 0.75 (1.90) REFERENCE .122 (3.10) .098 (2.50) .020 (0.50) .012 (0.30) .071 (1.80) .059 (1.50) .037 (0.95) REFERENCE .122 (3.10) .106 (2.70) .057 (1.45) .035 (0.90) .006 (0.15) .000 (0.00) 10 MAX. .022 (0.55) .008 (0.20) .010 (0.25) .004 (0.09) NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A) Dimensions: inches (mm) Sales Offices TelCom Semiconductor 1300 Terra Bella Avenue P.O. Box 7267 Mountain View, CA 94039-7267 TEL: 415-968-9241 FAX: 415-967-1590 E-Mail: liter@c2smtp.telcom-semi.com TC1055-01 6/5/97 TelCom Semiconductor Austin Product Center 9101 Burnet Rd. Suite 214 Austin, TX 78758 TEL: 512-873-7100 FAX: 512-873-8236 6 TelCom Semiconductor H.K. Ltd. 10 Sam Chuk Street, Ground Floor San Po Kong, Kowloon Hong Kong TEL: 852-2324-0122 FAX: 852-2354-9957 Printed in the U.S.A. |
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