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50mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
PRELIMINARY INFORMATION
TC1072 TC1072 50mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
FEATURES
s 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 Ouput can be Used as a Low Battery Detector, or Processor Reset Generator Bypass Input for Ultra-quiet Operation Over-Current and Over-Temperature Protection Space-Saving SOT-23A-6 Package Pin Compatible Upgrades for Bipolar Regulators 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!). TC1072 key features include ultra low noise operation (plus optional Bypass input); 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 TC1072 is out-ofregulation (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 TC1072 incorporates both over-temperature and over-current protection. The TC1072 is stable with an output capacitor of only 1F and has a maximum output current of 50mA. For higher output current versions, please see the TC1107, TC1108 and TC1073 (IOUT = 300mA) data sheets.
APPLICATIONS
s s s s s s s Battery Operated Systems Portable Computers Medical Instruments Instrumentation Cellular / GSM / PHS Phones Linear Post-Regulator for SMPS Pagers
ORDERING INFORMATION
Part No. Output Voltage **(V) Package
2.5 2.7 3.0 3.3 5.0
GENERAL DESCRIPTION
The TC1072 is a high accuracy (typically 0.5%) CMOS upgrade for older (bipolar) low dropout regulators. Designed specifically for battery-operated systems, the TC1072's TYPICAL APPLICATION
1M
Junction Temp. Range
TC1072-2.5VCH TC1072-2.7VCH TC1072-3.0VCH TC1072-3.3VCH TC1072-5.0VCH
SOT-23A-6* - 40C to +125C SOT-23A-6* - 40C to +125C SOT-23A-6* - 40C to +125C SOT-23A-6* - 40C to +125C SOT-23A-6* - 40C to +125C
VIN
1
VIN
VOUT
6
VOUT 1F
NOTE: *SOT-23A-6 is equivalent to the EIAJ (SC-74A) ** Other output voltages available. Please contact TelCom Semiconductor for details
PIN CONFIGURATION
2 GND
TC1072
Bypass
5 CBYPASS 470pF
VOUT Bypass ERROR 6 5 4
3
4 SHDN ERROR ERROR
TC1072 (SOT-23A-6*)
1 VIN 2 3
TOP VIEW
GND SHDN
Shutdown Control (from Power Control Logic)
NOTE: *SOT-23A-6 is equivalent to the EIAJ (SC-74A)
TC1072-01
6/16/97
1 TelCom Semiconductor reserves the right to make changes in the circuitry and specifications ot its devices.
PRELIMINARY INFORMATION
50mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
TC1072
ABSOLUTE MAXIMUM RATINGS*
Input Voltage .................................................................7V Output Voltage .................................. (- 0.3) to (VIN + 0.3) Power Dissipation .................... Internally Limited (Note 7) Operating Temperature .................... - 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 beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational 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 specified.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 Dropout Voltage (Note 4)
Test Conditions
Min
-- 50 VR - 2.5%
Typ
-- -- VR 0.5% -- 40 0.05 0.5 5 65 95 0 50 -- 64 200 0.04 260
Max
6.5 -- VR + 2.5% -- -- -- --
Units
V mA V ppm/C %/V % mV
Note 1 Note 2 (VR + 1V) < VIN < 6V IL = 0.1mA to IOUTMAX (Note 3) IL = 0.1mA IL = 20mA IL = 50mA (Note 4) IL = IOUTMAX, (Note 5) SHDN = VIH, IL = 0 SHDN = 0V FRE 1kHz VOUT = 0V Note 6 IL = IOUTMAX 470pF from Bypass to GND VIN = 2.5V to 6.5V VIN = 2.5V to 6.5V
-- -- --
IGND IIN IINSD PSRR IOUTSC VOUT/PD eN
Ground Pin Current Supply Current Shutdown Supply Current Power Supply Rejection Ratio Output Short Circuit Current Thermal Regulation Output Noise
-- -- -- -- -- -- --
-- -- 0.05 -- 450 -- --
A A A dB mA %/W nV/Hz
SHDN Input
VIH VIL SHDN Input High Threshold SHDN Input Low Threshold 45 -- -- -- -- 15 %VIN %VIN
TC1072-01
6/16/97
2
50mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
PRELIMINARY INFORMATION
TC1072
ELECTRICAL CHARACTERISTICS: VIN = VOUT + 1V, IL = 0.1mA, 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, 3.2V, 3.3V, 3.8V 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-6)
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 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-oftolerance by approximately - 5%. Reference bypass input. Connecting a 470pF to this input further reduces output noise. Regulated voltage output.
4 5 6
ERROR Bypass VOUT
TC1072-01
6/16/97
3
PRELIMINARY INFORMATION
50mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
TC1072
DETAILED DESCRIPTION
The TC1072 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 TC1072 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 opencircuited.
VIN 1F VOUT VOUT 1F C1 GND Bypass
VOUT VTH HYSTERESIS (VHYS)
ERROR VIH VOL
Figure 2. ERROR Output Operation
Output Capacitor
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, supplynoise rejection and transient response can be improved by increasing the value of the input and output capacitors and employing passive filtering techniques.
BATTERY
TC1072
V+ SHDN Shutdown Control (to CMOS Logic or Tie to VIN if unused) ERROR R1 1M
C3, 470pF
C2 Requires Only if ERROR is used as a Processor RESET Signal (See Text)
0.2F C2
BATTLOW or RESET
Bypass Input
Figure 1. Typical Application Circuit
ERROR Open Drain Output
ERROR is driven low whenenver VOUT falls out of regulation by more than - 5% (typical). The condition my be caused by low input voltage, output current limiting, or thermal limiting. The ERROR output voltage value (e.g. ERROR = VOL at 4.75 (typ) for a 5.0V regulator and 2.85 (typ) for a 3.0V regulator). ERROR ouput 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. Pull-up resistor R1 can be tied to VOUT, VIN or any other voltage less than (VIN +0.3V).
TC1072-01 6/16/97
A 470pF capacitor connected from the Bypass input to ground reduces noise present on the internal reference, which in turn significantly reduces output noise. If output noise is not a concern, this input may be left unconnected. Larger capacitor values may be used, but results in a longer time period to rated output voltage when power is initially applied.
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.
4
50mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
PRELIMINARY INFORMATION
TC1072
The following equation is used to calculate worst case actual power dissipation: 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.
= (125 - 55) 220 = 318mW In this example, the TC1072 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. 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-6 packag has a JA of approximately 220C/Watt when mounted on a single layer FR4 dielectric copper clad PC board. PD MAX = (TJMAX - TAMAX) 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 10% 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
TC1072-01
6/16/97
5
PRELIMINARY INFORMATION
50mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
TC1072
SOT-23A-6 & = part number code + temperature range and voltage TC1072 (V) 2.5 2.7 3.0 3.3 5.0 Code E1 E2 E3 E4 E6
represents year and quarter code represents lot ID number
PACKAGE DIMENSIONS SOT-23A-6*
.118 (3.00) .102 (2.60) .020 (0.50) .014 (0.35)
.069 (1.75) .059 (1.50)
.037 (0.95) REFERENCE .118 (3.00) .110 (2.80)
.057 (1.45) .035 (0.90) .006 (0.15) .000 (0.00)
10 MAX. .022 (0.55) .014 (0.35)
.008 (0.20) .004 (0.09)
NOTE: *SOT-23A-6 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
TC1072-01 6/16/97
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, 6/F 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, ERROR OUTPUT AND VREF BYPASS
PRELIMINARY INFORMATION
TC1073 TC1073 100mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
FEATURES
s 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 Ouput can be Used as a Low Battery Detector, or Processor Reset Generator Bypass Input for Ultra-quiet Operation Over-Current and Over-Temperature Protection Space-Saving SOT-23A-6 Package Pin Compatible Upgrades for Bipolar Regulators
GENERAL DESCRIPTION
The TC1073 is a high accuracy (typically 0.5%) CMOS upgrade for older (bipolar) low dropout regulators such as the LP2980. Designed specifically for battery-operated systems, the TC1073'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!). TC1073 key features include ultra low noise operation (plus optional Bypass input); 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 TC1073 is out-ofregulation (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 TC1073 incorporates both over-temperature and over-temeprature protection. The TC1073 is stable with an output capacitor of only 1F and has a maximum output current of 100mA. For higher output current versions, please see the TC1107, TC1108 (IOUT = 300mA) data sheets.
APPLICATIONS
s s s s s s s Battery Operated Systems Portable Computers Medical Instruments Instrumentation Cellular / GSM / PHS Phones Linear Post-Regulator for SMPS Pagers
TYPICAL APPLICATION
1M
ORDERING INFORMATION
Part No. Output Voltage**
2.5V 2.7V 3.0V 3.3V 5.0V
Package
Junction Temp. Range
VIN
1
VIN
VOUT
6
VOUT 1F
TC1073-2.5VCH TC1073-2.7VCH TC1073-3.0VCH TC1073-3.3VCH TC1073-5.0VCH
SOT-23A-6* - 40C to +125C SOT-23A-6* - 40C to +125C SOT-23A-6* - 40C to +125C SOT-23A-6* - 40C to +125C SOT-23A-6* - 40C to +125C
2
GND
TC1073
Bypass
5 CBYPASS 470pF
NOTE:
*SOT-23A-6 is equivalent to the EIAJ (SC-74) ** Other output voltages available. Please contact TelCom Semiconductor for details
3
4 SHDN ERROR ERROR
PIN CONFIGURATION
VOUT Bypass ERROR 6 5 4
Shutdown Control (from Power Control Logic)
TC1073 (SOT-23A-6*)
1 VIN 2 3
TOP VIEW
GND SHDN
NOTE: *SOT-23A-6 is equivalent to the EIAJ (SC-74)
TC1073-01 6/5/97
1 TelCom Semiconductor reserves the right to make changes in the circuitry and specifications ot its devices.
PRELIMINARY INFORMATION
100mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
TC1073
ABSOLUTE MAXIMUM RATINGS*
Input Voltage .................................................................7V Output Voltage .................................. (- 0.3) to (VIN + 0.3) Power Dissipation .................... Internally Limited (Note 7) Operating Temperature .................... - 40C < TJ < 125C Storage Temperature ............................ - 65C to +150C Maximum Voltage On Any Pin .......... VIN + 0.3V to - 0.3V
*Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational 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 Dropout Voltage (Note 4)
Test Conditions
Note 9 Note 9 Notes 1, 9 Note 2, 9 (VR + 1V) < VIN < 6V IL = 0.1mA to IOUTMAX (Note 3) IL = 0.1mA IL = 20mA IL = 50mA IL =100mA (Note 4) IL = IOUTMAX, (Note 5, 9) SHDN = VIH, IL = 0 SHDN = 0V SHDN < VIL FRE 1kHz VOUT = 0V Note 6
Min
-- 100 VR - 2.5%
Typ
-- -- VR 0.5% 20 40 0.05 0.5 20 70 100 200 0 50 -- 160 x VR 64 300 0.04 160 10 260
Max
6.5 -- VR + 2.5% -- -- -- --
Units
V mA V ppm/C % % mV
-- -- --
IGND IIN IINSD ROUT PSRR IOUTSC VOUT/PD TSD TSD eN
Ground Pin Current Supply Current Shutdown Supply Current Output Resistance during Shutdown Power Supply Rejection Ratio Output Short Circuit Current Thermal Regulation Thermal Shutdown Die Temperature Thermal Shutdown Hysteresis Output Noise
IL = IOUTMAX 470pF from Bypass to GND VIN = 2.5V to 6.5V VIN = 2.5V to 6.5V
-- -- -- 100 x VR -- -- -- -- -- --
-- 80 0.05 -- -- 500 -- -- -- --
A A A k dB mA %/W C C nV/Hz
SHDN Input
VIH VIL SHDN Input High Threshold SHDN Input Low Threshold 45 -- -- -- -- 15 %VIN %VIN
TC1073-01 6/5/97
2
100mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
PRELIMINARY INFORMATION
TC1073
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 Dranin 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-6)
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 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%. Reference bypass input. Connecting a 470pF to this input further reduces output noise. Regulated voltage output.
4 5 6
ERROR Bypass VOUT
TC1073-01 6/5/97
3
PRELIMINARY INFORMATION
100mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
TC1073
DETAILED DESCRIPTION
The TC1073 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 TC1073 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 opencircuited.
VIN 1F VOUT VOUT 1F C1 GND Bypass
VOUT VTH HYSTERESIS (VHYS)
ERROR VIH VOL
Figure 2. ERROR Output Operation
Output Capacitor
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, supplynoise rejection and transient response can be improved by increasing the value of the input and output capacitors and employing passive filtering techniques.
BATTERY
TC1073
V+ SHDN Shutdown Control (to CMOS Logic or Tie to VIN if unused) ERROR R1 1M
C3, 470pF
C2 Requires Only if ERROR is used as a Processor RESET Signal (See Text)
0.2F C2
BATTLOW or RESET
Bypass Input
Figure 1. Typical Application Circuit
ERROR Open Drain Output
ERROR is driven low whenenver VOUT falls out of regulation by more than - 5% (typical). The condition my be caused by low input voltage, output current limiting, or thermal limiting. The ERROR output voltage value (e.g. ERROR = VOL at 4.75 (typ) for a 5.0V regulator and 2.85 (typ) for a 3.0V regulator). ERROR ouput 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. Pull-up resistor R1 can be tied to VOUT, VIN or any other voltage less than (VIN +0.3V).
TC1073-01 6/5/97
A 470pF capacitor connected from the Bypass input to ground reduces noise present on the internal reference, which in turn significantly reduces output noise. If output noise is not a concern, this input may be left unconnected. Larger capacitor values may be used, but results in a longer time period to rated output voltage when power is initially applied.
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.
4
100mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
PRELIMINARY INFORMATION
TC1073
The following equation is used to calculate worst case actual power dissipation: 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.
= (125 - 55) 220 = 318mW In this example, the TC1073 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 sustituting 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-6 packag 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 10% VOUTMIN = 2.7V 0.5V ILOAD = 98mA TAMAX = 55C 1. Actual power dissipation 2. Maximum allowable dissipation
Find:
Actual power dissipation: PD (VINMAX - VOUTMIN)ILOADMAX = [(3.0 x 1.1) - (2.7 x .995)]40 x 10-3 = 60mW Maximum allowable power dissipation: PDMAX = (TJMAX - TAMAX) JA
TC1073-01 6/5/97
5
PRELIMINARY INFORMATION
100mA CMOS LDO WITH SHUTDOWN, ERROR OUTPUT AND VREF BYPASS
TC1073
MARKING
SOT-23A-6 & = part number code + temperature range and voltage TC1073 (V) 2.5 2.7 3.0 3.3 5.0 Code F1 F2 F3 F4 F6
represents year and quarter code represents lot ID number
PACKAGE DIMENSIONS SOT-23A-6*
.118 (3.00) .102 (2.60) .020 (0.50) .014 (0.35)
.069 (1.75) .059 (1.50)
.037 (0.95) REFERENCE .118 (3.00) .110 (2.80)
.057 (1.45) .035 (0.90) .006 (0.15) .000 (0.00)
10 MAX. .022 (0.55) .014 (0.35)
.008 (0.20) .004 (0.09)
NOTE: *SOT-23A-6 is equivalent to the EIAJ (SC-74)
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
TC1073-01 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, 6/F San Po Kong Kowloon Hong Kong TEL: 852-2324-0122 FAX: 852-2354-9957
Printed in the U.S.A.

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