Voltage Regulators AN79Nxx Series 3-pin negative output voltage regulator (300 mA type) ■ Overview AN79Nxx series The AN79Nxx series is a 3-pin, fixed negative output type monolithic voltage regulator. Stabilized fixed output voltage is obtained from unstable DC input voltage without using any external component IC. 12 types of output voltage are available: −4V, −5V, −6V, −7V, −8V, −9V, − 10V, −12V, −15V, −18V, −20V and −24V. They can be used widely in power circuits with current capacity of up to 300mA. Unit : mm 3.8 0.75±0.25 0.5±0.25 1.44 2.3 4.6 1 2 3 0.5±0.1 1.76 3.5 max. • No external components • Output voltage: −4V, −5V, −6V, −7V, −8V, −9V,−10V, −12V, −15V, −18V, −20V, −24V • Built-in overcurrent limit circuit • Built-in thermal overload protection circuit • Built-in ASO (area of safe operation) protection circuit 15.0 min. 1.94 ■ Features 10.8±0.3 8.0 +0.5 –0.1 3.05 1 : Common 2 : Input 3 : Output SSIP003-P-0000E ■ Block Diagram 1 R1 + Voltage Reference Common Error Amp. − R2 3 Output Q1 Starter Thermal Protection Pass Tr Current Limiter RSC 2 Input 1 AN79Nxx Series Voltage Regulators ■ Absolute Maximum Ratings at Ta = 25°C Parameter Symbol Input voltage VI Power dissipation PD Operating ambient temperature Storage temperature Rating −35 *1 Unit V −40 *2 8 *3 W Topr −20 to +80 °C Tstg −55 to +150 °C V *1 AN79N04, AN79N05, AN79N06, AN79N07, AN79N08, AN79N09, AN79N10, AN79N12, AN79N15, AN79N18 *2 AN79N20, AN79N24 *3 Follow the derating curve. When Tj exceeds 150°C, the internal circuit cuts off the output. ■ Electrical Characteristics at Ta = 25°C • AN79N04 (−4V type) Parameter Symbol Conditions Output voltage VO Tj = 25°C Output voltage tolerance VO VI = −6 to −25V, IO = 5 to 200mA Line regulation Load regulation Bias current REGIN REGL IBias V −4.2 V mV VI = −7 to −17V, Tj = 25°C 4 20 mV IO = 1 to 300mA, Tj = 25°C 20 80 mV IO = 5 to 200mA, Tj = 25°C 10 40 mV 3 5 mA 0.5 mA 0.1 mA Tj = 25°C Bias current fluctuation to load ∆IBias(L) IO = 5 to 200mA, Tj = 25°C RR −4.16 Unit 40 VI = −7 to −25V, Tj = 25°C Ripple rejection ratio −4 −3.8 Max 9 ∆IBias(IN) Vno −3.84 Typ VI = −6 to −25V, Tj = 25°C Bias current fluctuation to input Output noise voltage Min f = 10Hz to 100kHz VI = −7 to −17V, IO = 50mA, f = 120Hz 100 µV dB 60 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA − 0.4 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −9V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C 2 Voltage Regulators AN79Nxx Series ■ Electrical Characteristics at Ta = 25°C (continued) • AN79N05 (−5V type) Parameter Symbol Conditions Min −4.75 Output voltage VO Tj = 25°C Output voltage tolerance VO VI = −7 to −25V, IO = 5 to 200mA Line regulation Load regulation Bias current REGIN REGL IBias −4.8 VI = −7 to −25V, Tj = 25°C Typ −5 10 Max −5.2 Unit V −5.25 V 50 mV VI = −8 to −18V, Tj = 25°C 5 30 mV IO = 1 to 300mA, Tj = 25°C 20 100 mV IO = 5 to 200mA, Tj = 25°C 10 50 mV 3 5 mA Tj = 25°C Bias current fluctuation to input ∆IBias(IN) VI = −8 to −25V, Tj = 25°C 0.5 mA Bias current fluctuation to load ∆IBias(L) IO = 5 to 200mA, Tj = 25°C 0.1 mA Output noise voltage Vno Ripple rejection ratio RR f = 10Hz to 100kHz VI = −8 to −18V, IO = 50mA, f = 120Hz µV 125 dB 60 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA − 0.4 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −10V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C • AN79N06 (−6V type) Parameter Symbol Conditions Output voltage VO Tj = 25°C Output voltage tolerance VO VI = −8 to −25V, IO = 5 to 200mA Line regulation REGIN Load regulation REGL Bias current IBias Bias current fluctuation to input ∆IBias(IN) Bias current fluctuation to load ∆IBias(L) Output noise voltage Vno Ripple rejection ratio RR Min −5.75 Typ −6 −5.7 Max −6.25 Unit V −6.3 V VI = −8 to −25V, Tj = 25°C 11 60 mV VI = −9 to −19V, Tj = 25°C 6 40 mV IO = 1 to 300mA, Tj = 25°C 20 120 mV IO = 5 to 200mA, Tj = 25°C 10 60 mV 3 5 mA 0.5 mA 0.1 mA Tj = 25°C VI = −9 to −25V, Tj = 25°C IO = 5 to 200mA, Tj = 25°C f = 10Hz to 100kHz VI = −9 to −19V, IO = 50mA, f = 120Hz 150 µV dB 60 Minimum input/output voltage difference VDIF(min) IO = 5mA, Tj = 0 to 125°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C Output voltage temperature coefficient ∆VO/Ta IO = 200mA 500 mA − 0.4 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −11V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C 3 AN79Nxx Series Voltage Regulators ■ Electrical Characteristics at Ta = 25°C (continued) • AN79N07 (−7V type) Parameter Symbol Conditions Output voltage VO Tj = 25°C Output voltage tolerance VO VI = −9 to −25V, IO = 5 to 200mA Line regulation REGIN Load regulation REGL Bias current IBias Bias current fluctuation to input ∆IBias(IN) Bias current fluctuation to load ∆IBias(L) Output noise voltage Vno Ripple rejection ratio RR Min −6.7 Typ −7 −6.65 Max −7.3 Unit V −7.35 V VI = −9 to −25V, Tj = 25°C 12 70 mV VI = −10 to −20V, Tj = 25°C 7 35 mV IO = 1 to 300mA, Tj = 25°C 20 140 mV IO = 5 to 200mA, Tj = 25°C 10 70 mV 3 5 mA 0.5 mA 0.1 mA Tj = 25°C VI = −10 to −25V, Tj = 25°C IO = 5 to 200mA, Tj = 25°C f = 10Hz to 100kHz VI = −10 to −20V, IO = 50mA, f = 120Hz µV 175 dB 59 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA − 0.5 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −12V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C • AN79N08 (−8V type) Parameter Symbol Conditions Min Output voltage VO Tj = 25°C −7.7 Output voltage tolerance VO VI = −10.5 to −25V, IO = 5 to 200mA −7.6 Line regulation Load regulation Bias current REGIN REGL IBias VI = −10.5 to −25V, Tj = 25°C Typ −8 13 Max −8.3 Unit V −8.4 V 80 mV VI = −11 to −21V, Tj = 25°C 8 40 mV IO = 1 to 300mA, Tj = 25°C 25 160 mV IO = 5 to 200mA, Tj = 25°C 10 80 mV 3 5 mA Tj = 25°C Bias current fluctuation to input ∆IBias(IN) VI = −10.5 to −25V, Tj = 25°C 0.5 mA Bias current fluctuation to load ∆IBias(L) IO = 5 to 200mA, Tj = 25°C 0.1 mA Output noise voltage Vno Ripple rejection ratio RR f = 10Hz to 100kHz VI = −11.5 to −21.5V, IO = 50mA, f = 120Hz 200 µV dB 59 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C Output short-circuit current IO(Short) VI = −35V, Tj = 25°C Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA − 0.6 mV/°C 1.1 V 10 mA Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −14V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C 4 Voltage Regulators AN79Nxx Series ■ Electrical Characteristics at Ta = 25°C (continued) • AN79N09 (−9V type) Parameter Symbol Output voltage VO Output voltage tolerance VO Line regulation Load regulation Bias current REGIN REGL IBias Conditions Min Tj = 25°C −8.65 VI = −11.5 to −26V, IO = 5 to 200mA −8.55 VI = −11.5 to −26V, Tj = 25°C Typ −9 14 Max −9.35 Unit V −9.45 V 80 mV VI = −12 to −22V, Tj = 25°C 9 50 mV IO = 1 to 300mA, Tj = 25°C 25 180 mV IO = 5 to 200mA, Tj = 25°C 10 90 mV 3 5 mA Tj = 25°C Bias current fluctuation to input ∆IBias(IN) VI = −11.5 to −26V, Tj = 25°C 0.5 mA Bias current fluctuation to load ∆IBias(L) IO = 5 to 200mA, Tj = 25°C 0.1 mA Output noise voltage Vno Ripple rejection ratio RR f = 10Hz to 100kHz VI = −12 to −22V, IO = 50mA, f = 120Hz µV 225 dB 58 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA − 0.6 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −15V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C • AN79N10 (−10V type) Parameter Symbol Conditions Min Output voltage VO Tj = 25°C −9.6 Output voltage tolerance VO VI = −12.5 to −27V, IO = 5 to 200mA −9.5 Line regulation Load regulation Bias current REGIN REGL IBias Typ −10 Max −10.4 Unit V −10.5 V 80 mV VI = −12.5 to −27V, Tj = 25°C 15 VI = −13 to −23V, Tj = 25°C 10 50 mV IO = 1 to 300mA, Tj = 25°C 25 200 mV IO = 5 to 200mA, Tj = 25°C 10 100 mV Tj = 25°C 3.0 5 mA Bias current fluctuation to input ∆IBias(IN) VI = −12.5 to −27V, Tj = 25°C 0.5 mA Bias current fluctuation to load ∆IBias(L) IO = 5 to 200mA, Tj = 25°C 0.1 mA Output noise voltage Vno Ripple rejection ratio RR f = 10Hz to 100kHz VI = −13 to −23V, IO = 50mA, f = 120Hz 250 µV dB 58 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C Output short-circuit current IO(Short) VI = −35V, Tj = 25°C Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA − 0.7 mV/°C 1.1 V 10 mA Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −16V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C 5 AN79Nxx Series Voltage Regulators ■ Electrical Characteristics at Ta = 25°C (continued) • AN79N12 (−12V type) Parameter Symbol Conditions Min Output voltage VO Tj = 25°C −11.5 Output voltage tolerance VO VI = −14.5 to −30V, IO = 5 to 200mA −11.4 Line regulation Load regulation Bias current REGIN REGL IBias Typ −12 Max −12.5 Unit V −12.6 V 80 mV VI = −14.5 to −30V, Tj = 25°C 15 VI = −15 to −25V, Tj = 25°C 10 50 mV IO = 1 to 300mA, Tj = 25°C 25 240 mV IO = 5 to 200mA, Tj = 25°C 10 120 mV 3 5 mA Tj = 25°C Bias current fluctuation to input ∆IBias(IN) VI = −14.5 to −30V, Tj = 25°C 0.5 mA Bias current fluctuation to load ∆IBias(L) IO = 5 to 200mA, Tj = 25°C 0.1 mA Output noise voltage Vno Ripple rejection ratio RR f = 10Hz to 100kHz VI = −15 to −25V, IO = 50mA, f = 120Hz µV 300 dB 57 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA − 0.8 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −19V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C • AN79N15 (−15V type) Parameter Symbol Conditions Min Output voltage VO Tj = 25°C Output voltage tolerance VO VI = −17.5 to −30V, IO = 5 to 200mA −14.25 Line regulation Load regulation Bias current REGIN REGL IBias Bias current fluctuation to input ∆IBias(IN) Bias current fluctuation to load ∆IBias(L) Output noise voltage Vno Ripple rejection ratio RR −14.4 Typ −15 Max −15.6 Unit V −15.75 V 80 mV VI = −17.5 to −30V, Tj = 25°C 16 VI = −18 to −28V, Tj = 25°C 11 50 mV IO = 1 to 300mA, Tj = 25°C 25 240 mV IO = 5 to 200mA, Tj = 25°C 10 120 mV 3 5 mA 0.5 mA 0.1 mA Tj = 25°C VI = −17.5 to −30V, Tj = 25°C IO = 5 to 200mA, Tj = 25°C f = 10Hz to 100kHz VI = −18 to −28V, IO = 50mA, f = 120Hz 375 µV dB 56 VDIF(min) IO = 200mA, Tj = 25°C Output short-circuit current IO(Short) VI = −35V, Tj = 25°C Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA − 0.9 mV/°C Minimum input/output voltage difference 1.1 V 10 mA Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −23V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C 6 Voltage Regulators AN79Nxx Series ■ Electrical Characteristics at Ta = 25°C (continued) • AN79N18 (−18V type) Parameter Symbol Conditions Min Output voltage VO Tj = 25°C −17.3 Output voltage tolerance VO VI = −21 to −33V, IO = 5 to 200mA −17.1 Line regulation REGIN Load regulation REGL Bias current IBias Typ −18 Max −18.7 Unit V −18.9 V VI = −21 to −33V, Tj = 25°C 18 80 mV VI = −22 to −32V, Tj = 25°C 13 50 mV IO = 1 to 300mA, Tj = 25°C 30 300 mV IO = 5 to 200mA, Tj = 25°C 10 150 mV 3 5 mA Tj = 25°C Bias current fluctuation to input ∆IBias(IN) VI = −21 to −33V, Tj = 25°C 0.5 mA Bias current fluctuation to load ∆IBias(L) IO = 5 to 200mA, Tj = 25°C 0.1 mA Output noise voltage Vno Ripple rejection ratio RR f = 10Hz to 100kHz VI = −22 to −32V, IO = 50mA, f = 120Hz µV 450 dB 55 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA −1 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −27V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C • AN79N20 (−20V type) Parameter Symbol Conditions Output voltage VO Tj = 25°C Output voltage tolerance VO VI = −23 to −35V, IO = 5 to 200mA Line regulation REGIN Load regulation REGL Bias current IBias Bias current fluctuation to input ∆IBias(IN) Bias current fluctuation to load ∆IBias(L) Output noise voltage Vno Ripple rejection ratio RR Min −19.2 Typ −20 −19 Max −20.8 Unit V −21 V VI = −23 to −35V, Tj = 25°C 19 80 mV VI = −24 to −34V, Tj = 25°C 14 70 mV IO = 1 to 300mA, Tj = 25°C 30 300 mV IO = 5 to 200mA, Tj = 25°C 10 150 mV 3 5 mA 0.5 mA 0.1 mA Tj = 25°C VI = −23 to −35V, Tj = 25°C IO = 5 to 200mA, Tj = 25°C f = 10Hz to 100kHz VI = −24 to −34V, IO = 50mA, f = 120Hz 500 µV dB 54 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA −1 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −29V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C 7 AN79Nxx Series Voltage Regulators ■ Electrical Characteristics at Ta = 25°C (continued) • AN79N24 (−24V type) Parameter Symbol Conditions Min −22.8 Output voltage VO Tj = 25°C Output voltage tolerance VO VI = −27 to −38V, IO = 5 to 200mA Line regulation REGIN Load regulation REGL Bias current IBias Bias current fluctuation to input Bias current fluctuation to load −23 V V mV VI = −27 to −37V, Tj = 25°C 15 70 mV IO = 1 to 300mA, Tj = 25°C 30 300 mV IO = 5 to 200mA, Tj = 25°C 10 150 mV 3 5 mA 0.5 mA 0.1 mA Tj = 25°C ∆IBias(L) RR −25 −25.2 80 IO = 5 to 200mA, Tj = 25°C Ripple rejection ratio −24 Unit 20 VI = −27 to −38V, Tj = 25°C Vno Max VI = −27 to −38V, Tj = 25°C ∆IBias(IN) Output noise voltage Typ f = 10Hz to 100kHz VI = −28 to −38V, IO = 50mA, f = 120Hz µV 600 dB 54 Minimum input/output voltage difference VDIF(min) IO = 200mA, Tj = 25°C 1.1 V Output short-circuit current IO(Short) VI = −35V, Tj = 25°C 10 mA Peak output current IO(Peak) Tj = 25°C 500 mA Output voltage temperature coefficient ∆VO/Ta IO = 5mA −1 mV/°C Note 1) The specified condition Tj = 25°C means that the test should be carried out within so short a test time (within 10ms) that the characteristic value drift due to the chip junction temperature rise can be ignored. Note 2) Unless otherwise specified, VI = −33V, IO = 100mA, CI = 2µF, CO = 1µF and Tj = 0 to 125°C 8 Rth(j-c) = 15°C/W (max.) R (1) th(j-a) = 100°C/W (max.) 6 (2) 4 (3) 2 (4) 0 0 40 80 120 Ambient temperature Ta (°C) 8 160 Input transient response AN79N05 AN79N05 20 15 1.2 IO = 300mA 1.0 IO =1 00 mA 0m A IO = 5m A IO 0.8 =5 0.6 0.4 −50 0 50 100 150 Junction temperature Tj (°C) 10 5 10 0 −10 −20 0 2 4 6 Time t (µs) 8 10 Input voltage VI (V) Power dissipation PD (W) (1) Infinite heat sink (2) 5°C/W heat sink (3) 15°C/W heat sink (4) Without heat sink VDIF(min) Tj 1.4 Output voltage fluctuation (mV) PD Ta 10 Minimum input/output voltage difference VDIF(min) (V) ■ Main Characteristics Voltage Regulators AN79Nxx Series ■ Main Characteristics (continued) RR f 0.6 Output voltage fluctuation (V) 0.3 0 1 0 −1 −2 120 Ripple rejection ratio RR (dB) AN79N05 Load current IO (A) Load transient response AN79N05 IO = 50mA 100 80 60 40 20 0 0 10 20 30 40 10 50 100 1k 10k 100k Frequency f (Hz) Time t (µs) ■ Basic Regulator Circuit −VI Input −VO Output AN79Nxx CI − − + Common + CO Connect CI of 2µF when the input line is long. CO improves the transient response. 1µF ■ Usage Notes 1. Cautions for a basic circuit Di VI VO 3 1 CI 2 Figure 1 CO CI: When a wiring from a smoothing circuit to a three-pin regulator is long, it is likely to oscillate at output. A capacitor of 0.1µF to 0.47µF should be connected near an input pin. CO: Deadly needed to prevent from oscillation (0.33µF to 1.0µF). It is recommended to use a capacitor of a small internal impedance (ex. tantalum capacitor) when using it under a low temperature. When any sudden change of load current is likely to occur, connect an electrolytic capacitor of 10µF to 100µF to improve a transitional response of output voltage. Di: Normally unnecessary. But add it in the case that there is a residual voltage at the output capacitor Co even after switching off the supply power because a current is likely to flow into an output pin of the IC and damage the IC. 9 AN79Nxx Series Voltage Regulators ■ Usage Notes (continued) 2. Other caution items 1) Short-circuit between the input pin and GND pin If the input pin is short-circuitted to GND or is cut off when a large capacitance capacitor has been connected to the IC's load, a voltage of a capacitor connected to an output pin is applied between input/output of the IC and this likely results in damage of the IC. It is necessary, therefore, to connect a diode, as shown in figure 2, to counter the reverse bias between input/output pins. In 3 1 2 GND Output Out − + CO Figure 2 2) Floating of GND pin If a GND pin is made floating in an operating mode, an unstabilized input voltage is outputted. In this case, a thermal protection circuit inside the IC does not normally operate. In this state, if the load is short-circuited or overloaded, it is likely to damage the IC. ■ Application Circuit Example −VI Input Output AN79Nxx V O' − + − + Common 1µF R 2µF IQ IO | IO | = 10 VO' + IQ R