AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START General Description Features • • • • • • • • • • • Low VIN and wide VIN range: 1.0V to 5.5V Bias voltage (VVCC) range: 2.7V to 5.5V Low VOUT range: 0.8V to 3.3V Low dropout: 165mV typical at 1.5A, VVCC = 5V 2% accuracy over line, load and temperature range Power-Good (PG) output for supply monitoring and for sequencing of other supplies Programmable soft-start provides linear voltage startup Bias supply permits low VIN operation with good transient response Stable with any output capacitor ≥ 2.2µF DFN3030-10 and SOP-8L-EP: available in “Green” molding compound (No Br, Sb) Lead-free finish/ RoHS Compliant (Note 1) The AP7173 is a 1.5A low-dropout (LDO) linear regulator that features a user-programmable soft-start, an enable input and a power-good output. The soft-start reduces inrush current of the load capacitors and minimizes stress on the input power source during start-up. The enable input and power-good output allow users to configure power management solutions that can meet the sequencing requirements of FPGAs, DSPs, and other applications with different start-up and power-down requirements. The AP7173 is stable with any type of output capacitor of 2.2µF or more. A precision reference and feedback control deliver 2% accuracy over load, line, and operating temperature ranges. The AP7173 is available in both DFN3030-10 and SOP-8L-EP packages. Applications • • • • • PCs, Servers, Modems, and Set-Top-Boxes FPGA Applications DSP Core and I/O Voltages Post-Regulation Applications Applications With Sequencing Requirements Ordering Information AP 7173 - X X X Package Lead Free Packing FN : DFN3030-10 SP : SOP-8L-EP G : Green -7/13 : Tape & Reel Device AP7173-FN AP7173-SP Notes: Package Code FN SP Packaging (Note 2) DFN3030-10 SOP-8L-EP 7”/13” Tape and Reel Quantity Part Number Suffix 3000/Tape & Reel -7 2500/Tape & Reel -13 1. RoHS revision 13.2.2003. Glass and high temperature solder exemptions applied, see EU Directive Annex Notes 5 and 7. 2. Pad layout as shown on Diodes Inc. suggested pad layout document can be found on our website at http://www.diodes.com/datasheets/ap02001.pdf. AP7173 Rev. 4 1 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Pin Assignments ( Top View ) ( Top View ) IN 1 10 OUT IN 2 9 OUT PG 3 8 FB VCC 4 7 SS EN 5 6 GND IN 1 8 OUT PG 2 7 FB VCC 3 6 SS EN 4 5 GND DFN3030-10 SOP-8L-EP Pin Descriptions PIN # Pin Name SOP-8L-EP DFN3030-10 Description IN 1 1, 2 PG 2 3 VCC 3 4 EN 4 5 GND 5 6 SS 6 7 FB 7 8 Power Input pin. Power-Good pin, open-drain output. When the VOUT is below the PG threshold the PG pin is driven low; when the VOUT exceeds the threshold, the PG pin goes into a high-impedance state. To use the PG pin, use a 10kΩ to 1MΩ pull-up resistor to pull it up to a supply of up to 5.5V, which can be higher than the input voltage. Bias Input pin, provides input voltage for internal control circuitry. This voltage should be higher than the VIN. Enable pin. This pin should be driven either high or low and must not be floating. Driving this pin high enables the regulator, while pulling it low puts the regulator into shutdown mode. Ground. Soft-Start pin. Connect a capacitor between this pin and the ground to set the soft-start ramp time of the output voltage. If no capacitor is connected, the soft-start time is typically 100µS. Feedback pin. Connect this pin to an external voltage divider to set the output voltage. OUT 8 9, 10 Thermal Pad — — AP7173 Rev. 4 Regulated Output pin. Solder this pad to large ground plane for increased thermal performance. 2 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Block Diagram IN EN OUT Gate Driver Current Limit and Thermal Shutdown VCC SS + 0.8V PG FB + 0.72V GND Typical Application Circuit VOUT R3 VIN OUT IN VVCC C1 PG VCC C3 EN R1 C2 FB AP7173 R2 SS GND CSS Figure 1. Typical Application Circuit (Adjustable Output) AP7173 Rev. 4 3 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Typical Application Circuit (Continued) Table 1. Resistor Values for Programming the Output Voltage (Note 3) R1 (kΩ) Short 0.619 1.13 1.37 1.87 2.49 4.12 3.57 3.57 3.57 R2 (kΩ) Open 4.99 4.53 4.42 4.99 4.99 4.75 2.87 1.69 1.15 VOUT (V) 0.8 0.9 1 1.05 1.1 1.2 1.5 1.8 2.5 3.3 (Note: 3) VOUT = 0.8 x (1 + R1 / R2) Table 2. Capacitor Values for Programming the Soft-Start Time (Note 4) CSS Open 270pF 560pF 2.7nF 5.6nF 0.01μF SOFT-START TIME 0.1ms 0.5ms 1ms 5ms 10ms 18ms –7 (Note: 4) tSS(s) = 0.8 x CSS(F) / (4.4 x 10 ) Figure 2. Turn-On Response AP7173 Rev. 4 4 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Absolute Maximum Ratings Symbol ESD HBM ESD MM VIN, VVCC VEN VPG VSS VFB VOUT IOUT TJ TST Notes: (Note 5) Parameter Ratings Human Body Model ESD Protection Machine Model ESD Protection Input Voltage Range Enable Voltage Range Power-Good Voltage Range Soft-Start Voltage Range Feedback Voltage Range Output Voltage Range Maximum Output Current Junction Temperature Range Storage Junction Temperature Range Unit 4000 V 350 V -0.3 to +6 V -0.3 to +6 V -0.3 to +6 V -0.3 to +6 V -0.3 to +6 V -0.3 to VIN +0.3 V Internally Limited -40 to +150 ºC -65 to +150 ºC 5. 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 conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Recommended Operating Conditions Symbol VIN VVCC IOUT TA Notes Parameter Input Voltage (Note 6) Bias Voltage Output Current Operating Ambient Temperature Min 1.0 2.7 0 -40 Max 5.5 5.5 1.5 85 Unit V V A ºC 6. At VIN =1V, the maximum load currents may be lower than 1.5A. AP7173 Rev. 4 5 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Electrical Characteristics At VEN = 1.1V, VIN = VOUT + 0.5V, CVCC = 0.1uF, CIN = COUT = 10uF, IOUT = 50mA, VVCC = 5.0V, and TA = –40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C. Symbol VIN VVCC VREF VOUT ΔVOUT /ΔVIN / VOUT ΔVOUT /VOUT /ΔIOUT VDO ICL ISHORT IVCC ISHDN IFB PSRR TST ISS VEN, HI VEN, LO VEN, HYS IEN VPG, TH VPG, HYS VPG, LO IPG, LKG TSD θJA Notes: Parameter Test Conditions Input Voltage Range Bias Pin Voltage Range (Note 7) Internal Reference TA = +25 ºC (Adj.) Output Voltage Range VIN= 5V, IOUT= 1.5A 2.97V≤VVCC≤5.5V, Accuracy (Note 8) 50mA≤IOUT≤1.5A Line Regulation VOUT (NOM) + 0.5≤VIN, 5.5V Load Regulation 50mA≤IOUT≤1.5A IOUT = 1.5A,VVCC–VOUT(NOM)≥3.25V Dropout Voltage (Note 9) IOUT= 1.5A, VIN = VVCC Current Limit VOUT = 80% x VOUT (NOM) Short-Circuit Current VOUT < 0.2V Bias Pin Current Shutdown Supply VEN≤0.4V Current (IGND) Feedback Pin Current 1KHz, IOUT= 1A, Power-Supply Rejection VIN= 1.8V, VOUT= 1.5V (VIN to VOUT) 300KHz, IOUT =1A, VIN= 1.8V, VOUT =1.5V 1KHz, IOUT = 1A, Power-SupplyRejection VIN= 1.8V, VOUT =1.5V (VVCC to VOUT) 300KHz, IOUT = 1A, VIN= 1.8V, VOUT =1.5V Startup Time RLOAD for IOUT = 1.0A, CSS = open Soft-Start Charging VSS= 0.4V Current Enable Input High Level Enable Input Low Level Enable Pin Hysteresis Enable Pin Current VEN= 5V PG Trip Threshold VOUT decreasing PG Trip Hysteresis PG Output Low Voltage IPG= 1mA (sinking), VOUT<VPG, TH PG Leakage Current VPG= 5.25V, VOUT>VPG, TH Shutdown, temperature increasing Thermal Shutdown Temperature Reset, temperature decreasing DFN3030-10 (Note 10) Thermal Resistance Junction-to-Ambient SOP-8L-EP (Note 11) Min VOUT + VDO Typ. Max 5.5 Unit V 5.5 V 0.808 V 3.3 V 2 % 0.03 0.09 165 1.5 3 1 1 270 1.7 4 2 %/V %/A mV V A A mA 1 50 µA 0.1 1 µA 2.7 0.792 0.8 0.8 –2 2 0.6 –1 ±0.5 60 dB 30 50 dB 30 100 µS 440 nA 1.1 0 85 5.5 0.4 50 0.1 90 3 0.1 +150 +130 38 30 1 94 0.3 1 V V mV µA %VOUT %VOUT V µA ºC o C/W 7. VVCC should be higher or equal to VIN in this chip. 8. Tested at 0.8V; resistor tolerance is not taken into account. 9. Dropout is defined as the voltage from VIN to VOUT when VOUT is 3% below nominal. 10. Test condition for DFN3030-10: Device mounted on FR-4 substrate (2s2p), 2"*2" PCB, with 2oz copper trace thickness and large pad pattern. 11. Test condition for SOP-8L-EP: Device mounted on FR-4 substrate (2s2p), 2"*2" PCB, with 2oz copper trace thickness and large pad pattern. AP7173 Rev. 4 6 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Typical Performance Characteristics At TA = +25℃, VIN = VOUT(TYP) + 0.3V, VVCC = 5V, IOUT = 50mA, VEN = VIN, CIN = 1µF, CVCC = 4.7µF, and COUT = 10µF, unless otherwise noted. VIN LINE REGULATION VVCC LINE REGULATION 0.5 0.20 0.4 0.15 0.3 o 25 C o 125 C 0.05 0.00 o 25 C 0.2 o Vout(V) change in Vout(%) 0.10 125 C 0.1 0.0 -0.1 -0.05 o -40 C -0.2 o -40 C -0.10 -0.3 -0.15 -0.4 -0.20 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 -0.5 0.5 5.0 1.0 1.5 2.0 2.5 3.0 Vin-Vout(V) Vvcc-Vout(V) Figure 3 Figure 4 LOAD REGULATION 3.5 4.0 LOAD REGULATION 1.0 o 25 C 0.8 0.6 o Change Vout(%) 125 C 0.4 0.2 0.0 -0.2 -0.4 o -0.6 -40 C -0.8 -1.0 50 200 350 500 650 800 950 1100 1250 1400 1500 Iout(mA) Figure 5 Figure 6 VIN DROPOUT VOLTAGE vs. IOUT AND TEMPERATURE(TA) VIN DROPOUT VOLTAGE vs. (VVCC-VOUT) AND TEMPERATURE(TA) 300 240 280 220 260 180 VDropout(Vin-Vout)(mV) VDropout(Vin-Vout)(V) 200 o 25 C 160 140 o 125 C 120 100 80 60 -40 C 200 o 25 C 180 160 o -40 C 140 120 100 Iout=1.5A 80 40 20 20 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 Iout(mA) 0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 Vvcc-Vout(V) Figure 7 AP7173 Rev. 4 220 60 o 40 o 125 C 240 Figure 8 7 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Typical Performance Characteristics (Continued) At TA = +25℃, VIN = VOUT(TYP) + 0.3V, VVCC = 5V, IOUT = 50mA, VEN = VIN, CIN = 1µF, CVCC = 4.7µF, and COUT = 10µF, unless otherwise noted. VIN DROPOUT VOLTAGE vs. (VVCC-VOUT) AND TEMPERATURE(TA) VVCC DROPOUT VOLTAGE vs. IOUT AND TEMPERATURE(TA) 200 2000 180 VDropout(Vvcc-Vout)(mV) VDropout(Vin-Vout)(mV) 1800 Iout=0.5A 160 140 120 o 25 C o 125 C 100 80 60 1600 o 125 C 1400 o -40 C 1200 o 25 C 1000 40 800 20 o -40 C 0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 600 0.00 4.5 0.25 0.50 Figure 9 VIN PSRR vs. FREQUENCY Power Supply Rejection Ratio(dB) Power Supply Rejection Ratio(dB) Io=0.1A 60 Io=1.5A 50 40 Vin=1.8V Vout=1.2V Vvcc=5V Css=1nF 30 20 10 80 70 Io=0.1A 60 50 40 30 20 Vin=1.8V Vout=1.2V Vvcc=5V Css=1nF Io=1.5A 10 0 10 100 1000 10000 100000 0 10 500000 100 1000 10000 100000 Frequency(Hz) Frequency(Hz) Figure 11 Figure 12 VIN PSRR vs. (VIN-VOUT) 1000000 1E7 LOW-LEVEL PG VOLTAGE vs. CURRENT 0.8 90 Vout=1.2V Iout=1.5A Css=1nF VoL Low-Level PG Voltage(V) Power Supply Rejection Ratio(dB) 1.50 VVCC PSRR vs. FREQUENCY 70 1KHz 60 10KHz 50 100KHz 40 30 500KHz 20 0.7 0.6 0.5 0.4 0.3 0.2 0.1 10 0 0.00 1.25 90 80 70 1.00 Figure 10 90 80 0.75 Iout(A) Vvcc-Vout 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 Vin-Vout(V) 0 2 4 6 8 10 12 PG Current(mA) Figure 13 AP7173 Rev. 4 0.0 Figure 14 8 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Typical Performance Characteristics (Continued) At TA = +25℃, VIN = VOUT(TYP) + 0.3V, VVCC = 5V, IOUT = 50mA, VEN = VIN, CIN = 1µF, CVCC = 4.7µF, and COUT = 10µF, unless otherwise noted. VIN LINE TRANSIENT VVCC LINE TRANSIENT Figure 15 Figure 16 OUTPUT LOAD TRANSIENT TURN-ON RESPONSE Figure 17 Figure 18 VCC PIN CURRENT vs. IOUT AND TEMPERATURE (TA) 2.0 2.0 1.8 1.8 1.6 o 1.6 o 25 C 125 C 1.4 1.2 1.2 1.0 0.8 1.0 0.6 o -40 C o -40 C 0.4 0.4 0.2 AP7173 Rev. 4 125 C 25 C 0.8 0.6 0.0 0.0 o o 1.4 Ivcc(mA) Ivcc(mA) VCC PIN CURRENT vs. VVCC AND TEMPERATURE (TA) 0.2 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0.0 2.0 2.4 2.8 3.2 3.6 4.0 Iout(A) Vvcc(V) Figure 19 Figure 20 9 of 15 www.diodes.com 4.4 4.8 5.2 5.6 MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Typical Performance Characteristics (Continued) At TA = +25℃, VIN = VOUT(TYP) + 0.3V, VVCC = 5V, IOUT = 50mA, VEN = VIN, CIN = 1µF, CVCC = 4.7µF, and COUT = 10µF, unless otherwise noted. QUIESCENT CURRENT vs. IOUT p QUIESCENT CURRENT vs. VVCC g 1.25 1.50 Vout=1.2V 1.15 Quiescent Current(mA) Quiescent Current(IGND) (mA) 1.20 1.10 Vin=2.5V 1.05 1.00 0.95 0.90 Vin=1.8V Io=0A 1.25 Io=1.5A 1.00 Vin=1.8V Vout=1.2V 0.75 0.85 Io=0.5A 0.80 0.75 0.00 0.25 0.50 0.75 1.00 1.25 0.50 2.50 1.50 2.75 3.00 3.25 Iout(A) Vvcc(V) Figure 21 Figure 22 QUIESCENT CURRENT vs. TEMPERATURE 3.50 CURRENT LIMIT vs. (VVCC – VOUT) 1.50 3.0 2.9 2.8 1.25 Current limit(A) Quiescent Current(mA) Vvcc=5V 1.00 Vvcc=3.3V Vin=1.8V Vout=1.2V 2.7 2.6 o o 25 C -40 C 2.5 2.4 2.3 o 0.75 125 C 2.2 2.1 0.50 -50 -25 0 25 50 75 100 125 o 2.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Vvcc-Vout(V) Temperature( C) Figure 23 Figure 24 SOFT-START CHARGING CURRENT (I SS) vs. TEMPERATURE POWER-UP/POWER-DOWN 500 475 450 Iss(nA) 425 400 375 350 325 300 -50 -25 0 25 50 75 100 125 o Temperature( C) Figure 25 AP7173 Rev. 4 Figure 26 10 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Application Note BIAS VOLTAGE VVCC DROPOUT VOLTAGE The AP7173 is a low VIN, low dropout regulator that uses an NMOS pass FET. The VCC pin must be connected to a DC bias supply VVCC for the internal control circuitry and the gate drive of the pass FET to function properly and to obtain low dropout. The VVCC needs to be equal to or higher than the VIN and in the range of 2.7V-5.5V. Figure 27 illustrates the typical application circuit for the AP7173. The very low dropout makes the AP7173 well suited for high-current, low VIN/low VOUT applications. To achieve the specified low-dropout performance for such applications, the VCC pin should be connected to a separate supply of at least 3.25V higher than VOUT. Figure 28 shows an application circuit where VVCC is 5V and VOUT is 1.2V. VVCC (5V) VOUT R3 VIN +5V PG C1 VCC EN C3 VCC OUT IN R1 IN C2 IOUT (1.5A) VOUT (1.2V) + FB AP7173 VIN (1.5V) _ R2 SS Vref OUT R1 GND CSS C2 FB AP7173 R2 Figure 27. Typical Application Circuit for AP7173 Figure 28. Typical Application Circuit for AP7173 Using Separate VCC and IN Rails ADJUSTABLE OUTPUT VOLTAGE With an external voltage divider, the AP7173 can provide output voltage from 0.8V to 3.3V. R1 and R2 can be calculated for any output voltage using the following equation, where VREF=0.8 is the AP7173’s internal reference voltage. Refer to Table 1 for resistor combinations for commonly used output voltages. For maximum voltage accuracy, R2 should be ≤ 5kΩ. For applications where low dropout is not required or a separate VVCC supply is not available, the IN and VCC pins can be tied together. In this situation, a voltage difference of at least 1.7V between the VVCC and VOUT has to be maintained for the VVCC to provide enough gate drive to the pass FET. Therefore, the VOUT needs to be 1.7V or more below VIN, as shown in Figure 29. VOUT = VREF x (1 + R1/R2) VIN (3.0V) INPUT VIN AND BIAS VVCC CAPACITORS VCC It is important to keep the IN and VCC pins clear of large ripples, glitches and other noises by connecting capacitors to the IN and VCC pins. The required capacitance on these pins is strongly dependent on source and wiring impedance of the supplies. IOUT (1.5A) OUTPUT CAPACITOR The output capacitor affects the stability and transient response of the LDO. The AP7173 is designed to be stable for all types of output capacitors ≥ 2.2μF, single or multiple in parallel. Using high-quality, low ESR capacitors and placing them close to the OUT and GND pins can improve perfomance. AP7173 Rev. 4 VOUT (1.2V) + _ Vref OUT R1 To provide good decoupling for the input power supply VIN, it is recommended that a ceramic capacitor with capacitance of at least 1μF is connected between the IN and GND pins at a location as close to them as possible. High quality, low ESR capacitors should be used for better performance. It is critical to provide good decoupling to the VCC pin for the AP7173’s internal control circuitry to function properly. The minimum recommended capacitance for the VVCC is 1μF when the VVCC and VIN are separate supplies. If the VIN and VVCC are connected to the same supply, the recommended minimum capacitance for VVCC is 4.7μF. Again good quality, low ESR capacitors should be used for optimum performance. IN AP7173 C2 FB R2 Figure 29. Typical Application Circuit for AP7173 Without an Auxiliary VCC Rail PROGRAMMABLE SOFT-START The AP7173 features a voltage-controlled soft-start that is programmable with an external capacitor (CSS). The AP7173 achieves a monotonic soft-start by tracking the voltage ramp of the external soft-start capacitor until the ramp voltage reaches the internal reference voltage. The relationship between the soft-start time and the soft-start charging current (ISS), soft-start capacitance (CSS), and the internal reference voltage (VREF) is tSS = (VREF x CSS) / ISS Refer to Table 2 for suggested soft-start capacitor values. 11 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Application Note (Continued) ENABLE/SHUTDOWN The EN pin can be used with standard digital signals or relatively slow-ramping analog signals. Pulling the VEN below 0.4V turns the regulator off, while driving the VEN above 1.1V turns the regulator on. Figure 30 shows an example where an RC circuit is used to delay start the AP7173. If not used, the EN pin can be connected to the VCC or IN pin when the VIN is greater than 1.1V, as long as good decoupling measures are taken for the EN pin. VOUT R3 VIN OUT IN VVCC VCC R4 C3 C5 EN R1 C2 FB PG C1 AP7173 R2 SS GND For more effective protection against short-circuit failure, the AP7173 also includes a short-circuit foldback mechanism that lowers the current limit to a typical value of 1.0A when the VFB drops to below 0.2V. THERMAL PROTECTION Thermal shutdown limits the AP7173 junction temperature and protects the device from damage as a result of overheating. Thermal protection turns off the VOUT when the AP7173’s junction temperature rises to approximately +150°C, allowing it to cool down. When the junction temperature drops to approximately +130°C, the output is re-enabled. Therefore, the thermal protection circuit may cycle on and off at a rate dependent on the power dissipation, thermal resistance, and ambient temperature. POWER DISSIPATION CSS Figure 30. Delayed Start Using an RC Circuit to Enable AP7173 Thermal shutdown is intented to protect the AP7173 against abnormal overheating. For normal operation, excessive power dissipation should be avoided and good heatsinking should be provided. Power dissipation in the device is the product of the device dropout voltage and the load current, PD = (VIN - VOUT) x IOUT POWER-GOOD The power-good (PG) pin is an open-drain output and can be pulled up through a resistor of 10kΩ to1MΩ to VIN, VOUT or any other rail that is 5.5V or lower. When the VOUT ≥ VPG,TH+VPG,HYS, the PG output is high-impedance; if the VOUT drops to below VPG,TH, VVCC ≤ 1.9V or the device is disabled, the PG pin is pulled to low by an internal MOSFET. As can be seen, power dissipation can be minimized by using the lowest input voltage necessary to achieve the required output voltage regulation. To ensure that the device junction temperature does not exceed the specified limit of 125°C, an application should provide heat conduction paths that have junction-to-ambient thermal resistance lower than the calculated value here: OVER-CURRENT AND SHORT-CIRCUIT PROTECTION The AP7173 features a factory-trimmed, temperature and supply voltage compensated internal current limit and an over-current protection circuitry to protect the device against overload conditions. It limits the device current to a typical value of 3A and reduces the VOUT when the load tries to pull more current. AP7173 Rev. 4 RθJA = (125°C –TA ) / PD For the DFN package with exposed pad, the primary conduction path for heat is through the exposed pad to the printed circuit board (PCB). The pad should be attached to an appropriate amount of copper PCB area to ensure that the device does not overheat. 12 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Marking Information (1) DFN3030-10 ( Top View ) XX YMX Part Number AP7173 XX : BA : AP7173 Y : Year 0~9 M : Month A~L X : A~Z : Green Package DFN3030-10 Identification Code BA (2) SOP-8L-EP ( Top View ) 8 5 Logo Part No . AP 7173 YY WW X X E 1 4 ~ Internal code G : Green E : SOP-8L-EP Xth week : 01~ 52 Year : "07" = 2007 "08" = 2008 AP7173 Rev. 4 13 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Package Information (All Dimensions in mm) (1) DFN3030-10 0.15Typ. Seating Plane Side View 2X- 0.25 A 0.08 C 0/0.05 0.10 C 0.57/0.60 TOP MARK C 2.9/3.1 2.3/2.5 B A R0 .30 0 0.25/0.55 1.5/1.7 2.9/3.1 (Pin #1 ID) 2X- 0.25 B 0.50Typ. 0.375Typ. 0.2/0.3 0.10 C A B Bottom View (2) SOP-8L-EP Detail "A" Exposed pad 2.4Ref. 3.70/4.10 45° 0.35max. 5.79/6.20 3.70/4.10 7°~9° 7°~9° 1 1 0.20typ 1.75max. 1.30/1.50 3.3Ref. Bottom View 0.08/0.25 0.254 0.3/0.5 1.27typ 4.80/5.30 1 Gauge Plane Seating Plane 0.38/1.27 Detail "A" 8x-0.60 5.4 Exposed pad 8x-1.55 6x-1.27 Land Pattem Recommendation AP7173 Rev. 4 14 of 15 www.diodes.com MARCH 2008 © Diodes Incorporated AP7173 1.5A LOW DROPOUT LINEAR REGULATOR WITH PROGRAMMABLE SOFT-START Taping Orientation Notes: 12. The taping orientation of the other package type can be found on our website at http://www.diodes.com/datasheets/ap02007.pdf IMPORTANT NOTICE Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither does it convey any license under its patent rights, nor the rights of others. The user of products in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on our website, harmless against all damages. LIFE SUPPORT Diodes Incorporated products are not authorized for use as critical components in life support devices or systems without the expressed written approval of the President of Diodes Incorporated. 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