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NCV8730ASNADJT1G

NCV8730ASNADJT1G

  • 厂商:

    ONSEMI(安森美)

  • 封装:

    TSOP5_3X1.5MM

  • 描述:

    线性稳压器/LDO Vin=2.7V~38V Vout=1.2V~24V TSOP5_3X1.5MM

  • 数据手册
  • 价格&库存
NCV8730ASNADJT1G 数据手册
LDO Regulator, 150 mA, 38V, 1 mA IQ, with PG NCV8730 The NCV8730 device is based on unique combination of features − very low quiescent current, fast transient response and high input and output voltage ranges. The NCV8730 is CMOS LDO regulator designed for up to 38 V input voltage and 150 mA output current. Quiescent current of only 1 mA makes this device ideal solution for battery− powered, always−on systems. Several fixed output voltage versions are available as well as the adjustable version. The device (version B) implements power good circuit (PG) which indicates that output voltage is in regulation. This signal could be used for power sequencing or as a microcontroller reset. Internal short circuit and over temperature protections saves the device against overload conditions. Features • • • • • • • • • • • • • • Operating Input Voltage Range: 2.7 V to 38 V Output Voltage: 1.2 V to 24 V Capable of Sourcing 200 mA Peak Output Current Low Shutdown Current: 100 nA typ. Very Low Quiescent Current: 1 mA typ. Low Dropout: 290 mV typ. at 150 mA, 3.3 V Version Output Voltage Accuracy ±1% Power Good Circuit (Version B) Stable with Small 1 mF Ceramic Capacitors Built−in Soft Start Circuit to Suppress Inrush Current Over−Current and Thermal Shutdown Protections Available in Small TSOP−5 and WDFNW6 (2x2) Packages NCV Prefix for Automotive and Other Applications Requiring Unique Site and Control Change Requirements; AEC−Q100 Qualified and PPAP Capable These Devices are Pb−Free and are RoHS Compliant Typical Applications • • • • www.onsemi.com MARKING DIAGRAMS 5 TSOP−5 CASE 483 SN SUFFIX 5 1 XXXAYWG G 1 XXX = Specific Device Code A = Assembly Location Y = Year W = Work Week G = Pb−Free Package (Note: Microdot may be in either location) WDFNW6 (2x2) CASE 511DW MTW SUFFIX 1 XX M XX = Specific Device Code M = Date Code PIN ASSIGNMENTS TSOP−5 IN 1 GND 2 EN 3 5 OUT 4 NC/ADJ/PG CASE 483 WDFNW6 (2x2) Body Control Modules LED Lighting On Board Charger General Purpose Automotive 6 IN OUT 1 NC/ADJ 2 GND 3 EP 5 NC/PG 4 EN CASE511DW (Top Views) ORDERING INFORMATION See detailed ordering and shipping information on page 27 of this data sheet. © Semiconductor Components Industries, LLC, 2019 September, 2020 − Rev. 2 1 Publication Order Number: NCV8730/D NCV8730 TYPICAL APPLICATION SCHEMATICS VIN=6−38V IN C IN 1mF ON OUT NCV8730A 5.0V TSOP−5 / WDFN−6 EN OFF GND VIN=6−38V VOUT=5.0V COUT 1mF C IN 1mF IN C IN 1mF NCV8730B 5.0V TSOP−5 / WDFN−6 NC EN OFF GND VOUT=5V OUT NCV8730A ADJ TSOP−5 / WDFN−6 EN ADJ GND R1 2M4 PG R PG 100k COUT 1mF R2 750k Figure 2. Adjustable Output Voltage Application (No PG) VIN=6−38V VOUT=5.0V C OUT 1mF C FF 1nF 1.2V OFF OUT ON ON NC Figure 1. Fixed Output Voltage Application (No PG) VIN=6−38V IN IN C IN 1mF ON NCV8730B ADJ Only WDFN−6 1.2V ADJ EN PG VOUT=5V OUT GND PG OFF R1 2M4 C FF 1nF R2 750k COUT 1mF R PG 100k PG Figure 3. Fixed Output Voltage Application with PG Figure 4. Adjustable Output Voltage Application with PG ǒ V OUT + V ADJ @ 1 ) www.onsemi.com 2 Ǔ R1 ) I ADJ @ R 1 R2 NCV8730 SIMPLIFIED BLOCK DIAGRAM IN OUT Current limit UVLO Comparator UVLO I EN−PU = 300nA 1.95 V V CCEN V−REFERENCE AND SOFT−START V REF 1.2V EA RADJ1 V FB =1.2V EN ADJ Enable RADJ2 EN Comparator GND THERMAL SHUTDOWN 0.9 V PG PG Comparator DEGLITCH DELAY TMR 93% of V REF NC Note: Blue objects are valid for ADJ version Green objects are valid for FIX version Brown objects are valid for B version (with PG) Figure 5. Internal Block Diagram PIN DESCRIPTION Pin No. TSOP−5 Pin No. WDFN−6 Pin Name Description 1 6 IN Power supply input pin. 2 3 GND Ground pin. 5 1 OUT LDO output pin. 3 4 EN Enable input pin (high − enabled, low − disabled). If this pin is connected to IN pin or if it is left unconnected (pull−up resistor is not required) the device is enabled. 4 (Note 1) 2 ADJ Adjust input pin, could be connected to the resistor divider to the OUT pin. 4 (Note 1) 5 PG Power good output pin. Could be left unconnected or could be connected to GND if not needed. High level for power ok, low level for fail. 4 (Note 1) 2, 5 NC Not internally connected. This pin can be tied to the ground plane to improve thermal dissipation. NA EP EPAD Connect the exposed pad to GND. 1. Pin function depends on device version. www.onsemi.com 3 NCV8730 MAXIMUM RATINGS Rating Symbol Value Unit VIN −0.3 to 40 V VOUT Voltage VOUT −0.3 to [(VIN + 0.3) or 40 V; whichever is lower] V EN Voltage VEN −0.3 to (VIN + 0.3) V ADJ Voltage VFB/ADJ −0.3 to 5.5 V PG Voltage VPG −0.3 to (VIN + 0.3) V Output Current IOUT Internally limited mA PG Current IPG 3 mA TJ(MAX) 150 °C TSTG −55 to 150 °C ESD Capability, Human Body Model (Note 3) ESDHBM 2000 V ESD Capability, Charged Device Model (Note 3) ESDCDM 1000 V VIN Voltage (Note 2) Maximum Junction Temperature Storage Temperature Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected. 2. Refer to ELECTRICAL CHARACTERISTICS and APPLICATION INFORMATION for Safe Operating Area. 3. This device series incorporates ESD protection and is tested by the following methods: ESD Human Body Model tested per ANSI/ESDA/JEDEC JS−001, EIA/JESD22−A114 (AEC−Q100−002) ESD Charged Device Model tested per ANSI/ESDA/JEDEC JS−002, EIA/JESD22−C101 (AEC Q100−011D) THERMAL CHARACTERISTICS (Note 4) Characteristic Symbol WDFNW6 2x2 TSOP−5 Unit RthJA 61 142 °C/W Thermal Resistance, Junction−to−Case (top) RthJCt 200 80 °C/W Thermal Resistance, Junction−to−Case (bottom) RthJCb 14 N/A °C/W Thermal Resistance, Junction−to−Board (top) RthJBt 46 110 °C/W Thermal Characterization Parameter, Junction−to−Case (top) PsiJCt 3 21 °C/W Thermal Characterization Parameter, Junction−to−Board [FEM] PsiJB 46 113 °C/W Thermal Resistance, Junction−to−Air 4. Measured according to JEDEC board specification (board 1S2P, Cu of the board can be found in JESD51−7. layer thickness 1 oz, Cu area 650 mm2, no airflow). Detailed description ELECTRICAL CHARACTERISTICS (VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, CIN = COUT = 1.0 mF (effective capacitance – Note 5), TJ = −40°C to 125°C, ADJ tied to OUT, unless otherwise specified) (Note 6) Parameter Test Conditions Recommended Input Voltage Output Voltage Accuracy TJ = 25°C Symbol Min Typ Max Unit VIN 2.7 − 38 V VOUT −1 − 1 % −1 − 2 TJ = −40°C to +125°C ADJ Reference Voltage ADJ version only VADJ − 1.2 − V ADJ Input Current VADJ = 1.2 V IADJ −0.1 0.01 0.1 mA Line Regulation VIN = VOUT−NOM + 1 V to 38 V and VIN ≥ 2.7 V DVO(DVI) − − 0.2 %VOUT Load Regulation IOUT = 0.1 mA to 150 mA DVO(DIO) − − 0.4 %VOUT Quiescent Current (version A) VIN = VOUT−NOM + 1 V to 38 V, IOUT = 0 mA IQ − 1.3 2.5 mA Quiescent Current (version B) VIN = VOUT−NOM + 1 V to 38 V, IOUT = 0 mA − 1.8 3.0 Ground Current IOUT = 150 mA IGND − 325 450 mA Shutdown Current (Note 10) VEN = 0 V, IOUT = 0 mA, VIN = 38 V ISHDN − 0.35 1.5 mA Output Current Limit VOUT = VOUT−NOM − 100 mV IOLIM 200 280 450 mA Short Circuit Current VOUT = 0 V IOSC 200 280 450 mA Dropout Voltage (Note 7) IOUT = 150 mA VDO − 290 480 mV www.onsemi.com 4 NCV8730 ELECTRICAL CHARACTERISTICS (VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, CIN = COUT = 1.0 mF (effective capacitance – Note 5), TJ = −40°C to 125°C, ADJ tied to OUT, unless otherwise specified) (Note 6) (continued) Parameter Power Supply Ripple Rejection Test Conditions VIN = VOUT−NOM + 2 V IOUT = 10 mA Symbol Min Typ Max Unit PSRR − 80 − dB 10 kHz − 70 − 100 kHz − 42 − 1 MHz − 48 − VN − 240 − mVRMS 10 Hz Output Noise f = 10 Hz to 100 kHz VOUT−NOM = 5 V EN Threshold VEN rising VEN−TH 0.7 0.9 1.05 V EN Hysteresis VEN falling VEN−HY 0.01 0.1 0.2 V EN Internal Pull−up Current VEN = 1 V, VIN = 5.5 V IEN−PU 0.01 0.3 1.0 mA EN Input Leakage Current VEN = 30 V, VIN = 30 V IEN−LK −1.0 0.05 1.0 mA Start−up time (Note 8) VOUT−NOM ≤ 3.3 V tSTART 100 250 500 ms 300 600 1000 VOUT−NOM > 3.3 V Internal UVLO Threshold Ramp VIN up until output is turned on VIUL−TH 1.6 1.95 2.6 V Internal UVLO Hysteresis Ramp VIN down until output is turned off VIUL−HY 0.05 0.2 0.3 V PG Threshold (Note 9) VOUT falling VPG−TH 90 93 96 % PG Hysteresis (Note 9) VOUT rising VPG−HY 0.1 2.5 4.0 % PG Deglitch Time (Note 9) tPG−DG 75 160 270 ms PG Delay Time (Note 9) tPG−DLY 120 320 600 ms PG Output Low Level Voltage (Note 9) IPG = 1 mA VPG−OL − 0.2 0.4 V PG Output Leakage Current (Note 9) VPG = 30 V IPG−LK − 0.01 1.0 mA Thermal Shutdown Temperature Temperature rising from TJ = +25°C TSD − 165 − °C Thermal Shutdown Hysteresis Temperature falling from TSD TSDH − 20 − °C Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions. 5. Effective capacitance, including the effect of DC bias, tolerance and temperature. See the Application Information section for more information. 6. Performance guaranteed over the indicated operating temperature range by design and/or characterization. Production tested at TA = 25°C. Low duty cycle pulse techniques are used during the testing to maintain the junction temperature as close to ambient as possible. 7. Dropout measured when the output voltage falls 100 mV below the nominal output voltage. Limits are valid for all voltage versions. 8. Startup time is the time from EN assertion to point when output voltage is equal to 95% of VOUT−NOM. 9. Applicable only to version B (device option with power good output). PG threshold and PG hysteresis are expressed in percentage of nominal output voltage. 10. Shutdown current includes EN Internal Pull−up Current. www.onsemi.com 5 NCV8730 TYPICAL CHARACTERISTICS VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, COUT = 1.0 mF, ADJ tied to OUT, TJ = 25°C, unless otherwise specified VIN = (VOUT-NOM+ 1 V) to 38 V, VIN ≥ 2.7 V IOUT = 1 to 150 mA (V) 1.5% High limit 2.3 1.0% OUT OUTPUT VOLTAGE, V 2.5 High limit QUIESCENT CURRENT, IQ (mA) 2.0% VOUT-NOM= 15 V 0.5% VOUT-NOM= 5 V 0.0% VOUT-NOM= 1.2 V -0.5% Low limit -1.0% -1.5% 1.9 1.7 1.5 Version-A (non PG) 1.3 1.1 VIN = 38 V IOUT= 0 mA 0.9 -2.0% -40 -20 0 20 40 60 80 100 JUNCTION TEMPERATURE, TJ ( °C) 0.7 -40 120 Figure 6. Output Voltage vs. Temperature -20 0 20 40 60 80 JUNCTION TEMPERATURE, TJ ( °C) 100 120 Figure 7. Quiescent Current vs. Temperature 1.6 1.10 ENABLE THRESHOLD VOLTAGE, VEN -TH (V) High limit 1.4 SHUTDOWN CURRENT, I SHDN ( μA) Version-B (with PG) 2.1 Note: Shutdown current is measured at IN pin and includes EN pin pull-up current. 1.2 1.0 0.8 0.6 0.4 VIN = 38 V VEN = 0 V 0.2 0.0 -40 -20 0 20 40 60 80 100 1.05 High limit 1.00 0.95 0.90 0.85 0.80 0.75 Low limit 0.70 0.65 0.60 -40 120 -20 JUNCTION TEMPERATURE, T J ( °C) 0 20 40 60 80 100 120 JUNCTION TEMPERATURE, TJ (°C) Figure 8. Shutdown Current vs. Temperature Figure 9. Enable Threshold Voltage vs. Temperature 0.10 1.4 1.2 ADJ INPUT CURRENT, I ADJ (μA) ENABLE PULL - UP CURRENT, I EN-PU ( μA) 1.6 High limit 1.0 0.8 0.6 0.4 0.2 High limit 0.08 0.06 0.04 0.02 VEN = 1 V 0.0 -40 -20 0 20 40 60 80 100 0.00 -40 120 TEMPERATURE (°C) -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Figure 10. Enable Internal Pull−Up Current vs. Temperature Figure 11. ADJ Input Current vs. Temperature www.onsemi.com 6 NCV8730 TYPICAL CHARACTERISTICS VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, COUT = 1.0 mF, ADJ tied to OUT, TJ = 25°C, unless otherwise specified 500 High limit 450 DROPOUT VOLTAGE, V DROP (mV) 400 350 VOUT = VOUT-NOM - 100 mV IOUT = 150 mA All output voltage versions 300 250 200 150 100 50 0 -40 -20 0 20 40 60 80 100 JUNCTION TEMPERATURE, TJ ( °C) Figure 12. Dropout Voltage vs. Temperature www.onsemi.com 7 120 NCV8730 TYPICAL CHARACTERISTICS VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, COUT = 1.0 mF, ADJ tied to OUT, TJ = 25°C, unless otherwise specified 4.3V VIN VIN 8.3V 150mA 150mA 1mA IOUT 1mA VOUT 3.3V IOUT +55mV +58mV 3.3V -115mV -120mV C1: VIN C2: VOUT (ac) C4: IOUT VOUT 1.0V/div 50mV/div 100mA/div 20.0ms/div C1: VIN C2: VOUT (ac) C4: IOUT Figure 13. Load Transient − NCV8730−3.3 V, COUT = 1 mF 20.0ms/div Figure 14. Load Transient − NCV8730−3.3 V, COUT = 1 mF VIN 38.0V 2.0V/div 50mV/div 100mA/div VIN 4.3V 150mA 150mA 1mA IOUT 1mA VOUT 3.3V IOUT +58mV +37mV 3.3V VOUT -60mV -120mV C1: VIN C2: VOUT (ac) C4: IOUT 10.0V/div 50mV/div 100mA/div 20.0ms/div C1: VIN C2: VOUT (ac) C4: IOUT 1.0V/div 50mV/div 100mA/div 50.0ms/div Figure 16. Load Transient − NCV8730−3.3 V, COUT = 10 mF Figure 15. Load Transient − NCV8730−3.3 V, COUT = 1 mF VIN 4.3V 150mA VIN 6.0V 150mA IOUT 1mA 1mA +55mV +30mV 3.3V IOUT VOUT VOUT 5.0V -50mV -115mV C1: VIN C2: VOUT (ac) C4: IOUT 1.0V/div 50mV/div 100mA/div 50.0ms/div C1: VIN C2: VOUT (ac) C4: IOUT Figure 17. Load Transient − NCV8730−3.3 V, COUT = 22 mF 5.0V/div 50mV/div 100mA/div 20.0ms/div Figure 18. Load Transient − NCV8730−5.0 V, COUT = 1 mF www.onsemi.com 8 NCV8730 TYPICAL CHARACTERISTICS VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, COUT = 1.0 mF, ADJ tied to OUT, TJ = 25°C, unless otherwise specified VIN 38.0V VIN 6.0V 150mA 150mA 1mA IOUT 1mA VOUT 5.0V IOUT +48mV 5.0V +36mV VOUT -60mV -112mV C1: VIN C2: VOUT (ac) C4: IOUT 10.0V/div 50mV/div 100mA/div 20.0ms/div C1: VIN C2: VOUT (ac) C4: IOUT Figure 19. Load Transient − NCV8730−5.0 V, COUT = 1 mF VIN 15.5V 150mA 150mA 1mA IOUT 1mA VOUT 15.0V IOUT +34mV 5.0V -53mV C1: VIN C2: VOUT (ac) C4: IOUT 50.0ms/div Figure 20. Load Transient − NCV8730−5.0 V, COUT = 10 mF VIN 6.0V 5.0V/div 50mV/div 100mA/div +55mV VOUT -120mV 5.0V/div 50mV/div 100mA/div 50.0ms/div C1: VIN C2: VOUT (ac) C4: IOUT Figure 21. Load Transient − NCV8730−5.0 V, COUT = 22 mF 10.0V/div 100mV/div 100mA/div 20.0ms/div Figure 22. Load Transient − NCV8730−15.0 V, COUT = 1 mF VIN 38.0V VIN 15.5V 150mA 150mA 1mA 1mA VOUT 15.0V IOUT +40mV +50mV 15.0V IOUT VOUT -110mV -105mV C1: VIN C2: VOUT (ac) C4: IOUT 10.0V/div 100mV/div 100mA/div 20.0ms/div C1: VIN C2: VOUT (ac) C4: IOUT Figure 23. Load Transient − NCV8730−15.0 V, COUT = 1 mF 10.0V/div 50mV/div 100mA/div 50.0ms/div Figure 24. Load Transient − NCV8730−15.0 V, COUT = 10 mF www.onsemi.com 9 NCV8730 TYPICAL CHARACTERISTICS VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, COUT = 1.0 mF, ADJ tied to OUT, TJ = 25°C, unless otherwise specified VIN 15.5V VIN 15.5V 150mA 150mA IOUT 1mA VOUT 15.0V 1mA IOUT +45mV +16mV 15.0V -98mV C1: VIN C2: VOUT (ac) C4: IOUT VOUT -44mV 10.0V/div 50mV/div 100mA/div 50.0ms/div C1: VIN C2: VOUT (ac) C4: IOUT 10.0V/div 20mV/div 100mA/div 100.0ms/div Figure 25. Load Transient − NCV8730−15.0 V, COUT = 22 mF Figure 26. Load Transient − NCV8730−15.0 V, COUT = 50 mF Figure 27. PSRR − NCV8730−3.3 V, COUT = 1 mF, IOUT = 10 mA Figure 28. PSRR − NCV8730−3.3 V, COUT = 1 mF, IOUT = 100 mA Figure 29. PSRR − NCV8730−3.3 V, VIN = 4.3 V, IOUT = 100 mA Figure 30. PSRR − NCV8730−3.3 V, VIN = 8.3 V, IOUT = 100 mA www.onsemi.com 10 NCV8730 TYPICAL CHARACTERISTICS VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, COUT = 1.0 mF, ADJ tied to OUT, TJ = 25°C, unless otherwise specified Figure 31. Noise – FIX − 5.0 V, IOUT = 1 mA, COUT = 1 mF, Different VIN Figure 32. Noise – FIX − 5.0 V, COUT = 1 mF, Different IOUT Figure 33. Noise – FIX − 5.0 V, COUT = 1 mF + 10 mF, Different IOUT Figure 34. Noise – FIX − 5.0 V, COUT = 1 mF + 50 mF, Different IOUT Figure 35. Noise – FIX − 5.0 V, IOUT = 10 mA, Different COUT Figure 36. Noise – FIX − 5.0 V, IOUT = 150 mA, Different COUT www.onsemi.com 11 NCV8730 TYPICAL CHARACTERISTICS VIN = VOUT−NOM + 1 V and VIN ≥ 2.7 V, VEN = 1.2 V, IOUT = 1 mA, COUT = 1.0 mF, ADJ tied to OUT, TJ = 25°C, unless otherwise specified Figure 37. Noise – ADJ−set−5.0 V with Different CFF and FIX − 5.0 V Figure 38. Noise – FIX, IOUT = 10 mA, COUT = 1 mF, Different VOUT www.onsemi.com 12 NCV8730 APPLICATIONS INFORMATION Input Capacitor Selection (CIN) divider for adjustment. When it is connected to the OUT pin the output voltage of the circuit is simply the same as the nominal output voltage of the LDO. At this case, without ADJ resistor divider, the LDO should be loaded by at least 200 nA (by the application or added pre−load resistor). When connected to the resistor divider the output voltage could be computed as the ADJ reference voltage (1.2 V) multiplied by the resistors divider ratio, see following equation. Input capacitor connected as close as possible is necessary to ensure device stability. The X7R or X5R capacitor should be used for reliable performance over temperature range. The value of the input capacitor should be 1 mF or greater (max. value is not limited). This capacitor will provide a low impedance path for unwanted AC signals or noise modulated onto the input voltage. There is no requirement for the ESR of the input capacitor but it is recommended to use ceramic capacitor for its low ESR and ESL. A good input capacitor will limit the influence of input trace inductance and source resistance during load current changes. When a large load transients (like 1 mA to 150 mA) happens in the application the input power source of the LDO needs to provide enough power and the input voltage must not go below the level defined by this equation: VIN = VOUT−NOM + VDO otherwise the output voltage drop will be significantly higher (because LDO will enter the dropout state). In some cases when power supply powering the LDO has a poor load transient response or when there is a long connection between LDO and its power source then capacitance of input capacitor needs to be high enough to cover the LDO’s input voltage drop caused by load transient and maintains its value above the VIN = VOUT−NOM + VDO level (then CIN could be in range of hundreds of mF). ǒ V OUT + V ADJ @ 1 ) Ǔ R1 ) I ADJ @ R 1 R2 (eq. 1) Where: VOUT is output voltage of the circuit with resistor divider. VADJ is the LDO’s ADJ reference voltage. IADJ is the LDO’s ADJ pin input current. R1 and R2 are resistors of output resistor divider. At the classical “old style” regulators like LM317 etc. the resistors where small (100 W − 10 kW) to make regulator stable at light loads (divider was also a pre−load function). On NCV8730, which is very low quiescent current LDO regulator (1 mA), we need to care about current consumption of surrounding circuitry so we need to set the current through resistor divider flowing from VOUT through R1 and R2 to GND, as low as possible. On the other hand, the parasitic leakage current flowing into ADJ pin (IADJ) causes VOUT voltage error (given by IADJ ⋅ R1). The IADJ is temperature dependent so it is changing and we cannot compensate it in application, we just can minimize the influence by setting of R1 value low, what is in opposite to maximizing its value because of current consumption. So when selecting the R1 and R2 values we need to find a compromise between desired VOUT error (temperature dependent) and total circuit quiescent current. If we want to simplify this task, we can say the IR2 should be 100−times higher than IADJ at expected TJ temperature range. If we chose the ratio “IR2 to IADJ” higher (for example more than 100 as stated before), the ΔVOUT error caused by IADJ change over temperature would be lower and opposite, if the ratio “IR2 to IADJ” is smaller, the error would be bigger. In limited TJ temperature range −40°C to +85°C the IADJ is about 10−times smaller than in the full temperature range −40°C to +125°C (see typical characteristics graph of IADJ over temperatures), so we can use bigger R1, R2 values, as could be seen at next examples. Example 1: Desired VOUT voltage is 5.0 V. Computed maximal TJ in application (based on max. power dissipation and cooling) is 85°C. Than IADJ at 85°C is about: IADJ85 = 10 nA. Output Capacitor Selection (COUT) The LDO requires the output capacitor connected as close as possible to the output and ground pins. The LDO is designed to remain stable with output capacitor’s effective capacitance in range from 1 mF to 100 mF and ESR from 1 mW to 200 mW. The ceramic X7R or X5R type is recommended due to its low capacitance variations over the specified temperature range and low ESR. When selecting the output capacitor the changes with temperature and DC bias voltage needs to be taken into account. Especially for small package size capacitors such as 0402 or smaller the effective capacitance drops rapidly with the applied DC bias voltage (refer the capacitor’s datasheet for details). Larger capacitance and lower ESR improves the load transient response and PSRR. Output Voltage NCV8730 is available in two version from output voltage point of view. One is fixed output voltage version (FIX version) and the other one is adjustable output voltage version (ADJ version). The ADJ version has ADJ pin, which could be connected to the OUT pin directly, just to compensate voltage drop across the internal bond wiring and PCB traces or could be connected to the middle point of the output voltage resistor www.onsemi.com 13 NCV8730 VOUT =5V OUT ADJ version GND R1 3.76 MW ADJ version COUT 1mF IR1 1.01uA IADJ 10nA VOUT 5V ADJ GND IR2 1uA VR2 =VADJ 1.2V R1 376 kW COUT 1mF IR1 10.1uA IADJ 100nA VOUT 5V ADJ IR2 10uA VR2 =VADJ 1.2V R2 1.2 MW Figure 39. ADJ Output Voltage Schematic − Example 1 R2 120 kW Figure 40. ADJ Output Voltage Schematic − Example 2 We chose: We chose: I R2 + 100 @ I ADJ85 + 100 @ 10E−9 + 1 mA I R2 + 100 @ I ADJ125 + 100 @ 100E−9 + 10 mA Then: Then: V R 2 + R2 + 1.2 + 1.2 MW I R2 1E−6 R1 + VOUT =5V OUT V * V R2 V R1 5 * 1.2 + OUT + I R1 I ADJ85 ) I R2 10E−9 ) 1E−6 + R2 + V R2 + 1.2 + 120 kW I R2 10E−6 R1 + V * V R2 V R1 5 * 1.2 + OUT + I R1 I ADJ125 ) I R2 100E−9 ) 10E−6 3.8 + 3.762 MW 1.01E−6 + Verification: For low temperature (TJ = 25°C) the IADJ25 = 1 nA: ǒ V OUT + V ADJ @ 1 ) Verification: For low temperature (TJ = 25°C) the IADJ25 = 1 nA: Ǔ ǒ R1 ) I ADJ @ R 1 R2 ǒ V OUT + V ADJ @ 1 ) Ǔ Ǔ R ADJ1 ) I ADJ @ R ADJ1 R ADJ2 ǒ V OUT + 1.2 @ 1 ) 3.762E6 ) 1E−9 @ 3.762E6 1.2E6 Ǔ V OUT + 1.2 @ 1 ) 376.2E3 ) 1E−9 @ 376.2E3 120E3 + 4.966 V + 4.962 V For maximal temperature (TJ = 85°C) the IADJ85 = 10 nA: ǒ 3.8 + 376.2 kW 10.1E−6 For maximal temperature (TJ = 125°C) the IADJ125 = 100 nA: Ǔ ǒ V OUT + 1.2 @ 1 ) 3.762E6 ) 10E−9 @ 3.762E6 1.2E6 Ǔ V OUT + 1.2 @ 1 ) 376.2E3 ) 100E−9 @ 376.2E3 120E3 + 5.000 V + 5.000 V Output voltage error for temperatures 85°C to 25°C is: Output voltage error for temperatures 125°C to 25°C is: V * V OUT25 DV OUT + OUT85 @ 100 V OUT85 DV OUT + V OUT125 * V OUT25 @ 100 V OUT125 + 5.000 * 4.966 @ 100 + 0.68% 5.000 + 5.000 * 4.962 @ 100 + 0.76% 5.000 Total circuit quiescent current at TJ = 25°C is: Total circuit quiescent current at TJ = 25°C is: I Q(TOT) + I Q(LDO) ) I R1 + 1.3E−6 ) 1.01E−6 + 2.31 mA I Q(TOT) + I Q(LDO) ) I R1 + 1.3E−6 ) 10.1E−6 + 11.4 mA!!! We can see that current consumption of external resistor divider is almost the same as quiescent current of LDO. Example 2: Desired VOUT voltage is 5.0 V. Computed maximal TJ in application (based on max. power dissipation and cooling) is in this case higher, 125°C, to show the difference. Than maximal IADJ at 125°C is IADJ125 = 100 nA (based on Electrical characteristics table). We can see that error of VOUT voltage is almost the same as in example 1 (because we have used the same “IR2 to IADJ” ratio = 100x) but the application quiescent current is almost 10−times higher (because of 10−times higher divider current). CFF Capacitor Even the NCV8730 is very low quiescent current device, both the load transients over/under shoots and settling times are excellent. See the Typical characteristics graphs. www.onsemi.com 14 NCV8730 At adjustable application, the external resistor divider with input ADJ pin capacity and ADJ pin PCB trace capacity to GND makes a low pass filter what negatively affects the dynamic behavior of the LDO. On the next picture is shown how this unwanted side effect could be compensated by adding of feed−forward capacitor CFF across R1 resistor. VOUT=5V OUT R1 2M4 ADJ version GND ADJ CFF 1nF COUT 1mF 1.2V R2 750k Figure 44. PSRR – Different CFF Figure 41. ADJ Output Voltage Schematic − CFF Capacitor The value of the CFF depends on R1 and R2 resistor values. When R1, R2 values are in hundreds of kiloohms, proposed CFF value is 1 nF, as shown on picture above, for the best dynamic performance. Generally, the value could be in range from 0 to 10 nF. On next three pictures is shown the CFF capacitor influence to dynamic parameters. I OUT =1−to−150mA – 100mA/div VIN =4.3V – 1V/div C FF =0pF VOUT =3.3V – 50mV/div Figure 45. Startup C FF = 100p CFF =1nF In the NCV8730 device there are two main internal signals which triggers the startup process, the under−voltage lockout (UVLO) signal and enable signal. The first one comes from UVLO comparator, which monitors if the IN pin voltages is high enough, while the second one comes from EN pin comparator. Both comparators have embedded hysteresis to be insensitive to input noise. Not only the comparator but also the pull−up current source is connected to EN pin. Current source is sourcing IEN-PU = 300 nA current flowing out of the chip what ensures the level on the pin is high enough when it is left floating. The comparator compares the EN pin voltage with internal reference level 0.9 V (typ.). Hysteresis is 100 mV (typ.). The UVLO comparator threshold voltage is 1.95 V (typ.) and hysteresis is 200 mV (typ.). ASNADJ set to 3.3 V C FF =10pF Time – 10ms/div Figure 42. Load Transient – Different CFF ASNADJ set to 3.3 V VIN = 0´ 38V − 5V/div CFF =0pF VOUT =3.3V – 1V/div CFF = 100pF C FF =1nF Time – 2ms/div Figure 43. Startup Timing – Different CFF www.onsemi.com 15 NCV8730 IN OUT V IN UVLO IEN −PU = 300 nA 1.95 V V C CEN V−REFERENCE AND SOFT−START V R EF 1.2V EA C IN 1 mF RADJ1 GND DEGLITCH DELAY TMR VIUL−TH VIUL−TH – VIUL−HY VIN−TOP VEN = VIN PG PG Comparator 93% of VR EF EN VIN GND THERMAL SHUTDOWN 0.9 V C OUT 1 mF VIN−TOP RADJ2 EN Comparator V OUT Figure 49. Circuit – EN Pin Connected to IN Pin ADJ Enable 300 nA OUT LDO V EN V FB =1.2V EN IN Current limit UVLO Comparator VEN−TH VEN−TH – VEN−HY VOUT−NOM NC 95% of VOUT−NOM VOUT Time tSTART Figure 46. Internal Block Diagram – EN Pin Figure 50. Startup Timing – EN Pin Connected to IN Pin Startup by IN Pin Voltage When the LDO is started by IN pin voltage rise, it is turned ON when the voltage is higher than UVLO threshold level. This is the case of both following application circuits, the first one with EN pin floating and the second one with EN pin connected to IN pin. When the EN pin is floating (left unconnected) its voltage, after the LDO is powered, rises to VCCEN level (2.5 V – 4.5 V, VIN dependent) as the internal current source pulls the pin voltage up. VCCEN voltage level on EN pin is higher than EN comparator threshold so the LDO is turned ON. IN V IN C IN 1 mF OUT EN Startup by EN Pin Voltage When VIN voltage in the application is settled above the VIUL-TH level and control voltage to the EN pin is applied, the level higher than VEN−TH enables the LDO and the level lower than (VEN-TH – VEN-HY) disables it. Startup time is measured from point where VEN voltage reaches VEN−TH value to point when VOUT voltage reaches 95% of its nominal value. V OUT C OUT 1mF LDO V EN Startup time in both cases above is measured from the point where IN pin voltage reaches VIUL−TH value to point when OUT pin voltage reaches 95% of its nominal value. The reason why the LDO is started by the UVLO signal and not by the enable signal is the fact that the UVLO signal turns to valid state later then the enable. (EN pin voltage reaches the VEN-TH level prior the IN pin voltage reaches the VIUL-TH level). GND Figure 47. Circuit – Floating EN Pin VIN−TOP VIN V IN IN C IN 1mF VIUL−TH VIUL−TH – V IUL−HY VCCEN VOUT−NOM VEN−TH VEN−TH – V EN−HY V OUT COUT 1mF LDO V EN VEN OUT EN GND Figure 51. Circuit – LDO Controlled by VEN 95% of VOUT−NOM VOUT Time t START V IN V IUL−TH V IUL−TH – V IUL−HY V EN V EN−TH V EN−TH – V EN−HY Figure 48. Startup Timing – Floating EN Pin It is also possible to connect EN pin directly to IN pin in the whole input voltage range. The startup sequence is very similar to previous case, the only difference is that the EN pin voltage is not clamped to VCCEN level but it is the same as VIN voltage. VOUT−NOM 95% of VOUT−NOM V OUT Time t START Figure 52. Timing – VEN−Startup www.onsemi.com 16 NCV8730 Startup by IN Pin Voltage − Delayed signal makes it high because the transistor is connected as signal invertor. In this application we need to care about transistor’s leakage current which must be negligible compared to the internal pull−up current IEN−PU = 300 nA otherwise additional pull−up resistor REN will be needed. The maximum value of the EN resistor REN-MAX is computed from maximal external transistor leakage current (over desired temperature range) IT-LK-MAX and minimal input voltage VIN−MIN: The startup time triggered by IN pin voltage rise could be delayed by adding of EN pin capacitor (CEN). The startup sequence is following − after the VIN voltage is applied, the charging of CEN capacitor by internal pull−up current (IEN-PU) is started. When the CEN capacitor voltage (VCEN) reaches EN comparator’s threshold voltage (VEN−TH) the LDO is enabled. Charging of CEN continues up to the VCCEN level (2.5 V – 4.5 V, VIN dependent) with no following effect. The steepness of the LDO’s output voltage rise (soft−start time) is not affected by using of CEN capacitor. The additional delay time (tCEN−DELAY) could be computed by: t CEN−DELAY + C EN @ V EN−TH 0.9 V + C EN @ I EN−PU 300 nA R EN−MAX + (eq. 3) I SD(TOT) + I SD(LDO) ) I REN Value of the CEN capacitor could be in range from 0 to several microfarads. Capacitor’s leakage current must be negligible to internal pull−up current IEN−PU, otherwise the charging will be affected and adding of REN resistor from IN to EN pin will be needed. V IN IN C IN 1mF C EN EN I EN−PU I Q(TOT) R EN IN CIN 1 mF Figure 53. Circuit – CEN−Delayed VIN−Startup REN Opt. I REN V EN I EN−PU V IN VCTRL VCCEN VEN−TH (eq. 6) I Q(LDO) VIN VEN ǒVIN * VT−DSǓ I Q(TOT) + I Q(LDO) ) I T−LK GND (without CEN ) (eq. 5) Where VT−DS is the drain to source voltage of the transistor (given by RDSON and IREN). The overall application quiescent current when REN is used is influenced only by the transistor’s leakage current IT−LK. COUT 1 mF LDO V EN I REN + VOUT OUT (eq. 4) For safe, select the EN resistor value REN lower enough to computed REN-MAX. When REN is used the overall application shutdown current is increased because the current through REN resistor (IREN) is added to input shutdown current of the LDO (ISD(LDO)). The total application shutdown current (ISD(TOT)) is: (eq. 2) The total startup time (tSTART-CEN) with connected CEN capacitor is a sum of normal startup time (tSTART) and additional delay time caused by CEN capacitor (tCEN-DELAY): t START−CEN + t START ) t CEN−DELAY V IN−MIN I T−LK−MAX OUT VOUT COUT 1mF LDO EN GND IT Figure 55. Circuit – EN Pin Controlled by Transistor (with CEN ) VOUT−NOM VOUT (with CEN ) (without CEN ) 95% of VOUT−NOM VCTRL Time t CEN−DELAY t START t START−CEN VEN−TH VEN−TH – V EN−HY V EN Figure 54. Timing – CEN−Delayed VIN−Startup V OUT−NOM 95% of VOUT−NOM VOUT Startup by Transistor at EN Pin Time If the LDO needs to be controlled by transistor or generally by open collector / open drain circuit as shown at the next picture, the control behavior is inverted. High control signal makes the EN pin voltage low and low control t START Figure 56. Startup Timing – EN Pin Controlled by Transistor www.onsemi.com 17 NCV8730 Startup by Transistor at EN Pin − Delayed UVLO threshold value, the external resistor divider from IN pin to EN pin, is needed. Note that the specification of EN pin threshold voltage (0.7 V to 1.05 V over full operating temperature range) is not as precise as threshold voltage on dedicated UVLO devices. The reason is the EN circuit has to have ultra−low current consumption (NCV8730 ISHDN is 350 nA typ. even while IEN−PU is 300 nA typ. so EN comparator is powered by less than 50 nA typ.). We need to count with that when thinking about the IN pin UVLO design. Below is the application example to show what precision we can get. The startup time triggered by EN pin voltage rise, could be delayed the same way as IN pin triggered startup, by adding of CEN capacitor. The startup sequence is following – when the external NMOS control voltage (VCTRL) is high the CEN capacitor connected to the EN pin is shorted to GND and LDO is disabled. After the VCTRL is turned low the charging of CEN capacitor by the internal pull−up current source (IEN-PU) starts. When the CEN capacitor voltage (VCEN, which is the VEN in fact) reaches EN comparator’s threshold voltage (VENTH) the LDO is enabled. Charging of CEN then continues up to the VCCEN level (2.5 V – 4.5 V, VIN dependent) with no following effect. The steepness of the LDO’s output voltage rise (soft−start time) is not affected by using of CEN capacitor. The additional delay time (tCEN-DELAY) could be computed by eq. 2 and the total delayed startup time with CEN capacitor (tSTART-CEN) by eq. 3. What has been said about the CEN capacitor selection at previous paragraphs is applicable here as well. Also in this application we need to care about transistor’s leakage current which must be negligible compared to the internal pull−up current IEN−PU = 300 nA otherwise additional pull−up resistor REN will be needed. Same rules and computations as stated in previous paragraph about REN are applicable here. Note that REN would influence the speed of CEN capacitor charging. IQ(TOT) VIN CIN 1mF I Q(LDO) IN I REN REN Opt. V EN I EN−PU CIN 1 mF CEN 100pF Optional COUT 1 mF (with CEN) VOUT−NOM VOUT (without CEN) (with CEN) I REN2 R EN1 + V IN−UVLO−TH * V EN−TH I REN1 R EN2 + V EN−TH I REN1 ) I EN−PU (eq. 7) From that, we can get: ǒ GND VCCEN GND The two main equations for IN pin threshold computation are: V IN−UVLO−TH + V EN−TH @ 1 ) Ǔ (eq. 8) R EN1 * R EN1 @ I EN−PU R EN2 We can see that IN pin UVLO threshold is EN pin threshold multiplied by the resistor divider ratio as expected but it is unwillingly affected by IEN-PU pull−up current. As the IEN-PU current could vary up to the 1 mA max., we need to choose the IREN1 current several times higher to make the IEN-PU influence negligible. The good practice could be to choose IREN1 at least 10−times higher than IEN-PU (the bigger the better for the accuracy). An optional component in this application is CEN capacitor. Its main function is filtering out the spurious signals coming from IN power supply and the minor function is to delay the startup as described in section before. The value of CEN for filtering purpose could be in range from 10 pF to 10 nF. The time constant of this filter is given by: VCTRL (without CEN) EN VOUT COUT 1mF LDO I EN−PU REN2 OUT Figure 59. Circuit – IN Voltage UVLO by EN Pin Figure 57. Circuit – EN Pin with CEN Controlled by Transistor VEN REN1 I REN1 V EN C EN VCTRL I Q(LDO) IN VOUT OUT LDO EN I Q(TOT) VIN VEN−TH 95% of VOUT−NOM Time tCEN−DELAY tSTART tSTART −CEN t FILTER + C EN @ Figure 58. Startup Timing – EN Pin with CEN Controlled by Transistor R EN1 @ R EN2 R EN1 ) R EN2 (eq. 9) The side effect of the UVLO divider is increased overall power consumption. At no load state, the quiescent current IQ(TOT) of the application is: Enable Input as Inaccurate IN Pin UVLO I Q(TOT) + I Q(LDO) ) I REN1 The EN input pin on NCV8730 device is specified by threshold voltage and hysteresis both with minimum and maximum value, what allows using EN comparator as adjustable input voltage UVLO function. To set the VIN (eq. 10) So if we select the IREN1 value at least 10−times higher than IEN-PU-MAX (1 mA), then the UVLO divider current is www.onsemi.com 18 NCV8730 Output Current Limit almost 10-times higher than typical LDO’s quiescent current (1.3 mA). IN voltage UVLO application example: Desired VOUT voltage is 5 V, the LDO’s input voltage in normal state is 12 V. We want to turn−off the LDO’s output voltage when input voltage is below 10 V (max.). First, choose the IREN1 current as 10−times the maximum IEN-PU current: I REN1 + 10 @ I EN−PU + 10 @ 1 mA + 10 mA Output current is internally limited to 280 mA typ. The LDO will source this current when the output voltage drops down from the nominal output voltage (test condition is 90% of VOUT−NOM). If the output voltage is shorted to ground, the device continues with current limitation at the same current level. The current limit and short circuit protection will work properly over the whole temperature and input voltage ranges. There is no limitation for the short circuit duration. Minimal output current limit value is 200 mA what could be used to cover current demand peaks, higher than the LDO’s nominal output current (150 mA). (eq. 11) Then, to obtain REN1 and REN2 values for maximal VIN-UVLO-TH = 10 V, we need to put maximum value of VEN-TH (1.05 V) and minimum value of IEN-PU (0 mA) into the equations for REN1 and REN2: Inrush Current (eq. 12) At every application, the startup sequence needs a special care because during power−up the bypass capacitors connected to the power rail are charged from zero to input voltage level, what generates a current spike, so called inrush current. The size of such current spike depends on the voltage transient slope (the faster the bigger spike), on the total impedance of the loop from the power source to bypass capacitor (traces impedance, power source internal impedance and capacitor impedance; the lower the bigger spike) and on the capacitor value (the higher the bigger spike). This inrush current during startup could cause power source’s overcurrent event, damage of PCB traces, power line fuses blowing or spurious signal generation in surrounding application parts. For a simplified case when total impedance between input power source and bypass capacitor is zero, we can use following equation to compute the inrush current, based just on voltage transient slope (dV/dt) and the capacitor value: −V V 10 V−1.05 V R EN1 + IN−UVLO−TH EN−TH + + 895 kW I REN1 10 mA R EN2 + V EN−TH 1.05 + + 105 kW I REN1 ) I EN−PU 10 mA ) 0 mA The resulting VIN-UVLO-TH limits will be: ǒ V IN−UVLO−TH−MIN + V EN−TH−MIN @ 1 ) ǒ V IN−UVLO−TH−MIN + 0.7 @ 1 ) (eq. 13) R EN1 * R EN1 @ I EN−PU−MAX R EN2 Ǔ Ǔ 895 kW * 895 kW @ 1 mA 105 kW V IN−UVLO−TH−MIN + 5.77 V ǒ V IN−UVLO−TH−MAX + V EN−TH−MAX @ 1 ) ǒ V IN−UVLO−TH−MAX + 1.05 @ 1 ) Ǔ R EN1 * R EN1 @ I EN−PU−MIN R EN2 Ǔ 895 kW −895 kW @ 0 mA 105 kW V IN−UVLO−TH−MAX + 10.0 V I Q(TOT) + I Q(LDO) ) I REN1 + 1.3 mA ) 10 mA + 11.3 mA i INRUSH + C @ dV dt When higher IREN1 is selected the VIN-UVLO-TH-MIN would be slightly near the target value, the VIN-UVLO-TH-MAX would stay the same but the IQ(TOT) would be significantly higher: I REN1 + 100 @ I EN−PU + 100 @ 1 mA + 100 mA Example – when the voltage changes from 0 V to 24 V in 10 ms and bypass capacitor is 10 mF, the inrush current is: i INRUSH + 10 mF @ (eq. 14) We would get: R EN1 + 89.5 kW (eq. 16) 24 V * 0 V + 24A 10 ms (eq. 17) Of course, this is the worst case when impedances in the circuit are zero, but it shows why we need to care about startup and what defines the inrush current value. We can see the inrush current is lower when capacitance and voltage change are smaller or transition time is longer. In most cases, the capacitor value and the input voltage change are defined by the application so then the only thing we can do is to slow down the input voltage transition time. We can do it directly by changing input voltage rise time by soft−start circuit (related to Equation 16) or indirectly by adding a current limit block, which in combination with the capacitor will do the same (slower the input voltage rise), see the following equation: (eq. 15) R EN2 + 10.5 kW V IN−UVLO−TH−MIN + 6.58 V I Q(TOT) + I Q(LDO) ) I REN1 + 1.3 mA ) 100 mA + 101.3 mA We can see the IN pin UVLO threshold precision computed above (5.77 V or 6.58 V min. / 10.0 V max.) is not too high because the EN pin threshold and EN pin internal pull−up current specifications are not so tight as on dedicated UVLO devices but at some applications this precision could fit the needs. t START + C @ dV I LIMIT www.onsemi.com 19 (eq. 18) NCV8730 We see that voltage transition time (tSTART) is given by bypass capacitor value (C), by the voltage change (dV) and by current limit value (ILIMIT) of added current limit block. Now back to LDO application. Here we can see two different inrush current spikes. The first one is caused by the LDO’s input capacitor (CIN) charging from zero to the input voltage level. It happens when the previous power block (for example DC/DC) starts providing the input voltage to the LDO circuit. The maximum level of this inrush current is given by Equation 16. It doesn’t matter if LDO is enabled or disabled as this inrush current spike is related only to CIN and it can’t be suppressed by the LDO, it is matter of previous power block. This inrush current spike is shown at Figure 61, point (1). The second inrush current spike is generated by the LDO’s output capacitor (COUT) charging from zero to nominal output voltage level. It happens when the LDO is enabled by any way (by driving EN pin or by internal UVLO when EN pin is connected to IN pin). This inrush current is limited by the LDO’s soft−start and current limit functions. Soft−start function limits the speed of the output voltage rise to avoid possible latch−up of application circuit caused by high dV/dt what naturally suppresses input inrush current (related to Equation 16). The current limit function, used to guard the LDO and application against the overcurrent, is also used during the LDO’s startup to limit the input inrush current. Now focus onto the NCV8730 device. At the next picture we can see both, soft−start and current limit functions have been implemented, shown in red. At this device, the startup current limit level is the same as the normal operation current limit level (specified at the parametric table). current limit value). While at the case of big output capacitor (for example 47 mF), the soft−start time is not slow enough and the input current needs to be limited by the current limit function. Next picture shows both startup cases – with small (1 mF) and big (47 mF) output capacitors. Startup is caused by IN voltage rise, EN pin is connected to IN pin and device voltage version is 5.0 V. (3) C1: VIN C2: VOUT C4: I IN IEN −PU = 300nA EN V CCEN V−REFERENCE AND SOFT−START V REF 1.2V EA RADJ1 RADJ2 DV OUT t START 5V*0V + 470 mA (eq. 20) 500 ms Therefore, in this case the current limit is activated and limits the COUT charging current to about 280 mA (from the picture, point−3). This leads to enlarging of startup time to: ADJ t START + C OUT @ GND DV OUT I LIMIT 5V*0V t START + 47 mF @ + 870 ms 270 mA DEGLITCH DELAY TMR (eq. 19) With the COUT = 47 mF, the inrush current should be 47−times higher than in case of 1 mF: THERMAL SHUTDOWN PG Comparator 93 % of V REF 200 μs/div 1.0V/div 1.0V/div 200mA/div 5V*0V i INRUSH−1mF + 1 mF @ + 9 mA 550 ms Enable 0.9 V 47μF i INRUSH−47mF + 47 mF @ V FB =1.2V EN Comparator 1μF i INRUSH + C OUT @ Current limit UVLO IIN VIN VOUT With the COUT = 1 mF, the inrush current (seen at IIN signal at point−2) is almost zero, its level is defined by soft−start time which is about 550 ms (from the picture). OUT 1.95 V 47μF Figure 61. IN UVLO Comparator 1μF (2) 0³6 V, t R = 10μs (1) PG (eq. 21) One additional thing could be seen at the picture above and it is a small current spike highlighted as a point−1 at the IIN curve. It is the inrush current caused by input voltage transient (from 0 V to 6 V in 10 ms) and input capacitor CIN = 100 nF. As stated before, for this current spike is responsible the prior power source, not the LDO (in this case the test equipment which generates the VIN transient). The CIN inrush current amplitude is: NC Figure 60. A few practical notes. If the LDO’s output capacitor value is small (for example 1 mF), then soft−start limited output voltage rise is slow enough to suppress the inrush current (output capacitor charging current, generated by dVOUT/dt, based on Equation 16, is significantly smaller than the i INRUSH_POINT−1 + 100 nF @ www.onsemi.com 20 6V*0V + 60 mA (eq. 22) 10 ms NCV8730 Power Supply Rejection Ratio different power supply voltage to the LDO’s VOUT level. Below are the connections examples. The LDO features high power supply rejection ratio even it is very low quiescent current device. See the Typical characteristics section for the graphs over different conditions. The PSRR at higher frequencies (from about 100 kHz) can be tuned by the selection of COUT capacitor, applied input voltage and proper PCB layout (minimizing impedance from load to COUT). IN 5.0V OUT COUT 1 mF BMT500 EN VCC RPG PG GND Application PGI CTRL PG Output Version B of the NCV8730 device contains PG circuit for the VOUT voltage level monitoring. Internally it is combined from PG comparator, deglitch/delay timer and output NMOS transistor (highlighted by red color at picture below). At both, ADJ and FIX versions, the PG comparator compares internal feedback signal voltage (VFB) with the 93% of VREF (typ.) what makes the function independent to the output voltage absolute value (it always compares set VOUT with 93% of its nominal value). Figure 63. Circuit Example – PG Connected to LDO’s Output IN 5.0V OUT BMT500 EN VCCA COUT 1 mF PG GND 3.3V VCCD R PG IN OUT UVLO I EN −PU = 300 nA 1.95 V V CCEN V−REFERENCE AND SOFT−START VR EF 1.2V EA ADJ Enable 0.9 V RADJ2 GND THERMAL SHUTDOWN PG PG Comparator 93% of VR EF Following timing diagrams show the situation when LDO falls out of regulation 3 times (output voltage drops down from nominal value) because of (for example) insufficient IN pin voltage. Note that the VPG voltage at “power ok state” follows the voltage where the RPG is connected because the PG output is in Hi−Z state and just RPG connection point defines the VPG level. In the first example when RPG is connected to LDO’s output, the VPG follows the LDO’s VOUT including the drops. In the second example the RPG is connected to LDO independent power rail (3.3 V) so the VPG is not following the LDO’s output voltage. RADJ1 EN Comparator Appl. Part 2 (MCU) Figure 64. Circuit Example – PG Connected to Application Power Supply VFB =1.2V EN PGI CTRL Current limit UVLO Comparator Appl. Part 1 (analog) DEGLITCH DELAY TMR NC Note: Blue objects are valid for ADJ version Green objects are valid for FIX version Red objects are valid for B version (with PG) t OUT−LOW < t PG−DG t PG−DG 5V Figure 62. Power Good Output Block Diagram The PG output is in high impedance state (Hi−Z) to show “power ok state” when the VOUT voltage is above the PG threshold level (VPG-TH) or is shorted to GND pin to show “power fail state” when the VOUT falls below the level (VPG-TH – VPG-HY). The PG threshold voltage is 93% of VOUT-NOM (typ.) and the hysteresis is 2% of VOUT-NOM (typ.). Because the PG output is open drain type it needs to be connected by external pull resistor to a voltage level, which defines the PG pin voltage at time when it is in Hi−Z state. It allows connections of PG pin to circuit with the same or t PG−DLY V PG−TH V PG−TH – VPG−HY VOUT R PG~10kW (t~500ns) 5V R PG ~100kW (t~5ms) V PG Time Time region 1 2 3 4 Figure 65. Timing – PG Connected to LDO’s Output www.onsemi.com 21 NCV8730 t OUT−LOW < t PG−DG t PG−DG 5V t PG−DLY through the RPG to the grounded PG pin. This is just a case of the power fail state so probably not a concern too. At the electrical characteristics table we can find the parameter “PG Output Low Level Voltage (VPG-OL)” which defines the drop across the PG internal transistor when it sinks current 1 mA. We can take this current condition (1 mA) as a maximal PG current (IPG−MAX) for the RPG−MIN computation (as we know the PG drop at this level, 0.4 V max.). If the application input current IPGI is negligible to IRPG we can compute the RPGI−MIN by: V PG−TH V PG−TH – VPG−HY VOUT R PG~10kW (t~500ns) 3.3V R PG ~100kW (t~5ms) VPG Time Time region 1 2 3 R PG−MIN + 4 Figure 66. Timing – PG Connected to Application Power Supply 3.3 V V CC−RPG I PG−MAX (eq. 23) And, for example, when RPG is connected to 3.3 V power rail: The timing diagrams have been divided into 4 time regions to show different situations: In region−1, the VOUT drop is not deep enough so the PG output shows “power ok state”. In region−2, the VOUT drop is deeper and crosses the VPG-TH threshold level but the duration of the drop is shorter then PG deglitch time (tPG-DG = 160 ms typ.) so the PG output still shows “power ok state”. Note that the deglitch time has been intentionally implemented to filter out spurious output voltage drops (caused for example by fast load transients etc.). In both two first regions the VPG is high and follows the voltage level where the RPG resistor is connected to (VLDO(OUT) or VCCD). In region−3, the VOUT drop is deep enough and the duration is longer then tPG-DG time so the PG output is shorted to GND pin and shows power fail state. In region−4, the VOUT returns back to its nominal value. When it crosses the level (VPG-TH – VPG-HY) the PG output turns from short to GND into Hi−Z state, not immediately, but after the PG delay time (tPG-DLY = 320 ms typ.). The PG delay ensures that low PG pulse, showing “power fail state”, is always longer than the tPG-DLY time and then could be caught by the application circuit (for example by MCU). R PG−MIN + V CC−RPG 3.3 V + + 3.3 kW (eq. 24) I PG−MAX 1 mA V CC−RPG R PG I RPG BMTxxx Application V PG PG I PG GND PGI I PGI Note: I PG = I RPG when I PGI = 0mA Figure 67. Circuit Example for RPG Value Selection From the opposite side, RPG is limited to its maximum value, based on: maximum PG leakage current IPG−LK−MAX, maximum threshold voltage of the application input VPGI−TH−MAX and maximum application input leakage current IPGI−LK−MAX. Then: R PG−MAX + V CC−RPG * V PGI−TH−MAX I PG−LK−MAX ) I PGI−LK−MAX (eq. 25) For example, when RPG is connected to 3.3 V power rail, max. threshold voltage of the application input is 1.3 V and application input leakage current is 3 mA max.: RPG Value Selection R PG−MAX + As shown on the Figure 65 and Figure 66 in the time region-4, the steepness of PG signal return to high level depends on the RPG pull−up resistance (with relation to capacitance of LDO’s PG output, parasitic capacitance of PG signal PCB traces and the application circuit PGI input capacitance. The lower RPG resistance the faster PG return to high level. At the most applications, the PG return speed to high level is not a concern, mainly because of the fact that the LDO already delays the PG return by the tPG-DLY time (320 ms typ.) intentionally so the returning speed itself is negligible. The next view to the RPG value is the power consumption at “power fail state” when the current from the supply flows + V CC−RPG * V PGI−TH−MAX I PG−LK−MAX ) I PGI−LK−MAX (eq. 26) 3.3 V * 1.3 V + 500 kW 1 mA ) 3 mA Based on results above, the RPG value could be selected in range from 3.3 kW to 500 kW to fit the example application. Thermal Shutdown When the LDO’s die temperature exceeds the thermal shutdown threshold value the device is internally disabled. The IC will remain in this state until the die temperature decreases by the thermal shutdown hysteresis value. Once www.onsemi.com 22 NCV8730 the IC temperature falls this way, the LDO is back enabled. The thermal shutdown feature provides the protection against overheating due to some application failure and it is not intended to be used as a normal working function. Where: (TJ − TA) is the temperature difference between the junction and ambient temperatures and θJA is the thermal resistance (dependent on the PCB as mentioned above). For reliable operation junction temperature should be less than +125°C. The power dissipated by the LDO for given application conditions can be calculated by the next equation: Power Dissipation Power dissipation caused by voltage drop across the LDO and by the output current flowing through the device needs to be dissipated out from the chip. The maximum power dissipation is dependent on the PCB layout, number of used Cu layers, Cu layers thickness and the ambient temperature. The maximum power dissipation can be computed by following equation: P D(MAX) + TJ * TA 125 * T A + [W] q JA q JA P D + V IN @ I GND ) ǒV IN * V OUTǓ @ I OUT [W] (eq. 28) Where: IGND is the LDO’s ground current, dependent on the output load current. Connecting the exposed pad and NC pin to a large ground planes helps to dissipate the heat from the chip. The relation of θJA and PD(MAX) to PCB copper area and Cu layer thickness could be seen on the Figures 68 and 69. (eq. 27) Figure 68. qJA and PD(MAX) vs. Copper Area Figure 69. qJA and PD(MAX) vs. Copper Area Figure 70. Maximum Output Current vs. Input Voltage Figure 71. Maximum Output Current vs. Input Voltage www.onsemi.com 23 NCV8730 PCB Layout Recommendations Besides the LDO application circuit, each demo board includes some supporting staff, the same at all boards: • Positions for optional through hole SMB connectors at IN, OUT and EN pins (Molex 73100−0258 or compatible) mainly for line/load transients, PSRR, noise and startup testing the demo board includes. • Edge connector where all these signal leads too (the appropriate receptacle type is SAMTEC MECF−20−01−L−DV−WT). • Thermal management circuit (heating transistor and diodes as temperature sensors). To obtain good LDO’s stability, transient performance and good regulation characteristics place CIN and COUT capacitors as close as possible to the device pins and make the PCB traces wide, short and place capacitors to the same layer as the LDO is (to avoid connection through vias). The same rules should be applied to the connections between COUT and the load – the less parasitic impedance the better transients and regulation at the point of load. To minimize the solution size, use 0402 or 0201 capacitor sizes with appropriate effective capacitance in mind. Regarding high impedance ADJ pin, prevent capacitive coupling of the trace to any switching signals in the circuitry. Adequate input power filtering is always a good practice. For load transients the input capacitor value must be high enough to cover the current demands especially if the power source is connected by long traces/wires with high impedance. Demo Boards Below are the main part of the schematics and top/bottom board layout pictures of the NCV8730 demo boards for various packages. These boards have been used during evaluation to capture the data shown in this datasheet like: transients, PSRR, startups etc. At some of these pictures are shown details of PCB traces surrounding the LDO including CIN, COUT, resistor divider R1/R2, feed forward capacitor CFF and IN/OUT−FORCE/SENSE connections. Generally, when testing LDOs dynamic performance on demo board which is connected to laboratory power supply typically by long cables, the device needs additional input capacitor. This capacitor covers the voltage drop generated by the load current transients at the impedance of long connection cables (note this is very different to normal application where the distance of the LDO to its power source is short). Figure 72. Edge Connector Pinout (All Demo Boards) Figure 73. Thermal Circuit (All Demo Boards) www.onsemi.com 24 NCV8730 NCV8730ASN/BSN (TSOP−5 package) Demo Board (2 layer PCB, rev. 1) Figure 74. TSOP−5 Demo Board (2 layer, rev. 1) – Schematics (Main Part) Figure 76. TSOP−5 Demo Board (2 layer, rev. 1) – PCB Bottom Layer Figure 75. NCV8730 Demo Board (2 layer, rev. 1) – PCB Top Layer Figure 77. TSOP−5 Demo Board (2 layer, rev. 1) – PCB Top Layer, Zoomed, Added Signal Labels www.onsemi.com 25 NCV8730 NCV8730AMT/BMT (WDFN−6 2x2 package) Demo Board (2 layer PCB, rev. 1) Figure 78. WDFN−6 2x2 Demo Board (2 layer, rev. 1) – Schematics (Main Part) Figure 79. WDFN−6 2x2 Demo Board (2 layer, rev. 1) – PCB Top Layer Figure 80. WDFN−6 2x2 Demo Board (2 layer, rev. 1) – PCB Bottom Layer Figure 81. WDFN−6 2x2 Demo Board (2 layer, rev. 1) – PCB Top Layer, Zoomed, Added Signal Labels www.onsemi.com 26 NCV8730 ORDERING INFORMATION Part Number Marking Voltage Option (VOUT−NOM) NCV8730ASNADJT1G PA2 ADJ NCV8730ASN180T1G PAH 1.8 V NCV8730ASN330T1G PAE 3.3 V NCV8730ASN500T1G PAG 5.0 V NCV8730BMTWADJTBG Q2 ADJ NCV8730BMTW330TBG QF 3.3 V NCV8730BMTW500TBG QG 5.0 V NCV8730BMTW1500TBG QH 15.0 V Version Package Shipping Without PG TSOP−5 (Pb−Free) 3000 / Tape & Reel With PG WDFNW6 2x2 (Pb−Free) 3000 / Tape & Reel NOTE: To order any other package, voltage version or PG / non PG variant, please contact your ON Semiconductor representative. www.onsemi.com 27 MECHANICAL CASE OUTLINE PACKAGE DIMENSIONS TSOP−5 CASE 483 ISSUE N 5 1 SCALE 2:1 NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994. 2. CONTROLLING DIMENSION: MILLIMETERS. 3. MAXIMUM LEAD THICKNESS INCLUDES LEAD FINISH THICKNESS. MINIMUM LEAD THICKNESS IS THE MINIMUM THICKNESS OF BASE MATERIAL. 4. DIMENSIONS A AND B DO NOT INCLUDE MOLD FLASH, PROTRUSIONS, OR GATE BURRS. MOLD FLASH, PROTRUSIONS, OR GATE BURRS SHALL NOT EXCEED 0.15 PER SIDE. DIMENSION A. 5. OPTIONAL CONSTRUCTION: AN ADDITIONAL TRIMMED LEAD IS ALLOWED IN THIS LOCATION. TRIMMED LEAD NOT TO EXTEND MORE THAN 0.2 FROM BODY. D 5X NOTE 5 2X DATE 12 AUG 2020 0.20 C A B 0.10 T M 2X 0.20 T 5 B 1 4 2 B S 3 K DETAIL Z G A A TOP VIEW DIM A B C D G H J K M S DETAIL Z J C 0.05 H C SIDE VIEW SEATING PLANE END VIEW GENERIC MARKING DIAGRAM* SOLDERING FOOTPRINT* 0.95 0.037 MILLIMETERS MIN MAX 2.85 3.15 1.35 1.65 0.90 1.10 0.25 0.50 0.95 BSC 0.01 0.10 0.10 0.26 0.20 0.60 0_ 10 _ 2.50 3.00 1.9 0.074 5 5 XXXAYWG G 1 1 Analog 2.4 0.094 XXX = Specific Device Code A = Assembly Location Y = Year W = Work Week G = Pb−Free Package 1.0 0.039 XXX MG G Discrete/Logic XXX = Specific Device Code M = Date Code G = Pb−Free Package (Note: Microdot may be in either location) 0.7 0.028 SCALE 10:1 mm Ǔ ǒinches *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. DOCUMENT NUMBER: DESCRIPTION: 98ARB18753C TSOP−5 *This information is generic. Please refer to device data sheet for actual part marking. Pb−Free indicator, “G” or microdot “ G”, may or may not be present. Electronic versions are uncontrolled except when accessed directly from the Document Repository. Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red. PAGE 1 OF 1 ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries. ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor the rights of others. © Semiconductor Components Industries, LLC, 2018 www.onsemi.com MECHANICAL CASE OUTLINE PACKAGE DIMENSIONS WDFNW6 2x2, 0.65P CASE 511DW ISSUE B DATE 15 JUN 2018 SCALE 4:1 GENERIC MARKING DIAGRAM* XXMG G M G = Month Code = Pb−Free Package (Note: Microdot may be in either location) *This information is generic. Please refer to device data sheet for actual part marking. Pb−Free indicator, “G” or microdot “ G”, may or may not be present. Some products may not follow the Generic Marking. DOCUMENT NUMBER: DESCRIPTION: 98AON79327G WDFNW6 2x2, 0.65P Electronic versions are uncontrolled except when accessed directly from the Document Repository. Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red. PAGE 1 OF 1 ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries. ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor the rights of others. © Semiconductor Components Industries, LLC, 2018 www.onsemi.com ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries. ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. 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