ncv8881 ON Semiconductor, ncv8881 Datasheet
ncv8881
Available stocks
Related parts for ncv8881
ncv8881 Summary of contents
Page 1
... NCV8881 1.5A Automotive Buck Regulator with Watchdog The NCV8881 consists of a Buck switching regulator (SMPS) with a combination SMPS output undervoltage monitor and CPU watchdog circuit. In addition, two fixed−voltage low dropout regulator outputs are provided, and share an LDO output voltage status output. Once enabled, regulator operation continues until the Watchdog signal is no longer present ...
Page 2
... SENSE NOPULSE DBST2 5V REGULATOR VIN_OV /UVLO FAULT(H) ENABLE HYSTERESIS UNDERVOLTAGE SW_UV MONITOR SHORT CKT OC MONITOR RUN PWM COMPARATOR NCV8881 Figure 2. NCV8881 Detailed Block Diagram http://onsemi.com 2 REGULATED 5.0V CS5P0 RMON LDO MONITOR REGULATED 8.5V CS8P5 BATTERY REGULATED SMPS OUTPUT L1 COUT DFW CZ1 RP2 ...
Page 3
MAXIMUM RATINGS Rating Min/Max Voltage on WDI Min/Max Voltage on RDLY Min/Max Voltage on RESB Min/Max Voltage on EN Max EN Current Min EN Current (with zero VIN voltage) Min/Max Voltage on SYNC Min/Max Voltage on ROSC Min/Max Voltage COMP ...
Page 4
PIN FUNCTION DESCRIPTIONS Pin No. Symbol 1 IGNBUF This open drain output is pulled low whenever the EN signal is latched and a low level is recognized at the EN input. 2 WDI CMOS compatible Watchdog pulse input from a ...
Page 5
... < 1.2 V, sinking 0.5 mA IGBLO EN T (Note 4) TSD (Note 4) http://onsemi.com 5 Min Typ Max 5.0 5.6 6.0 4.2 4.6 5.0 0 1.6 1 0.8 1.4 3.0 NCV8881 is disabled 10 0.02 0.1 160 170 180 35 Unit °C °C ...
Page 6
... ESR for stability (Note 5) Co PSRR 0.5 V 100 Hz sine VIN pp wave (Note 5) 8P5 kW (Note 5) 8P5LOAD 8P5 into the NCV8881 CLP8P5 8P5 V > V and V > V 5P0 5UVSTT 8P5 V V < < V RBLO 5P0 5UVSTP 8P5 sinking 0 ...
Page 7
SMPS REGULATOR ELECTRICAL CHARACTERISTICS (V otherwise) Min/Max values are valid for the temperature range −40°C vT design or statistical correlation. Parameter SOFT−START Soft−Start Completion Time VOLTAGE REFERENCE (FB Pin) FB Voltage (COMP connected to FB) FB PIN MONITOR (SMPS Output ...
Page 8
SMPS REGULATOR ELECTRICAL CHARACTERISTICS (V otherwise) Min/Max values are valid for the temperature range −40°C vT design or statistical correlation. Parameter SYNCHRONIZATION Minimum High Pulse Width Minimum Low Pulse Width DUTY CYCLE LIMITATIONS Minimum Off Time Minimum On Time CURRENT ...
Page 9
WATCHDOG ELECTRICAL CHARACTERISTICS (V the temperature range −40° 150°C unless noted otherwise, and are guaranteed by test, design or statistical correlation. J Parameter WATCHDOG INPUT (WDI pin) Input High Voltage Input Low Voltage Input Current Threshold Frequency RDLY ...
Page 10
FAULT RESPONSES INPUTS FAULT EVENT EN EN Latch VIN Undervoltage L UNLATCH VIN Undervoltage H UNLATCH VIN Overvoltage L Stays Latched VIN Overvoltage H Stays Latched Thermal Shutdown L Stays Latched Thermal Shutdown H Stays Latched 5P0 Out of Regulation ...
Page 11
TYPICAL PERFORMANCE CHARACTERISTICS 14.0 12.0 13.2 V SUPPLY 10.0 8.0 6.0 V SUPPLY 6.0 4.0 2.0 0.0 −40 − TEMPERATURE (°C) Figure 3. Supply Current (EN Low) vs. Temperature 50.0 45.0 40.0 35.0 30.0 25.0 ...
Page 12
TYPICAL PERFORMANCE CHARACTERISTICS 20.8 20.7 20.6 20.5 20.4 20.3 20.2 20.1 20.0 19.9 19.8 −40 − TEMPERATURE (°C) Figure STOP Voltage vs. IN Temperature 810 808 806 804 802 800 798 796 ...
Page 13
TYPICAL PERFORMANCE CHARACTERISTICS 8.500 8.495 8.490 8.485 8.480 8.475 8.470 9.0 12.0 15.0 VOLTAGE (V) Figure 15. 8P5 Output Voltage vs. Input Voltage 200 180 160 140 120 100 80 60 −40 − TEMPERATURE (°C) ...
Page 14
TYPICAL PERFORMANCE CHARACTERISTICS 0.05 0.04 0.03 0.02 0.01 0.00 −40 − TEMPERATURE (°C) Figure 21. RESB Low Voltage vs. Temperature 1.050 1.045 1.040 1.035 1.030 1.025 1.020 1.015 1.010 −40 − ...
Page 15
TYPICAL PERFORMANCE CHARACTERISTICS 750 ROSC = 0 740 730 720 710 700 690 680 670 660 650 −40 − TEMPERATURE (°C) Figure 27. Maximum Switching Frequency vs. Temperature 80.0 79.0 78.0 77.0 76.0 75.0 −40 ...
Page 16
TYPICAL PERFORMANCE CHARACTERISTICS 5.30 5.20 5.10 5.00 4.90 4.80 4.70 4.60 −40 − TEMPERATURE (°C) Figure 33. Soft−Start Time vs. Temperature 650 600 550 500 450 400 350 300 250 200 150 100 50 0 ...
Page 17
TYPICAL PERFORMANCE CHARACTERISTICS 350 T = 25°C J 300 250 200 150 100 LOAD CURRENT (kW) Figure 39. 5P0 Dropout Voltage vs. Load Current 250 T = 25°C J 200 150 ...
Page 18
... INPUT VOLTAGE VIN is the power supply input for all NCV8881 functions. Prior to the appearance of a valid high at the Enable input (EN pin), VIN voltage above the V STRT a low level at the Reset output (RESB). INPUT UNDERVOLTAGE SHUTDOWN An Undervoltage Lockout (UVLO) circuit monitors the voltage at the VIN pin ...
Page 19
RESB LOW LDOS ON, SMPS OFF Temp > Shutdown RESB LOW LDOS, SMPS OFF LDOMON ACTIVE VIN < 19V & Temp <Shutdown 5P0 or 8P5 in regulation UNLATCH ENABLE Temp <Shutdown 1 SS Timer Expired 2 SMPS in regulation 3 ...
Page 20
ENABLE (EN PIN) After VIN rises above below V STRT maintain a standby mode which keeps the switching regulator, Watchdog Circuit, and LDO outputs off, and minimizes supply current. In this state the RESB output is low. ...
Page 21
... EN pin (Figure 44) allows a wide range of activation/deactivation voltages. Note that this divider is also used in conjunction with an internal zener clamp to keep the EN pin voltage below the maximum voltage rating when NCV8881 Enable Input VILmax Programming Range versus VIHmin Setting ...
Page 22
... The Ignition Buffer output IGNBUF reports the EN pin voltage level (high or low) detected by the EN input circuitry when the EN signal is latched. The NCV8881 will pull the IGNBUF output low if the Enable signal is low, and release the IGNBUF output if the Enable signal is high. The IGNBUF output is an open drain device which requires an external pullup resistor to a logic supply ...
Page 23
... OUTPUT VOLTAGE REGULATION MONITOR When the FB voltage is below V low, and the POR, BOOT and Watchdog Delays are initialized. When FB voltage exceeds V Delay begins to time out. If, when the FB voltage is below V FBMONL input is low, the NCV8881 will completely shut off (see Figures 46 through 48). ) 170 Current is Limited Figure 46 ...
Page 24
VIN ENABLE 8P5 5P0 SOFT−START TIMER Regulation Threshold Short−Circuit Threshold SMPS OUTPUT Figure 47. SMPS Overload after Successful Startup #1 SMPS OVERLOAD AFTER SUCCESSFUL STARTUP # VIN ENABLE 8P5 5P0 SOFT−START TIMER Regulation Threshold ...
Page 25
VIN ENABLE 8P5 5P0 SOFT−START TIMER Regulation Threshold Short−Circuit Threshold SMPS OUTPUT Figure 49. SMPS Short−Circuit during Startup VIN ENABLE 8P5 5P0 SOFT−START TIMER Regulation Threshold Short−Circuit Threshold SMPS OUTPUT Figure 50. ...
Page 26
... low when the Watchdog Delay expires (no falling edge has occurred at the WDI input), RESB is pulled low and the NCV8881 shuts off all power outputs (SMPS and LDOs) and minimizes supply current. In order to ensure that WDI pulses keep RESB from being ...
Page 27
VIN ENABLE POR DELAY BOOT DELAY RESB WATCHDOG DELAY WDI 3.3V 5V Figure 52. Watchdog Never Appears; EN Input HIGH WATCHDOG STUCK HIGH, THEN RECOVERS; ENABLE = HIGH VIN ...
Page 28
WATCHDOG STUCK LOW, THEN RECOVERS; ENABLE = HIGH VIN ENABLE POR DELAY BOOT DELAY RESB WDI 3.3V 5V Figure 54. Watchdog Stuck LOW, Then Normal; EN Input HIGH VIN ENABLE POR DELAY RESB BOOT ...
Page 29
... NCV8881 SMPS is heavily loaded. A secondary 0.1 mF ceramic capacitor positioned as closely as possible between the VIN and GND pins of the NCV8881 provides greater reduction of input perturbations than further increasing the value of the primary ceramic capacitor, and can be more effectively positioned than the larger 4 ...
Page 30
... D(avg) OUT The freewheeling diode should have a current rating equal to the maximum NCV8881 current limit, such as the MBRA340T3. Inductor Selection Mechanical and electrical considerations, as well as cost influence the selection of an output inductor. From a mechanical perspective, smaller inductor values generally correspond to smaller physical size. Since the inductor is ...
Page 31
IN(RMS) Where D is the Duty Cycle = t /( forward voltage of the freewheeling diode. Another consideration for the value of the input capacitor is the ability to supply ...
Page 32
... The only two absolutes are that the ORDERING INFORMATION Device NCV8881PWR2G †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. 1 ...
Page 33
... BSC H 3.45 3.66 0.136 0.144 J 0.25 0.32 0.010 0.012 K 0.00 0.10 0.000 0.004 L 4.72 4.93 0.186 0.194 10.05 10.55 0.395 0.415 R 0.25 0.75 0.010 0.029 Exposed Pad 0.188 0.376 C L 0.150 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative NCV8881/D ...