NCV8613B
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3
PIN FUNCTION DESCRIPTIONS
Pin No. Symbol Description
1 ASO_RAIL Output/Input of the automatic switchover (ASO) circuitry. Place a 1 uF ceramic capacitor on this
pin to provide local bypassing to the LDO linear regulator pass devices.
2 VIN−B Primary power supply input. Connect battery to this pin through a blocking diode.
3 VIN−H Holdup power supply rail. Connect a storage capacitor to this pin to provide a temporary backup
rail during loss of battery supply. A bleed resistor (typically 1 kW) is needed from VIN−B to this pin
in order to trickle charge this capacitor.
4 VIN−A Voltage monitor which determines whether the 8 V supply is able to power the outputs. If the 8 V
supply is present, the FET’s connected to VIN−B and VIN−H will be turned off, and the 8 V supply
will be providing power to the outputs. If the 8 V supply is not present, the FET’s on VIN−B and
VIN−H will be left on, and the greater of those voltages will be driving the outputs.
5 VBATT_MON VBATT monitor pin. To operate overvoltage shutdown, HV_DET and BO_DET, connect this pin to
ASO_RAIL or battery. To eliminate overvoltage shutdown, HV_DET and BO_DET, tie this pin to
ground.
6 HV_DET High−voltage detect output. When VBATT_MON surpasses 17 V, this pin will be driven to ground.
During normal operation, this pin is held at V
PP
.
7 BO_DET Brown out indicator output. When VBATT_MON and VIN−A falls below 7.5 V, this pin will be driv-
en to ground. During normal operation, this pin is held at V
PP
.
8 NC No Connect
9 GND Ground. Reference point for internal signals. Internally connected to pin 13. Ground is not connec-
ted to the exposed pad of the DFN20 package.
10 HOT_FLG Thermal warning indicator. This pin provides an early warning signal of an impending thermal
shutdown.
11 IGNIN Ignition buffer input
12 IGOUT Ignition buffer logic output
13 GND Ground. Reference point for internal signals. Internally connected to pin 9. Ground is not connec-
ted to the exposed pad of the DFN20 package.
14 DLY Delay pin. Connect a capacitor to this pin to set the delay time.
15 RST Reset pin. Monitors V
OUT1.
16 V
PP
Supply rail for the push−pull outputs of the control signals HOT_FLG, RST, HV_DET & BO_DET
17 V
OUT1
5 V output. Voltage is internally set.
18 V
OUT2
3.3 V output. Voltage is internally set.
19 V
OUT3
3.3 V output. Voltage is internally set.
20 VIN_S3 Supply rail for the standby linear regulator VOUT3. Tie this pin to ASO_RAIL or a separate supply
rail.
EP − Exposed Pad of DFN device. This pad serves as the main path for thermal spreading. The Ex-
posed Pad is not connected to IC ground.
