4 Pin Configuration and Functions

Figure 4-1 32-Pin DFC SSOP Package Top View

Table 4-1 Pin Functions

PIN		I/O⁽¹⁾	DESCRIPTION
NAME	NO.	I/O⁽¹⁾	DESCRIPTION
GND1	1, 16	P	Primary Side Ground. Connect all GND1 pins together and to the PCB ground plane on the primary side. Prioritize pin 1 for supply and input filter decoupling.
nFLT2 (DOUT)	2	O	Fault Indicator Output 2. nFLT2 is used to interrupt the host when a fault occurs. Faults that are unmasked pull nFLT2 low when the fault occurs. nFLT2 is high when all faults are either non-existent or masked. It is recommended to add an external pull up resistor to VCC1 if faster rise time is needed. Additionally, nFLT2 may be configured as DOUT (push/pull) to provide the host controller a PWM signal with a duty cycle relative to the ADC input of interest.
VCC1	3	P	Primary Side Power Supply. Connect a 3V to 5.5V power supply to VCC1. Bypass VCC1 to GND1 with ceramic bulk capacitance as close to the VCC1 pin as possible.
nFLT1	4	O	Fault Indicator Output 1. nFLT1 is used to interrupt the host when a fault occurs. Faults that are unmasked pull nFLT1 low when the fault occurs. nFLT1 is high when all faults are either non-existent or masked. It is recommended to add an external pull up resistor to VCC1 if faster rise time is needed.
GD0	5	I	OUTL1/2 and OUTH1/2 Selector Inputs. GD* select combinations of OUT1 and OUT2 with user-selectable resistors. Drive all GD* high to force the gate of the power transistor low and reset all faults. See Adjustable Gate Drive Outputs (OUTL* OUTH*) for more details. Tie to GND1 if not used.
GD1	6	I
GD2	7	I
ASC_EN_PRI	8	I	Primary-side Active Short Circuit Enable Input. ASC_EN_PRI enables the ASC function and forces the output to follow the ASC_PRI pin input state. When ASC_EN_PRI is low, the OUT* pins follow the INP and INN pin logical truth table. Tie to GND1 if not used.
ASC_PRI	9	I	Primary-side Active Short Circuit Polarity Input. The OUT* pins follow the logic level at ASC_PRI when the ASC_EN_PRI input is driven high. See the ASC section for more details. Tie to GND1 if not used.
INN	10	I	Negative PWM Input. INN is connected to the INP from the opposite arm of the half-bridge. If INP and INN overlap, the Shoot Through Protection (STP) engages and forces output low. Tie to GND1 if not used.
INP	11	I	Positive PWM Input. INP drives the state of the driver output. With the driver enabled, when INP is high, OUTH* is pulled high. When INP is low, OUTL* is pulled low. CMOS input logic level determined by the VCC1 voltage. INP is connected to the INN of the opposite arm of the half-bridge. If INP and INN overlap, STP engages and forces output low.
SCLK	12	I	SPI Clock. SCLK is the clock signal for the main SPI interface. The SPI interface operates with clock rates up to 4MHz.
nCS	13	I	SPI Chip Selection Input. nCS is an active low input used to activate the SPI peripheral device. Drive nCS low during SPI communication. When nCS is high, SDO is set to disabled (high-impedance) and commands on SDI are ignored. Tie to VCC1 if not used.
SDI	14	I	SPI Data Input. SDI is the data input for the main SPI interface. Data is sampled on the falling edge of CLK, SDI must be in a stable condition to ensure proper communication.
SDO	15	O	SPI Data Output. SDO is the data output for the main SPI interface. Data is clocked out on the falling edge of CLK, SDO is changed with a rising edge of CLK.
VEE2	17, 28	P	Secondary Negative Power Supply. Connect all VEE2 supply inputs together. Connect a -12V to 0V power supply to VEE2. The total voltage rail from VCC2 to VEE2 must not exceed 30V. Bypass VEE2 to GND2 with at least 1uF of low-impedance ceramic capacitors as close to pin 28 as possible, to encourage gate current flow through pin 28.
ASC_EN_SEC	18	I	Secondary-side Active Short Circuit Enable Input. ASC_EN_SEC enables the ASC function, overriding the INP command and forcing the output of the driver to the defined safe state, set by CONTROL2[ASC_LEV_SEL] register. When ASC_EN_SEC is low, the output is controlled by primary side pins. Tie to GND2 if not used.
ASC_SEC	19	I	ASC_SEC (AI2) defaults to Active Short Circuit Polarity Input. When programmed as ASC_SEC, the OUT* pins follow the logic level at ASC_SEC when the ASC_EN_SEC input is driven high.
AI2	19	I	ASC_SEC (AI2) can be programmed as an ADC input that digitizes analog voltages up to 4.0V. Additionally, a programmable “digital comparator” is available to signal faults when the voltage is above/below (selectable) the programmed threshold. This is useful for monitoring the DC-LINK voltage or phase voltage during the switching cycle. Tie to GND2 if not used.
AI1	20	I	Analog Input 1. AI1 is an ADC input that digitizes analog voltages up to 4.0V. Additionally, a programmable “digital comparator” is available to signal faults when the voltage is above/below (selectable) the programmed threshold. This is useful for monitoring the DC-LINK voltage or phase voltage during the switching cycle. Tie to GND2 if not used.
VREF	21	P	Internal ADC Voltage Regulator Output. VREF provides an external 5.0V reference voltage, which is internally scaled down to 4.0V for the ADC. Bypass VREF to GND2 with at least 1uF of ceramic capacitance.
GND2	22	P	Gate Drive Supply Reference. Connect GND2 to the power FET source/ IGBT emitter. ASC_EN_SEC, ASC_SEC (AI2), AI1, VREF, and DESAT are referenced to GND2.
DESAT	23	I	Current Sense Input/ Desaturation based Short Circuit Detection Input. DESAT (CS) is configurable to sense over-current conditions in resistor sense applications, or DESAT over-current in VCE/VDS sensing applications. For DESAT applications, bypass DESAT to GND2 with a ceramic capacitor and, in parallel, connect a Schottky diode with the cathode connected to the DESAT pin, and the anode connected to GND2. See the applications section for details on calculating the component values. Additionally, connect the DESAT pin to a resistor to the anode of a diode to the collector of the power FET. The DESAT pin detects a fault when the VDS/VCE voltage of the power FET exceeds the SPI programmable threshold while the power FET is on. Tie to GND2 if not used.
CS	23	I	Current Sense Positive Input/ Desaturation based Short Circuit Detection Input. CS (DESAT) is configurable to sense over-current and short-circuit conditions in resistor sense applications, or DESAT over-current in VCE/VDS sensing applications. For sense resistor based applications, connect DESAT (CS) pin to the positive side of the sense element through an RC. The current limit threshold is programmable via SPI. Tie to GND2 if not used.
VCC2	24	P	Secondary Positive Power Supply. Connect a 15V to 30V power supply to VCC2. The total voltage rail from VCC2 to VEE2 must not exceed 30V. Bypass VCC2 to GND2 and VCC2 to VEE2 with bulk ceramic capacitance as close to the VCC2 pin as possible. Additional capacitance may be needed depending on the gate charge of the power device.
VCP	25	P	High-side Drive Supply. VCP supplies power for the OUTH* drive. Bypass VCP to VCC2 with a ceramic capacitor between 10nF and 100nF, as close to the VCP pin as possible.
OUTH1	26	O	Gate driver source pins (OUTH1 = 15A_PK, OUTH2 = 5A_PK). When the driver is active and commanded high, OUTH* pins are used to source current to the gate of the power FET to drive the output high. Connect OUTH* pins to the gate of the power FET through individual gate resistors. The value of the gate resistor is chosen based on the slew rate required for the application. Different slew rates are programmed by using different resistor values for OUTH1 and OUTH2. The two outputs are enabled “on the fly” using the GD* inputs to set 3 different slew rates (OUTH1 only, OUTH2 only, and OUTH1 + OUTH2).
OUTH2	27	O
OUTL1	29	O	Gate driver sink pins (OUTL1 = 15A_PK, OUTL2 = 5A_PK). When the driver is active and commanded low, OUTL* pins are used to sink current from the gate of the power FET to drive the gate low. Connect OUTL* pins to the gate of the power FET through individual gate resistors. The value of the gate resistor is chosen based on the slew rate required for the application. Different slew rates are programmed by using different resistor values for OUTL1 and OUTL2. The two outputs are enabled “on the fly” using the GD* inputs to set 3 different slew rates (OUTL1 only, OUTL2 only, and OUTL1 + OUTL2).
OUTL2	30	O
CLAMP	31	O	Miller Clamp pin. The CLAMP pin is used to hold the gate of the power FET strongly to VEE2 while the power FET is "off". CLAMP is configurable as an internal Miller clamp, or to drive an external clamping circuit. When using the internal clamping function, connect CLAMP directly the power FET gate. When configured as an external clamp, connect CLAMP to the gate of an external pulldown MOSFET. Disable and tie to VEE2 if not used.
VCECLP	32	I	VCE Clamp Input. VCECLP clamps to a diode above the VCC2 rail and indicates a fault when the voltage at VCECLP is above the VCECLPth voltage. Bypass VCECLP to VEE2 with ceramic capacitor and, in parallel, connect a resistor. See the applications section for details on calculating the component values. Additionally, connect VCECLP to the anode of a zener diode to the collector/drain of the power FET. Tie to VEE2 if not used.

(1) I = Input, O = Output, I/O = Input or Output, G = Ground, P = Power.