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Delphi Oxygen Sensor Unit

The Delphi Oxygen Sensor Unit (HEX) device is a monolithic silicon circuit that functions as an interface and a signal conditioner between six oxygen sensors, six miscellaneous analog inputs and a microcontroller. The HEX contains a multiplexer that selects between any one of eight inputs by three external digital select lines. The six independent oxygen sensor interface channels have 450mV bias through 1.2 MOhms, 4.5X gain, input common mode ±2V, 410Hz low pass filter, open input detect which forces output to known state and rail to rail output swing. The six independent analog signal inputs have high input impedance, Vdd/Gnd clamping diodes, and no interaction between channels. The two eight-channel multiplexers each have 3 oxygen sensor interfaces, 3 analog signal channels and 1 'test' channel with preset output voltage. The HEX is designed to operate with a nominal 4.9 to 5.1V supply and is capable of operating over the ambient temperature range of -40 to 125°C.

Features

Six independent oxygen sensor interface channels
Six independent analog signal inputs
Open circuit detect for each OS input forces output to know state
One 'test' channel set known verifiable voltage
Analog inputs immune to signals above Vdd or below ground

Packaging

Available in a 28-pin SO

Typical Applications

Automotive engine controls
Exhaust system
ADC 'front end'

Recommended Operating Conditions

Characteristic	Symbol	Value	Unit
Supply Voltage	Vdd	4.9 to 5.1	V
Output Drive Current	IoutA, IoutB	±10	µA
Oscillator Resistor	Oscres	150 ± 5%	KOhms
Operating Temp. Range, Ambient	Ta	-40 to 125	°C

Absolute Maximum Ratings

Characteristic	Symbol	Value	Unit
Supply Voltage	Vdd	-0.3 to 7.0	V
Input Voltage	Vin	-13 to Vdd+0.3	V
Storage Temp. Range	Tstg	-65 to 150	°C
Max. Junction Temp.		150	°C

Electrical Performance Characteristics - HEX

Characteristics	Symbol	Condition	Min	Max	Unit
Supply Current	ldd	Worst Case Conditions		12	mA
Input Voltage High	Vih	MSELx	0.7		VDD
Input Voltage Low	Vil	MSELx		0.3	VDD
Input Current High	lih	MSELx: Vin=Vih		80	µA
Input Current Low	lil	MSELx: Vin=Vil	10		µA
Linear Region Common Mode Input Voltage	Vcm	OSPx-OSNx=0 950 mV	-2	+2	V
Differential Input Impedance	Rin		1.05	1.50	MOhms
Differential Input Voltage Linear Region	Vin	VIn-OSPx=OSNx	50	950	mV
Open Circuit Output Volt.	Voc	Either input open, lout=-2 µA	0.395	0.415	VDD
Output Impedance	Rout	Oxygen Sensor Channels Only		2500	Ohm
Output High Clamp Voltage Error	Vhcl	Vhcl=Vout-Vin; Vin=0-100mV⁄100mV to Vdd-100 mV⁄Vin=Vdd-100mV to Vdd		20⁄ 10⁄ 20	mV
Output Low Clamp Voltage Error	Vlcl	Vlcl=Vout-Vin; Vin=GND		20	mV
Test Channel Verifiable Output Voltage	Vov	MSELC,B,A=111	0.594	0.614	Vdd
On-State Resistance	Ron	Measured from input to output, (not including resistors) ANx to OUTx		1300	Ohm
Rise Time Response	Tr	900mVp-p, 100Hz square wave, differential input Cload=20pF 10% to 90%		1.2	ms
Fall Time Response	Tf	Same as above, only 90% to 10%		1.2	ms
Crosstalk Between any Two Channels (shorted input)	Cs	Vin=-2 to 26.5V (-40 to 25°C) Vin=-2 to 16V (-40 to 125°C) through a 10KOhm resistor		20	mVp
Control Input to Signal Crosstalk	Ci	Rload=10KOhm at both input and output		20	mVp

Delphi Oxygen Sensor Unit (51k)