A4231 ALPHA-MICRO | Alldatasheet

Document overview

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Technical content

The a4231 is a proximity sensor integrated circuit to be used with a broad range of inductive single-coiled proximity transducers in proximity detection applications  Monolithic IC in bipolar technology  User-adjustable sensing range by means of a single external resistor  User-adjustable hysteresis (0…15%)  5.5V…35V broad supply voltage range  Low-voltage operation possible using stabilised 4.5V…5.5V voltage source  Internal voltage regulator to improve immunity against fluctuations of supply voltage  Broad operating temperature range: -25°C...90°C  Can work with a broad selection of inductive transducers  NPN open collector output with guaranteed sink current of 150mA  Output overload/over current protection  Integrated power-on and detect LED drivers  Normally open(NO)/normally closed(NC) select pin  Broad range of operating frequencies: 100kHz…1MHz  Output over current and short-circuit protection  Easy temperature compensation of proximity transducers  Package – QFN-24 example application schematic a4231L2 L Inductive Transducer Vcc NO/NC NO/NC OutN OutN CRE S GND VCCRF Cdet, 10% (optional) CDE T D_LED 220nF/6.3V 20% Rhyst, 5% (optional) min. 2.2uF/40V electrolytic 220nF/6.3V 20% ceramic 91kohm P_LED Covl, 10% 100nF/6.3V COVLRH RF CF 100nF/6.3V 10% Rref RS,N 1R6 5% 125mW RSN CB GND1 Typical application schematic of a proximity sensor/detector

electrical characteristics

The typical values are given for VCC =24V and Tj = 25°C unless otherwise specified. # Symbol Parameter Conditions Min Typ Max Unit 1 IVCC,OFF Supply current Output inactive (off) 3.8 4.8 mA 2 IVCC,ON Supply current Output active (on) 8.5 12 mA 3 VSAT,OUT Output saturation voltage IOUT=150mA 0.50 0.70 V 4 ILED LED current 1.0 1.2 1.6 mA

5 ILKG Output leakage current <1 20 μA

6 ITH,OVL Overload threshold current*1) 158 190 220 mA

*1) –overload threshold current is the level of the output current which triggers the overload protection circuit. AC and Timing Characteristics The typical values are given for VCC =24V and Tj = 25°C unless otherwise specified. # Symbol Parameter Conditions Min Typ Max Unit 1 fOSC Operating frequency Defined by external LC tank 0.1 1.0 MHz

2 RN Negative resistance

frequency*1) CDET=4.7pF, fOSC=600kHz CDET=33pF fOSC=100kHz kHz

4 HW Hysteresis width Depends on RHYST 0 15 %

5 tR Output rise time Load=1kohm <1.5 μs 6 tF Output fall time*2) Load=1kohm <1 μs

7 TS,OVL Sampling period in

Depends on COVL 50 120 250 ms

8 TSTARTUP Startup time*3) 50 120 250 ms

10 CIN Input capacitance Measured between Pin L1

and AC ground (Pin L2) for fOSC=0.2…1MHz and |RN| =2…100kohm 6 8.5 13 pF *1) – these are maximum switching frequencies of the IC itself; switching frequencies of sensors may be higher than those given above, *2) – the fall time on leaving the start-up interval depends on the load used and can be as long as 10ms, *3) – this is the maximum start-up time of the chip itself; this parameter does not reflect performance of a sensor; during the start-up interval the output is inactive (OFF) regardless of the state of the NO/NC pin.