LTC1099 UUUPIN FUNCTIONSVIN (Pin 1): Analog Input. INT (Pin 9): Output that goes low when the conversion in process is complete and goes high after data is read. DB0 to DB3 (Pins 2 to 5): Data Outputs. DB0 = LSB. GND (Pin 10): Ground Connection. WR/RDY (Pin 6): WR/RDY is an input when M0DE = VCC. Falling edge of WR switches internal S/H to hold then REF– (Pin 11): Low Reference Potential (Analog Ground). starts conversion. WR/RDY is an open drain output (active REF+ (Pin 12): High Reference Potential. V pull-down) when M0DE = GND. RDY goes low at start of REF = Full Scale = (REF+) – (REF–). conversion and pull-down is turned off when conversion is complete. Resistive pull-up is usually used in this mode. CS (Pin 13): Chip Select. When high, data outputs are high impedance and all inputs are ignored. MODE (Pin 7): WR-RD when MODE = VCC. RD when M0DE = GND. No internal pull-down. DB4 to DB7 (Pins 14 to 17): Data Outputs. DB7 = MSB. RD (Pin 8): A Low on RD with CS Low Activates Three- OFL (Pin 18): Overflow Output. Goes low when VIN > VREF. State Outputs. With MODE = GND and CS low, the falling TC (Pin 19): User Adjustable Conversion Time. edge of RD switches internal S/H to hold and starts conversion. VCC (Pin 20): Positive Supply. 4.75V ≤ VCC ≤ 5.25V. TEST CIRCUITSt1H tr = 20ns, CL = 10pF tr V V CC CC 90% RD 50% 10% GND RD t DATA 1H CS OUT V0H 90% CL 1k DATA OUT GND t0H tr = 20ns, CL = 10pF t V r CC VCC VCC 90% 1k RD 50% RD 10% DATA GND CS OUT t0H CL VCC DATA OUT 10% V0L 1099 F01 Figure 1. Three-State Test Circuit 5