W921F840

The W921F840 is a single-chip CMOS 4-bit microcontroller that is a subset of W921F880. W921F840 is powerful microcontroller for wide range consuming applications, requiring few external components, which is especially suited for telecommunication design. It is available in 40-pin DIP package.

W921F840 has some features as follows: (1)operating voltage is from 2.7 V to 5.5 V; (2)look-up table addressing mide; (3)multiplexed four channel voltage comparator; (4)one channel beep tone generator; (5)one channel 8-bit D/A converter; (6)one channel DTMF generator.

What comes next is about W921F840's absolute maximum ratings: (1)DC supply voltage: -0.3 V to 7.0 V; (2)input/output voltage: VSS-0.3 V and VDD+0.3 V; (3)operating temperature: -20 to 70 ; (4)storage temperature: -55 to 150 . Then is its electrical characteristics: (1)operating voltage: 2.7 V min, 3.0 V typ and 5.5 max; (2)input high voltage: 0.7VDD V min and VDD max; (2)D/A DC reference voltage: 0 VDD min and 2/3 VDD max; (3)pre-emphasis: 1 dB min, 2 dB typ and 3 dB; (4)DTMF output voltage: 130 mVrms min, 150 mVrms typ and 170 mVrms max; (5)DTMF distortion: -30 dB typ and -23 dB max; (6)D/A resoultion voltage: 1/256 Vadc.