HV38

The HV38 is a 32-channel column driver IC designed for gray-shade display use. A bidirectional shift register working on both clock edges is used to index input data, in groups of 4, into a set of data latches. These are compared to the contents of a master binary counter. Each time the master counter begins to increment, a hold capacitor (OH) on each channel is charged until the contents of the data latches are matched by that in the counter. Each channel's CH thus is charged to an individual level, VH, which is then transferred to the output by a source-follower structure that allows both sourcing and sinking of output current. DlR is a shift-direction-select pin which has been provided to allow the user to interchange the shift register data input When the DIR input is high, data is shifted in thru D1 to D4 in ascending order from HVOUT1 to HVOUT32. When the DIR input is low, data is shifted in descending order from HVOUT32 to HVOUT1. In the HV38, the ramp generator circuitry (VR) obtains its (low- current) bias from VPP1. This allows the output bias, VPP2, to be ramped down to zero when output current is not required, thus saving energy.

The features of HV38 can be summarized as (1)5V CMOS inputs; (2)up to 60V modulation voltage; (3)capable of 16 levels of gray shading; (4)16MHz data throughput rate; (5)32 outputs per device (can be cascaded); (6)minimum 15 mA high-voltage output sourcelsink capability; (7)Pin-programmable shift direction (DIR); (8)D/A conversion can be performed in as little as 3.2s; (9)diodes in output structure allow usage in energy recovery systems; (10)integrated high-voltage CMOS technology; (11)available in 3-sided 64-lead gullwing package or as dice.

The absolute maximum ratings of HV38 are (1)supply voltage, VDD: -0.5V to +7.5V; (2)supply voltage, VPP: -0.5V to +70V; (3)logic input levels: -0.5V to VDD +0.5V; (4)ground currents: 1.5A; (5)continuous total power dissipationt ceramic: 1200mW/Plastic: 1500mW; (6)lead temperature 1.6mm from case for 10 seconds: 260°C; (7)storage temperature range: -65°C to 150°C; (8) operating temperature range: -40°C to 85°C.