HV257

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. Continuous operation of the device at the absolute rating level may affect device reliability. All voltages are referenced to device ground.

The Supertex HV257 is a 32 channel high voltage sample and hold amplifi er array integrated circuit. It operates on a single high voltage supply, up to 300V, and two low voltage supplies, V_DD and V_NN.

All 32 sample and hold circuits contains HV257 share a common analog input, VSIG. The individual sample and hold circuits are selected by a 5 to 32 logic decoder. The sampled voltage on the holding capacitor is buffered by a low voltage amplifi er and amplifi ed by a high voltage amplifi er with a closed loop gain of 72V/V. The internal closed loop gain is set for an input voltage range of 0V to 4.096V. The input voltage can be up to 5.0V but the ou put will saturate. The maximum output voltage swing is 5V below the V_PP high voltage supply. The outputs can drive capacitive loads of up to 3000pF.

The HV257 maximum output source and sink current can be adjusted by using two external resistors. An external R_SOURCE resistor controls the maximum sourcing current, and an external R_SINK resistor controls the maximum sinking current. The current limit is approximated 12.5V divided by the external resistor value. The HV257 setting is common for all 32 outputs. A low voltage silicon junction diode is made available to help monitor the die temperature.