Supertex inc. HV257DB2 High Voltage Sample and Hold Amplifier Array Specifications General Description The Supertex HV257DB2 is a 32-Channel, 295V, sample and hold amplifier array with a nominal gain of 72V/V. The purpose of the HV257DB2 is to provide a means to easily evaluate the Supertex HV257FG device. A high voltage supply, VPP, and four low voltage supplies, AVDD and DVDD, AVNN and DVNN, are required. Referring to the demo board drawing shown below, the logic and VSIG connections are on the left, the high voltage outputs are on the bottom, and the supplies are on the right. Please follow the power up/ down sequence to avoid damaging the device. Parameter Value VPP, High voltage supply: 300V AVDD / DVDD, Low voltage positive supply: 6.0 to 7.5V AVNN / DVNN, Low voltage negative supply: -4.5 to -6.5V VSIG, Input signal range: 0 to 5.0V HVOUT, Output voltage swing 0 to 295V AV, Closed loop gain 72V/V ±5% SR, Output slew rate into 100pF load 2.0V/µs Board Layout and Connections C10 C1 DGND DVDD DVNN AGND No Connect AVDD AVNN VPP D1 Doc.# DSDB-HV257DB1 B032114 D2 Acceptable Power Down Sequences 1) Inputs & Anode 2) VDD 3) VNN 4) VPP or 1) Inputs & Anode 2) VPP 3) VDD 4) VNN C2 C6 R1 R2 Supertex inc. Acceptable Power Up Sequences 1) VPP 2) VNN 3) VDD 4) Inputs & Anode or 1) VNN 2) VDD 3) VPP 4) Inputs & Anode C3 U1 HV257 C7 The device can be damaged due to improper power up/down sequence. To prevent damage, please follow the acceptable power up/down sequences. Two external diodes, D1 and D2, are added in the demo board to prevent damage during power Up/Down. The first diode is a high voltage diode across VPP and AVDD. Any low current high voltage diode can be used. The second diode can be any low voltage schottky diode across AVNN and GND. C4 C5 C8 C9 pin1 HVOUT31 Power Up/Down Sequence R3 HV257DB2 EN A0 A1 A2 A3 A4 VSIG VSGND HVOUT0 Inputs and Outputs The output of the HV257FG will swing from 0 to 295V. The internal closed loop gain is set at 72V/V. An input voltage of 4.096V will give an output of 295V. Input voltages of up to 5.0V can be applied but will cause the amplifier to saturate. When EN is high, the addressed output, determined by A0 to A4, will be sampling the input signal VSIG. When EN is low, all the internal sampling switches are open. The output current source and sink for all 32 channels can be adjusted using R1 and R2. The limit is approximately 12.5V divided by the resistor value. The demo board uses 24.9kΩ for ±500µA limiting. Temperature Diode The HV257FG has an integrated silicon diode to help monitor the die temperature if desired. Pin 95 is the anode and pin 96 is the cathode. Pads are available on the board for these connections. Supertex inc. www.supertex.com HV257DB2 Circuit Diagram VPP AVDD AVNN C1 10nF C8 0.1µF C6 0.1µF D1 C7 0.1µF Byp-AVDD Byp-AVPP Byp-AVNN VPP C2 0.1µF ANODE AVDD AVNN R1 24.9kΩ C3 0.1µF RSOURCE R2 24.9kΩ DVDD DVNN C4 0.1µF DGND HV257FG RSINK D2 AGND CATHODE DVDD HVOUT0 DVNN HVOUT1 C5 0.1µF HVOUT2 A0 A1 Logic Control Inputs High Voltage Outputs HVOUT30 A2 HVOUT31 A3 A4 EN + Analog Input - VSIG AGND C9 0.1µF AGND C10 0.1µF DGND R3 0Ω Bill of Materials Part Description Value Package Manufacturer Part Number C1 X7R chip capacitor 500V, 0.01µF±10% 0805 Tecate CMC-500103KX0805T C2-C9 X7R chip capacitor 25V, 0.1µF±10% 0805 Tecate CMC-025104KX0805T C10 X7R chip capacitor 10V, 1.0µF±10% 0805 Any --- R1 Chip resistor 24.9kΩ, ±1% 0805 Any --- R2 Chip resistor 24.9kΩ, ±1% 0805 Any --- R3 Chip resistor 0Ω 0805 Any --- D1 Rectifier diode 400V, 1.0A SMA Diodes Inc US1G D2 Schottky diode 20V, 20mA SOD-323 Diodes Inc SD103CWS U1 Amplifier array 300V 100-Lead MQFP Supertex HV257FG Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives an adequate “product liability indemnification insurance agreement.” Supertex inc. does not assume responsibility for use of devices described, and limits its liability to the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications refer to the Supertex inc. (website: http//www.supertex.com) Supertex inc. ©2014 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited. Doc.# DSDB-HV257DB1 B032114 2 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com