HV257DB2
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.
Inputs and Outputs
The output of the HV257FG will swing from 0V 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 V . When EN is low,
all the internal sampling switches are opSeIGn.
Temperature Diode
The HV257FG has an integrated silicon diode to help moni-
tor 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.
Circuit Diagram
C7
0.1µF
C8
VPP
C1
10nF
0.1µF
C6
D1
D2
0.1µF
Byp-VPP Byp-AVDD Byp-AVNN
VPP
AVDD
C2
0.1µF
AVDD
AVNN
Anode
AVNN
C3
0.1µF
R1
Cathode
24.9KΩ
RSINK
AGND
HV257FG
R2
24.9KΩ
RSOURCE
DVDD
HVOUT
HVOUT
HVOUT
0
1
2
DVDD
DVNN
DVNN
C4
0.1µF
C5
0.1µF
DGND
High
Voltage
Outputs
A0
A1
A2
A3
A4
EN
Logic
Control
Inputs
HVOUT30
HVOUT31
VSIG
AGND
39
DGND
AGND
+
C9
0.1µF
Analog
Input
43, 89
-
R3
0Ω
C10
0.1µF
Bill of Materials
Description
Value
Package
0805
Manufacturer Part Number
C1
X7R chip capacitor
X7R chip capacitor
X7R chip capacitor
Chip resistor
500V, 0.01µF 10ꢀ
25V, 0.1µF 10ꢀ
10V, 1.0µF 10ꢀ
24.9KΩ, 1ꢀ
24.9KΩ, 1ꢀ
0Ω
Tecate
Tecate
Any
CMC-500103KX0805T
C2-C9
C10
R1
0805
CMC-025104KX0805T
0805
---
0805
Any
---
R2
Chip resistor
0805
Any
---
R3
Chip resistor
0805
Any
---
D1
Rectifier diode
Schottky diode
Amplifier array
400V, 1.0A
SMA
Diodes Inc
Diodes Inc
Supertex
US1G
SD103CWS
HV257FG
D2
20V, 20mA
SOD-323
100-Lead MQFP
U1
300V
NR041207
2
SUPERTEX [ Supertex, Inc ]
