AN-H59

Supertex inc.
AN-H59
Application Note
High Voltage DC/DC Converter for
Supertex Ultrasound Transmitter Demoboards
By Afshaneh Brown, Applications Engineer,
and Jimes Lei, Applications Manager
Introduction
The Supertex AN-H59DB1 demoboard is a high voltage
DC/DC converter. It can provide up to +90V voltage supply
for VPP and -90V for VNN. It also provides +8.0 to +10V
voltage supply for VDD, floating power supplies of VNN +8.0 to
VNN +10V for VNF and VPP -8.0 to VPP -10V for VPF. The input
supply voltage is 12V.
To accommodate all three demoboards, the AN-H59DB1
demoboard has adjustable VPP, VNN, VDD, VPF and VNF. The
purpose of the AN-H59DB1 is to aid in the evaluation of
the three transmitter demoboards. The intention of this
application note is to provide a general circuit description on
how each of the output voltages is generated.
The AN-H59DB1 circuitry consists of two high voltage PWM
Current-Mode controllers, a DC/DC transformer driver, and
three low dropout regulators. The Supertex AN-H59DB1
uses a high-voltage, current mode, PWM controller boost
topology to generate +15 to +90V and a high-voltage current
mode PWM controller buck-boost topology to generate -15
to -90V power supply voltage for Supertex HV738DB1 and
HV748DB1 ultrasound transmitter demoboards.
The VSUB pin on the HV738DB1 and HV748DB1 can either
be connected to the most positive supply voltage on the
demoboard, or can be left floating.
Each of the transmitter demoboards has slightly different
operating voltages as summarized below.
Board
VPP
VNN
VDD
VPF
VNF
HV738DB1 +65V -65V +8.0V
VPP -8.0V
VNN +8.0V
HV748DB1 +75V -75V +9.0V
VPP -9.0V
VNN +9.0V
To power up the AN-H59DB1, ensure that the 3.3V power
supply will be powered up first, and then the 12V power
supply. The sequences on the HV738DB1 and HV748DB1
took into consideration using the protection diodes on each
power line.
The circuit is shown in Figure 6, the component placement
in Figure 5, and the bill of materials is at the end of this
application note.
Application Circuit
Supertex inc.
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
AN-H59
VPP Circuit Description
The circuit in Figure 1 shows U5, the Supertex high voltage current mode PWM controller, being used to generate
the high voltage power supply for VPP. The maximum output
power for VPP was set for 10mA at 90V, which is 900mW.
With an input voltage of 12V, a converter frequency of 110
kHz with a 100µH inductor was chosen to provide the desired output power.
The converter frequency is set by an external resistor, R20,
across OSCIN and OSCOUT pins of U5. A 154kΩ resistor will
set the frequency to about 110 kHz. R24 is the current sense
resistor. 2.2Ω was used to set the maximum peak current
limit to about 450mA. An RC filter, R23 and C15, is added
between the current sense resistor and the current sense
terminal pin 3 of U5. This reduces the leading edge spike on
R24 from entering the current sense pin.
Inductor L1 is being charged from the 12V input by M3.
When M3 turns off, the energy in L1 is discharged into C16,
which is the VPP output through D8. The VPP voltage is divided down by feedback resistors R25, R26, and R27. The
wiper of R26 is connected to pin 14 of U5. The overall converter will regulate the voltage on pin 14 to 4.0V. Different
VPP output voltages can be obtained by adjusting R26.
When the wiper for R26 is set to the top, VPP can be calculated as:
V = V x R25 + R26 + R27
PP
FB
(
R26 + R27
)
where VFB is 4.0V
VPP = 4.0V x
+ 14.3k
( 232k100k+ 100k
) = 12.1V
+ 14.3k
When the wiper for R26 is set to the bottom, VPP can be
calculated as:
V = V x R25 + R26 + R27
PP
FB
(
VPP = 4.0V x
)
R27
100k + 14.3k
( 232k +14.3k
) = 96.9V
By adjusting potentiometer R26, VPP meets the adjustable
target range of 15 to 90V.
Comparator U6 will turn on LED D7 when the VPP output is
out of regulation due to excessive load. During initial power
up, C16 will be at 0V. D7 is therefore expected to be on until
C16 is charged to the desired regulation voltage.
Figure 1: Adjustable VPP Power Supply
VIN = 12V
R20
154kΩ
8
OSCIN
OSCOUT
C12
10µF
7
L1
100µH
4
M3
TN2510
6 VDD
R21
383kΩ
C13
0.1µF
VIN
1
10
5
D7
LED
R22
3.32kΩ
2 VIN
9
1
8
U6
LM2903 4
+
U5 OUT
HV9110NG
BIAS
SENSE
C14
1.0µF
DISCH
Supertex inc.
FB
+15V to +90V
GND
R24
2.2Ω
11
R26
100kΩ
12
R27
14.3kΩ
COMP
RESET
14
C16
2.2µF
R25
232kΩ
GND
SHUTDOWN
13
VPP
R23
1.0kΩ
C15
470pF
VREF
3
2
3
D8
MMBD914
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
2
AN-H59
VNN Circuit Description
The circuit in Figure 2 shows U7, the Supertex high voltage
current mode PWM controller, being used to generate the
high voltage power supply for VNN. The function of U7 is very
similar to what was described in the VPP circuit description
for U5. However, in this circuit a negative voltage is generated from a positive input voltage source, therefore requiring a buck-boost topology. The maximum output power for
VNN was set for -10mA at -90V which is 900mW. With an
input voltage of 12V, a converter frequency of 110 kHz with
a 100µH inductor was chosen to provide the desired output
power.
Inductor L2 is being charged from the 12V input by the parallel combination of M6 and M7. When M6 and M7 turn off,
the energy in L2 is discharged into C23, which is the VNN
output through D10. M6 and M7 are high voltage P-channel
MOSFETs. U7 is designed to drive a high voltage N-channel MOSFET. The drive output for U7 therefore needs to be
inverted. This is accomplished by M4 and M5.
The feedback voltage that U7 detects on pin 14 is +4.0V.
The VNN that needs to be sensed is a negative voltage. A circuit is needed to make sure the feedback voltage is positive.
This is consists of Q4, Q5, R33, R34, R35, R37, and R38.
Q4 becomes a constant current sink set by the VNN voltage
and R35. The same current will be flowing through R33 and
R34.
The voltage on the base of Q5 will be VIN minus the voltage
drop across the sum of R33 and R34. By varying R34, the
base voltage on Q5 will change. Q5 becomes a constant
current source with a value set by its base voltage and R37.
The current source of Q5 is going into R38, which creates
a positive voltage that is now proportional to the magnitude
of VNN.
R35
VNN = VBE - (
) x (VBE + VFB x R37 ),
R33 + R34
R38
where VBE = 0.6V, VFB = 4.0V.
When R34 is set to 100k, VNN is calculated to be:
273k
VNN = 0.6V - (
) x (0.6V + 4.0V x 14.7k )
4.99k + 100k
40.2k
= -4.0V
When R34 is set to 0k, VNN is calculated to be:
273k ) x (0.6V + 4.0V x 14.7k )
VNN = 0.6V - (
4.99k + 0k
40.2k
= -97.4V
By adjusting potentiometer R34, VNN meets the adjustable
target range of -15 to -90V.
Comparator U8 will turn on LED D9 when the VNN output is
out of regulation due to excessive load. During initial power
up, C23 will be at 0V. D9 is therefore expected to be on until
C23 is charged to the desired regulation voltage.
Figure 2: Adjustable VNN Power Supply
VIN = 12V
8
6
C17
10µF
R29
383kΩ
VIN = 12V
R30
3.32kΩ
9
1
8
U8 4
LM2903
+
OUT 4
U7
HV9110NG
M5
TN2106K1
BIAS
VREF
GND
DISCH
SENSE 3
3
2
13
C19
1.0µF
R34
100kΩ
7
M4
TP2104K1
R33
4.99kΩ
M6, M7
TP2510N8
X2
D10
MMBD914
R37
14.7kΩ
Q5
FMMT551
Q4
FMMT494
R38
40.2kΩ
R35
237kΩ
VNN
10
5
D9
LED
OSCOUT
VDD
2 VIN
1
C18
0.1µF
OSCIN
C21
10µF
C20
10µF
R28
154kΩ
14
Supertex inc.
COMP
FB
SHUTDOWN
11
RESET 12
R31
1.0kΩ
C22
470pF
L2
100µH
R32
2.2Ω
C23
2.2µF
-15V to -90V
GND
R36
10kΩ
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
3
AN-H59
VPF and VNF Circuit Description
The three transmitter demoboards require two floating low
voltage supplies, VPF and VNF. The floating supplies need to
be adjustable to accommodate the different operating requirements for the three different boards. The VPF is 8.0 to
10V below the high voltage VPP positive supply. The VNF is
8.0 to 10V above the high voltage VNN negative supply. The
two floating supplies are generated by using two isolated
transformers, T1 and T2, and an isolated transformer driver,
U1, as shown in Figure 4. Both outputs utilize adjustable low
dropout linear regulators, U2 and U3, as shown in Figure 3.
U2 and U3 are both Linear Technology LT1521, which has a
reference voltage of 3.75V on the ADJ pin. For VPF, resistors
R6, R7, and R8 set the output VPF voltage. R7 is a potentiometer for adjusting VPF. VPF can be calculated with the following
equation:
V = V x R6 + R7 + R8
PF
(
ADJ
)
R7 + R8
When R7 is set to 20kΩ, VPF becomes:
VPF = 3.75V x
+ 20k + 24.9k
( 45.3k20k
) = 7.53V
+ 24.9k
(
45.3k + 0k + 24.9k
0 +24.9k
)
LED indicators, D5 and D11, start to turn on when the input
current to U2 and U3 reaches an arbitrary value of 40mA.
This is set by Q1 and R3 for VPF and Q2 and R9 for VNF. The
input current can be calculated with the following equation:
Input current = VEB = 0.5V = 41.3mA
R 12.1Ω
50mA current limits are added to protect against output
shorts. The current limiter is consists of a depletion-mode
MOSFET and a series source resistor. The resistor sets the
current limit and can be estimated with the following equation:
RSERIES =
When R7 is set to 0Ω, VPF becomes:
VPF = 3.75V x
Please note that the OUT pin on U2 is referenced to VPP,
thereby setting VPF to be 8.0 to 10V below VPP. VNF can also
be calculated in a similar manner using resistors R12, R13,
and R14. Please note that the GND pin on U3 is referenced
to VNN thereby setting VNF to be 8.0 to 10V above VNN.
VTH x ( √I / I - 1) where,
LIM
DSS
ILIM
VTH = pinch-off voltage for M1 and M2: -2.5V
ILIM = desired current limit: 50mA
IDSS = saturation current for M1 and M2: 1.1A
= 10.6V
RSERIES = 39.3Ω. A 40.2Ω resistor was used.
Figure 3: Adjustable VPF and VNF Power Supply
R3
12.1Ω
VIN = 12V
13
11
C1
10µF
4
R1
16.9kΩ
R2
16.9kΩ
7
6
VIN
COLA
3
SHUTDOWN
RSL
COLB
14
2
9
3
8
4
7
D1
MMBD914
Q1
FMMT551
C2
10µF
D2
D1
CTX02-16076 MMBD914
U1
LT3439
M1
DN3525
R42
1.5kΩ
R9
12.1Ω
CT
C11
470µF 5
SYNC
10
GND
1,16
PGND
2
9
3
8
4
7
D3
MMBD914
Q2
FMMT551
C5
10µF
R43
1.5kΩ
8
R39
100kΩ
R15
4.99kΩ
3,6,7
R11
40.2Ω
GND
R10
4.99kΩ
5
3,6,7
C6
10µF
VPP
R6
45.3kΩ
R7
20kΩ
IN
OUT 1
U3
LT1521
ADJ 2
SHUTDOWN
GND
VFP
VNF
R12
45.3kΩ
R13
20kΩ
R14
24.9kΩ
D4
D1
CTX02-16076 MMBD914
Supertex inc.
+8.0 to +10V
C4
10µF
R8
24.9kΩ
8
R40
100kΩ
D11
LED
OUT 1
U2
LT1521
ADJ 2
5
SHUTDOWN
IN
C3
10µF
D5
LED
M2
DN3525
RT
R4
40.2Ω
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
4
+8.0 to +10V
C7
10µF
VNN
AN-H59
VDD Circuit Description
The VDD output voltage utilizes an adjustable low dropout linear regulator, U4 LT1521, as shown in Figure 4. The desired
adjustable output voltage range is 8.0 to 10V to accommodate the different operating VDD voltages for the three different transmitter demoboards.
The LT1521 has a reference voltage of 3.75V on the adj pin.
Resistors R17, R18, and R19 set the output VDD voltage.
R18 is a potentiometer for adjusting VDD. VDD can be calculated with the following equation:
VDD = VADJ x
+ R18 + R19
( R17R18
)
+ R19
When R18 is set to 0Ω, VDD becomes:
VDD = 3.75V x
An LED indicator, D6, is included in case of excessive input,
IIN, current. D6 is starts to turn on when the input current
reaches an arbitrary value of 20mA. This is set by Q3 and
R15. When the emitter-base junction of Q3 is forward biased
(0.5V), Q3 will start to turn on, thereby forward biasing D6.
The IIN value to turn D6 on can be calculated with the following equation:
When R18 is set to 20kΩ, VDD becomes:
VDD = 3.75V x
+ 24.9k
( 45.3k 0+ +0k24.9k
) = 10.6V
IIN =
+ 24.9k
( 45.3k20k+ 20k
) = 7.53V
+ 24.9k
VEB
0.5V
=
= 20.6mA
R15 24.3Ω
Figure 4: Adjustable VDD Power Supply
VIN = 12V
R15
24.3kΩ
Q3
FMMT551
C8
10µF
3.3V Input Terminal
8
R41
100kΩ
R16
3.32kΩ
C9
10µF
D6
LED
The AN-H59DB1 has a 3.3V input terminal that is directly
connected to the output terminal, VCC. There is no circuitry
on this board that uses the 3.3V supply. It is only there as a
convenient connection to the 8-pin header. VCC is the logic
supply voltage for HV738DB1 and HV748DB1 and can operate from 1.2 to 5V. However, most users will operate VCC at
either 3.0 or 3.3V.
5
3, 6, 7
OUT
IN
U4
LT1521
ADJ
SHUTDOWN
GND
1
2
VDD
R17
45.3kΩ
R18
20kΩ
C10
10µF
R19
24.9kΩ
+8.0 to 10V
GND
Input and Output Power
The output voltages from the AH-H59DB1 are all generated
from the 12V input line. With no load on the outputs, the
measured input current was about 70mA. This input current
can vary from board to board due to variations in the isolated
transformer.
The maximum output power is:
POUT(MAX) = PVPP(MAX) + PVNN(MAX) + PVPF(MAX) + PVNF(MAX) + PVDD(MAX)
POUT(MAX) = 0.9W + 0.9W + 0.4W + 0.4W + 0.2W
POUT(MAX) = 2.8W
Under this condition, the 12V input current was measured
to be 340mA. Input power is therefore 4.08W. This gives an
approximate overall efficiency of 69% at full load.
Supertex inc.
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
5
AN-H59
VPF and VNF Output Current
The AN-H59DB1 can supply more than 40mA of current for
the VPF and VNF outputs. The INF and IPF input currents for the
HV738 or the HV748 can be found in their respective data
sheet but are summarized below:
Part #
IPF-mode 4
INF-mode 4
HV738
30mA
12mA
HV748
50mA
25mA
This is for continuous 5.0 MHz operation. For ultrasound, the
high voltage transmitter is operating at very low duty cycles;
1% or lower. At a 1% duty cycle, the average current is expected to be a 100 times lower. The 40mA output current capability on the AN-H59DB1 is more than sufficient to power
up the HV738 or the HV748.
Conclusion
The main purpose of AN-H59DB1 power supply demoboard
is to help the evaluation of the Supertex HV738DB1 and
HV748DB1 demoboards by reducing the number of power
supplies needed. The AN-H59DB1 was designed to operate
from a single 12V input which should be commonly available
in any engineering laboratory.
The five on-board LEDs allow the user to quickly determine
whether there is an overload condition on each of the supply
lines. The five potentiometers allow the user to easily adjust
each supply to meet their particular needs.
Figure 5: AN-H59 Component Placement
Supertex inc.
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
6
AN-H59
Figure 6: AN-H59 Circuit Schematic
R20
154kΩ
8
D7
LED
BIAS
10
8
R25
232kΩ
N/C
4
R26
100kΩ
13
COMP
SHUTDOWN
C14
10µF
14
RESET
FB
R3
12.1Ω
13
11
C1
10µF
1
R1
16.9kΩ
7
R1
16.9kΩ
6
VIN
COLA
D1
MMBD914
3
2
SHUTDOWN
RSL
COLB
14
8
4
7
C2
10µF
CT
C11
470pF
5
SYNC
10
GND
1, 16
PGND
R5
4.99kΩ
9
3
8
4
D5
LED
C5
10µF
R43
1.5kΩ
D11
LED
GND
8
6
C17
10µF
C18
0.1µF
D9
LED
1
10
5
9
8
U8
LM2903
OSCIN
OSCOUT
OUT
U7
HV9110NG
VIN
R6
45.3kΩ
C4
10µF
R7
20kΩ
GND
R8
24.9kΩ
8
OUT
5
3, 6, 7
VPF
VNF
1
U3
LT1521
IN
ADJ 2
C6
10µF
R12
45.3kΩ
R13
20kΩ
SHUTDOWN
GND
C7
10µF
Q3
FMMT551
VPP
VPF
COMP
SHUTDOWN
14
FB
M5
TN2510
D10
MMBD914
RESET
3
11
L2
100µH
R31
1.0kΩ
R16
3.32kΩ
C9
10µF
5
3, 6, 7
OUT
IN U4
LT1521
ADJ
SHUTDOWN
GND
GND
J1
VDD
1
2
R17
14.3kΩ
R18
20kΩ
VCC
1
R36
10kΩ
12
R41
100kΩ
VDD
C23
2.2µF
R32
2.2Ω
C22
470µF
VNN
R37
14.7kΩ
Q4
FMMT494
R38
40.2kΩ
R35
237kΩ
M6, M7
TN2510
8
D6
LED
C10
10µF
GND
R19
24.9kΩ
VCC
Supertex inc.
VNF
Q5
FMMT551
R34
100kΩ
VREF
N/C
R33
4.99kΩ
C21
10µF
4
GND
SENSE
13
C19
1.0nF
8
R14
24.9kΩ
M4
TN2510
R15
24.3Ω
C8
10µF
2
SHUTDOWN
7
BIAS
3
+
- 2
4
C3
10µF
C20
10µF
VDD
2
R29
383kΩ
1
IN
VNN
R28
154kΩ
R30
3.32kΩ
U2
LT1521
1
D4
MMBD914
12V
3.3V
5
3, 6, 7
R40
100kΩ
R10
4.99kΩ
OUT
ADJ
R11
M2
DN3525 40.2Ω
7
T2
CTX02-16076
8
Q2
FMMT551
D3
MMBD914
2
R42
1.5kΩ
R9
12.1Ω
RT
R27
14.3kΩ
12
R39
100kΩ
Q1
FMMT551
T2
D2
CTX02-16076 MMBD914
U1
LT3439
11
R4
M1
DN3525 40.2Ω
9
3
R24
2.2kΩ
C15
470pF
3
+
- 2
U6
LM2903
C16
2.2µF
GND
9
1
3
SENSE
VPP
M3
TN2510
R23
1.0kΩ
VREF
5
R22
3.32kΩ
4
U5 OUT
HV9110NG
1
C13
0.1µF
D8
MMBD914
VDD
2 VIN
R21
383kΩ
L1
100µH
OSCOUT 7
OSCIN
6
C12
10pF
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
7
AN-H59
Bill of Materials
Reference
Description
Package
Manufacturer
Part No.
C1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 12,
17, 20, 21
Chip Capacitor, 10µF, 16V
1206
Any
---
C11, 15, 22
Chip Capacitor, 470pF, 100V
805
Any
---
C13, 18
Chip Capacitor, 0.1µF, 25V
805
Any
---
C14, 19
Chip Capacitor, 1.0nF, 50V
805
Any
---
C16, 23
Chip Capacitor, 2.2µF, 100V
1210
Any
---
R1, 2
16.9kΩ, Chip Resistor
805
Any
---
R3, 9
12.1Ω, Chip Resistor
805
Any
---
R4, 11
40.2Ω, Chip Resistor
805
Any
---
R5, 10, 33
4.99kΩ, Chip Resistor
805
Any
---
R6, 12, 17
45.3kΩ, Chip Resistor
805
Any
---
R7, 13, 18
20kΩ, Potentiometer
---
Any
---
R8, 14, 19
24.9kΩ, Chip Resistor
805
Any
---
R15
24.3Ω, Chip Resistor
805
Any
---
R16, 22, 30
3.32kΩ, Chip Resistor
805
Any
---
R20, 28
154kΩ, Chip Resistor
805
Any
---
R21, 29
383kΩ, Chip Resistor
805
Any
---
R23, 31
1.02kΩ, Chip Resistor
805
Any
---
R24, 32
2.20Ω, Chip Resistor
1206
Any
---
R25
232kΩ, Chip Resistor
0805
Any
---
R26, 34
100kΩ, Potentiometer
---
Any
---
R27
14.3kΩ, Chip Resistor
0805
Any
---
R35
237kΩ, Chip Resistor
0805
Any
---
R36
10.2kΩ, Chip Resistor
0805
Any
---
R37
14.7kΩ, Chip Resistor
0805
Any
---
R38
40.2kΩ, Chip Resistor
0805
Any
---
R39, 40, 41
100kΩ, Chip Resistor
0805
Any
---
R42,43
1.5kΩ, Chip Resistor
1206
Any
---
L1,2
Inductor, 100µH
---
Cooper Electronic
SD3814-101-R
D1, 2, 3, 4, 8, 10
100V, Fast Recovery Diode
SOT-23
Fairchild
MMBD914
D5, 6, 7, 9, 11
Red LED
0805
Lumex
SML-LXT0805SRW
Q1, 2, 3, 5
PNP, 60V, Bipolar Transistor
SOT-23
Zetex Inc
FMMT551TA
Q4
NPN, 120V, Bipolar Transistor
SOT-23
Zetex Inc
FMMT494TA
U1
IC, Low Noise Transformer Driver
16-TSSOP
Linear Technology
LT3439EFE#PBF
U2, 3, 4
IC, Adjustable Linear Regulator
SO-8
Linear Technology
LT1521CS8#PBF
Supertex inc.
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
8
AN-H59
Bill of Materials (cont.)
Reference
Description
Package
Manufacturer
Part No.
U5, 7
High-voltage current-mode
PWM controller
SO-14
Supertex Inc.
HV9110NG-G
U6, 8
IC, Dual Voltage comparator
SO-8
Texas Instruments
LM2903DR
T1, 2
Transformer
---
Cooper Electronic
CTX02-16076
M1, 2
MOSFETs
Depletion Mode, N-channel, 250V
SOT-89
Supertex Inc.
DN3525N8-G
M3
MOSFET
Enhancement Mode, N-channel 100V
SOT-89
Supertex Inc.
TN2510N8
M4
MOSFET
Enhancement Mode, P-channel 40V
SOT-23
Supertex Inc.
TP2104K1
M5
MOSFET
Enhancement Mode, N-channel 60V
SOT-23
Supertex Inc.
TN2106K1
M6, 7
MOSFETs
Enhancement Mode, P-Channel 100V
SOT-89
Supertex Inc.
TP2510N8
J1
8 Position, 0.100” Pitch,
rectangular connector
---
Tyco Electronic Amp
770602-8
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)
©2012 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited.
021312
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com