Supertex inc.
High Voltage Protection T/R Switch
with Clamp Diodes
Features
►
Up to ±100V input voltage protection
►
Low on resistance - 15Ω typical
►
Integrated clamp diodes
►
Fast switching speed
►
Four electrically isolated channels
►
No external supplies needed
MD0101
The Supertex MD0101 is a four channel, high voltage, current limiting
protection device. It is designed to protect a low noise receiver from the
high voltage transmit pulses in ultrasound applications and is commonly
referred to as a T/R (transmit and receive) switch. Each channel has
three terminals; Tx, Rx, and R
GND
. The analog switch terminals are
Tx and Rx. Rx has integrated clamping diodes to R
GND
to protect the
receiver against high voltages. Voltages greater than ±0.6V will start
forward biasing the clamp diodes to R
GND
.
The MD0101 can be considered as a normally closed switch with a
typical switch resistance of 15Ω, allowing small signals to pass. Once
the voltage drop across the switch exceeds a nominal value of ±1.0V,
the device will start to turn off. In the off state, the MD0101 can withstand
up to ±100V across its terminals. A small amount of current, 200µA, is
allowed to flow through.
The MD0101 is not limited to just ultrasound applications. It can also
be used for resettable fuses to protect power lines, output short circuit
protection, and data acquisition. The MD0101 is available in an 18-
Lead, 5x5mm DFN package as a four channel device for high density
requirements.
General Description
Applications
►
Medical ultrasound imaging
►
NDT applications
►
Fast resettable fuses
►
High side switches
►
Data acquisition
Typical Application Circuit
One of
128 Channels
Transmitter
Logic
Control
and
Signal
Processing
+90V
Piezo
Transducers
-90V
TX
RX
Receiver
RX
MD0101
TX
RGND
High Voltage
Switches
T/R Switch
Doc.# DSFP-MD0101
C070213
Supertex inc.
www.supertex.com
MD0101
Ordering Information
Part Number
MD0101K6-G
MD0101K6-G M932
Package
18-Lead DFN (5x5)
18-Lead DFN (5x5)
Packing
490/Tray
2500/Reel
NC
1
18 NC
17 Rx1
16 RGND1
15 Rx2
14 RGND2
13 Rx3
12 RGND3
11 Rx4
10 RGND4
Tx1 2
NC
3
Pin Configuration
-G denotes a lead (Pb)-free / RoHS compliant package
Tx2 4
NC
ESD Sensitive Device
5
Tx3 6
Absolute Maximum Ratings
1
Parameter
V
TX
- V
RX
, Differential voltage drop
Maximum junction temperature
Storage temperature range
Power dissipation, 18-Lead DFN
2
1.
NC
7
Tx4 8
Value
0 to ±110V
+125°C
-65°C to 150°C
1.6W
NC
9
(top view)
(Pad is at bottom of device)
18-Lead DFN
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.
Mounted on FR4 board, 25mm x 25mm x 1.57mm
Product Marking
MD 01 01
LL LLL L
YYWW
AAACCC
L = Lot Number
YY = Last Digit of Year Sealed
WW = Code for Week Sealed
A = Assembler ID
C = Country of Origin
= “Green” Packaging
2.
Typical Thermal Resistance
Package
18-Lead DFN
a
θ
ja
30 C/W
O
Package may or may not include the following marks: Si or
18-Lead DFN
Electrical Characteristics
(T
= 25ºC, unless otherwise specified)
Sym
V
TX-RX
R
SW
V
TRIP
V
OFF
I
A-B(OFF)
I
PEAK
T
OFF
T
ON
C
TX(ON)
C
TX(OFF)
BW
T
J
V
RX
C
D
Parameter
Max. differential input voltage from TX to RX
Switch ON resistance from TX to RX
V
TX - RX
trip point to turn off
Switch turn off voltage
Switch off current
Peak switching current
Turn off time
Turn on time
Switch ON capacitance from TX to RX
Switch OFF capacitance from TX to RX
Small signal bandwidth
Operating junction temperature
Diode forward voltage drop
RX capacitance to RGND
Min
±100
-
-
-
-
-
-
-
-
-
-
-40
-
-
Typ
-
15
±1.0
±2.0
±200
±60
-
-
15
9.0
100
-
±1.6
20
Max
-
-
±2.0
-
±300
-
20
20
-
-
-
+125
-
-
Units Conditions
V
Ω
V
V
µA
mA
ns
ns
pF
pF
MHz
°C
V
pF
I
TX-RX
= ±500µA
I
TX-RX
= ±5.0mA
---
I
TX-RX
= ±1.0mA
V
TX-RX
= ±100V
---
---
---
SW = ON
V
TX-RX
= 25V
R
LOAD
= 50Ω
---
I
RX
= ±200mA, RGND = 0V,
TX = Open
RGND = 0V, TX = Open
Doc.# DSFP-MD0101
C070213
2
Supertex inc.
www.supertex.com
MD0101
Block Diagram
TX
RX
Switch Control
RGND
Typical I-V Characteristics
+I
PEAK
I
TX - RX
I
TX - RX
= +200µA
-100V
-V
OFF
+1.0mA
-V
TRIP
+V
TRIP
+1.0mA
I
TX - RX
= -200µA
R
SW
= 15Ω
+V
OFF
V
TX - RX
+100V
-I
PEAK
Functional Description
The Supertex MD0101 can be considered a normally closed
switch, controlled by a switch control (please refer to the
block diagram). The switch control monitors the voltage
drop across terminals TX and RX. If the voltage difference
is greater than ±1.0V, the T/R switch will start to open. Once
in the open state, there is a small amount of current flow-
ing through the T/R switch, 200µA, to detect if the high volt-
age is still present or not. The T/R switch will not close until
the voltage across terminals TX and RX drops below ±2.0V.
Connecting the RGND to ground will allow the initial peak
current, about 60mA, to flow through the switch then to the
clamp diodes to RGND. The clamp diode I-V Curve is shown
in Figure 8. If external diodes are desired, the RGND pin can
be connected to the corresponding RX pin or left floating.
The external diodes can then be connected to RX to ground.
The MD0101 does not require a power supply. There are
only three pins per channel; one connects to the transmitter
side, one connects to the receiver side, and the other one is
the ground connection for diodes.
On Resistance
When the voltage across terminals TX and RX is below
±1.0V, the switch is in the receive mode, and the R
ON
is typi-
cally 15Ω. Once the voltage across the terminals TX and RX
is greater than ±2.0V, the switch is in the transmit mode and
blocks the high voltage pulses from passing through to the
receiver and damaging it.
Doc.# DSFP-MD0101
C070213
3
Supertex inc.
www.supertex.com
MD0101
Switch Capacitance
The typical switch ON capacitance, C
SW(ON)
, is 21pF. This is
measured from TX to RX when the switch is ON. The switch
OFF capacitance is a function of the voltage across the T/R
switch. The C
TX(OFF)
is about 11 - 6.5pF for 10 - 90V of the
transmit voltage. Please see Figure 1 for the C-V curve of
the C
TX(OFF)
.
Figure 3: T
OFF
Timing Diagram
+10V
V
TX
+2V
Figure 1: C
TX-RX
vs V
TX-RX
13.0
12.0
11.0
10%
V
RX
C
TX-RX
(pF)
Figure 4: T
OFF
at V
TX
= 10V
10.0
9.0
8.0
7.0
6.0
0
10
20
30
40
50
60
70
80
90
100
V
TX-RX
T
ON
and T
OFF
Time
The T
ON
and T
OFF
of the MD0101 are less than 20ns, which
provide a fast switch between the transmit mode and the
receive mode. The T
ON
and T
OFF
are input rise/fall time de-
pendent. The T/R switch turns ON and OFF faster when the
rise and fall times of the transmit pulse are faster. On the
other hand, the switch turns ON and OFF slower if the rise
and fall times of the transmit pulse are slower. The T
OFF
and
T
ON
set ups are shown in Figure 2 and Figure 5 respectively.
Figure 2: Test set up for T
OFF
500ns
Figure 4 shows the actual waveform and measurement of
the T
OFF
. The T
OFF
is measured from 2.0V of the V
TX
to 10%
of the V
RX
.
Transmitter
TX
+10V
Figure 5: Test set up for T
ON
500ns
0V
Transmitter
TX
+10V
0V
RX
10
MD0101
RGND
TX
15
2.0V
(Floating or connect to RX)
RX
MD0101
RGND
TX
(Floating or connect to RX)
Doc.# DSFP-MD0101
C070213
4
Supertex inc.
www.supertex.com
MD0101
Figure 6: T
ON
Timing Diagram
V
TX
+10V
Figure 8: RX Clamp Diodes to RGND
500
450
I-V Curve
+2V
0V
I
f
(mA)
400
350
300
250
200
150
100
50
V
RX
2V
1V
1V
0V
0
0.00
0.25
0.50
0.75
1.00
V
f
(V)
1.25
1.50
1.75
2.00
2.25
Figure 7: T
ON
at V
TX
= 10V
Figure 7 shows the actual waveform and measurement of
the T
ON
. The T
ON
is measured from 2.0V of the V
TX
to 1.0V of
the V
RX
.
Doc.# DSFP-MD0101
C070213
5
Supertex inc.
www.supertex.com
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
