Supertex inc.
Four-Channel
High Voltage Protection T/R Switch
Features
►
Up to ±130V input voltage protection
►
Low on resistance - 15Ω typical
►
Fast switching speed
►
Four electrically isolated channels
►
No external supplies needed
MD0105
General Description
The Supertex MD0105 is a 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.
The MD0105 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 two terminals exceeds a nominal
value of ±2.0V, the device will start to turn off. In the off state, the
MD0105 can withstand up to ±130V across its terminals. A small
amount of current, typically 200µA, is allowed to flow through.
The MD0105 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 MD0105 is
available in an 18-Lead 5x5mm DFN package as a four-channel
device.
Applications
►
Medical ultrasound imaging
►
NDT applications
►
Fast resettable fuses
►
High side switches
►
Data acquisition
Typical Application Circuit
+130V
Transmitter
Logic
Control
and
Signal
Processing
Piezo
Transducers
-130V
TX
RX
Receiver
B
MD0105
T/R Switch
A
High Voltage
Switches
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
MD0105
Ordering Information
Package Option
Device
5.00x5.00mm body
1.00mm height (max)
0.50mm pitch
Pin Configurations
18-Lead DFN
NC
A1
NC
A2
NC
A3
NC
A4
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
NC
B1
NC
B2
NC
B3
NC
B4
NC
MD0105
MD0105K6-G
-G indicates package is RoHS compliant (‘Green’)
E
ESD Sensitive Device
NC
Absolute Maximum Ratings
1
Parameter
V
A
- V
B
, Differential voltage drop
Maximum junction temperature
Storage temperature range
Power dissipation, 18-Lead DFN
2
Value
0 to ±140V
+125°C
-65°C to 150°C
1.6W
(top view)
(Pads are at bottom of device)
18-Lead DFN (K6)
Product Marking
MD 01 05
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
Notes:
1. 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.
2. Mounted on FR4 board, 25mm x 25mm x 1.57mm
18-Lead DFN (K6)
Package may or may not include the following marks: Si or
Electrical Characteristics
(T
J
= 25ºC, unless otherwise specified)
Sym
BV
A-B
R
SW
V
TRIP
V
OFF
I
A-B(OFF)
I
PEAK
T
OFF
T
ON
C
SW(ON)
C
SW(OFF)
BW
T
J
Parameter
Breakdown voltage from A to B or B to A
Switch ON resistance from A to B or B to A
V
A-B
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 A to B or B to A
Switch OFF capacitance from A to B or B to A
Small signal bandwidth
Operating junction temperature
Min
±130
-
-
-
-
-
-
-
-
-
-
-40
Typ
-
15
±1.0
±2.0
±200
±60
-
-
21
15
100
-
Max
-
-
±2.0
-
±300
-
20
20
-
-
-
+125
Units Conditions
V
Ω
V
V
µA
mA
ns
ns
pF
pF
MHz
°C
I
A-B
= ±1.0mA
I
A-B
= ±5.0mA
---
I
A-B
= ±1.0mA
V
A-B
= ±130V
---
---
---
SW = ON
V
SW
= 25V
R
LOAD
= 50Ω
---
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
2
Tel: 408-222-8888
www.supertex.com
MD0105
Block Diagram
COM
Switch Control
A
B
Typical I-V Characteristics
+I
PEAK
I
A-B
I
A-B
= +200µA
-130V
-V
OFF
+1.0mA
-V
TRIP
+V
TRIP
+1.0mA
I
A-B
= -200µA
R
SW
= 15Ω
+V
OFF
V
A-B
+130V
-I
PEAK
Functional Description
The Supertex MD0105 can be considered as a normally
closed switch controlled by a switch control (please refer to
the block diagram). The switch control monitors the voltage
drop across terminals A and B. If the voltage difference is
greater than ±2.0V, the T/R switch will start to open. Once
in the open state, there is a small amount of current flowing
through the T/R switch, 200µA, to detect if the high voltage
is still present or not.
The T/R switch will not close until the voltage across termi-
nal A and B drops below ±2.0V. A pair of back-to-back di-
odes from the receive side of the switch to ground is needed
to complete the circuit and to allow the initial peak current
(about 60mA) to flow through the switch so it can drop ±2.0V.
If the diodes are not present, then there is no current path
and the voltage drop across terminal A and B will be less
than ±2.0V, so the switch will remain in the closed position.
The MD0105 does not require any power supply. There are
only two active pins; one connects to the transmitter side,
one connects to the receiver side.
On Resistance
When the voltage across terminals A and B are below
±2.0V,
the switch is in the receive mode and the R
ON
is typically 15Ω.
Once the voltage across the terminals A and B is greater
than ±2.0V, the switch is in the transmit mode and blocking
the high voltage pulses from passing through to the receiver
and damaging it.
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
3
Tel: 408-222-8888
www.supertex.com
MD0105
Switch Capacitance
T
ON
and T
OFF
Time
The typical switch On capacitance (C
SW(ON)
) is 21pF. This is
measured from A to B when the switch is ON. The switch
OFF capacitance is a function of the voltage across the T/R
switch. The C
SW(OFF)
is about 12 to 19 pF for 10V to 130V of
the transmit voltage.
The T
ON
and T
OFF
of the MD0105 are less than 20ns, which
provide a fast switch between the transmit mode and the re-
ceive mode. The T
ON
and T
OFF
are input rise/fall time depen-
dent. 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.
Pin Description
Pad
1
2
3
4
5
6
7
8
9
Name
NC
A1
NC
A2
NC
A3
NC
A4
NC
Description
No internal connection
Switch terminal A1
No internal connection
Switch terminal A2
No internal connection
Switch terminal A3
No internal connection
Switch terminal A4
No internal connection
Pad
10
11
12
13
14
15
16
17
18
Center Tab
Name
NC
B4
NC
B3
NC
B2
NC
B1
NC
---
Description
No internal connection
Switch terminal B4
No internal connection
Switch terminal B3
No internal connection
Switch terminal B2
No internal connection
Switch terminal B1
No internal connection
Connect to ground
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
4
Tel: 408-222-8888
www.supertex.com
MD0105
18-Lead DFN Package Outline (K6)
D
1
5.00x5.00mm body, 1.00mm height (max), 0.50mm pitch
Note 1
(Index Area
D/2 x E/2)
1
D2
Note 1
(Index Area
D/2 x E/2)
E
E2
Top View
θ
b
e
Bottom View
View B
Note 3
A
A1
A3
Seating
Plane
Note 2
L
L1
Side View
View B
Notes:
1. A Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier can be: a molded mark/identifier; an embedded metal marker; or
a printed indicator.
2. Depending on the method of manufacturing, a maximum of 0.15mm pullback (L1) may be present.
3. The inner tip of the lead may be either rounded or square.
Symbol
Dimension
(mm)
MIN
NOM
MAX
A
0.80
0.90
1.00
A1
0.00
0.02
0.05
A3
0.20
REF
b
0.18
0.25
0.30
D
4.85*
5.00
5.15*
D2
4.20
†
4.35
†
4.45
†
E
4.85*
5.00
5.15*
E2
3.50
†
3.65
†
3.75
†
e
0.50
BSC
L
0.30
†
0.40
†
0.50
†
L1
0.00*
-
0.15
θ
0
O
-
14
O
JEDEC Registration MO-229, Variation VJJD-2, Issue C, Aug. 2003.
* This dimension is not specified in the JEDEC drawing.
† This dimension differs from the JEDEC drawing.
Drawings not to scale.
Supertex Doc. #:
DSPD-18DFNK65X5P050, Version A013111.
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline
information go to
http://www.supertex.com/packaging.html.)
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)
©2011
Supertex inc.
All rights reserved. Unauthorized use or reproduction is prohibited.
Doc.# DSFP-MD0105
B080211
5
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
Supertex inc.
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