Supertex inc. MD0105 Four-Channel High Voltage Protection T/R Switch Features ►► ►► ►► ►► ►► General Description Up to ±130V input voltage protection Low on resistance - 15Ω typical Fast switching speed Four electrically isolated channels No external supplies needed Applications ►► ►► ►► ►► ►► Medical ultrasound imaging NDT applications Fast resettable fuses High side switches Data acquisition 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. Typical Application Circuit +130V Transmitter Logic Control and Signal Processing Piezo Transducers -130V TX RX Receiver Supertex inc. B MD0105 T/R Switch A High Voltage Switches ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com MD0105 Pin Configurations Ordering Information Package Option 18-Lead DFN Device 5.00x5.00mm body 1.00mm height (max) 0.50mm pitch MD0105 MD0105K6-G -G indicates package is RoHS compliant (‘Green’) ESD Sensitive Device E NC 1 18 NC A1 2 17 B1 NC 3 16 NC A2 4 15 B2 NC 5 14 NC A3 6 13 B3 NC 7 12 NC A4 8 11 B4 NC 9 10 NC Absolute Maximum Ratings1 18-Lead DFN (K6) Parameter (top view) (Pads are at bottom of device) Value VA - VB, Differential voltage drop 0 to ±140V Maximum junction temperature +125°C Storage temperature range Product Marking -65°C to 150°C MD0105 LLLLLL 1.6W Power dissipation, 18-Lead DFN2 YYWW AAACCC 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. L = Lot Number YY = Last Digit of Year Sealed WW = Code for Week Sealed A = Assembler ID C = Country of Origin = “Green” Packaging 18-Lead DFN (K6) Package may or may not include the following marks: Si or 2. Mounted on FR4 board, 25mm x 25mm x 1.57mm Electrical Characteristics (TJ = 25ºC, unless otherwise specified) Sym Parameter Min Typ Max BVA-B Breakdown voltage from A to B or B to A ±130 - - V IA-B = ±1.0mA RSW Switch ON resistance from A to B or B to A - 15 - Ω IA-B = ±5.0mA VTRIP VA-B trip point to turn off - ±1.0 ±2.0 V --- VOFF Switch turn off voltage - ±2.0 - V IA-B = ±1.0mA Switch off current - ±200 ±300 µA VA-B = ±130V IPEAK Peak switching current - ±60 - mA --- TOFF Turn off time - - 20 ns --- TON Turn on time - - 20 ns --- CSW(ON) Switch ON capacitance from A to B or B to A - 21 - pF SW = ON CSW(OFF) Switch OFF capacitance from A to B or B to A - 15 - pF VSW = 25V Small signal bandwidth - 100 - MHz -40 - +125 °C IA-B(OFF) BW TJ Operating junction temperature Supertex inc. Units Conditions RLOAD = 50Ω --- ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com 2 MD0105 Block Diagram COM Switch Control A B Typical I-V Characteristics +IPEAK IA-B IA-B = +200µA -130V -VOFF +1.0mA -VTRIP +VTRIP +VOFF VA-B +1.0mA +130V IA-B = -200µA RSW = 15Ω -IPEAK 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 terminal A and B drops below ±2.0V. A pair of back-to-back diodes 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 Supertex inc. 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 RON 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. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com 3 MD0105 Switch Capacitance The typical switch On capacitance (CSW(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 CSW(OFF) is about 12 to 19 pF for 10V to 130V of the transmit voltage. TON and TOFF Time The TON and TOFF of the MD0105 are less than 20ns, which provide a fast switch between the transmit mode and the receive mode. The TON and TOFF are input rise/fall time dependent. 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 Name 1 NC 2 Description Pad Name No internal connection 10 NC No internal connection A1 Switch terminal A1 11 B4 Switch terminal B4 3 NC No internal connection 12 NC No internal connection 4 A2 Switch terminal A2 13 B3 Switch terminal B3 5 NC No internal connection 14 NC No internal connection 6 A3 Switch terminal A3 15 B2 Switch terminal B2 7 NC No internal connection 16 NC No internal connection 8 A4 Switch terminal A4 17 B1 Switch terminal B1 9 NC No internal connection 18 NC No internal connection Center Tab --- Connect to ground Supertex inc. Description ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com 4 MD0105 18-Lead DFN Package Outline (K6) 5.00x5.00mm body, 1.00mm height (max), 0.50mm pitch D Note 1 (Index Area D/2 x E/2) 1 D2 1 Note 1 (Index Area D/2 x E/2) E E2 e b Top View View B Bottom View Note 3 θ A A3 A1 L Seating Plane L1 Note 2 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) A A1 MIN 0.80 0.00 NOM 0.90 0.02 MAX 1.00 0.05 A3 0.20 REF b D D2 E E2 e 0.18 4.85* 4.20† 4.85* 3.50† 0.25 5.00 4.35† 5.00 3.65† 0.30 5.15* 4.45† 5.15* 3.75† 0.50 BSC L L1 θ 0.30† 0.00* 0O 0.40† - - 0.50† 0.15 14O 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) Supertex inc. ©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