Supertex inc. MD0100 High Voltage Protection T/R Switch Features General Description Applications The MD0100 can be considered as a normally closed switch with a typical switching resistance of 15Ω that allows 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 MD0100 can withstand up to ±100V across its terminals. A small amount of current, typical of 200µA, is allowed to flow through. ►► ►► ►► ►► ►► ►► ►► ►► ►► ►► Up to ±100V input voltage protection Low on resistance - 15Ω typical Fast switching speed Effectively, a simple two terminal device No external supplies needed Medical ultrasound imaging NDT applications Fast resettable fuses High side switches Data acquisition The Supertex MD0100 is a high voltage, two terminal, bidirectional, current-limiting protection device. The two terminals are interchangeable. 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 applications for the MD0100 are not limited to just ultrasound. It can also be used for resettable fuses to protect power lines, output short circuit protection, and data acquisition. The MD0100 is available in the SOT-89 package as a single channel device for ease of assembly. It is also available in a 4.0x4.0mm 8-Lead DFN package as a two channel device for high density requirements. Typical Application Circuit +90V Transmitter Logic Control and Signal Processing -90V TX RX Receiver Doc.# DSFP-MD0100 C070113 Piezo Transducers B MD0100 T/R Switch A High Voltage Switches Supertex inc. www.supertex.com MD0100 Pin Configuration Ordering Information Part Number MD0100DK6-G (Dual Channel) MD0100N8-G (Single Channel) Package Options Packing 8-Lead (4x4) DFN 3000/Reel 3-Lead TO-243AA (SOT-89) 2000/Reel -G denotes a lead (Pb)-free / RoHS compliant package Absolute Maximum Ratings 8 COM1 2 7 COM1 A2 3 6 COM2 B2 4 5 COM2 A1 1 B1 COM1 COM2 1 Parameter VA-B, differential voltage drop (top view) (Pads are at bottom of device) 0 to ±110V Maximum junction temperature COM +125°C Storage temperature range Power dissipation, 8-Lead DFN 8-Lead DFN Value -65°C to 150°C 1.1W 2 Power dissipation, SOT-892 1.6W 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 A SOT-89 Product Marking Typical Thermal Resistance Package θja 8-Lead DFN 44OC/W 3-Lead TO-243AA (SOT-89) 133OC/W B COM 0100 YWLL Y = Last Digit of Year Sealed W = Code for Week Sealed LL = Lot Number = “Green” Packaging 8-Lead DFN Package may or may not include the following marks: Si or Y = Last Digit of Year Sealed W = Code for Week Sealed = “Green” Packaging M10YW SOT-89 Package may or may not include the following marks: Si or Electrical Characteristics (T = 25ºC, unless otherwise specified) J Sym Parameter Min Typ Max VA-B Max. differential input voltage from A to B ±100 - - V IA-B = ±500µA RSW Switch ON resistance from A to B - 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 = ±100V Peak switching current - ±60 - mA See Fig. 8 IA-B(OFF) IPEAK Doc.# DSFP-MD0100 C070113 2 Units Conditions Supertex inc. www.supertex.com MD0100 Electrical Characteristics (T = 25ºC, unless otherwise specified) J Sym Parameter Min Typ Max TOFF TON Turn off time - - 20 ns See Fig. 2, 3 & 4 Turn on time - - 20 ns See Fig. 5, 6 & 7 CSW(ON) Switch ON capacitance from A to B - 21 - pF SW = ON CSW(OFF) Switch OFF capacitance from A to B - 15 - pF VSW = 25V Small signal bandwidth - 100 - MHz -40 - +125 °C BW TJ Operating junction temperature Units Conditions RLOAD = 50Ω --- Block Diagram COM Switch Control A B Typical I-V Characteristics +IPEAK IA-B IA-B = +200µA -100V -VOFF +1.0mA -VTRIP +VTRIP +1.0mA +VOFF VA-B +100V IA-B = -200µA RSW = 15Ω -IPEAK Doc.# DSFP-MD0100 C070113 3 Supertex inc. www.supertex.com MD0100 Functional Description Figure 1: CSW(OFF) vs VSW The Supertex MD0100 can be considered as a normally closed switch controlled by a switch control. (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, 200uA, 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 within ±2.0V. A pair of back-to-back diodes from the receive side of the switch to ground are 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. 20 19 18 CSW (pF) 17 16 15 14 13 12 11 10 0 10 20 30 40 50 60 70 80 90 VSW (V) TON and TOFF Time The other purpose of the diode is to clamp voltage spikes to ±0.7V during transmit cycle. A low voltage diode, for example 1.0V diode, is sufficient since it will only see ±0.7V. A BAV99T dual diode from Diodes, Inc. was used in our test circuit. The TON and TOFF of the MD0100 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 MD0100 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 TOFF and TON set up are shown in Figure 2 and Figure 5 respectively. On Resistance Figure 2: Test set up for TOFF When the voltage across terminals A and B is within ±2.0V, the switch is in the receive mode, and the RON is typically 15Ω. Once the voltage across terminals A and B 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. 500ns +10V 0V Tx The MD0100 does not require any power supply. There are only two active pins; one connects to the transmitter side and the other one connects to the receiver side. Transmitter VB Switch Capacitance The typical switch ON capacitance (CSW(ON)) is 21pF. This is measured from A to B or B to A when the switch is ON. MD0100 VA 10Ω 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 100V of the transmit voltage. Please see Figure 1 for the C-V curve of the CSW(OFF). Doc.# DSFP-MD0100 C070113 4 Supertex inc. www.supertex.com MD0100 Figure 3: TOFF Timing Diagram Figure 6: TON Timing Diagram VA +10V +10V VA +2V +2V 0V VB 10% VB 2V 1V 0V Figure 4: TOFF at VA = 10V Figure 7: TON at VA = 10V 2V 2V 1V 10% Figure 4 shows the actual waveform and measurement of the Figure 7 shows the actual waveform and measurement of TOFF. TOFF is measured from 2V of the VA to 10% of the VB. the TON. The TON is measured from 2V of the VA to 1V of the VB. From the above waveform, the TON is 6.6ns. From the above waveform, the TOFF is 11ns. Figure 5: Test Set Up for TON Figure 8: Test Set Up for IPEAK IPEAK 500ns +10V 0 - 5V B tr = 10ms Tx MD0100 A V 0V Transmitter 2V 15Ω Doc.# DSFP-MD0100 C070113 VB MD0100 VA 5 Supertex inc. www.supertex.com MD0100 Figure 9: Typical Application Circuit Figure 11: Typical Waveform 100ns +90V Transmitter Tx CH2 -90V CH1 VB MD0100 VA 1KΩ Figure 10: Typical Waveform Figure 11 shows VA and VB in the same voltage scale, 2.0V/ DIV. Figure 10 shows the waveforms of VA and VB of the test circuit shown in Figure 9. There is a small bump of about 0.5V at the tail of the VB signal because the transmit signal falls into the ±2.0V range, and the MD0100 turns back ON again. Figure 11 shows a magnified view of the VA. Doc.# DSFP-MD0100 C070113 6 Supertex inc. www.supertex.com MD0100 Pin Description (8-Lead DFN) Pin Name Description 1 A1 Switch terminal A1 2 B1 Switch terminal B1 3 A2 Switch terminal A2 4 B2 Switch terminal B2 5 COM2 6 COM2 7 COM1 8 COM1 Heat Slug 1 COM1 Leave floating Heat Slug 2 COM2 Leave floating Leave floating Leave floating Pin Description (SOT-89) Name A COM B Doc.# DSFP-MD0100 C070113 Description Switch terminal A Leave floating Switch terminal B 7 Supertex inc. www.supertex.com MD0100 8-Lead DFN Package Outline (K6) 4.00x4.00mm body, 1.00mm height (max), 1.00mm pitch (dual pad) K1 D 8 D2 K1/2 D2 8 E2 E E2 Note 1 Note 1 (Index Area D/2 x E/2) Note 1 (Index Area D/2 x E/2) 1 1 Top View View B Bottom View Note 3 θ A A3 L Seating Plane A1 L1 e b Note 2 View B Side View 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 - MAX 1.00 0.05 A3 0.20 REF b D D2 E E2 0.25 3.90 1.35 3.90 1.35 0.30 4.00 1.45 4.00 1.45 0.35 4.10 1.55 4.10 1.55 e 1.00 BSC K1 0.50 REF L L1 θ 0.40 0.00 0O 0.50 - - 0.60 0.15 14O Drawings not to scale Supertex Doc. #: DSPD-8DFNK64x4P100, Version C010813 Doc.# DSFP-MD0100 C070113 8 Supertex inc. www.supertex.com MD0100 3-Lead TO-243AA (SOT-89) Package Outline (N8) D D1 C E H L 1 2 E1 3 b b1 e A e1 Top View Symbol Dimensions (mm) Side View A b b1 C D D1 E E1 e MIN 1.40 0.44 0.36 0.35 4.40 1.62 2.29 2.00 NOM - - - - - - - - MAX 1.60 0.56 0.48 0.44 4.60 1.83 2.60 2.29 e1 † 1.50 BSC 3.00 BSC H L 3.94 0.73† - - 4.25 1.20 JEDEC Registration TO-243, Variation AA, Issue C, July 1986. † This dimension differs from the JEDEC drawing Drawings not to scale. Supertex Doc. #: DSPD-3TO243AAN8, Version F111010. (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. ©2013 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited. Doc.# DSFP-MD0100 C070113 9 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com