Supertex inc. MD0101 High Voltage Protection T/R Switch with Clamp Diodes Features ►► ►► ►► ►► ►► ►► General Description 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 Applications ►► ►► ►► ►► ►► 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 RGND. The analog switch terminals are Tx and Rx. Rx has integrated clamping diodes to RGND to protect the receiver against high voltages. Voltages greater than ±0.6V will start forward biasing the clamp diodes to RGND. 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. Medical ultrasound imaging NDT applications Fast resettable fuses High side switches Data acquisition 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 18Lead, 5x5mm DFN package as a four channel device for high density requirements. Typical Application Circuit One of 128 Channels +90V Transmitter Logic Control and Signal Processing Piezo Transducers -90V TX RX Receiver RX MD0101 TX RGND High Voltage Switches T/R Switch Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com MD0101 Pin Configuration Ordering Information Package Option NC 18-Lead DFN Device 5.00x5.00mm body 1.00mm height (max) 0.50mm pitch Tx1 2 MD0101K6-G Tx2 4 MD0101 NC NC -G indicates package is RoHS compliant (‘Green’) 18 NC 1 17 Rx1 16 RGND1 3 15 Rx2 14 RGND2 5 13 Rx3 Tx3 6 NC 12 RGND3 7 11 Rx4 Tx4 8 NC ESD Sensitive Device E 10 RGND4 9 Absolute Maximum Ratings1 18-Lead DFN (K6) Parameter (top view) (Pad is at bottom of device) Value VTX - VRX, Differential voltage drop 0 to ±110V Maximum junction temperature +125°C Storage temperature range Product Marking MD0101 LLLLLL -65°C to 150°C 1.6W Power dissipation, 18-Lead DFN2 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 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 18-Lead DFN (K6) Package may or may not include the following marks: Si or Electrical Characteristics (T = 25ºC, unless otherwise specified) J Sym BVTX-RX Parameter Min Typ Max Units Conditions Breakdown voltage from TX to RX ±100 - - V ITX-RX = ±500µA RSW Switch ON resistance from TX to RX - 15 - Ω ITX-RX = ±5.0mA VTRIP VTX - RX trip point to turn off - ±1.0 ±2.0 V --- VOFF Switch turn off voltage - ±2.0 - V ITX-RX = ±1.0mA Switch off current - ±200 ±300 µA VTX-RX = ±100V IPEAK Peak switching current - ±60 - mA --- TOFF Turn off time - - 20 ns --- TON Turn on time - - 20 ns --- CTX(ON) Switch ON capacitance from TX to RX - 15 - pF SW = ON CTX(OFF) Switch OFF capacitance from TX to RX - 9.0 - pF VTX-RX = 25V Small signal bandwidth - 100 - MHz RLOAD = 50Ω -40 - +125 °C --- IA-B(OFF) BW TJ Operating junction temperature VRX Diode forward voltage drop - ±1.6 - V IRX = ±200mA, RGND = 0V, TX = Open CD RX capacitance to RGND - 20 - pF RGND = 0V, TX = Open Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com 2 MD0101 Block Diagram TX RX RGND Switch Control Typical I-V Characteristics +IPEAK ITX - RX ITX - RX = +200µA -100V -VOFF +1.0mA -VTRIP +VTRIP +VOFF VTX - RX +1.0mA +100V ITX - RX = -200µA RSW = 15Ω -IPEAK 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 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 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. Supertex inc. 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 RON is typically 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. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com 3 MD0101 Switch Capacitance The typical switch ON capacitance, CSW(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 CTX(OFF) is about 11 - 6.5pF for 10 - 90V of the transmit voltage. Please see Figure 1 for the C-V curve of the CTX(OFF). Figure 1: CTX-RX vs VTX-RX Figure 3: TOFF Timing Diagram +10V VTX +2V 10% VRX 13.0 12.0 Figure 4: TOFF at VTX = 10V CTX-RX (pF) 11.0 10.0 9.0 8.0 7.0 6.0 0 10 20 30 40 50 60 VTX-RX 70 80 90 100 TON and TOFF Time The TON and TOFF of the MD0101 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. The TOFF and TON set ups are shown in Figure 2 and Figure 5 respectively. Figure 2: Test set up for TOFF 500ns Transmitter +10V Figure 5: Test set up for TON 500ns Transmitter 0V TX Figure 4 shows the actual waveform and measurement of the TOFF. The TOFF is measured from 2.0V of the VTX to 10% of the VRX. 0V TX RX 10Ω TX MD0101 RGND (Floating or connect to RX) +10V 2.0V 15Ω RX MD0101 TX RGND (Floating or connect to RX) Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com 4 MD0101 Figure 6: TON Timing Diagram VTX Figure 8: RX Clamp Diodes to RGND +10V I-V Curve 500 450 +2V 400 0V 2V If (mA) VRX 350 1V 1V 300 250 200 150 100 50 0 0.00 0V 0.25 0.50 0.75 1.00 1.25 Vf (V) 1.50 1.75 Figure 7: TON at VTX = 10V Figure 7 shows the actual waveform and measurement of the TON. The TON is measured from 2.0V of the VTX to 1.0V of the VRX. Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com 5 2.00 2.25 MD0101 Pin Description Pad Name Description 1 NC No internal connection 2 TX1 Transmitter side of transmit/receive switch 1 3 NC No internal connection 4 TX2 Transmitter side of transmit/receive switch 2 5 NC No internal connection 6 TX3 Transmitter side of transmit/receive switch 3 7 NC No internal connection 8 TX4 Transmitter side of transmit/receive switch 4 9 NC No internal connection 10 RGND4 11 RX4 12 RGND3 13 RX3 14 RGND2 15 RX2 16 RGND1 17 RX1 Receiver side for transmit/receive switch 1 18 NC No internal connection Center Tab --- Connect to ground Clamp diode ground for transmit/receive switch 4 Receiver side for transmit/receive switch 4 Clamp diode ground for transmit/receive switch 3 Receiver side for transmit/receive switch 3 Clamp diode ground for transmit/receive switch 2 Receiver side for transmit/receive switch 2 Clamp diode ground for transmit/receive switch 1 Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com 6 MD0101 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 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 † † e † † 0.50 BSC L L1 θ 0.00* 0O 0.40† - - 0.50 0.15 14O 0.30 † † 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-MD0101 B080211 7 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com