Multi-channel programmable transipedance amplifier with multiplexer for read out SSOP20

Transcription

1 DATASHEET MTI08DQ Multi-channel programmable transipedance amplifier with multiplexer for read out SSOP20 Order No.: AEZ00 Status: certified INTRODUCTION The MTI-devices are an integrated circuits family of programmable transimpedance amplifiers with 8 channels per IC (more custom specifics on request). The MTI-devices are mainly used for signal conditioning of sensors with current outputs. They are especially suitable for connecting of photodiodes of array and row sensors. The possibility to adjust the transimpedance gain in 8 stages is a special feature. The adjustment is made by programming each channel separately via SPI. Using two digital input signals to control a multiplexer circuit the signals of the amplifier s outputs can be read out to one output MOUT with or without sample and hold in between. The device packages (naked chip on request) are RoHS conform and optimized for SMD manufacturing. In case of using bare chips (die and chip-on-board) please contact our sales team for availability of bare chips. 1 BLOCK DIAGRAM Figure 1: Block diagram MTI08DQ SCLK SDI CSXN SAMPLE RDCLK PDXN SW_CH1 SPI SW_R0 SW_R1 SW_R2 SW_C CONTROL UNIT Power-On-Reset VDDD VSSD VSSA VDDA MAZeT GmbH db08240e RD RD C R IIN<1> VOUT<1> OPAMP 1 C R IIN<X> VOUT<X> OPAMP X MTI08D Production data information is current as of publication date. Products conform to specifications per the terms of MAZeT GmbH. The information in this document is subject of change without notice, please confirm that this is the latest version. Please check with a MAZeT sales representative for availability and further information. Full legal notices can be found on the final page. MULTIPLEXER with or without SAMPLE & HOLD VSSA MOUT Pb

2 INTRODUCTION BLOCK DIAGRAM DESCRIPTION OF INTERFACE Pin Assignment Adjustment of Transimpedance via SPI Switchable Frequency Range via SPI Switchable Reference Voltage for Channel Power Down Mode DESCRIPTION OF FUNCTION Introduction Multiplexer Output Temperature Compensation... 5 General considerations... 5 Special case Photo diode s cathode is connected to VDDA Digital Interface ELECTRICAL CHARACTERISTICS Maximum Conditions Operating Conditions AC/DC-Characteristics PACKAGES Shape and Dimensions Pin Configuration Soldering Information ORDERING INFORMATION LEGAL NOTES AND WARNINGS mazet.de db08240e certified_ Page 2 of 17

3 2 DESCRIPTION OF INTERFACE 2.1 Pin Assignment SIGNAL NAME TYPE A/D 1 FUNCTION VDDA input a Power supply analog VSSA input a Power supply analog VDDD input d Power supply digital VSSD input d Power supply digital input a Reference voltage SCLK input d SPI clock input (pull up) SDI input d SPI data input (pull up) CSXN input d SPI chip select (pull up, low active) SAMPLE input d Multiplexers control unit sample clock input or reset input (pull up) READCLK input d Multiplexer s control unit read out clock input (pull up) PDXN input d Power-down mode (pull up, low active) IIN<X> input a Analog current input of amplifier X MOUT output a Analog voltage output of sample & hold multiplexer 2.2 Adjustment of Transimpedance via SPI SETTINGS OF DIGITAL REGISTERS FOR TRANSIMPEDANCE SW_R2 SW_R1 SWR_0 TRANSIMPEDANCE R M 2 stage M stage M stage M stage M stage M stage M stage M stage Switchable Frequency Range via SPI SETTINGS OF DIGITAL REGISTER FOR FREQUENCY RANGE SW_C MAXIMUM CAPACITANCE OF PHOTO-SENSOR 0 50 pf pf 1 Analog or digital 2 Default after power-on-reset and Power Down Mode mazet.de db08240e certified_ Page 3 of 17

4 2.4 Switchable Reference Voltage for Channel 1 SETTINGS OF DIGITAL REGISTER SWITCH SW_CH1 REFERENCE VOLTAGE CHANNEL 1 0 identical to input 3 1 V()/2 for VSSA=0 V 2.5 Power Down Mode SETTINGS OF DIGITAL INPUT PD BIAS CURRENT OF THE IC VSSD < 8 µa VDDD typical 4 3 DESCRIPTION OF FUNCTION 3.1 Introduction The MTI-devices are programmable transimpedance amplifiers with different numbers of channels (In this case: MTI08 8 channels). There is one transimpedance amplifier per channel between a current input IIN<X> and an internal voltage output VOUT<X>. The output signal can be selected via multiplexer with or without sample and hold circuit for reading out the internal voltage at VOUT<X>. The multiplexers output is at pin MOUT. The transimpedance of the channels is selectable in 8 stages. This adjustment can be effected by programming of digital registers SWCHANX (bits SW_R) via SPI for every channel separately. Additionally, programmable for every channel, is a compensation of the input capacity of photo-sensors for two possible frequency ranges (register SWCHANX, bit SW_C). All channels are compensated for an external input capacity of the photo-sensor of smaller than 50 pf (bit SW_C = '0'). The second input of all transimpedance amplifiers is used for a common supply by a reference voltage necessarily fed in through the pin. Alternatively the reference voltage of channel 1 is switchable to an internal reference, which is 0.5 relating to VSSA. This is useful for temperature compensation of channels 2 to 8 by using channel 1 as a reference channel (q. v. chapter 3.3). The power supply for the MTI-devices is typical 3.3 V to 5 V. The digital and the analog supply are separated to minimize the crosstalk of both parts. The Power Down Mode is adjusted by PDXN = VSSD and switches off the functionality. In that case the output MOUT becomes tri-state. The digital registers are reset to restart accurately defined after Power Down Mode is canceled (PDXN=VDDD). 3 Default after power-on-reset and Power Down Mode 4 Default by pull up mazet.de db08240e certified_ Page 4 of 17

5 3.2 Multiplexer Output There is a multiplexer implemented for reading out the internal voltage output VOUT<X> of each transimpedance amplifier. The type of the multiplexer is selectable between a connection of the amplifier's output with MOUT via analog switch or a sample and hold stage in between (register MUXTYPE). The multiplexer's control unit needs the input signals at pin SAMPLE and RDCLK for the time management of the read out procedure. In case of a sample and hold stage every amplifier's output voltage is stored separately on a capacitance during the sample part. After sampling the results can be read out at pin MOUT. Every falling edge of the read out clock at pin RDCLK starts a new time section to read out the stored voltage values of the hold part for each channel. The first channel to start with can be adjusted by the digital register RDOUTSTRT (programmed via SPI). The following channels are read out counting upwards but channel 1 follows after channel 8. In case of less than 8 channels should be read out the number of falling clock edges at RDCLK is reduced between two samplings. The timing diagram below shows a fictive example for the output voltage at pin MOUT concerning the digital signals of SAMPLE and RDCLK. During the sampling the output MOUT is equal to the reference voltage at pin. In case of direct connection of the amplifier's output with MOUT via analog switch the aforesaid sampling corresponds to a reset time during the pin MOUT is tri-state. Starting with the read out clock at pin RDCLK the amplifiers outputs are connected to the pin MOUT one after another. The read out sequence is equal to the explained one above for the sample and hold version. Figure 2: Multiplexer Output MOUT SAMPLE RDCLK trds trdclk trdh tsmplpw MOUT VOUT<1> VOUT<2> VOUT<X> VOUT<3> t=t0 t 3.3 Temperature Compensation General considerations One property of the implemented transimpedance resistor is its temperature coefficient (TC R) with a typical value of -3300ppm/K. There is one way to reduce the TC R by using one channel of the E-MTI08D as reference channel (preferably channel 1). The input of this channel is connected to an external resistor which needs an input voltage unlike to. mazet.de db08240e certified_ Page 5 of 17

6 Figure 3: separated TIA channel (VIN VTC) for temperature compensation VDDA ID IIN = ID RTIA IIN VTIA ID VSSA IIN = ID TIA CHANNEL FOR MEASURING RTC VIN REXT VTC TIA CHANNEL FOR TEMPERATURE COMPENSATION The output voltage of the measuring channel is as follows defined: VTIA IIN RTIA Therefore the input current IIN is the one the external sensor produces. The output voltage of the reference channel results as follows: VTC VIN REXT RTC T The voltages VTIA(T) and VTC(T) have to be detected for a temperature compensation using a µcontroller: VTIA VTC VTIA VTC For instance the voltage VTC(T0) is constant data which is detected during the system's initialization and the dominant temperature T0 at that time. Further measurements are normalized to that constant data. VTIAcorrected 0 VTC T VTIA VTC T But the resulting temperature coefficient for the measuring channel still depends on the involved variables: VIN TC TC( REXT ) C( VIN ) C( ) VIN VIN Thereby the TC(REXT) is the temperature coefficient of the external resistor, TC(VIN) is the temperature coefficient of the voltage VIN and TC() is the temperature coefficient of the voltage. mazet.de db08240e certified_ Page 6 of 17

7 The following in equation has to be fulfilled concerning the selection of REXT, RTC, VIN and : REXT RTC VIN 1 The compliance of the in equation guarantees that the reference channel is inactive during saturation. At any time the absolute value for the transimpedance resistor RTC can be calculated for temperature predominating. RTC T REXT VIN VTC T Special case Photo diode s cathode is connected to VDDA A consequence of chapter is that the count of additional external devices depends on what type of photo diode is used. In case of the photo diode s cathode is connected to VDDA the possibility exists to use channel 1 as a reference channel with the internal reference voltage of 0.5 (register MUXTYPE_CH1, bit SW_CH1 = 1 ). Figure 4: separated TIA channel ( VTC) for temperature compensation VDDA ID IIN = ID RTIA IIN<X> IIN VTIA RD RD RTC TIA CHANNEL FOR MEASURING REXT IIN<1> VTC 0.5 TIA CHANNEL 1 FOR TEMPERATURE COMPENSATION The equations change in the following way (IIN = ID): VTC VTIA IIN RTIA REXT RTC T mazet.de db08240e certified_ Page 7 of 17

8 The voltages VTIA(T) and VTC(T) have to be detected for a temperature compensation using a µcontroller ( VTC(T) corresponds to 0.5!): VTIA VTIA 0. VTC VTC 5 Scaling and correction respectively happen in the same way. VTIAcorrected The resulting temperature coefficient is: 0 VTC T VTIA VTC T TC TC( REXT ) C( ) Thereby the TC(REXT) is the temperature coefficient of the external resistor and TC() is the temperature coefficient of the voltage. There is only one additional device (REXT) necessary to implement for that system. 3.4 Digital Interface The digital interface consists of a SPI to program the digital registers. The SPI is implemented as an 8 bit shift register. The 8 bits are divided into 2 half-bytes - one for the address (ADR) and the other one for the data (DB). The mapping of the data register concerning the addresses is shown in the tables below. The order of the transmitted data is defined as followed: first serial bit = MSB of the data half-byte last serial bit = LSB of the address half-byte Start and finish of the transmission is controlled by input signal of the pin CSXN (low active). The timing diagram of the SPI interface is shown in the figure below. Figure 5: timing diagram of SPI interface SCLK SDI BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0 BIT7 BIT6 CSXN tsdis tcsxns tsdih tcsxnh tcsxnpw mazet.de db08240e certified_ Page 8 of 17

9 Table 1: SWCHANX register SWCHANX register, address half byte = 0000/b to 0111/b for channel 0 to channel 8 SPI HALF BYTE BIT NAME RESET VALUE DESCRIPTION / FUNCTION 1 3 SW_C 0/b 0 channel compensated for less than 50pF input capacitance 1 channel compensated for less than 5pF input capacitance 1 2:0 SW_R 000/b programming of transimpedance bit combination: bit2 bit1 bit transimpedance 0,2 MΩ transimpedance 0,4 MΩ transimpedance 0,8 MΩ transimpedance 1,6 MΩ transimpedance 3,2 MΩ transimpedance 6,4 MΩ transimpedance 12,8 MΩ transimpedance 25,6 MΩ Table 2: RDOUTSTRT register RDOUTSTRT register, address half byte = 1000/b SPI HALF BYTE BIT NAME RESET VALUE DESCRIPTION / FUNCTION 1 3-0/b do not use 1 2:0 RDOST 000/b start value of multiplexer and read out order bit combination: bit2 bit1 bit channel 1 to channel 2 to 8 and channel 3 to 8 and 1 to channel 4 to 8 and 1 to channel 5 to 8 and 1 to channel 6 to 8 and 1 to channel 7 to 8 and 1 to channel 8 and 1 to 7 mazet.de db08240e certified_ Page 9 of 17

10 Table 3: MUXTYPE_CH1 register MUXTYPE_CH1 register, address half byte = 1001/b SPI HALF BYTE BIT NAME RESET VALUE DESCRIPTION / FUNCTION 1 3:2-00/b do not use 1 1 SW_CH1 0/b switchable reference voltage for channel 1: 0 identical to input 1 V()/2 for VSSA=0V 1 0 MUXTYPE 0/b selection of multiplexer type: 0 multiplexer output with sample & hold 1 multiplexer output without sample & hold 4 ELECTRICAL CHARACTERISTICS 4.1 Maximum Conditions Violations of absolute maximum conditions are not allowed under any circumstances; otherwise the IC can be destroyed. All voltages are referenced to VSSA = VSSD = 0 V. Table 4: Maximum Conditions PARAMETER NAME MIN MAX UNIT Sower supply (analog) VDDA V Input and output voltages (analog) IC-pinning 0.3 VDDA+0.3 V Power supply (digital) VDDD V Input and output voltages (digital) IC-pinning 0.3 VDDD+0.3 V Power dissipation POP 0.11 W Operating temperature TOP 125 C Storage temperature TSTG C mazet.de db08240e certified_ Page 10 of 17

11 4.2 Operating Conditions All voltages are referenced to VSSA = VDDA = 0 V. Table 5: Operating Conditions PARAMETER NAME MIN TYP MAX UNIT CONDITION Supply voltage analog VDDA to V VDDAVDDD Supply voltage digital VDDD 3.0 e 3.3 to V < 0.3V Bias current E-MTI08D Bias current E-MTI08D I(VDDA, VDDD) I(VDDA, VDDD) ma 27 C, VDDA= VDDD=5.5 V 8 µa PD=VSSD Operating temperature TOP C Input high level VVT+TTL 2.4 V TTL schmitt-trigger input Input low level VVT-TTL 0.8 V Input hysterese VHYST- TTL 0.2 V VIH VIL VIL VIH VDDD=5.0 V Input current of pull up IILPU µa VIN = VSSD Setup time SDI tsdis 10 ns Setup time CSXN tcsxns 20 ns Hold time SDI tsdih 10 ns Hold time CSXN tcsxnh 40 ns Pulse width CSXN tcsxnpw 40 ns SPI clock frequency fsclk 25 MHz Setup time RDCLK trds 0.02 µs Period of RDCLK trdclk 1 µs Hold time RDCLK trdh 1 µs Pulse width SAMPLE trdclk 1 µs Reference voltage 0.4 VDD0.4 V 5 minimum supply voltage of 2.7V is possible if register MUXTYPE = 1 mazet.de db08240e certified_ Page 11 of 17

12 4.3 AC/DC-Characteristics Unless otherwise specified the data of this table is valid for T OP = 27 C and VDDA = VDDD = 5 V. All voltages are referenced to VSSA = VSSD = 0 V. PARAMETER NAME MIN TYP MAX UNIT CONDITION 2.56 µa stage µa stage 2 Input current Feedback resistor Signal frequency at input SW_C = 0 (CPHOTO-SENSOR < 50 pf) Signal frequency at input SW_C = 1 (CPHOTO-SESNOR < 5pF) I(IIN<X>) R f3db f3db 0.64 µa stage µa stage µa stage µa stage µa stage µa stage MΩ stage MΩ stage MΩ stage MΩ stage MΩ stage MΩ stage MΩ stage MΩ stage khz stage 1, TOP (0) khz stage 2, TOP (0) khz stage 3, TOP (0) khz stage 4, TOP (0) khz stage 5, TOP (0) khz stage 6, TOP (0) khz stage 7, TOP (0) khz stage 8, TOP (0) khz stage 1, TOP (0) khz stage 2, TOP (0) khz stage 3, TOP (0) khz stage 4, TOP (0) khz stage 5, TOP (0) khz stage 6, TOP (0) khz stage 7, TOP (0) mazet.de db08240e certified_ Page 12 of 17

13 PARAMETER NAME MIN TYP MAX UNIT CONDITION khz stage 8, TOP (0) Temperature coefficient of the feedback resistor Offset voltage of transimpedance amplifier Offset voltage of sample & hold multiplexer Switch resistor for MUX without sample and hold TCR 3300 ppm/k VTIAOFF mv TOP (0) VMUXOFF mv TOP (0) RSWMUX 10 kω TOP (0), VDDA= VDDD=2.7 V Capacitive load at MOUT CLOAD 50 pf ILOAD < 0.5mA per output Input capacitance of external connected photosensors Input capacitance of external connected photosensors CPHOTO- SENSOR CPHOTO- SENSOR 50 pf bit SW_C = 0 per channel 5 pf bit SW_C = 1 per channel Tolerance of the feedback resistors between all channels TOLR % DC input current; for all stages 6 VTIAOFF = VOUT<X> ; results from input offset voltage and input leakage current 7 VMUXOFF = MOUT ; results from charge injection of sample & hold switches 8 Up to max. 1% available on request mazet.de db08240e certified_ Page 13 of 17

14 5 PACKAGES 5.1 Shape and Dimensions Figure 6: Shape and dimensions of the package (dimensions mm) A 1 A tapered edge 1) w e b L D E H 1) As shown in the figure PIN 1 is located on the bottom of the left corner of the outline. PIN 1 TYP PACKAGE D E H A A1 e b L w E-MTI08DQ SSOP20 Jedec MO Pin Configuration Figure 7: Pin configuration 1 20 VDDA IIN<1> 2 19 MOUT IIN<2> IIN<3> 3 4 MTI08D TOPVIEW (not to scale) PDXN VDDD IIN<4> 5 16 SAMPLE IIN<5> 6 15 RDCLK IIN<6> IIN<7> 7 8 SSOP20 Jedec MO CSXN SDI IIN<8> 9 12 SCLK VSSA VSSD mazet.de db08240e certified_ Page 14 of 17

15 5.3 Soldering Information The solder reflow profile should fulfil the specifications for the reflow profile parameters given in Table 6. These parameters follow the IPC/JEDEC standard J-STD-020D.1. The temperature should be measure at the top of the package. Figure 8: Recommended reflow profile Table 6: Reflow profile parameters PROFILE PARAMETER ASSEMBLY, CONVECTION Ramp-up rate (Tsmax to Tp) 2-3 C/second Preheat temperature (Tsmin to Tsmax) 150 C to 200 C Preheat time (ts) Time above T L, 217 C (t L) seconds seconds Peak temperature (Tp) 260 C Time within 5 C of peak temperature (tp) Ramp-down rate Time 25 C to peak temperature seconds 6 C/second 8 minutes max. mazet.de db08240e certified_ Page 15 of 17

16 ORDERING INFORMATION NAME Status PACKAGE Article MTI08DQ Series SSOP AEZ00

17 LEGAL NOTES AND WARNINGS Failure to comply with these instructions could result in death or serious injury. Misuse of documentation The information contained in this document is the property of MAZeT. Photocopying or otherwise reproducing any part of the catalog, whether electronically or mechanically is prohibited, except where the express permission of MAZeT GmbH has been obtained. In general, all company and brand names, as well as the names of individual products, are protected by brand, patent or product law. Personal Injury All products are conform to the specifications in accordance with the terms and conditions of MAZeT s standard warranty. Production processing does not necessarily include testing of all parameters. MAZeT solutions are not designed or intended for use in critical applications, in which the failures or malfunctions of the product may result in personal injury or death. Use of MAZeT products in life support systems is expressly unauthorized and any such use by customer is completely at their own risk. State of document - The information provided in this document is for reference only. Do not use this document as product installation guide since products can be under development to improve performance or any other purpose. Before you start any development or place an order please contact your supplier or MAZeT for the latest version of this document. MAZeT explicitly reserves the right to make technical changes to information described in the document. RoHS Directive 2011/65/EU /REACH INFORMATION - RoHS compliance and PB free: The products of MAZeT fully comply with the current RoHS-directives. Our semiconductor products do not contain any of the six substance chemical categories, for example including the restriction on lead usage (lead weight may not exceed 0.1% in homogeneous materials). RoHS compliant products are suitable for the usage in lead-free specified processes, when designed to be soldered at high temperatures. REACH information: MAZeT products do not contain any of the latest REACH Substances of Very High Concern (SVHC) regarding the Europe Union (EU) Regulation 1907/2006. The latest 155 substances restricted per the REACH Regulation were last updated on June 16, Please refer to the following for the most current candidate list of substances: Information and Disclaimer The information provided in this document is based on the knowledge of the MAZeT GmbH as of the date of publication. The MAZeT GmbH cannot give warranty regarding the accuracy of information provided by third parties. MAZeT may not have conducted testing or chemical analysis on all incoming material or chemicals. MAZeT GmbH performs and continues to perform reasonable measures to provide the most accurate data at the given time. Additional efforts to integrate information provided by third parties are performed and continue to be performed. Certain supplier information may be proprietary or limited and not available at release. WARRANTY DISCLAIMER - THE WARRANTY EXPRESSED HEREIN SHALL BE IN LIEU OF ANY OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES OR CONDITIONS OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, WHICH ARE EXPRESSLY DISCLAIMED, AND IS IN LIEU OF ANY AND ALL OTHER OBLIGATIONS OR LIABILITY ON SUPPLIER'S PART. FOR THE AVOIDANCE OF DOUBT, SUPPLIER SHALL NOT BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL LOSS OR DAMAGE, INCLUDING LOSS OF REVENUE OR PROFIT, OF ANY KIND OR NATURE, ARISING AT ANY TIME, FROM ANY CAUSE WHATSOEVER RESULTING FROM THE USE OR OPERATION OF THE PRODUCTS OR ANY BREACH OF THIS LIMITED WARRANTY. Legal liability - MAZeT assumes no responsibility for the use of any foreign products or circuits described in this document or customer product design, conveys no license, either expressed or implied, under any patent or other right, and makes no representation that the foreign circuits are free of patent infringement. MAZeT further makes no claim as to the suitability of its products for any particular purpose, nor does MAZeT assume any liability arising out of the use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. ESD Warning Sensor handling precautions should be observed to avoid static discharge. mazet.de db08240e certified_ Page 17 of 17