LTC1391 8-Channel Analog Multiplexer with Cascadable Serial Interface U DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The LTC ® 1391 is a high performance CMOS 8-to-1 analog multiplexer. It features a serial digital interface that allows several LTC1391s to be daisy-chained together, increasing the number of MUX channels available using a single digital port. Low RON: 45Ω Single 2.7V to ±5V Supply Operation Analog Inputs May Extend to Supply Rails Low Charge Injection Serial Digital Interface Low Leakage: ±5nA Max Guaranteed Break-Before-Make TTL/CMOS Compatible for All Digital Inputs Cascadable to Allow Additional Channels Can Be Used as a Demultiplexer The LTC1391 features a typical RON of 45Ω, a typical switch leakage of 50pA and guaranteed break-beforemake operation. Charge injection is ±10pC maximum. All digital inputs are TTL and CMOS compatible when operated from single or dual supplies. The inputs can withstand 100mA fault current. U APPLICATIONS ■ ■ ■ The LTC1391 is available in 16-pin PDIP, SSOP and narrow SO packages. For applications requiring 2-way serial data transmission, see the LTC1390 data sheet. Data Acquisition Systems Communication Systems Signal Multiplexing/Demultiplexing , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATION 3V, 8-Channel 12-Bit ADC On-Resistance vs Analog Input Voltage 3V 300 2 3 ANALOG INPUTS 4 5 6 7 8 16 V+ 15 D 14 – V 13 S0 S1 S2 S3 S4 DOUT LTC1391 DIN S5 CS S6 CLK S7 GND SERIAL INTERFACE TO MUX AND ADC 0.1µF OPTIONAL A/D INPUT FILTER 1 2 3 4 VREF VCC +IN CLK LTC1285 –IN DOUT GND CS/SHDN 1µF 8 TA = 25°C 250 7 ON-RESISTANCE (Ω) 1 6 5 12 11 10 9 V + = 2.7V V – = 0V 200 150 100 50 V + = 5V V – = –5V 0 –5 –4 –3 –2 –1 0 1 2 3 ANALOG INPUT VOLTAGE (V) DATA IN CLK CS DATA OUT 4 5 1391 TA02 1391 TA01 1 LTC1391 W U U U W W W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) TOP VIEW Total Supply Voltage (V + to V –) .............................. 15V Input Voltage Analog Inputs ................... (V – – 0.3V) to (V + + 0.3V) Digital Inputs ......................................... – 0.3V to 15V Digital Outputs ..........................– 0.3V to (V + + 0.3V) Power Dissipation.............................................. 500mW Operating Temperature Range LTC1391C ............................................... 0°C to 70°C LTC1391I........................................... – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C S0 1 16 V + S1 2 15 D S2 3 14 V – S3 4 13 DOUT S4 5 12 DIN S5 6 11 CS S6 7 10 CLK S7 8 9 ORDER PART NUMBER LTC1391CGN LTC1391CN LTC1391CS LTC1391IGN LTC1391IN LTC1391IS GND GN PACKAGE N PACKAGE 16-LEAD PLASTIC SSOP 16-LEAD PDIP S PACKAGE 16-LEAD PLASTIC SO GN PART MARKING 1391 1391I TJMAX = 125°C, θJA = 110°C/ W (GN) TJMAX = 125°C, θJA = 70°C/ W (N) TJMAX = 125°C, θJA = 100°C/ W (S) Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS V + = 5V, V – = – 5V, GND = 0V, TA = operating temperature range, unless otherwise specified. SYMBOL PARAMETER Switch VANALOG Analog Signal Range RON On-Resistance IS(OFF) ID(OFF) ID(ON) Digital VINH VINL IINL, IINH VOH VOL Dynamic fCLK tON tOFF tOPEN OIRR QINJ 2 ∆RON vs VS ∆RON vs Temperature Off Input Leakage Off Output Leakage On Channel Leakage High Level Input Voltage Low Level Input Voltage Input Current High Level Output Voltage Low Level Output Voltage Clock Frequency Enable Turn-On Time Enable Turn-Off Time Break-Before-Make Interval Off Isolation Charge Injection CONDITIONS (Note 2) VS = ±3.5V ID = 1mA VS = 4V, VD = – 4V, VS = – 4V, VD = 4V Channel Off VS = 4V, VD = – 4V, VS = – 4V, VD = 4V Channel Off VS = VD = ±4V Channel On V + = 5.25V V + = 4.75V VIN = 5V, 0V V + = 4.75V, IO = – 10µA IO = – 360µA V + = 4.75V, IO = 1.6mA MIN ● –5 TMIN 25°C TMAX 45 20 0.5 ±0.05 ● ±0.05 ● ±0.05 ● ● UNITS 5 75 75 120 V Ω Ω Ω % %/°C nA nA nA nA nA nA ±5 ±20 ±5 ±20 ±5 ±20 0.8 ±5 ● ● MAX 2.4 ● 2.4 ● (Note 2) VS = 2.5V, RL = 1k, CL = 35pF VS = 2.5V, RL = 1k, CL = 35pF 35 VS = 2VP–P, RL = 1k, f = 100kHz RS = 0, CL = 1000pF, VS = 1V (Note 2) TYP 4.74 4.50 0.5 260 100 155 70 ±2 0.8 5 400 200 ±10 V V µA V V V MHz ns ns ns dB pC LTC1391 ELECTRICAL CHARACTERISTICS V + = 5V, V – = – 5V, GND = 0V, TA = operating temperature range, unless otherwise specified. SYMBOL Dynamic CS(OFF) CD(0FF) Supply I+ I– PARAMETER CONDITIONS MIN Input Off Capacitance Output Off Capacitance Positive Supply Current Negative Supply Current TYP MAX 5 10 All Logic Inputs Tied Together, VIN = 0V or 5V All Logic Inputs Tied Together, VIN = 0V or 5V ● ● UNITS pF pF 15 – 15 40 – 40 µA µA TYP MAX UNITS 2.7 300 300 350 V Ω Ω Ω % %/°C nA nA nA nA nA nA V + = 2.7V, V – = GND = 0V, TA = operating temperature range, unless otherwise specified. SYMBOL PARAMETER Switch VANALOG Analog Signal Range RON On-Resistance IS(OFF) ID(OFF) ID(ON) Digital VINH VINL IINL, IINH VOH VOL Dynamic fCLK tON tOFF tOPEN QIRR QINJ CS(OFF) CD(OFF) Supply I+ ∆RON vs VS ∆RON vs Temperature Off Input Leakage Off Output Leakage On Channel Leakage High Level Input Voltage Low Level Input Voltage Input Current High Level Output Voltage Low Level Output Voltage CONDITIONS MIN (Note 2) VS = 1.2V IO = 1mA ● VS = 2.5V, VD = 0.5V; VS = 0.5V, VD = 2.5V (Note 3) Channel Off VS = 2.5V, VD = 0.5V; VS = 0.5V, VD = 2.5V (Note 3) Channel Off VS = VD = 0.5V, 2.5V (Note 3) Channel On V + = 3.0V V + = 2.4V VIN = 2.7V, 0V V + = 2.7V, IO = – 20µA IO = – 400µA V + = 2.7V, IO = 20µA IO = 400µA 250 20 0.5 ±0.05 ● ±0.05 ● ±0.05 ● ● 0.8 ±5 ● ● 2.0 ● (Note 2) VS = 1.5V, RL = 1k, CL = 35pF (Note 4) VS = 1.5V, RL = 1k, CL = 35pF (Note 4) (Note 4) VS = 2VP–P, RL = 1k, f = 100kHz RS = 0, CL = 1000pF, VS = 1V (Note 2) Positive Supply Current All Logic Inputs Tied Together, VIN = 0V or 2.7V 125 ● ±5 ±20 ±5 ±20 ±5 ±20 2.0 ● Clock Frequency Enable Turn-On Time Enable Turn-Off Time Break-Before-Make Interval Off Isolation Charge Injection Input Off Capacitance Output Off Capacitance The ● denotes specifications which apply over the full operating temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. 0 TMIN 25°C TMAX 2.68 2.30 0.01 0.20 490 190 290 70 ±1 5 10 0.2 0.8 5 800 400 ±5 2 V V µA V V V V MHz ns ns ns dB pC pF pF µA Note 2: Guaranteed by Design. Note 3: Leakage current with a single 2.7V supply is guaranteed by correlation with the ±5V leakage current specifications. Note 4: Timing specifications with a single 2.7V supply are guaranteed by correlation with the ±5V timing specifications. 3 LTC1391 U W TYPICAL PERFORMANCE CHARACTERISTICS Driver Output Low Voltage vs Output Current On-Resistance vs Temperature 0.65 1.2 1.0 OUTPUT VOLTAGE (V) 250 200 150 100 V + = 5V V – = –5V VS = 0V 50 TA = 25°C 1.1 V + = 2.7V V – = 0V VS = 1.2V 0.60 0.8 0.7 0.6 0.5 0.4 V + = 5V V– 0.3 –20 20 40 60 0 TEMPERATURE (°C) 0 80 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 OUTPUT CURRENT (mA) 1391 G01 0.30 V + = 2.7V V – = 0V IO = 400µA 0.25 0.10 –40 –20 40 60 0 20 TEMPERATURE (°C) 80 1391 G03 5.0 4.0 –1.0 –1.5 V + = 5V V – = –5V –2.0 V + = 5V V – = –5V IO = 1.6mA 4.5 V + = 2.7V V – = 0V OUTPUT VOLTAGE (V) OUTPUT CURRENT (mA) 0.35 Driver Output High Voltage vs Temperature 0 –2.5 –3.0 3.5 3.0 2.5 V + = 2.7V V – = 0V IO = 400µA 2.0 1.5 1.0 –3.5 –4.0 2.0 0.40 1391 G02 Driver Output High Voltage vs Output Current –0.5 0.45 0.15 0.1 0 –40 0.50 0.20 = –5V 0.2 V + = 5V V – = –5V IO = 1.8mA 0.55 V + = 2.7V V – = 0V 0.9 OUTPUT VOLTAGE (V) 300 ON-RESISTANCE (Ω) Driver Output Low Voltage vs Temperature 0.5 TA =25°C 2.5 3.0 3.5 4.0 OUTPUT VOLTAGE (V) 4.5 5.0 0 –40 –20 40 60 0 20 TEMPERATURE (°C) 80 1391 G05 1391 G04 U U U PIN FUNCTIONS S0, S1, S2, S3, S4, S5, S6, S7 (Pins 1, 2, 3, 4, 5, 6, 7, 8): Analog Multiplexer Inputs. DOUT into three-state and enables the selected channel for analog signal transmission. GND (Pin 9): Digital Ground. Connect to system ground. DIN (Pin 12): Digital Input (TTL/CMOS Compatible). Input for the channel selection bits. CLK (Pin 10): System Clock (TTL/CMOS Compatible). The clock synchronizes the channel selection bits and the serial data transfer from DIN to DOUT. CS (Pin 11): Channel Select Input (TTL/CMOS Compatible). A logic high on this input enables the LTC1391 to read in the channel selection bits and allows digital data transfer from DIN to DOUT. A logic low on this input puts 4 DOUT (Pin 13): Digital Output (TTL/CMOS Compatible). Output from the internal shift register. V – (Pin 14): Negative Supply. D (Pin 15): Analog Multiplexer Output. V + (Pin 16): Positive Supply. LTC1391 U U W U APPLICATIONS INFORMATION Multiplexer Operation Figure 1 shows the block diagram of the components within the LTC1391 required for MUX operation. The LTC1391 uses DIN to select the active channel and the chip select input, CS, to switch on the selected channel as shown in Figure 2. When CS is high, the input data on the DIN pin is latched into the 4-bit shift register on the rising clock edge. The input data consists of the “EN” bit and a string of three bits for channel selection. If “EN” bit is logic high as illustrated in the first input data sequence, it enables the selected channel. After the clocking in of the last channel selection bit B0, the CS pin must be pulled low before the next rising clock edge to ensure correct operation. Once CS is pulled low, the previously selected channel is switched off to ensure a break-before-make interval. After a delay of tON, the selected channel is switched on allowing signal transmission. The selected channel remains on until the next falling edge of CS. After a delay of tOFF, the LTC1391 terminates the analog signal transmission and allows the CLK CONTROL LOGIC DIN 4-BIT SHIFT REGISTER CS selection of next channel. If the “EN” bit is logic low, as illustrated in the second data sequence, it disables all channels and there will be no analog signal transmission. Table 1 shows the various bit combinations for channel selection. Table 1. Logic Table for Channel Selection ACTIVE CHANNEL EN B2 B1 BO All Off 0 X X X S0 1 0 0 0 S1 1 0 0 1 S2 1 0 1 0 S3 1 0 1 1 S4 1 1 0 0 S5 1 1 0 1 S6 1 1 1 0 S7 1 1 1 1 Digital Data Transfer Operation The block diagram of Figure 3 shows the components within the LTC1391 required for serial data transfer. When CS is held high, data is fed into the 4-bit shift register and then shifted to DOUT. Data appears at DOUT after the fourth rising edge of the clock as shown in Figure 4. The last four CLK ANALOG OUTPUT (D) MUX BLOCK ANALOG INPUTS (S0 TO S7) CONTROL LOGIC DIN 4-BIT SHIFT REGISTER CS DOUT 1391 F03 1391 • F01 Figure 1. Simplified Block Diagram of the MUX Operation Figure 3. Simplified Block Diagram of the Digital Data Transfer Operation CLK CS DIN EN HIGH B2 B1 EN LO B0 B2 B1 B0 ANY ANALOG INPUT D t ON t OFF 1391 • F02 Figure 2. Multiplexer Operation 5 LTC1391 U U W U APPLICATIONS INFORMATION bits clocked into the LTC1391 shift register before CS is taken low select the MUX channel that is turned on. This allows a series of devices, with the DOUT of one device connected to the DIN of the next device, to be programmed with a single data stream. CLK DIN 1 D1 2 D2 3 D3 4 D4 DOUT D5 D1 D2 D3 D4 D5 To ensure that only one channel is switched on at any one time, two sets of channel selection bits are needed for DATA as shown in Figure 6. The first data sequence is used to switch off one MUX and the second data sequence is used to select one channel from the other MUX or vice versa. In other words, if bit “ENA” is high and bit “ENB” is low, one channel of MUX A is switched on and all channels of MUX B are switched off. If bit “ENA” is low and bit “ENB” is high, all channels at MUX A are switched off and one channel of MUX B is switched on. Care should be taken to ensure that only one LTC1391 is enabled at any one time to prevent two channels from being enabled simultaneously. 1391 • F04 Figure 4. Digital Data Transfer Operation CLK 1 2 3 4 5 6 7 8 Multiplexer Expansion Several LTC1391s can be daisy-chained to expand the number of multiplexer inputs. No additional interface ports are required for the expansion. Figure 5 shows two LTC1391s connected at their analog outputs to form a 16-to-1 multiplexer at the input to an LTC1400 A/D converter. 2 3 ANALOG INPUTS 4 5 6 7 8 1 2 3 ANALOG INPUTS 4 5 6 7 8 V+ S1 D S2 V– S3 S4 S5 S6 S7 S1 D S2 V– S5 S6 S7 A2 A1 A0 ENB B2 B1 B0 1391 • F06 Figure 6. Data Sequence for MUX Expansion 5V + OPTIONAL A/D INPUT FILTER 1 2 15 14 DOUT LTC1391 12 DIN A 11 CS 10 CLK 9 GND V+ S4 16 13 S0 S3 ENA 0.1µF 0.1µF S0 DIN –5V 5V 1 CS + 10µF VCC VSS AIN CONV LTC1400 3 VREF CLK 0.1µF 4 GND DOUT 0.1µF 10µF 10µF –5V 0.1µF 8 7 + 6 5 DATA OUT 16 15 14 13 DOUT LTC1391 12 DIN B 11 CS 10 CLK 9 GND DATA IN CS CLK 1391 • F05 Figure 5. Daisy-Chaining Two LTC1391s for Expansion 6 LTC1391 U TYPICAL APPLICATIONS Daisy-Chaining Five LTC1391s 5V 0.1µF BYPASS CAPACITORS FROM V + TO GND FOR EACH LTC1391 1 2 3 ANALOG INPUTS 4 5 6 7 8 1 2 3 ANALOG INPUTS 4 5 6 7 8 1 2 3 ANALOG INPUTS 4 5 6 7 8 1 2 3 ANALOG INPUTS 4 5 6 7 8 1 2 3 ANALOG INPUTS 4 5 6 7 8 16 1 15 2 – 14 3 S0 V+ S1 D S2 S3 S4 S5 S6 S7 V LTC1391 13 DOUT A 12 DIN 11 CS 10 CLK 9 GND S0 V+ S1 D S2 S3 S4 S5 S6 S7 S1 D S4 S5 S6 S7 S1 D S4 S5 S6 S7 V+ S1 D S3 S4 S5 S6 S7 DATA OUT 16 15 16 15 16 15 14 V– LTC1391 13 DOUT D 12 DIN 11 CS 10 CLK 9 GND S0 S2 +IN V LTC1391 13 DOUT C 12 DIN 11 CS 10 CLK 9 GND V+ S3 7 CLK LTC1286 6 –IN DOUT 4 5 CS GND 0.1µF – 14 S0 S2 8 LTC1391 13 DOUT B 12 DIN 11 CS 10 CLK 9 GND V+ S3 VCC 14 V– S0 S2 VREF 16 15 14 V– LTC1391 13 DOUT E 12 DIN 11 CS 10 CLK 9 GND DATA IN CS CLK 1391 TA04 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 7 LTC1391 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. GN Package 16-Lead Plastic SSOP (Narrow 0.150) (LTC DWG # 05-08-1641) 0.189 – 0.196* (4.801 – 4.978) 0.015 ± 0.004 × 45° (0.38 ± 0.10) 0.007 – 0.0098 (0.178 – 0.249) 0.053 – 0.068 (1.351 – 1.727) 0.009 (0.229) REF 16 15 14 13 12 11 10 9 0.004 – 0.0098 (0.102 – 0.249) 0° – 8° TYP 0.016 – 0.050 (0.406 – 1.270) 0.008 – 0.012 (0.203 – 0.305) 0.229 – 0.244 (5.817 – 6.198) 0.0250 (0.635) BSC 0.150 – 0.157** (3.810 – 3.988) * DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE GN16 (SSOP) 1098 1 2 3 5 6 4 7 8 N Package 16-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.130 ± 0.005 (3.302 ± 0.127) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( 0.015 (0.381) MIN +0.025 0.325 –0.015 +0.635 8.255 –0.381 ) 0.770* (19.558) MAX 0.045 – 0.065 (1.143 – 1.651) 0.065 (1.651) TYP 0.125 (3.175) MIN 0.005 (0.127) MIN 0.100 ± 0.010 (2.540 ± 0.254) 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 0.255 ± 0.015* (6.477 ± 0.381) 0.018 ± 0.003 (0.457 ± 0.076) N16 0695 *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) S Package 16-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.386 – 0.394* (9.804 – 10.008) 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0.016 – 0.050 0.406 – 1.270 0.014 – 0.019 (0.355 – 0.483) 15 14 13 12 11 10 9 0.004 – 0.010 (0.101 – 0.254) 0° – 8° TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 8 16 0.053 – 0.069 (1.346 – 1.752) 0.050 (1.270) TYP 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 2 3 4 5 6 7 8 S16 0695 LTC1391 U TYPICAL APPLICATION Interfacing LTC1391 with LTC1257 for Demultiplex Operation 1 2 3 ANALOG OUTPUTS 4 5 6 7 8 V+ S0 S1 D S3 DOUT LTC1391 DIN S5 CS S6 CLK S7 TTL COMPATIBLE AT V + = 5V GND 5V ≤ V + ≤ 12V 15 14 V– S2 S4 16 0.1µF 47k 13 12 OPTIONAL D/A OUTPUT FILTER 11 10 1 9 2 DATA CLK CS CLK VCC 8 7 VOUT LTC1257 6 3 LOAD VREF 5 4 DOUT GND DIN 0.1µF 1391 TA03 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1285 LTC1286 LTC1390 LTC1451 3V 12-Bit ADC 5V 12-Bit ADC Serial-Controlled 8-to-1 Analog Multiplexer 5V 12-Bit DAC Micropower, Auto Shutdown, SO-8 Package, SPI, QSPI + MICROWIRETM Compatible Micropower, Auto Shutdown, SO-8 Package, SPI, QSPI + MICROWIRE Compatible Low RON, Bidirectional Serial Interface, Low Power, 16-Pin SO Complete VOUT DAC, SO-8 Package, Daisy-Chainable, Low Power LTC1452 LTC1453 5V and 3V 12-Bit DAC 3V 12-Bit DAC Multiplying VOUT DAC, SO-8 Package, Rail-to-Rail Output, Low Power Complete VOUT DAC, SO-8 Package, Daisy-Chainable, Low Power MICROWIRE is a trademark of National Semiconductor. 9 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977 1391f, sn1391 LT/GP 0896 7K • PRINTED IN USA 9 LINEAR TECHNOLOGY CORPORATION 1995