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19-0448; Rev 0; 11/95
Serially Controlled, Low-Voltage, 8-Channel SPST Switch
_______________General Description
The MAX395 8-channel, serially controlled, single-pole/single-throw (SPST) analog switch offers eight separately controlled switches. The switches conduct equally well in either direction. On-resistance (100 max) is matched between switches to 5 max and is flat (10 max) over the specified signal range. These CMOS devices can operate continuously with dual power supplies ranging from 2.7V to 8V or a single supply between +2.7V and +16V. Each switch can handle rail-to-rail analog signals. The off leakage current is only 0.1nA at +25C or 5nA at +85C. Upon power-up, all switches are off, and the internal shift registers are reset to zero. The MAX395 is electrically equivalent to two MAX391 quad switches controlled by a serial interface, and is pin compatible with the MAX335. The serial interface is compatible with SPITM/QSPITM and MicrowireTM. Functioning as a shift register, it allows data (at DIN) to be clocked in synchronously with the rising edge of clock (SCLK). The shift register's output (DOUT) enables several MAX395s to be daisy chained. All digital inputs have 0.8V to 2.4V logic thresholds, ensuring both TTL- and CMOS-logic compatibility when using 5V supplies or a single +5V supply.
____________________________Features
o SPITM/QSPITM, MicrowireTM-Compatible Serial Interface o 8 Separately Controlled SPST Switches o 100 Signal Paths with 5V Supplies o Rail-to-Rail Signal Handling o Asynchronous RESET Input o Pin Compatible with Industry-Standard MAX335 o 2.7V to 8V Dual Supplies +2.7V to +16V Single Supply o >2kV ESD Protection per Method 3015.7 o TTL/CMOS-Compatible Inputs (with +5V or 5V Supplies)
MAX395
______________Ordering Information
PART MAX395CNG MAX395CWG MAX395C/D MAX395ENG TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C PIN-PACKAGE 24 Narrow Plastic DIP 24 Wide SO Dice* 24 Narrow Plastic DIP
________________________Applications
Serial Data-Acquisition Systems Avionics Audio Signal Routing Industrial and ProcessControl Systems ATE Equipment Networking
MAX395EWG -40C to +85C 24 Wide SO MAX395MRG -55C to +125C 24 Narrow CERDIP** * Contact factory for dice specifications. ** Contact factory for availability.
__________________Pin Configuration
TOP VIEW
SCLK V+ DIN GND NO0 COM0 NO1 COM1 NO2 1 2 3 4 5 6 7 8 9 LOGIC
________________Functional Diagram
NO0 NO7
MAX395
24 CS 23 RESET 22 DOUT 21 V20 NO7 19 COM7 18 NO6 17 COM6 16 NO5 15 COM5 14 NO4 13 COM4
COM0
COM7
PARALLEL REGISTER AND TRANSLATOR
DIN
8-BIT SHIFT REGISTER
DOUT
RESET
COM2 10 NO3 11 COM3 12
MAX395
SCLK CLOCK TRANSLATOR LATCH CS CS TRANSLATOR
DIP/SO
SPI and QSPI are trademarks of Motorola, Inc. Microwire is a trademark of National Semiconductor Corp.
________________________________________________________________ Maxim Integrated Products 1
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Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
ABSOLUTE MAXIMUM RATINGS
Voltages Referenced to GND V+ ...........................................................................-0.3V, +17V V- ............................................................................-17V, +0.3V V+ to V-...................................................................-0.3V, +17V SCLK, CS, DIN, DOUT, RESET .................-0.3V to (V+ + 0.3V) NO, COM .................................................(V- - 2V) to (V+ + 2V) Continuous Current into Any Terminal..............................30mA Peak Current, NO_ or COM_ (pulsed at 1ms,10% duty cycle)..................................100mA Continuous Power Dissipation (TA = +70C) Narrow Plastic DIP (derate 13.33mW/C above +70C)...1067mW Wide SO (derate 11.76mW/C above +70C)...............941mW Narrow CERDIP (derate 12.50mW/C above +70C)....1000mW Operating Temperature Ranges MAX395C_ G .......................................................0C to +70C MAX395E_ G ....................................................-40C to +85C MAX395MRG ..................................................-55C to +125C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10sec) .............................+300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS--Dual Supplies
(V+ = +4.5V to +5.5V, V- = -4.5V to -5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER ANALOG SWITCH Analog Signal Range COM, NO On-Resistance COM, NO On-Resistance Match Between Channels (Note 2) COM, NO On-Resistance Flatness (Note 2) NO Off Leakage Current (Note 3) VCOM, VNO RON RON RFLAT(ON) V+ = 5V, V- = -5V, VCOM = 3V, INO = 1mA V+ = 5V, V- = -5V, VCOM = 3V, INO = 1mA V+ = 5V, V- = -5V, INO = 1mA, VCOM = -3V, 0V, 3V V+ = 5.5V, V- = -5.5V, VCOM = -4.5V, VNO = 4.5V V+ = 5.5V, V- = -5.5V, VCOM = 4.5V, VNO = -4.5V V+ = 5.5V, V- = -5.5V, VCOM = -4.5V, VNO = 4.5V V+ = 5.5V, V- = -5.5V, VCOM = 4.5V, VNO = -4.5V V+ = 5.5V, V- = -5.5V, VCOM = VNO = 4.5V C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M -0.1 -10 -0.1 -10 -0.1 -10 0.1 -10 -0.2 -20 0.01 0.002 0.002 0.002 0.002 V60 V+ 100 125 5 10 10 15 0.1 10 0.1 10 0.1 10 0.1 10 0.2 20 nA nA nA V SYMBOL CONDITIONS MIN TYP (Note 1) MAX UNITS
INO(OFF)
COM Off Leakage Current (Note 3) COM On Leakage Current (Note 3) DIGITAL I/O DIN, SCLK, CS, RESET Input Voltage Logic Threshold High DIN, SCLK, CS, RESET Input Voltage Logic Threshold Low DIN, SCLK, CS, RESET Input Current Logic High or Low DOUT Output Voltage Logic High DOUT Output Voltage Logic Low SCLK Input Hysteresis
ICOM(OFF)
ICOM(ON)
VIH VIL IIH, IIL VDOUT VDOUT SCLKHYST VDIN, VSCLK, V CS = 0.8V or 2.4V IDOUT = 0.8mA IDOUT = -1.6mA
C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M
2.4 0.8 -1 2.8 0 100 0.03 1 V+ 0.4
V V A V V mV
2
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Serially Controlled, Low-Voltage, 8-Channel SPST Switch
ELECTRICAL CHARACTERISTICS--Dual Supplies (continued)
(V+ = +4.5V to +5.5V, V- = -4.5V to -5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP (Note 1) 200 90 5 15 2 2 2 8 -90 <-90 MAX UNITS
MAX395
SWITCH DYNAMIC CHARACTERISTICS Turn-On Time Turn-Off Time Break-Before-Make Delay Charge Injection (Note 4) NO Off Capacitance COM Off Capacitance Switch On Capacitance Off Isolation Channel-to-Channel Crosstalk POWER SUPPLY Power-Supply Range V+ Supply Current V- Supply Current tON tOFF tBBM VCTE CNO(OFF) CCOM(OFF) C(ON) VISO VCT V+, VI+ IDIN = CS = SCLK = 0V or V+, RESET = 0V or V+ DIN = CS = SCLK = 0V or V+, RESET = 0V or V+ From rising edge of CS From rising edge of CS From rising edge of CS CL = 1nF, VNO = 0V, RS = 0 VNO = GND, f = 1MHz VCOM = GND, f = 1MHz VCOM = VNO = GND, f = 1MHz RL = 50, CL = 15pF, VNO = 1VRMS, f = 100kHz RL = 50, CL = 15pF, VNO = 1VRMS, f = 100kHz TA = +25C C, E, M TA = +25C C, E, M TA = +25C TA = +25C TA = +25C TA = +25C TA = +25C TA = +25C TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M 3 7 -1 -2 0.1 400 500 400 500 10 ns ns ns pC pF pF pF dB dB
8 20 30 1 2
V A A
_______________________________________________________________________________________
3
Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
TIMING CHARACTERISTICS--Dual Supplies (Figure 1)
(V+ = +4.5V to +5.5V, V- = -4.5V to -5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SERIAL DIGITAL INTERFACE SCLK Frequency Cycle Time CS Lead Time CS Lag Time SCLK High Time SCLK Low Time Data Setup Time Data Hold Time DIN Data Valid after Falling SCLK (Note 4) Rise Time of DOUT (Note 4) Allowable Rise Time at DIN, SCLK (Note 4) Fall Time of DOUT (Note 4) Allowable Fall Time at DIN, SCLK (Note 4) RESET Minimum Pulse Width SYMBOL CONDITIONS MIN TYP MAX (Note 1) 2.1 UNITS
fSCLK tCH + tCL tCSS tCSH2 tCH tCL tDS tDH tDO tDR tSCR tDF tSCF tRW 50% of SCLK to 10% of DOUT, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF
C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M TA = +25C C, E, M C, E, M C, E, M C, E, M C, E, M TA = +25C
0 480 240 240 190 190 200 0
MHz ns ns ns ns ns ns ns
17 -17 85 400 100 2 100 2 70
ns ns s ns s ns
Note 1: The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column. Note 2: RON = RON(max) - RON(min). On-resistance match between channels and on-resistance flatness are guaranteed only with specified voltages. Flatness is defined as the difference between the maximum and minimum value of on-resistance as measured over the specified analog signal range. Note 3: Leakage parameters are 100% tested at maximum rated hot temperature and guaranteed by correlation at room temp. Note 4: Guaranteed by design. Note 5: Leakage testing at single supply is guaranteed by testing with dual supplies. Note 6: See Figure 6. Off isolation = 20log10 VCOM/VNO, VCOM = output. NO = input to off switch. Note 7: Between any two switches. See Figure 3.
4
_______________________________________________________________________________________
Serially Controlled, Low-Voltage, 8-Channel SPST Switch
ELECTRICAL CHARACTERISTICS--Single +5V Supply
(V+ = +4.5V to +5.5V, V- = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER ANALOG SWITCH Analog Signal Range COM, NO On-Resistance VCOM, VNO RON V+ = 5V, VCOM = 3.5V, INO = 1mA V+ = 5.5V, VCOM = 4.5V, VNO = 0V V+ = 5.5V, VCOM = 0V, VNO = 4.5V V+ = 5.5V, VCOM = 4.5V, VNO = 0V V+ = 5.5V, VCOM = 0V, VNO = 4.5V V+ = 5.5V, VCOM = VNO = 4.5V C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M -0.1 -10 -0.1 -10 -0.1 -10 -0.1 -10 -0.2 -20 0.002 0.002 0.002 0.002 0.002 V125 V+ 175 225 0.1 10 0.1 10 0.1 10 0.1 10 0.2 20 nA nA nA V SYMBOL CONDITIONS MIN TYP (Note 2) MAX UNITS
MAX395
NO Off Leakage Current (Notes 4, 5)
INO(OFF)
COM Off Leakage Current (Notes 4, 5) COM On Leakage Current (Notes 4, 5) DIGITAL I/O DIN, SCLK, CS, RESET Input Voltage Logic Threshold High DIN, SCLK, CS, RESET Input Voltage Logic Threshold Low DIN, SCLK, CS, RESET Input Current Logic High or Low DOUT Output Voltage Logic High DOUT Output Voltage Logic Low SCLK Input Hysteresis
ICOM(OFF)
ICOM(ON)
VIH VIL IIH, IIL VDOUT VDOUT SCLKHYST VDIN, VSCLK, V CS = 0.8V or 2.4V IDOUT = -0.8mA IDOUT = 1.6mA
C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C TA = +25C TA = +25C TA = +25C
2.4 0.8 -1 2.8 0 100 200 90 15 2 -90 <-90 10 400 500 400 500 0.03 1 V+ 0.4
V V A V V mV
SWITCH DYNAMIC CHARACTERISTICS Turn-On Time Turn-Off Time Break-Before-Make Delay Charge Injection (Note 4) Off Isolation (Note 6) Channel-to-Channel Crosstalk (Note 7) POWER SUPPLY V+, V- Supply Current I+ DIN = CS = SCLK = 0V or V+, RESET = 0V or V+ TA = +25C C, E, M 7 20 30 A tON tOFF tBBM VCTE VISO VCT From rising edge of CS From rising edge of CS From rising edge of CS CL = 1nF, VNO = 0V, RS = 0 RL = 50, CL = 15pF, VNO = 1VRMS, f = 100kHz RL = 50, CL = 15pF, VNO = 1VRMS, f = 100kHz ns ns ns pC dB dB
_______________________________________________________________________________________
5
Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
TIMING CHARACTERISTICS--Single +5V Supply (Figure 1)
(V+ = +4.5V to +5.5V, V- = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SERIAL DIGITAL INTERFACE SCLK Frequency Cycle Time (Note 4) CS Lead Time (Note 4) CS Lag Time (Note 4) SCLK High Time (Note 4) SCLK Low Time (Note 4) Data Setup Time (Note 4) Data Hold Time (Note 4) DIN Data Valid after Falling SCLK (Note 4) Rise Time of DOUT (Note 4) Allowable Rise Time at DIN, SCLK (Note 4) Fall Time of DOUT (Note 4) Allowable Fall Time at DIN, SCLK (Note 4) RESET Minimum Pulse Width SYMBOL CONDITIONS MIN TYP (Note 2) MAX UNITS
fSCLK tCH + tCL tCSS tCSH2 tCH tCL tDS tDH tDO tDR tSCR tDF tSCF tRW 50% of SCLK to 10% of DOUT, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF
C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M TA = +25C C, E, M C, E, M C, E, M C, E, M C, E, M TA = +25C
0 480 240 240 190 190 200 0
2.1
MHz ns ns ns ns ns ns ns
17 -17 85 400 100 2 100 2 70
ns ns s ns s ns
Note 1: The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column. Note 2: RON = RON(max) - RON(min). On-resistance match between channels and on-resistance flatness are guaranteed only with specified voltages. Flatness is defined as the difference between the maximum and minimum value of on-resistance as measured over the specified analog signal range. Note 3: Leakage parameters are 100% tested at maximum rated hot temperature and guaranteed by correlation at room temp. Note 4: Guaranteed by design. Note 5: Leakage testing at single supply is guaranteed by testing with dual supplies. Note 6: See Figure 6. Off isolation = 20log10 VCOM/VNO, VCOM = output. NO = input to off switch. Note 7: Between any two switches. See Figure 3.
6
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Serially Controlled, Low-Voltage, 8-Channel SPST Switch
ELECTRICAL CHARACTERISTICS--Single +3V Supply
(V+ = +3.0V to +3.6V, V- = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER ANALOG SWITCH Analog Signal Range COM, NO On-Resistance VCOM, VNO RON V+ = 3.0V, VCOM = 1.5V, INO = 1mA V+ = 3.0V, VCOM = 3V, VNO = 0V V+ = 3.6V, VCOM = 0V, VNO = 3V V+ = 3.6V, VCOM = 3V, VNO = 0V V+ = 3.6V, VCOM = 0V, VNO = 3V V+ = 3.6V, VCOM = 3V, VNO = 0V V+ = 3.6V, VCOM = 0V, VNO = 3V C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C C, E, M -0.1 -5 -0.1 -5 -0.1 -5 0.1 -5 -0.1 -10 -0.1 -10 0.002 0.002 0.002 0.002 0.002 0.002 V270 V+ 500 600 0.1 5 0.1 5 0.1 5 0.1 5 0.1 10 0.1 10 nA nA nA V SYMBOL CONDITIONS MIN TYP (Note 2) MAX UNITS
MAX395
NO Off Leakage Current (Notes 4, 5)
INO(OFF)
COM Off Leakage Current (Notes 4, 5)
ICOM(OFF)
COM On Leakage Current (Notes 4, 5) DIGITAL I/O DIN, SCLK, CS, RESET Input Voltage Logic Threshold High DIN, SCLK, CS, RESET Input Voltage Logic Threshold Low DIN, SCLK, CS, Input Current Logic High or Low DOUT Output Voltage Logic High DOUT Output Voltage Logic Low SCLK Input Hysteresis
ICOM(ON)
VIH VIL IIH, IIL VDOUT VDOUT SCLKHYST VDIN, VSCLK, V CS = 0.8V or 2.4V IDOUT = 0.1mA IDOUT = -1.6mA
C, E C, E C, E C, E, M C, E, M C, E, M TA = +25C C, E, M TA = +25C C, E, M TA = +25C TA = +25C TA = +25C TA = +25C
2.4 0.8 -1 2.8 0 100 260 90 15 2 -90 <-90 10 600 800 300 400 0.03 1 V+ 0.4
V V A V V mV
SWITCH DYNAMIC CHARACTERISTICS Turn-On Time Turn-Off Time Break-Before-Make Delay Charge Injection (Note 4) Off Isolation (Note 6) Channel-to-Channel Crosstalk (Note 7) POWER SUPPLY V+ Supply Current I+ DIN = CS = SCLK = 0V or V+, TA = +25C RESET = 0V or 5V C, E, M 6 20 30 A tON tOFF tBBM VCTE VISO VCT From rising edge of CS From rising edge of CS From rising edge of CS CL = 1nF, VNO = 0V, RS = 0 RL = 50, CL = 15pF, VNO = 1VRMS, f = 100kHz RL = 50, CL = 15pF, VNO = 1VRMS, f = 100kHz ns ns ns pC dB dB
_______________________________________________________________________________________
7
Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
TIMING CHARACTERISTICS--Single +3V Supply (Figure 1)
(V+ = +3.0V to +3.6V, V- = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SERIAL DIGITAL INTERFACE SCLK Frequency Cycle Time (Note 4) CS Lead Time (Note 4) CS Lag Time (Note 4) SCLK High Time (Note 4) SCLK Low Time (Note 4) Data Setup Time (Note 4) Data Hold Time (Note 4) DIN Data Valid after Falling SCLK (Note 4) Rise Time of DOUT (Note 4) Allowable Rise Time at DIN, SCLK (Note 4) Fall Time of DOUT (Note 4) Allowable Fall Time at DIN, SCLK (Note 4) RESET Minimum Pulse Width SYMBOL CONDITIONS MIN TYP (Note 2) MAX UNITS
fSCLK tCH + tCL tCSS tCSH2 tCH tCL tDS tDH tDO tDR tSCR tDF tSCF tRW 50% of SCLK to 10% of DOUT, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF 20% of V+ to 70% of V+, CL = 10pF
C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M C, E, M TA = +25C C, E, M C, E, M C, E, M C, E, M C, E, M TA = +25C
0 480 240 240 190 190 200 0
2.1
MHz ns ns ns ns ns ns ns
38 -38 150 400 300 2 300 2 105
ns ns s ns s ns
Note 1: The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column. Note 2: RON = RON(max) - RON(min). On-resistance match between channels and on-resistance flatness are guaranteed only with specified voltages. Flatness is defined as the difference between the maximum and minimum value of on-resistance as measured over the specified analog signal range. Note 3: Leakage parameters are 100% tested at maximum rated hot temperature and guaranteed by correlation at room temp. Note 4: Guaranteed by design. Note 5: Leakage testing at single supply is guaranteed by testing with dual supplies. Note 6: See Figure 6. Off isolation = 20log10 VCOM/VNO, VCOM = output. NO = input to off switch. Note 7: Between any two switches. See Figure 3.
8
_______________________________________________________________________________________
Serially Controlled, Low-Voltage, 8-Channel SPST Switch
__________________________________________Typical Operating Characteristics
(V+ = +5V, V- = -5V, GND = 0V, TA = +25C, unless otherwise noted.)
ON-RESISTANCE vs. VCOM (DUAL SUPPLIES)
MAX395 TOC1
MAX395
ON-RESISTANCE vs. VCOM AND TEMPERATURE (DUAL SUPPLIES)
MAX395 TOC2
ON-RESISTANCE vs. VCOM (SINGLE SUPPLY)
V+ = 2.5V 350 300 RON () V- = 0V
MAX395 TOC3
140 120 100 V = 3V RON () 80 60 V = 5V 40 20 0 -5 -4 -3 -2 -1 0 1 2 3 4 5 VCOM (V) V = 2.5V
110 V = 5.5V 100 90 RON () 80 70 60 50 40 30 -5 -4 -3 -2 -1 0 1 2 3 4 5 VCOM (V) TA = -55C TA = +125C TA = +85C TA = +25C
400
250 200 V+ = 3V 150 100 50 0 0 2 4 6 VCOM (V) 8 10 12 V+ = 5V V+ = 9V V+ = 12V
ON-RESISTANCE vs. VCOM AND TEMPERATURE (SINGLE SUPPLY)
160 140 RON () 120 100 80 60 40 0.1 0 1 2 3 4 5 -50 -25 VCOM (V) TA = +25C TA = -55C V+ = 5V V- = 0V TA = +125C TA = +85C
MAX395 TOC4
OFF-LEAKAGE vs. TEMPERATURE
MAX395 TOC5
ON-LEAKAGE vs. TEMPERATURE
V = 5.5V 1000 ON-LEAKAGE (pA)
MAX395 TOC6
180
1000 V = 5.5V 100 OFF-LEAKAGE (pA)
10,000
100
10
10 1
1
0.1 0 25 50 75 TEMPERATURE (C) 100 125 -50 -25 0 25 50 75 TEMPERATURE (C) 100 125
CHARGE INJECTION vs. VCOM
MAX395 TOC7
TURN-ON/OFF TIMES vs. VCOM
A: V+ = 5V, V- = 5V B: V+ = 5V, V- = 0V
MAX395 TOC8
DATA HOLD TIME vs. POWER-SUPPLY VOLTAGE
40 30 DATA HOLD TIME (ns) 20 10 0 -10 -20 -30 -40
MAX395 TOC9
5 4 3
250
50
200 tON, tOFF (ns)
2 Qj (pC) 1 0 -1 -2 -3 -4 -5 -5 -4 -3 -2 -1 0 1 2 3 4 5 VCOM (V)
150 A = tON A = tOFF 50 B = tON B = tOFF
100
0 -5 -4 -3 -2 -1 0 1 2 3 4 5 VCOM (V)
-50 0 2 4 6 8 SUPPLY VOLTAGE (V)
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9
Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
____________________________Typical Operating Characteristics (continued)
(V+ = +5V, V- = -5V, GND = 0V, TA = +25C, unless otherwise noted.)
DATA SETUP TIME vs. POSITIVE SUPPLY VOLTAGE
MAX395 TOC10
POWER-SUPPLY CURRENT vs. TEMPERATURE
MAX395 TOC11
MINIMUM SCLK PULSE WIDTH vs. POSITIVE SUPPLY VOLTAGE
MAX395 TOC12
100 90 DATA SETUP TIME (ns) 80 70
100 V = 5.5V 10 I+
35
30
I+, I-, (A)
60 50 40 30 20 10 0 0 2 4 6 8 SUPPLY VOLTAGE (V)
SCLK (ns) I-50 125
1
25
0.1
20
0.01
15
0.001 -25 0 25 50 75 100 TEMPERATURE (C)
10 0 2 4 6 8 SUPPLY VOLTAGE (V)
FREQUENCY RESPONSE
0 -20 LOSS (dB) PHASE -40 -60 -80 -100 10k ISOLATION OF A BARE SOCKET OFF ISOLATION V = 5V 50 IN AND OUT 100k 1M 10M 100M 1G INSERTION LOSS
TOC13
TOTAL HARMONIC DISTORTION vs. FREQUENCY
0 PHASE (DEGREES) -20 -40 -60 -80 10 TDH (%) V = 5V 600 IN AND OUT
MAX395 TOC14
20
100
MAX395
1
0.1
-100 -120 0.01 10 100 1k 10k FREQUENCY (Hz)
FREQUENCY (Hz)
______________________________________________________________Pin Description
PIN 1 2 3 4 5, 7, 9, 11, 14, 16, 18, 20 6, 8, 10, 12, 13, 15, 17, 19 21 22 23 24 NAME SCLK V+ DIN GND NO0-NO7 COM0-COM7 VDOUT RESET CS FUNCTION Serial Clock Digital Input Positive Analog Supply Voltage Input Serial Data Digital Input Ground. Connect to digital ground. (Analog signals have no ground reference; they are limited to V+ and V-.) Normally Open Analog Switches 0-7 Common Analog Switches 0-7 Negative Analog Supply Voltage Input. Connect to GND for single-supply operation Serial Data Digital Output. (High is sourced from V+.) Reset Input. Connect to digital (logic) supply (or V+). Drive low to set all switches off and set internal shift registers to 0. Chip-Select Digital Input (Figure 1)
Note: NO_ and COM_ pins are identical and interchangeable. Either may be considered as an input or an output; signals pass equally well in either direction. 10 ______________________________________________________________________________________
Serially Controlled, Low-Voltage, 8-Channel SPST Switch
_______________Detailed Description
Basic Operation
The MAX395's interface can be thought of as an 8-bit shift register controlled by CS (Figure 2). While CS is low, input data appearing at DIN is clocked into the shift register synchronously with SCLK's rising edge. The data is an 8-bit word, each bit controlling one of eight switches in the MAX395 (Table 1). DOUT is the shift register's output, with data appearing synchronously with SCLK's falling edge. Data at DOUT is simply the input data delayed by eight clock cycles. When shifting the input data, D7 is the first bit in and out of the shift register. While shifting data, the switches remain in their previous configuration. When the eight bits of data have been shifted in, CS is driven high. This updates the new switch configuration and inhibits further data from entering the shift register. Transitions at DIN and SCLK have no effect when CS is high, and DOUT holds the first input bit (D7) at its output. More or less than eight clock cycles can be entered during the CS low period. When this happens, the shift register will contain only the last eight serial data bits, regardless of when they were entered. On the rising edge of CS, all the switches will be set to the corresponding states. The MAX395's three-wire serial interface is compatible with SPITM, QSPITM, and MicrowireTM standards. If interfacing with a Motorola processor serial interface, set CPOL = 0. The MAX395 is considered a slave device (Figures 2 and 3). Upon power-up, the shift register contains all zeros, and all switches are off. The latch that drives the analog switch is updated on the rising edge of CS, regardless of SCLK's state. This meets all the SPI and QSPI requirements.
MAX395
Daisy Chaining
For a simple interface using several MAX395s, "daisy chain" the shift registers as shown in Figure 5. The CS pins of all devices are connected together, and a stream of data is shifted through the MAX395s in series. When CS is brought high, all switches are updated simultaneously. Additional shift registers may be included anywhere in series with the MAX395 data chain.
tCLL CS
***
tCSH2
tCSS tCSH0
tCH
***
tOFF
SCLK tDS tDH
***
tCL
tCSH1
DIN tDO
***
DOUT COM OUT
***
Figure 1. Timing Diagram
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11
Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
Addressable Serial Interface
CS SWITCHES UPDATED SCLK
When several serial devices are configured as slaves, addressable by the processor, DIN pins of each decode logic individually control CS of each slave device. When a slave is selected, its CS pin is driven low, data is shifted in, and CS is driven high to latch the data. Typically, only one slave is addressed at a time. DOUT is not used.
__________Applications Information
DIN D7 D6 D5 D4 D3 D2 D1 D0 DATA BITS DOUT D0 D7 D6 D5 D4 D3 D2 D1 D0
Multiplexers
The MAX395 can be used as a multiplexer, but to obtain the same electrical performance with slightly improved programming speed, use the MAX349 8channel mux or the MAX350 dual 4-channel mux, both in 18-pin packages.
DATA BITS FROM PREVIOUS DATA INPUT
Figure 2. Three-Wire Interface Timing
Table 1. Serial-Interface Switch Programming
DATA BITS RESET D7 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 X 0 1 X X X X X X X X X X X X X X D6 X X X 0 1 X X X X X X X X X X X X D5 X X X X X 0 1 X X X X X X X X X X D4 X X X X X X X 0 1 X X X X X X X X D3 X X X X X X X X X 0 1 X X X X X X D2 X X X X X X X X X X X 0 1 X X X X D1 X X X X X X X X X X X X X 0 1 X X D0 X X X X X X X X X X X X X X X 0 1 All switches open, D7-D0 = 0 Switch 7 open (off) Switch 7 closed (on) Switch 6 open (off) Switch 6 closed (on) Switch 5 open (off) Switch 5 closed (on) Switch 4 open (off) Switch 4 closed (on) Switch 3 open (off) Switch 3 closed (on) Switch 2 open (off) Switch 2 closed (on) Switch 1 open (off) Switch 1 closed (on) Switch 0 open (off) Switch 0 closed (on) FUNCTION
12
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Serially Controlled, Low-Voltage, 8-Channel SPST Switch
8x1 Multiplexer
To use the MAX395 as an 8x1 multiplexer, connect all common pins together (COM0-COM7) to form the mux output; the mux inputs are NO0-NO7. The mux can be programmed normally, with only one channel selected for every eight clock pulses, or it can be programmed in a fast mode, where channel changing occurs on each clock pulse. In this mode, the channels are selected by sending a single high pulse (corresponding to the selected channel) at DIN, and a corresponding CS low pulse for every eight clock pulses. As this is clocked through the register by SCLK, each switch sequences one channel at a time, starting with Channel 7.
Dual, Differential 4-Channel Multiplexer
To use the MAX395 as a dual (4x2) mux, connect COM0-COM3 together and connect COM4-COM7 together, forming the two outputs. The mux input pairs become NO0/NO4, NO1/NO5, NO2/NO6, and NO3/NO7. The mux can be programmed normally, with only one differential channel selected for every eight clock pulses, or it can be programmed in a fast mode, where channel changing occurs on each clock pulse. In fast mode, the channels are selected by sending two high pulses spaced four clock pulses apart (corresponding to the two selected channels) at DIN, and a corresponding CS low pulse for each of the first eight clock pulses. As this is clocked through the register by
MAX395
SCLK
SK SO SI I/O MICROWIRE PORT
DOUT
MISO MOSI SCK I/O
MAX395 DIN
DOUT CS
MAX395 DIN
SCLK CS
SPI PORT
CPOL = 0, CPHA = 0 THE DOUT-SI CONNECTION IS NOT REQUIRED FOR WRITING TO THE MAX395, BUT MAY BE USED FOR DATA-ECHO PURPOSES. THE DOUT-MISO CONNECTION IS NOT REQUIRED FOR WRITING TO THE MAX395, BUT MAY BE USED FOR DATA-ECHO PURPOSES.
Figure 3. Connections for Microwire
Figure 4. Connections for SPI and QSPI
SCLK
SCLK
SCLK
SCLK
MAX395
DIN DIN DOUT DIN
MAX395
DOUT DIN
MAX395
DOUT
CS
CS
CS
CS TO OTHER SERIAL DEVICES
Figure 5. Daisy-Chained Connection
______________________________________________________________________________________ 13
Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
DIN SCLK CS1 CS2 CS3 TO OTHER SERIAL DEVICES
CS
CS
CS
MAX395
SCLK SCLK
MAX395
SCLK
MAX395
DIN
DIN
DIN
Figure 6. Addressable Serial Interface
Reset Function
D4 SCLK SW4 DIN FOUR CLOCK PULSES SW0 D0
RESET is the internal reset pin. It is usually connected to a logic signal or V+. Drive RESET low to open all switches and set the contents of the internal shift register to zero simultaneously. When RESET is high, the part functions normally and DOUT is sourced from V+. RESET must not be driven beyond V+ or GND.
Power-Supply Considerations
Overview The MAX395 construction is typical of most CMOS analog switches. It has three supply pins: V+, V-, and GND. V+ and V- are used to drive the internal CMOS switches and to set the limits of the analog voltage on any switch. Reverse ESD-protection diodes are internally connected between each analog signal pin and both V+ and V-. If any analog signal exceeds V+ or V-, one of these diodes will conduct. During normal operation, these (and other) reverse-biased ESD diodes leak, forming the only current drawn from V+ or V-. Virtually all the analog leakage current is through the ESD diodes. Although the ESD diodes on a given signal pin are identical, and therefore fairly well balanced, they are reverse biased differently. Each is biased by either V+ or V- and the analog signal. This means their leakages vary as the signal varies. The difference in the two diode leakages to the V+ and V- pins constitutes the analog signal-path leakage current. All analog leak-
Figure 7. Differential Multiplexer Input Control
SCLK, each switch sequences one differential channel at a time, starting with channel 7/0. After the first eight bits have been sent, subsequent channel sequencing can occur by repeating this sequence or, even faster, by sending only one DIN high pulse and one CS low pulse for each four clock pulses.
SPDT Switches
To use the MAX395 as a quad, single-pole/doublethrow (SPDT) switch, connect COM0 to NO1, COM2 to NO3, COM4 to NO5, and COM6 to NO7, forming the four "common" pins. Program these four switches with pairs of instructions, as shown in Table 2.
14
______________________________________________________________________________________
Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
Table 2. SPDT Switch Programming
DATA BITS RESET D7 0 1 1 1 1 1 1 1 1 X 0 1 X X X X X X D6 X 1 0 X X X X X X D5 X X X 0 1 X X X X D4 X X X 1 0 X X X X D3 X X X X X 0 1 X X D2 X X X X X 1 0 X X D1 X X X X X X X 0 1 D0 X X X X X X X 1 0 All switches open, D7-D0 = 0 Switch 7 off and 6 on Switch 6 off and 7 on Switch 5 off and 4 on Switch 4 off and 5 on Switch 3 off and 2 on Switch 2 off and 3 on Switch 1 off and 0 on Switch 0 off and 1 on FUNCTION
age current flows to the supply terminals, not to the other switch terminal. This is why both sides of a given switch can show leakage currents of either the same or opposite polarity. There is no connection between the analog signal paths and GND. V+ and GND power the internal logic and logic-level translators, and set both the input and output logic limits. The logic-level translators convert the logic levels to switched V+ and V- signals to drive the analog signal gates. This drive signal is the only connection between the logic supplies (and signals) and the analog supplies. V+, and V- have ESD-protection diodes to GND. The logic-level inputs and output have ESD protection to V+ and to GND. The logic-level thresholds are CMOS and TTL compatible when V+ is +5V. As V+ is raised, the threshold increases slightly. So when V+ reaches +12V, the threshold is about 3.1V; slightly above the TTL guaranteed high-level minimum of 2.8V, but still compatible with CMOS outputs.
Single Supply The MAX395 operates from a single supply between +3V and +16V when V- is connected to GND. All of the bipolar precautions must be observed.
High-Frequency Performance
In 50 systems, signal response is reasonably flat up to 50MHz (see Typical Operating Characteristics). Above 20MHz, the on-response has several minor peaks that are highly layout dependent. The problem is not turning the switch on, but turning it off. The off-state switch acts like a capacitor and passes higher frequencies with less attenuation. At 10MHz, off isolation is about -45dB in 50 systems, becoming worse (approximately 20dB per decade) as frequency increases. Higher circuit impedances also make off isolation worse. Adjacent channel attenuation is about 3dB above that of a bare IC socket, and is due entirely to capacitive coupling.
Bipolar Supplies The MAX395 operates with bipolar supplies between 3.0V and 8V. The V+ and V- supplies need not be symmetrical, but their sum cannot exceed the absolute maximum rating of 17V. Do not connect the MAX395 V+ to +3V and connect the logic-level pins to TTL logic-level signals. This exceeds the absolute maximum ratings and can damage the part and/or external circuits.
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15
Serially Controlled, Low-Voltage, 8-Channel SPST Switch MAX395
___________________Chip Topography
COM5 NO5 NO3 NO2 COM4 COM3 COM2 NO4
COM6 NO6 COM7 NO7
COM1 NO1 0.120" COM0 (3.05mm)
NO0
GND V-
DOUT
RESET
CS SCLK
V+ DIN
0.100" (2.54mm)
TRANSISTOR COUNT: 500 SUBSTRATE CONNECTED TO V+.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
16 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 (c) 1995 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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