19-1358; Rev 0; 4/98 Force-Sense Switches All digital inputs have +0.8V and +2.4V logic thresholds, ensuring both TTL- and CMOS-logic compatibility. Applications Features ♦ 6Ω Force Signal Paths (±15V Supplies) 1Ω Force Signal Matching (±15V Supplies) ♦ 60Ω Sense-Guard Signal Paths (±15V Supplies) 8Ω Sense-Guard Signal Matching (±15V Supplies) ♦ Rail-to-Rail Signal Handling ♦ Break-Before-Make Switching (MAX4556) ♦ tON and tOFF = 275ns (±15V Supplies) ♦ Low 1µA Power Consumption ♦ >2kV ESD Protection per Method 3015.7 ♦ TTL/CMOS-Compatible Inputs Ordering Information TEMP. RANGE PART 0°C to +70°C MAX4554CPE PIN-PACKAGE 16 Plastic DIP MAX4554CSE 0°C to +70°C 16 Narrow SO MAX4554C/D MAX4554EPE MAX4554ESE 0°C to +70°C -40°C to +85°C -40°C to +85°C Dice* 16 Plastic DIP 16 Narrow SO Ordering Information continued at end of data sheet. *Contact factory for availability. Automated Test Equipment (ATE) Calibrators Precision Power Supplies Automatic Calibration Circuits Rail-to-Rail is a registered trademark of Nippon Motorola Ltd. Asymmetric Digital Subscriber Line (ADSL) with Loopback Pin Configurations/Functional Diagrams/Truth Tables TOP VIEW MAX4554 NOG1 1 16 COMG NOS1 2 15 COMS NOF1* 3 14 COMF* V- 4 13 V+ EN 1 0 0 0 0 GND 5 12 VL NOF2* 6 11 IN1 NOS2 7 10 IN2 NOG2 8 9 EN DIP/SO IN1 X 0 0 1 1 MAX4554 IN2 COMG X OFF 0 OFF 1 NOG2 0 NOG1 NOG1 1 & NOG2 COMS OFF OFF NOS2 NOS1 NOS1 & NOS2 COMF* OFF OFF NOF2* NOF1* NOF1* & NOF2* NOTE: SWITCH POSITIONS SHOWN WITH IN_ = LOW *INDICATES HIGH-CURRENT, LOW-RESISTANCE FORCE SWITCH X = DON’T CARE MAX4555/MAX4556 shown at end of data sheet. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 408-737-7600 ext. 3468. MAX4554/MAX4555/MAX4556 General Description The MAX4554/MAX4555/MAX4556 are CMOS analog ICs configured as force-sense switches for Kelvin sensing in automated test equipment (ATE). Each part contains high-current, low-resistance switches for forcing current, and higher resistance switches for sensing a voltage or switching guard signals. The MAX4554 contains two force switches, two sense switches, and two guard switches configured as two triple-pole/single-throw (3PST) normally open (NO) switches. The MAX4555 contains four independent single-pole/single-throw (SPST) normally closed (NC) switches, two force switches, and two sense switches. The MAX4556 contains three independent single-pole/double-throw (SPDT) switches, of which one is a force switch and two are sense switches. These devices operate from a single supply of +9V to +40V or dual supplies of ±4.5V to ±20V. On-resistance (6Ω max) is matched between switches to 1Ω max. Each switch can handle Rail-to-Rail® analog signals. The off-leakage current is only 0.25nA at +25°C and 2.5nA at +85°C. The MAX4554 is also fully specified for +20V and -10V operation. ABSOLUTE MAXIMUM RATINGS (Voltages referenced to GND) V+ ...........................................................................-0.3V to +44V V- ............................................................................-25V to +0.3V V+ to V-...................................................................-0.3V to +44V All Other Pins (Note 1) ..........................(V- - 0.3V) to (V+ + 0.3V) Continuous Current into Force Terminals .......................±100mA Continuous Current into Any Other Terminal....................±30mA Peak Current into Force Terminals (pulsed at 1ms, 10% duty cycle).................................±300mA Peak Current into Any Other Terminal (pulsed at 1ms, 10% duty cycle).................................±100mA ESD per Method 3015.7 ..................................................>2000V Continuous Power Dissipation (TA = +70°C) Plastic DIP (derate 10.53mW/°C above +70°C) ...........842mW Narrow SO (derate 8.7mW/°C above +70°C) ...............696mW Operating Temperature Ranges MAX455_C_ E ......................................................0°C to +70°C MAX455_E_ E ...................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10sec) .............................+300°C Note 1: Signals on analog or digital pins exceeding V+ or V- are clamped by internal diodes. Limit forward diode current to maximum current rating. 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—MAX4554 (+20V, -10V Supplies) (V+ = +20V, V- = -10V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS 6Ω ANALOG SWITCH (FORCE) Analog Signal Range On-Resistance On-Resistance Match (Note 4) VCOMF, VNOF_ (Note 3) C, E RON VCOMF = 10V, ICOMF = 10mA ∆RON VCOMF = 10V, ICOMF = 10mA V- +25°C 3.5 C, E +25°C 0.4 C, E V 6 Ω 1 1.5 RFLAT(ON) VCOMF = +5V, 0V, -5V; ICOMF = 10mA +25°C NOF_ Off-Leakage Current INOF_(OFF) V+ = 22V, V- = -11V, VCOMF = ±10V, VNOF_ = 10V +25°C -0.25 C, E -2.5 COMF Off-Leakage Current ICOMF(OFF) V+ = 22V, V- = -11V, VCOMF = ±10V, VNOF_ = 10V COMF On-Leakage Current ICOMF(ON) Q 0.5 C, E 1.5 2.0 +25°C -0.5 C, E -2.5 V+ = 22V, V- = -11V, VCOMF = ±10V +25°C -0.5 C, E -10 VCOMF = 0, Figure 13 C, E (Note 3) C, E ± Charge Injection V+ 7 On-Resistance Flatness (Note 5) ± MAX4554/MAX4555/MAX4556 Force-Sense Switches 0.03 0.25 2.5 0.03 0.5 2.5 0.06 0.5 10 80 Ω Ω nA nA nA pC 60Ω ANALOG SWITCH (SENSE-GUARD) Analog Signal Range On-Resistance On-Resistance Match (Note 4) 2 VCOMS, VCOMG, VNOS_, VNOG_ RON VCOM_ = 10V, ICOM_ = 1mA ∆RON VCOM_ = 10V, ICOM_ = 1mA +25°C V- 34 C, E +25°C V+ V 60 Ω 70 5 C, E _______________________________________________________________________________________ 8 10 Ω Force-Sense Switches (V+ = +20V, V- = -10V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS On-Resistance Flatness (Note 5) RFLAT(ON) VCOM_ = +5V, 0V, -5V; ICOM_ = 10mA NOS_, NOG_ Off-Leakage Current INOS_(OFF), INOG_(OFF) V+ = 22V; V- = -11V; VCOM_ = ±10V; VNOS_, VNOG_ = ±10V COMS, COMG Off-Leakage Current ICOMS(OFF), ICOMG(OFF) V+ = 22V; V- = -11V; VCOM_ = ±10V; VNOS_, VNOG_ = ±10V COMS, COMG On-Leakage Current ICOMS(ON), ICOMG(ON) V+ = 22V, V- = -11V, VCOM_ = ±10V Charge Injection Q VCOM_ = 0, Figure 13 TA +25°C C, E +25°C C, E +25°C C, E +25°C C, E +25°C MIN -0.25 -2.5 -0.25 -2.5 -0.5 -5.0 TYP (Note 2) MAX 3.5 9 10 0.25 2.5 0.25 2.5 0.5 5.0 0.02 0.02 0.04 6 UNITS Ω nA nA nA pC LOGIC INPUT IN_, EN Input Logic Threshold High VIN_H, V ENH C, E IN_, EN Input Logic Threshold Low VIN_L, V ENL C, E 0.8 1.6 VIN_ = V EN = 0 or VL C, E -0.5 0.03 0.5 +25°C C, E +25°C C, E +25°C C, E +25°C C, E +25°C C, E +25°C C, E +25°C 150 300 350 300 350 300 350 300 350 500 600 275 350 22 pF IN_, EN Input Current Logic High or Low IIN_H, IIN_L, I ENH , I ENL 1.6 2.4 V V µA SWITCH DYNAMIC CHARACTERISTICS Turn-On Time (Force) tON VCOMF = 3V, RL = 300Ω, Figure 10 Turn-On Time (Sense-Guard) tON VCOMS, VCOMG = 10V; RL = 1kΩ; Figure 10 Turn-Off Time (Force) tOFF VCOMF = 3V, RL = 300Ω, Figure 10 Turn-Off Time (Sense-Guard) tOFF VCOMS, VCOMG = 10V; RL = 1kΩ; Figure 10 Enable Time On tEN VCOM_ = 10V, Figure 11 Enable Time Off tEN VCOM_ = 10V, Figure 11 NOF_ Off-Capacitance 150 130 130 375 170 ns ns ns ns ns ns COFF VNOF = GND, f = 1MHz, Figure 14 NOS_, NOG_ Off-Capacitance COFF VNOS_, VNOG_ = GND; f = 1MHz; Figure 14 +25°C 7 pF COMF Off-Capacitance COFF VCOMF = GND, f = 1MHz, Figure 14 +25°C 50 pF COMS, COMG Off-Capacitance COFF VCOMS, VCOMG = GND; f = 1MHz; Figure 14 +25°C 15 pF COMF On-Capacitance CON VCOMF = GND, f = 1MHz, Figure 14 +25°C 130 pF COMS, COMG On-Capacitance CON VCOMS, VCOMG = GND; f = 1MHz; Figure 14 +25°C 30 pF Total Harmonic Distortion (Force) THD +25°C 0.007 % Off Isolation (Force) VISO +25°C -30 dB RIN_ = 50Ω, ROUT = 50Ω, f = 1MHz, VCOM_ = 100mVRMS, Figure 15 _______________________________________________________________________________________ 3 MAX4554/MAX4555/MAX4556 ELECTRICAL CHARACTERISTICS—MAX4554 (+20V, -10V Supplies) (continued) ELECTRICAL CHARACTERISTICS—MAX4554 (+20V, -10V Supplies) (continued) (V+ = +20V, V- = -10V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS POWER SUPPLY Power-Supply Range V+, VL, V- VL ≥ 4.5V C, E ±4.5 ±20 +25°C -1.0 1.0 C, E -5.0 5.0 V+ Supply Current I+ V+ = 22V; V- = -11V; V EN, V IN_ = 0 or VL V- Supply Current I- V+ = 22V; V- = -11V; V EN, V IN_ = 0 or VL +25°C -1.0 1.0 C, E -5.0 5.0 VL Supply Current IL+ V+ = 22V; V- = -11V; V EN, V IN_ = 0 or VL +25°C -1.0 1.0 C, E -5.0 5.0 IGND V+ = 22V; V- = -11V; V EN, V IN_ = 0 or VL +25°C -1.0 1.0 C, E -5.0 5.0 Ground Current V µA µA µA µA ELECTRICAL CHARACTERISTICS—MAX4554 (±15V Supplies) (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS 6Ω ANALOG SWITCH (FORCE) Analog Signal Range On-Resistance On-Resistance Match (Note 4) VCOMF, VNOF_ (Note 3) RON VCOMF = ±10V, ICOMF = 10mA ∆RON VCOMF = ±10V, ICOMF = 10mA On-Resistance Flatness (Note 5) RFLAT(ON) VCOMF = +5V, 0V, -5V; ICOMF = 10mA NOF_ Off-Leakage Current INOF_(OFF) V+ = 16.5V, V- = -16.5V, VCOMF = ±10V, VNOF_ = COMF Off-Leakage Current ICOMF(OFF) V+ = 16.5V, V- = -16.5V, VCOMF = ±10V, VNOF_ = COMF On-Leakage Current ICOMF(ON) Q V- +25°C 4 C, E V+ V 6 Ω 7 +25°C 0.5 C, E 1 1.5 +25°C 0.1 C, E 1 1.5 +25°C -0.25 10V C, E -2.5 +25°C -0.5 ± Charge Injection C, E ± MAX4554/MAX4555/MAX4556 Force-Sense Switches 10V C, E -5.0 V+ = 16.5V, V- = -16.5V, VCOMF = ±10V +25°C -0.5 C, E -10 VCOMF = 0, Figure 13 +25°C (Note 3) C, E 0.03 0.25 2.5 0.03 0.5 5.0 0.06 0.5 10 100 Ω Ω nA nA nA pC 60Ω ANALOG SWITCH (SENSE-GUARD) Analog Signal Range On-Resistance 4 VCOMS, VCOMG, VNOS_, VNOG_ RON VCOM_ = ±10V, ICOM_ = 1mA +25°C V- 38 C, E _______________________________________________________________________________________ V+ V 60 Ω 70 Force-Sense Switches (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER On-Resistance Match (Note 4) SYMBOL ∆RON CONDITIONS TA +25°C VCOM_ = ±10V, ICOM_ = 1mA RFLAT(ON) VCOM_ = +5V, 0V, -5V; ICOM_ = 1mA NOS_, NOG Off-Leakage Current INOS_(OFF), INOG_(OFF) V+ = 16.5V; V- = -16.5V; VCOM_ = ±10V; VNOS_, VNOG_ = COMS, COMG Off-Leakage Current ICOMS(OFF), ICOMG(OFF) V+ = 16.5V; V- = -16.5V; VCOM_ = ±10V; VNOS_, VNOG_ = COMS, COMG On-Leakage Current ICOMS(ON), ICOMG(ON) 5 MAX 9 10 +25°C 1.5 C, E 5 6 +25°C -0.25 ± 10V C, E -2.5 +25°C -0.25 ± Q TYP (Note 2) C, E On-Resistance Flatness (Note 5) Charge Injection MIN 10V C, E -2.5 V+ = 16.5V, V- = -16.5V, VCOM_ = ±10V +25°C -0.5 C, E -5.0 VCOM_ = 0, Figure 13 +25°C 0.01 0.25 2.5 0.01 0.25 2.5 0.02 0.5 5.0 4 UNITS Ω Ω nA nA nA pC LOGIC INPUT IN_, EN Input Logic Threshold High VIN_H, V ENH C, E IN_, EN Input Logic Threshold Low VIN_L, V ENL C, E 0.8 1.6 V EN = 0 or VL C, E -0.5 0.03 0.5 135 275 IN_, EN Input Current Logic High or Low IIN_H, IIN_L, I ENH , I ENL 1.6 2.4 V V µA SWITCH DYNAMIC CHARACTERISTICS Turn-On Time (Force) tON VCOM_ = ±10V, RL = 300Ω, Figure 10 +25°C Turn-On Time (Sense-Guard) tON VCOM_ = ±10V, RL = 1kΩ, Figure 10 +25°C Turn-Off Time (Force) tOFF VCOM_ = ±10V, RL = 300Ω, Figure 10 +25°C Turn-Off Time (Sense-Guard) tOFF VCOM_ = ±10V, RL = 1kΩ, Figure 10 +25°C Enable Time On tEN VCOM_ = ±10V, RL = 300Ω, Figure 11 +25°C Enable Time Off tEN VCOM_ = ±10V, RL = 300Ω, Figure 11 +25°C C, E 325 135 C, E 225 275 170 C, E 275 325 135 C, E 225 275 310 C, E 500 600 170 C, E 300 400 ns ns ns ns ns ns NOF_ Off-Capacitance COFF VNOF = GND, f = 1MHz, Figure 14 +25°C 22 pF NOS_, NOG_ Off-Capacitance COFF VNOS_, VNOG_ = GND; f = 1MHz; Figure 14 +25°C 9 pF COMF Off-Capacitance COFF VCOMF = GND, f = 1MHz, Figure 14 +25°C 29 pF COMS, COMG Off-Capacitance COFF VCOMS_, VCOMG _= GND; f = 1MHz; Figure 14 +25°C 9 pF _______________________________________________________________________________________ 5 MAX4554/MAX4555/MAX4556 ELECTRICAL CHARACTERISTICS—MAX4554 (±15V Supplies) (continued) ELECTRICAL CHARACTERISTICS—MAX4554 (±15V Supplies) (continued) (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS COMF On-Capacitance CON VCOMF = GND, f = 1MHz, Figure 14 +25°C 107 pF COMS, COMG On-Capacitance CON VCOMS, VCOMG_ = GND; f = 1MHz; Figure 14 +25°C 29 pF Total Harmonic Distortion (Force) THD +25°C 0.007 % Off Isolation (Force) VISO +25°C -30 dB POWER SUPPLY Power-Supply Range V+, VL, V- RIN_ = 50Ω, ROUT = 50Ω, f = 1MHz, VCOM_ = 100mVRMS, Figure 15 VL ≥ 4.5V V+ Supply Current I+ V+ = 16.5V; V- = -16.5V; V EN, V IN_ = 0 or V+ V- Supply Current I- V+ = 16.5V; V- = -16.5V; V EN, V IN_ = 0 or V+ VL Supply Current IL+ V+ = 16.5V; V- = -16.5V; V EN, V IN_ = 0 or V+ IGND V+ = 16.5V; V- = -16.5V; V EN, V IN_ = 0 or V+ Ground Current C, E +25°C C, E +25°C C, E +25°C C, E +25°C C, E ±4.5 -1.0 -5.0 -1.0 -5.0 -1.0 -5.0 -1.0 -5.0 0.001 0.001 0.001 ±20 1.0 5.0 1.0 5.0 1.0 5.0 1.0 5.0 V µA µA µA µA ELECTRICAL CHARACTERISTICS—MAX4555 (±15V Supplies) (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS 6Ω ANALOG SWITCH (FORCE) Analog Signal Range On-Resistance On-Resistance Match (Note 4) VCOM_, VNO_ (Note 3) C, E RON VCOM_ = ±10V, ICOM_ = 10mA ∆RON VCOM_ = ±10V, ICOM_ = 10mA V- +25°C 3.8 C, E +25°C 0.3 C, E VCOM_ = +5V, 0V, -5V; ICOM_ = 10mA +25°C NC_ Off-Leakage Current INC_(OFF) V+ = 16.5V, V- = -16.5V, VCOM_ = ±10V, VNO_ = 10V +25°C -0.25 C, E -2.5 COM_ Off-Leakage Current ICOM_(OFF) V+ = 16.5V, V- = -16.5V, VCOM_ = ±10V, VNO_ = 10V +25°C -0.5 C, E -5.0 COM_ On-Leakage Current ICOM_(ON) V+ = 16.5V, V- = -16.5V, VCOM_ = ±10V +25°C -0.5 C, E -10 VCOM_ = 0, Figure 13 +25°C 0.05 C, E ± 6 Q V 6 Ω 1 1.5 RFLAT(ON) Charge Injection V+ 7 On-Resistance Flatness (Note 5) ± MAX4554/MAX4555/MAX4556 Force-Sense Switches 1 1.5 0.03 0.25 2.5 0.03 0.5 5.0 0.06 0.5 10 100 _______________________________________________________________________________________ Ω Ω nA nA nA pC Force-Sense Switches (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS 30Ω ANALOG SWITCH (SENSE-GUARD) Analog Signal Range On-Resistance On-Resistance Match (Note 4) VCOM_, VNO_ (Note 3) C, E RON VCOM_ = ±10V, ICOM_ = 10mA ∆RON VCOM_ = ±10V, ICOM_ = 10mA V- +25°C 15 C, E +25°C 0.6 C, E Ω 4 5 RFLAT(ON) VCOM_ = +5V, 0V, -5V; ICOM_ = 10mA +25°C NC_ Off-Leakage Current INC_(OFF) V+ = 16.5V, V- = -16.5V, VCOM_ = ±10V, VNO_ = 10V +25°C -0.3 C, E -2.5 COM_ Off-Leakage Current ICOM_(OFF) V+ = 16.5V, V- = -16.5V, VCOM_ = ±10V, VNO_ = 10V +25°C -0.3 C, E -2.5 COM_ On-Leakage Current INC_(ON) V+ = 16.5V, V- = -16.5V, VNC_ = ±10V +25°C -0.6 C, E -5.0 VCOM_ = 0, Figure 13 +25°C 0.6 C, E ± ± Q V 30 45 On-Resistance Flatness (Note 5) Charge Injection V+ 5 6 0.01 0.3 2.5 0.01 0.3 2.5 0.02 0.6 5.0 4 Ω Ω nA nA nA pC LOGIC INPUT IN_ Input Logic Threshold High VIN_H C, E IN_ Input Logic Threshold Low VIN_L C, E 0.8 1.6 IN_ Input Current Logic High or Low IIN_H, IIN_L VIN_ = 0.8V or 2.4V C, E -0.5 0.03 1.6 2.4 V V 0.5 µA SWITCH DYNAMIC CHARACTERISTICS Turn-On Time (Force) tON VCOM_ = ±3V, RL = 300Ω, Figure 10 +25°C 155 Turn-On Time (Sense-Guard) tON VCOM_ = ±10V, RL = 1kΩ, Figure 10 +25°C Turn-Off Time (Force) tOFF VCOM_ = ±3V, RL = 300Ω, Figure 10 +25°C Turn-Off Time (Sense-Guard) tOFF VCOM_ = ±10V, RL = 1kΩ, Figure 10 +25°C COM_ Off-Capacitance (Force) COFF VCOM_, VNO_ = GND; f = 1MHz; Figure 14 +25°C 29 pF COM_ On-Capacitance (Sense-Guard) CON VCOM_, VNO_ = GND; f = 1MHz; Figure 14 +25°C 9 pF COM_ On-Capacitance (Force) CON VCOM_, VNO_ = GND; f = 1MHz; Figure 14 +25°C 107 pF COM_ Off-Capacitance (Sense-Guard) COFF VCOM_, VNO_ = GND; f = 1MHz; Figure 14 +25°C 29 pF C, E 275 325 125 C, E 225 275 190 C, E 275 325 125 C, E 225 275 ns ns ns ns _______________________________________________________________________________________ 7 MAX4554/MAX4555/MAX4556 ELECTRICAL CHARACTERISTICS—MAX4555 (±15V Supplies) (continued) ELECTRICAL CHARACTERISTICS—MAX4555 (±15V Supplies) (continued) (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS NC_ Off-Capacitance (Force) COFF VCOM_, VNO_ = GND; f = 1MHz; Figure 14 +25°C 22 pF NC_ Off-Capacitance (Sense-Guard) COFF VCOM_, VNO_ = GND; f = 1MHz; Figure 14 +25°C 9 pF Total Harmonic Distortion (Force) THD +25°C 0.007 % Off Isolation (Force) (Note 6) VISO +25°C -38 dB POWER SUPPLY Power-Supply Range RIN = 50Ω, ROUT = 50Ω, f = 1MHz, VCOM_ = 100mVRMS, Figure 15 V+, VL, V- V+ Supply Current I+ V+ = 16.5V; V- = -16.5V; V EN, V IN_ = 0 or V+ V- Supply Current I- V+ = 16.5V; V- = -16.5V; V EN, V IN_ = 0 or V+ VL Supply Current IL+ V+ = 16.5V; V- = -16.5V; V EN, V IN_ = 0 or V+ IGND V+ = 16.5V; V- = -16.5V; V EN, V IN_ = 0 or V+ Ground Current C, E +25°C C, E +25°C C, E +25°C C, E +25°C C, E ±4.5 -1.0 -5.0 -1.0 -5.0 -1.0 -5.0 -1.0 -5.0 0.001 0.001 0.001 0.001 ±20 1.0 5.0 1.0 5.0 1.0 5.0 1.0 5.0 V µA µA µA µA ELECTRICAL CHARACTERISTICS—MAX4556 (±15V Supplies) (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS 6Ω ANALOG SWITCH (FORCE) Analog Signal Range On-Resistance On-Resistance Match (Note 4) VCOM1, VNO1, VNC1 (Note 3) C, E RON VCOM1 = ±10V, ICOM1 = 10mA ∆RON VCOM1 = ±10V, ICOM1 = 10mA RFLAT(ON) VCOM1 = +5V, 0V, -5V; ICOM1 = 10mA NO1, NC1 Off-Leakage Current INO1(OFF), INC1(OFF) V+ = 16.5V; V- = -16.5V; VCOM1 = ±10V; VNO1, VNC1 = COM1 Off-Leakage Current ICOM1(OFF) V+ = 16.5V, V- = -16.5V, VCOM1 = ±10V, VNO1 = 10V COM1 On-Leakage Current ICOM1(ON) 8 Q +25°C 3.8 C, E +25°C 0.3 C, E 10V V+ V 6 Ω 7 1 1.5 0.05 C, E 1 1.5 +25°C -0.25 C, E -2.5 +25°C -0.5 C, E -5.0 V+ = 16.5V, V- = -16.5V, VCOM1 = ±10V +25°C -0.5 C, E -10 VCOM1 = 0, Figure 13 +25°C ± Charge Injection V- +25°C On-Resistance Flatness (Note 5) ± MAX4554/MAX4555/MAX4556 Force-Sense Switches 0.03 0.25 2.5 0.03 0.5 5.0 0.06 0.5 10 100 _______________________________________________________________________________________ Ω Ω nA nA nA pC Force-Sense Switches (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS TA MIN TYP (Note 2) MAX UNITS 60Ω ANALOG SWITCH (SENSE-GUARD) Analog Signal Range VCOM_, VNO_, VNC_ (Note 3) C, E On-Resistance Flatness (Note 5) RFLAT(ON) VCOM_ = +5V, 0V, -5V; ICOM_ = 10mA NO_, NC Off-Leakage Current INO_(OFF), INC_(OFF) V+ = 16.5V; V- = -16.5V; VCOM_ = ±10V; VNO_, VNC_ = ± COM_ Off-Leakage Current ICOM_(OFF) V+ = 16.5V; V- = -16.5V; VCOM_ = ±10V; VNO_, VNC_ = ± COM_ On-Leakage Current ICOM_(ON) V+ = 16.5V, V- = -16.5V, VCOM_ = ±10V +25°C C, E +25°C C, E +25°C C, E +25°C C, E +25°C C, E +25°C C, E VCOM_ = 0, Figure 13 +25°C On-Resistance On-Resistance Match (Note 4) Charge Injection RON VCOM_ = ±10V, ICOM_ = 10mA ∆RON VCOM_ = ±10V, ICOM_ = 10mA Q 10V 10V V36 5 0.6 -0.25 -2.5 -0.25 -2.5 -0.5 -5.0 0.01 0.01 0.02 V+ V 60 70 9 10 5 6 0.25 2.5 0.25 2.5 0.5 5.0 Ω 5 Ω Ω nA nA nA pC LOGIC INPUT IN_ Input Logic Threshold High VIN_H C, E IN_ Input Logic Threshold Low VIN_L C, E 0.8 1.6 IN_ Input Current Logic High or Low IIN_H, IIN_L C, E -0.5 0.03 0.5 150 250 125 300 225 275 VIN_ = 0 or VL 1.6 2.4 V V µA SWITCH DYNAMIC CHARACTERISTICS +25°C Transition Time (Force) tTRANS VCOM_ = ±10V, RL = 300Ω, Figure 10 Transition Time (Sense-Guard) tTRANS VCOM_ = ±10V, RL = 1kΩ, Figure 10 C, E +25°C C, E Break-Before-Make Time tBBM VCOM_ = ±10V, RL = 1kΩ, Figure 12 +25°C NO1, NC1 Off-Capacitance (Force) COFF VNO1, VNC1 = GND; f = 1MHz; Figure 14 COM1 On-Capacitance (Force) CON NO_, NC_ Off-Capacitance (Sense-Guard) ns 15 ns +25°C 21 pF VCOM1 = GND, f = 1MHz, Figure 14 +25°C 137 pF COFF VNO_, VNC_ = GND; f = 1MHz; Figure 14 +25°C 7 pF COM_ On-Capacitance (Sense-Guard) CON VCOM_ = GND, f = 1MHz, Figure 14 +25°C 30 pF Total Harmonic Distortion (Force) THD +25°C 0.007 % Off Isolation (Force) VISO +25°C -30 dB RIN = 50Ω, ROUT = 50Ω, f = 1MHz, VCOM_ = 100mVRMS, Figure 15 1 ns _______________________________________________________________________________________ 9 MAX4554/MAX4555/MAX4556 ELECTRICAL CHARACTERISTICS—MAX4556 (±15V Supplies) (continued) MAX4554/MAX4555/MAX4556 Force-Sense Switches ELECTRICAL CHARACTERISTICS—MAX4556 (±15V Supplies) (continued) (V+ = +15V, V- = -15V, VL = 5V, GND = 0V, VIN_H = 2.4V, VIN_L = 0.8V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL POWER SUPPLY Power-Supply Range V+, VL, V- CONDITIONS VL ≥ 4.5V V+ Supply Current I+ V+ = 16.5V, V- = -16.5V, VIN_ = 0 or VL V- Supply Current I- V+ = 16.5V, V- = -16.5V, VIN_ = 0 or VL VL Supply Current IL+ V+ = 16.5V, V- = -16.5V, VIN_ = 0 or VL IGND V+ = 16.5V, V- = -16.5V, VIN_ = 0 or VL Ground Current Note 2: Note 3: Note 4: Note 5: 10 TA C, E +25°C C, E +25°C C, E +25°C C, E +25°C C, E MIN ±4.5 -1.0 -5.0 -1.0 -5.0 -1.0 -5.0 -1.0 -5.0 TYP (Note 2) 0.001 0.001 0.001 0.001 MAX ±20 1.0 5.0 1.0 5.0 1.0 5.0 1.0 5.0 The algebraic convention is used in this data sheet; the most negative value is shown in the minimum column. Guaranteed by design. ∆RON = ∆RON(MAX) - ∆RON(MIN). Resistance flatness is defined as the difference between the maximum and the minimum value of on-resistance as measured over the specified analog signal range. ______________________________________________________________________________________ UNITS V µA µA µA µA Force-Sense Switches MAX4554 FORCE SWITCH ON-RESISTANCE vs. VCOM AND TEMPERATURE RDS(ON) (Ω) 25 5 20 MAX4555 SENSE 15 55 50 TA = +85°C 4 3 TA = +25°C 2 0 5 10 15 -10 VCOM (V) -5 0 5 10 15 -15 20 -5 5 10 15 ON-LEAKAGE CURRENT vs. TEMPERATURE 100 MAX4554/5/6-04 100 MAX4555 SENSE V+ = 15V, V- = -15V, VCOM = 10V 10 ON-LEAKAGE (nA) MAX4554/MAX4556 SENSE & GUARD 10 0 VCOM (V) SWITCH ON-RESISTANCE vs. VCOM (SINGLE +15V SUPPLY) SWITCH ON-RESISTANCE (Ω) -10 VCOM (V) MAX4554/5/6-05 -5 TA = -40°C 10 0 -10 30 15 0 -15 TA = +25°C 35 20 1 FORCE 5 40 25 TA = -40°C 10 TA = +85°C 45 RDS(ON) (Ω) 30 MAX4554/5/6-02 MAX4554/MAX4556 SENSE & GUARD 60 ± FORCE 1 0.1 SENSE & GUARD 0.01 FORCE 0.001 0.0001 1 -50 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 75 100 MAX4554 CHARGE INJECTION vs. VCOM (+20V, -10V SUPPLIES) 60 1 FORCE 0.1 FORCE 80 125 MAX4554/5/6-07 100 Q (pC) OFF-LEAKAGE (nA) 50 OFF-LEAKAGE CURRENT vs. TEMPERATURE V+ = 15V, V- = -15V, VNC OR VNO = ±10V VCOM = 10V 10 25 0 TEMPERATURE (°C) MAX4554/5/6-06 100 -25 VCOM (V) ± SWITCH ON-RESISTANCE (Ω) 35 6 MAX4554/5/6-01 40 SENSE/GUARD SWITCH ON-RESISTANCE vs. VCOM AND TEMPERATURE MAX4554/5/6-03 SWITCH ON-RESISTANCE vs. VCOM (DUAL SUPPLIES) 40 20 0.01 SENSE & GUARD 0.001 SENSE & GUARD 0 -20 -40 0.0001 -50 -25 0 25 50 75 TEMPERATURE (°C) 100 125 -10 -5 0 5 10 15 20 VCOM (V) ______________________________________________________________________________________ 11 MAX4554/MAX4555/MAX4556 __________________________________________Typical Operating Characteristics (V+ = +15V, V- = -15V, GND = 0V, TA = +25°C, unless otherwise noted.) ____________________________________Typical Operating Characteristics (continued) (V+ = +15V, V- = -15V, GND = 0V, TA = +25°C, unless otherwise noted.) FORCE 450 tEN(ON) 400 60 180 MAX4554/5/6-09 500 MAX4554/5/6-08 100 80 MAX4555/4556 ON/OFF/TRANSITION TIMES vs. TEMPERATURE (+20V/-10V SUPPLIES) MAX4554 ON/OFF/ENABLE TIMES vs. TEMPERATURE (+20V, -10V SUPPLIES) 160 0 120 300 250 TIME (ns) TIME (ns) 20 tEN(OFF) 200 100 -20 80 40 tON 20 tOFF 50 -40 0 -15 -10 -5 0 5 10 15 0 -40 -15 VCOM (V) 10 35 60 -40 85 -15 TEMPERATURE (°C) 35 60 LOGIC-LEVEL THRESHOLD vs. LOAD VOLTAGE 5 LOGIC-LEVEL THRESHOLD (V) A: I+ = 16.5V B: I- = -16.5V 10 C: IL = 5.5V 1 0.1 A B MAX4554/5/6-12 6 MAX4554/5/6-11 100 0.01 10 TEMPERATURE (°C) SUPPLY CURRENT vs. TEMPERATURE I+, I-, IL (µA) MAX4556 tTRANS 100 60 150 SENSE & GUARD MAX4555 tON/tOFF 140 350 40 MAX4554/5/6-10 MAX4555/MAX4556 CHARGE INJECTION vs. VCOM (+15V SUPPLIES) Q (pC) 4 3 2 1 0.001 C 0.0001 -75 -55 -50 -25 0 25 0 50 75 5 10 15 20 FORCE SWITCH FREQUENCY RESPONSE FORCE SWITCH TOTAL HARMONIC DISTORTION vs. FREQUENCY 120 90 60 30 OFF LOSS -60 -70 -80 0 -30 -60 ON PHASE -90 -120 -150 -120 -180 0.1 1 10 FREQUENCY (MHz) 100 1000 V+ = +15V V- = -15V 5Vp-p, 600Ω IN & OUT 10 THD (%) -20 -30 -40 -50 100 180 150 PHASE (degrees) MAX4554/5/6-13 ON LOSS 25 MAX4554/5/6-14 VL (V) -90 -100 -110 12 0 85 100 TEMPERATURE (°C) 0 -10 SWITCH LOSS (dB) MAX4554/MAX4555/MAX4556 Force-Sense Switches 1 0.1 0.01 0.001 10 100 1k 10k FREQUENCY (Hz) ______________________________________________________________________________________ 100k 85 Force-Sense Switches PIN NAME FUNCTION MAX4554 MAX4555 MAX4556 1 — — NOG1 — — 1, 2 NO3, NO2 2 — — NOS1 — 2, 15*, 10*, 7 14*, 15, 16 COM1, COM2 COM3, COM4 3* — — NOF1* — 3, 14, 11, 6 — NC1, NC2, NC3, NC4 — — 3* NO1* 4 4 4 V- Negative Analog Supply Voltage Input. Connect to GND for singlesupply operation. 5 5 5 GND Ground. Connect to digital ground. (Analog signals have no ground reference; they are limited to V+ and V-.) Analog Guard Channel 1 Normally Open Terminal Analog Signal Normally Open Terminals Analog Sense Channel 1 Normally Open Terminal Analog Signal Common Terminals. COM2 and COM3 are low-resistance (force) switches on the MAX4555. COM1 is a low-resistance (force) switch on the MAX4556. Analog Force Channel 1 Normally Open Terminal Analog Signal Normally Closed Pins. NC2 and NC3 are low-resistance (force) switches. Analog Force Signal Normally Open Terminal 6* — — NOF2* — — 6* NC1* Analog Force Channel 2 Normally Open Terminal Analog Force Signal Normally Closed Terminal 7 — — NOS2 Analog Sense Channel 2 Normally Open Terminal — — 7, 8 NC2, NC3 8 — — NOG2 9 — — EN 11, 10 1, 16, 9, 8 9, 10, 11 IN1, IN2, IN3, IN4 12 12 12 VL Logic-Level Positive Supply Input. Connect to logic (+5V) supply. Can be connected to V+ for single-supply operation. 13 13 13 V+ Positive Analog Supply Voltage Input. Internally connected to substrate. 14* — — COMF* Analog Force Channel Common Terminal 15 — — COMS Analog Sense Channel Common Terminal 16 — — COMG Analog Guard Channel Common Terminal Analog Signal Normally Closed Terminal Analog Guard Channel 2 Normally Open Terminal Enable Logic-Level Digital Input. Connect to GND to enable all switches. Logic-Level Digital Inputs. See Truth Tables. * Indicates high-current, low-resistance (force) switch terminal. Note: NO_, NC_, and COM_ pins are identical and interchangeable. Any may be considered as an input or output; signals pass equally well in either direction. ______________________________________________________________________________________ 13 MAX4554/MAX4555/MAX4556 Pin Description MAX4554/MAX4555/MAX4556 Force-Sense Switches ______________Force-Sense Philosophy When a precise voltage must be applied to a load that draws appreciable current, the resistance of the conductors connecting the source and the load can degrade the load voltage. The resistance of the conductors forms a voltage divider with the load, so that the load voltage is lower than the source voltage. The greater the distance between the source and the load, and the greater the current or conductor resistance, the greater the degradation. The resulting signal reduction can be overcome and the signal at the load guaranteed by using a 4-wire technique known as Kelvin sensing, or force-sense. The basic idea behind the force-sense philosophy is to use four wires, forcing a voltage or current through two high-current wires to the load, and measuring (sensing) the voltage with two separate wires that carry very low or negligible current. One of two basic configurations is used, depending on whether or not feedback is employed: 1) The sensed voltage can be completely independent of the forced voltage or current, as in the case of a 4-wire ohmmeter, where a constant current is forced through one pair of wires and the voltage at the resistor is measured by another pair. 2) The sensed voltage can be part of a feedback circuit to force the load voltage to the desired value, as in the case of a 4-wire power supply. (In rare cases, this method is also used to measure resistance; the source is forced to produce a desired voltage in the resistor, and the source current required to achieve this voltage is measured.) In all cases, the resistance of the high-current conductors can be ignored and the sensed voltage is an accurate measure of the load (or resistor’s) voltage, despite appreciable voltage loss in the wires connecting the source and load. There are two limitations to this scheme. First, the maximum source voltage (compliance) must be able to overcome the combined voltage loss of the load and the connecting wires. In other words, the conductors in the force circuit can have significant resistance, but there is a limit. Second, the impedance of the sensing circuit (typically a voltmeter, A/D converter, or feedback amplifier) must be very high compared to the load resistance and the sense wire resistance. These limitations are usually simple to overcome. The source compliance is usually required to be only a volt more than the load voltage, and the sense circuit usually has a multimegohm impedance. Typical 4-wire force-sense configurations are shown in Figure 1. 14 4-WIRE RESISTANCE MEASUREMENT (CONSTANT CURRENT) FORCE CURRENT VOLTAGE MEASUREMENT SENSE VOLTAGE MEASURED RESISTANCE V SENSE VOLTAGE FORCE CURRENT CURRENT SOURCE WIRE AND TERMINAL RESISTANCE 4-WIRE POWER SUPPLY FORCE CURRENT VOLTAGE MEASUREMENT FEEDBACK V SENSE VOLTAGE LOAD SENSE VOLTAGE FORCE CURRENT CURRENT SOURCE WIRE AND TERMINAL RESISTANCE 4-WIRE RESISTANCE MEASUREMENT (CONSTANT VOLTAGE) V FORCE VOLTAGE SENSE VOLTAGE FEEDBACK MEASURED RESISTANCE V SENSE VOLTAGE VOLTAGE MEASUREMENT FORCE VOLTAGE VOLTAGE SOURCE WIRE AND TERMINAL RESISTANCE ARROWS INDICATE SIGNAL DIRECTION, NOT POLARITY Figure 1. 4-Wire Force-Sense Measurements ______________________________________________________________________________________ Force-Sense Switches When measuring a precise voltage from a high-resistance source, or when measuring a very small current or forcing it into a load, unwanted leakage currents can degrade the results. These leakage currents may exist in the insulation of wires connecting the source and the measuring device. Higher source voltages, higher source impedances, longer wires, lower currents, and higher temperatures further degrade the measurement. The effect has both DC and low-frequency AC components; AC signals are generally capacitively coupled into the high-impedance source and wiring. The AC and DC effects are hard to separate, and are generally grouped under the designation “low-frequency noise.” This signal degradation can be overcome and the measured signal guaranteed by using a 3-wire technique known as guarding. A “guard,” “guard channel,” or “driven guard” is formed by adding a third wire to a 2-wire measurement. It consists of a physical barrier (generally the surrounding shield of a coaxial cable) that is actively forced to the same voltage as is being measured on its inner conductor. The forcing of the driven guard is from the output of a low-impedance buffer amplifier whose high-impedance input is connected to the source. The idea is not just to buffer or shield the signal with a low-impedance source but, by forcing the shield to the same potential as the signal, to also force the leakage currents between the signal and the outside world to extremely small values. Any unwanted leakage current from the source must first go through the coaxial-cable insulation to the shield. Since the shield is at the same potential, there is virtually no unwanted leakage current, regardless of the insulation resistance. The shield itself can have significant leakage currents to the outside world, but it is separated from the measured signal. The physical positioning of the guard around the signal is extremely important in maintaining low leakage. Since the guard can be at potentials far from ground, conventional coaxial cable is often replaced by triaxial cable (i.e., cable with a center conductor and two separate inner and outer shields). The signal is the center conductor, the inner shield is the guard, and the outer shield is the chassis ground. The outer shield isolates the inner driven guard from ground, physically protects the driven guard, and acts as a secondary Faraday shield for external noise. The physical guard must be maintained continuously from the source to the measuring device, including paths on printed circuit boards, where the guard becomes extra traces surrounding the signal traces on both sides (and above and below the signal traces on multilevel boards.) This is one case where a ground plane is not appropriate. In extreme cases, such as with nano-voltmeters and femto-ammeters, printed circuit boards cannot be adequately shielded and are eliminated from the guarded signal paths altogether. Figure 2 shows both the basic 3-wire guarded measurement and a 5-wire variation, used for balanced signals that are elevated from ground potential. The 5-wire configuration is really two 3-wire circuits sharing a common ground. Figure 2 also shows the configuration using triaxial cable. ____Force-Sense-Guard Philosophy Force-sense measurements are combined with guarded measurements when a wide range of voltages and currents are encountered, or when voltage and current must be accurately measured or controlled simultaneously. This frequently occurs in automatic test equipment (ATE) and in some critical physical or chemical sensor applications where voltage and/or current measurements can span many decades. Two techniques are used: 8-wire and 12-wire. 8-Wire Measurements Figure 3 shows an 8-wire guarded force-sense power supply. A precise voltage is forced to the load, and load current is sensed without interacting with the output voltage, and without unwanted leakage currents. Separate twin-axial, or “twinax” cable is used for each of the positive and negative wires. Each cable has a twisted-pair of wires surrounded by a common shield, which is connected as the driven guard. Since the force and sense wires are at approximately the same potential, they can be protected by the same driven guard. In critical applications, two special 4-wire cables and connectors are substituted for the two twinax cables and separate ground wire. These cables add a second shield, which replaces the chassis-to-chassis ground wire and reduces noise. Figure 3 shows current sensing with a fixed precision resistor and voltmeter, but other methods (such as op amps with feedback) are frequently employed, particularly if current limiting is required. One of the advantages of Figure 3’s circuit is that leakage in the current-sensing path has no effect on the output voltage. The two diodes in the force-sense feedback path protect the force-sense amplifier from operating open loop if either the force or sense wires are disconnected from the load. These diodes must have both lower forward voltage and lower reverse leakage than the current being measured. ______________________________________________________________________________________ 15 MAX4554/MAX4555/MAX4556 __________________Guard Philosophy MAX4554/MAX4555/MAX4556 Force-Sense Switches BALANCED 5-WIRE GUARD CIRCUIT BASIC 3-WIRE GUARD CIRCUIT DRIVEN GUARD (COAX CABLE SHIELD) DRIVEN GUARD (COAX CABLE SHIELD) GUARD AMPLIFIER GUARD AMPLIFIER SENSE VOLTAGE OR CURRENT LEAKAGE CURRENT VOLTAGE OR CURRENT SOURCE LEAKAGE CURRENT LEAKAGE CURRENT VOLTAGE OR CURRENT SOURCE 3-WIRE GUARD CIRCUIT USING TRIAX TRIAX CABLE GUARD AMPLIFIER SIGNAL GUARD GROUND GUARD AMPLIFIER SENSE VOLTAGE OR CURRENT DRIVEN GUARD (COAX CABLE SHIELD) LEAKAGE CURRENT TRIAX CABLE/CONNECTOR VOLTAGE OR CURRENT SOURCE CENTER WIRE INNER SHEILD OUTER SHEILD Figure 2. 3-Wire and 5-Wire Guarded Measurements 16 ______________________________________________________________________________________ SENSE VOLTAGE OR CURRENT Force-Sense Switches MAX4554/MAX4555/MAX4556 8-WIRE PRECISION SOURCE-MONITOR FORCE-SENSE AMPLIFIER V+ CURRENT SENSE +FORCE +SENSE +DRIVEN GUARD V TWINAX CABLE VV+ GUARD AMPLIFIER VV+ LEAKAGE CURRENT VOLTAGE SOURCE LOAD LEAKAGE CURRENT V+ V- GUARD AMPLIFIER V+V V -DRIVEN GUARD -SENSE -FORCE TWINAX CABLE CURRENT SENSE VFORCE-SENSE AMPLIFIER Figure 3. 8-Wire Guarded Force-Sense Measurements Note that although the positive and negative circuits are identical, they are not redundant. Both are always used, even when one side of the load is grounded, because maintaining a precision output voltage requires losses in the ground leads to be corrected by a force-sense amplifier. If more than one power supply and load are operated together, and they have a common connection, this requirement becomes even more critical. Separate 8-wire connections prevent current changes in one load from changing voltage in the other load. 12-Wire Measurements Figure 4 shows a 12-wire circuit, which is an elaboration of the 8-wire system using separate driven guards for the force and sense wires. Four sets of triaxial cables and connectors are used. The extra wires are used for two reasons: 1) They provide better shielding by having separate chassis grounds on each cable, rather than separate ground wires external to the signal cables; 2) In test equipment, where connection changes are frequent, it is very convenient to use four triax connectors or two quadrax (dual triax) connectors for each load. In addition, this method is slightly better for power supplies or measurements that switch between constant voltage and constant current, since separate driven guards reduce circuit capacitance. Also, when troubleshooting, it is convenient to be able to interchange force and sense leads. ______________________________________________________________________________________ 17 MAX4554/MAX4555/MAX4556 Force-Sense Switches 12-WIRE PRECISION SOURCE-MONITOR + FORCE-SENSE AMPLIFIER V+ CURRENT SENSE V TRIAX CABLE +FORCE +GUARD GROUND VV+ LEAKAGE CURRENT VTRIAX CABLE +SENSE +GUARD GROUND + FORCE-GUARD AMPLIFIER V+ +SENSE GUARD AMPLIFIER V- LEAKAGE CURRENT V+ VOLTAGE SOURCE LOAD (OPTIONAL GROUND) VLEAKAGE CURRENT V+ - SENSE-GUARD AMPLIFIER V- FORCE-GUARD AMPLIFIER V+ GROUND - GUARD -SENSE TRIAX CABLE LEAKAGE CURRENT V+ V- GROUND - GUARD - FORCE +V V CURRENT SENSE V- - FORCE-SENSE AMPLIFIER TRIAX CABLE TRIAX CABLE/CONNECTOR CENTER WIRE (FORCE/SENSE) INNER SHEILD (GUARD) OUTER SHEILD (GROUND) Figure 4. 12-Wire Guarded Force-Sense Measurements 18 ______________________________________________________________________________________ Force-Sense Switches When a precision source or measurement must be connected sequentially to several circuits, all sense and guard connections must be switched simultaneously, and at least one of the force connections must be switched. To maintain safety and low noise levels, the ground (or chassis) connection should never be disconnected. The force circuit switch should have low-resistance, high-current capability, but the sense and guard circuit switches require only moderate resistance and current capability. The sense and guard switches should have lower leakage than the lowest measured current. CMOS switches should also be operated from power supplies higher than the highest circuit voltage to be switched. _______________Detailed Description The MAX4554/MAX4555/MAX4556 are CMOS analog ICs configured as force-sense switches. Each part contains low-resistance switches for forcing current, and higher resistance switches for sensing a voltage or driving guard wires. Analog signals on the force, sense, or guard circuits can range from V- to V+. Each switch is completely symmetrical and signals are bidirectional; any switch terminal can be an input or output. The switches’ open or closed states are controlled by TTL/CMOS-compatible input (IN_) pins. The MAX4555 and MAX4556 are characterized and guaranteed only with ±15V supplies, but they can operate from a single supply up to +44V or non-symmetrical supplies with a voltage totaling less than +44V. The MAX4554 is fully characterized for operation from ±15V supplies, and it is also fully specified for operation with +20V and -10V supplies. A separate logic supply pin, VL, allows operation with +5V or +3V logic, even with unusual V+ values. The negative supply pin, V-, must be connected to GND for single-supply operation. The MAX4554 contains two force switches, two sense switches, and two guard switches configured as two 3PST switches. The two switches operate independently of one another, but they have a common connection, allowing one source to be connected simultaneously to two loads, or two sources to be connected to one load. An enable pin, EN, turns all switches off when driven to logic high. The MAX4554 is also fully specified for operation with +20V and -10V supplies. The MAX4555 contains four independent SPDT, NC switches; two are force switches and two are sense switches. The MAX4556 contains three independent SPDT switches; one is a force switch and two are sense switches. Switch Resistances Each IC contains four internal switches: four low-current sense-guard switches and two high-current force switches. Each sense-guard switch has an on-resistance of approximately 60Ω, while each force switch has an on-resistance of approximately 6Ω. The MAX4555’s two low-current sense-guard switches are connected in parallel to produce lower on-resistance and allow higher current. Power-Supply Considerations Overview The MAX4554/MAX4555/MAX4556’s construction is typical of most CMOS analog switches. They have four supply pins: V+, V-, VL, and GND. V+ and V- are used to drive the internal CMOS switches and set the analog voltage limits on any switch. Reverse ESD protection diodes are internally connected between each analog and digital signal pin and both V+ and V-. If any signal exceeds V+ or V-, one of these diodes will conduct. During normal operation these reverse-biased ESD diodes leak, forming the only current drawn from the signal paths. Virtually all the analog leakage current comes through the ESD diodes to V+ or V-. 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 from the signal path to the V+ and V- pins constitutes the analog-signal-path leakage current. All analog leakage current flows to the supply terminals, not to the other switch terminal. This explains how 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 or VL. The analog signal paths consist of an N-channel and P-channel MOSFET with their sources and drains paralleled, and their gates driven out of phase to V+ and V- by the logic-level translators. VL and GND power the internal logic and logic-level translator and set the input logic threshold. The logiclevel translator converts the logic levels to switched V+ and V- signals for driving the gates of the analog switches. This drive signal is the only connection between GND and the analog supplies. V+ and V- have ESD-protection diodes to GND. The logic-level inputs (IN_, and EN) have ESD protection to V+ and V-, but not to GND; therefore, the logic signal can go below GND (as low as V-) when bipolar supplies are used. The logic-level threshold VIN is CMOS and TTL compatible when VL is between 4.5V and 36V (see Typical Operating Characteristics). ______________________________________________________________________________________ 19 MAX4554/MAX4555/MAX4556 Switching Guarded and Force-Sense Signals MAX4554/MAX4555/MAX4556 Force-Sense Switches Increasing V- has no effect on the logic-level thresholds, but it does increase the drive to the internal Pchannel switches, reducing the overall switch on-resistance. V- also sets the negative limit of the analog signal voltage. Bipolar-Supply Operation The MAX4554/MAX4555/MAX4556 operate with bipolar supplies between ±4.5V and ±18V. However, since all factory characterization is done with ±15V supplies (and +20V, -10V for MAX4554), operation at other supplies is not guaranteed. The V+ and V- supplies need not be symmetrical, but their sum cannot exceed the absolute maximum rating of 44V (see Absolute Maximum Ratings). VL must not exceed V+. Single-Supply Operation The MAX4554/MAX4555/MAX4556 operate from a single supply between +4.5V and +44V when V- is con- nected to GND. All of the bipolar precautions must be observed. __________Applications Information Switching 4-Wire Force-Sense Circuits Figure 5 shows how to switch a single voltage or current source between two loads using two MAX4555s. A single CMOS inverter ensures that only one switch is on at a time. On each MAX4555, switches 2 and 3 are the high-current switches, so they should be used for force circuits. By interchanging loads and sources, the circuit can be reversed to switch two sources to a single load. Additional MAX4555s and loads or sources can be added to expand the circuit, but additional IN_ address decoding must be incorporated. V+ FORCE COM2 SENSE COM1 V- VL MAX4555 NC2 NC1 FEEDBACK V SENSE FORCE LOAD1 COM4 NC4 COM3 NC3 IN2 VOLTAGE/CURRENT SOURCE IN1 LOGIC IN LOAD 0 1 CMOS INVERTER IN GND IN4 IN3 2 1 V+ COM2 V- VL MAX4555 NC2 COM1 NC1 COM4 NC4 COM3 NC3 LOAD2 IN2 IN1 GND IN4 IN3 Figure 5. Using the MAX4555 to Switch 4-Wire Force-Sense Circuits from One Source to Two Loads 20 ______________________________________________________________________________________ Force-Sense Switches would be close to (but not exactly equal to) the desired value; this would not cause any damage to the device. Switching 3-Wire Guarded Circuits Figure 7 shows how to switch a single guarded voltage or current source between two loads using the MAX4554 or MAX4556. By interchanging loads and sources, the circuits can be reversed to switch two sources to a single load. If the loads have a common connection, the switch to that node can be eliminated. Note that these circuits use sense (high-resistance) switches to switch the common wire. This is permissible only if the load currents are very low. If the currents are high, the common connection should not be switched unless another force switch is substituted. V+ V- VL MAX4556 FORCE COM1 SENSE COM2 SENSE COM3 NC1 NO1 NC2 NO2 FEEDBACK V NC3 LOAD1 LOAD2 LOAD1 NO3 FORCE IN1 VOLTAGE/CURRENT SOURCE GND IN2 LOGIC IN LOAD 0 1 1 2 IN IN3 V+ V- VL MAX4554 NOF1 FORCE FCOM NOF2 SENSE SCOM NOS1 NOS2 SENSE GCOM FEEDBACK V LOAD2 NOG2 FORCE NOG1 IN1 VOLTAGE/CURRENT SOURCE LOGIC IN LOAD 0 1 1 2 GND EN IN2 IN CMOS INVERTER Figure 6. Using the MAX4554/MAX4556 to Switch 4-Wire Force-Sense Circuits from One Source to Two Loads ______________________________________________________________________________________ 21 MAX4554/MAX4555/MAX4556 Figure 6 shows how to switch a single voltage or current source between two loads using the MAX4554 or MAX4556. By interchanging loads and sources, the circuits can be reversed so that they switch two sources to a single load. The two loads are electrically connected together at one point, but may be physically separated. This means that one force wire does not need to be switched, but the corresponding sense wires do. The MAX4554 has independent 3PST, NO switches driven out of phase by an external CMOS inverter, so that one switch is on while the other is off. If both switches were turned on at the same time, both loads would be connected, and the resulting voltage at either load MAX4554/MAX4555/MAX4556 Force-Sense Switches V+ V- VL MAX4556 NC1 NO1 NC2 NO2 COM1 GUARD AMPLIFIER COM2 NC3 COM3 LOAD2 LOAD1 LOAD2 LOAD1 NO3 IN1 GND IN2 VOLTAGE OR CURRENT SOURCE IN 0 1 IN IN3 LOGIC LOAD 1 2 V+ V- MAX4554 GUARD AMPLIFIER VL NOG1 GCOM NOG2 FCOM NOF1 NOF2 SCOM NOS1 NOS2 IN1 GND EN VOLTAGE OR CURRENT SOURCE IN 0 1 LOGIC LOAD 1 2 IN IN2 CMOS INVERTER Figure 7. Using the MAX4554/MAX4556 to Switch 3-Wire Guarded Circuits from One Source to Two Loads 22 ______________________________________________________________________________________ Force-Sense Switches Switching 8-Wire Guarded Circuits Figure 9 shows how to switch a single 8-wire guarded force-sense voltage or current source between two loads using two MAX4556s or two MAX4554s. By interchanging loads and sources, the circuits can be reversed so that they switch two sources to a single load. The two loads are shown isolated from each another, but if they have a common connection then the circuit must remain as shown in order to maintain accurate load voltage. High-Frequency Performance Although switching speed is restricted, once a switch is in a steady state it exhibits good RF performance. In 50Ω systems, signal response is reasonably flat up to 50MHz (see Typical Operating Characteristics). The force switches have lower on-resistance, so their insertion loss in 50Ω systems is lower. Above 20MHz, the on-response has several minor peaks that are highly layout dependent. The problem with high-frequency operation is not turning the switches on, but turning them off. The off-state switches act like capacitors and pass higher frequencies with less attenuation. At 10MHz, off-isolation between input or output signals is approximately -30dB in 50Ω systems, degrading (approximately 20dB per decade) as frequency increases. Higher circuit impedances also degrade offisolation. V+ COM1 GUARD AMPLIFIER COM2 V- VL MAX4555 NC1 NC2 LOAD2 COM3 COM4 IN1 IN2 NC3 NC4 GND LOAD1 IN3 VOLTAGE OR CURRENT SOURCE IN 0 1 IN IN4 LOGIC LOAD 2 1 Figure 8. Using the MAX4555 to Switch 3-Wire Guarded Circuits from One Source to Two Loads ______________________________________________________________________________________ 23 MAX4554/MAX4555/MAX4556 Figure 8 shows how to switch a single guarded voltage or current source between two grounded loads using a MAX4555. By interchanging loads and sources, the circuits can be reversed so that two sources are switched to a single load. MAX4554/MAX4555/MAX4556 Force-Sense Switches FORCE-SENSE AMPLIFIER V+ V+ V- VL CURRENT SENSE NC1 NC2 NC3 NO1 NO2 NO3 GND MAX4556 V- V+ V VL VCOM1 COM2 COM3 V+ MAX4556 NC1 NO1 COM1 IN1 NC2 COM2 NO2 NC3 COM3 NO3 GUARD AMPLIFIER V- IN2 V+ IN3 INA V+ LEAKAGE CURRENT V- LEAKAGE CURRENT VVL VOLTAGE SOURCE IN1 TWINAX CABLE +FORCE +SENSE +DRIVEN GUARD V+ LOAD 1 LOAD 2 IN2 GUARD AMPLIFIER GND IN IN3 MAX4556 NC1 NC2 NC3 NO1 NO2 NO3 GND COM1 COM2 COM3 VV+ V CURRENT SENSE VFORCE-SENSE AMPLIFIER V+ LOGIC IN A,B LOAD 0 1 1 2 IN1 IN2 IN3 INA V+ V- VL CURRENT SENSE MAX4554 V VV+ V- VL COMF COMS COMG V+ MAX4554 NOG1 COMG GUARD AMPLIFIER NOG2 NOF1 COMF NOF2 V- IN LEAKAGE CURRENT V- LEAKAGE CURRENT V+ GUARD AMPLIFIER EN GND IN2 CMOS INVERTER CURRENT SENSE V- LOGIC IN A,B LOAD 0 2 1 1 LOAD 1 VL IN1 NOG1 NOS1 NOF1 NOG2 NOS2 NOF2 EN GND IN2 -DRIVEN GUARD -SENSE -FORCE TWINAX CABLE INB Figure 9. Switching 8-Wire Guarded Force-Sense Measurements from One Precision Source-Monitor to Two Loads 24 LOAD 2 MAX4554 V FORCE-SENSE AMPLIFIER V- COMG COMS COMF VV+ LOGIC IN A,B LOAD 0 2 1 1 IN2 V+ NOS1 NOS2 IN1 TWINAX CABLE +FORCE +SENSE +DRIVEN GUARD INB VOLTAGE SOURCE V+ COMS IN1 NC1 NC2 NC3 NO1 NO2 NO3 EN GND -DRIVEN GUARD -SENSE -FORCE TWINAX CABLE ______________________________________________________________________________________ Force-Sense Switches V+ VL V+ VL VL NO_ OR NC_ V+ 50% VIN_ 0V VIN_ MAX4554 MAX4555 MAX4556 COM_ IN_ 50Ω GND EN V- V+ VOUT 300Ω 90% 35pF VOUT V- 90% 0V V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION. tOFF tON Figure 10. Address Transition Time VL V+ VL V+ VL VL NO_ ADDRESS SELECT V+ 50% VEN 0V IN_ MAX4554 COM_ VEN GND EN V- 50Ω V+ VOUT 300Ω 90% 35pF VOUT V- 90% 0V tTRANS tTRANS V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION. Figure 11. Enable Transition Time VIN_ IN_ 50Ω V+ VL V+ VL VIN_ NO_ VNO_, NC_ 80% VOUT COM_ V- 50% 0V V+ NC_ MAX4556 GND t R < 5ns t F < 5ns V+ VOUT 300Ω V- 35pF 0V tOPEN V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION. Figure 12. Break-Before-Make Interval ______________________________________________________________________________________ 25 MAX4554/MAX4555/MAX4556 ______________________________________________Test Circuits/Timing Diagrams MAX4554/MAX4555/MAX4556 Force-Sense Switches _________________________________Test Circuits/Timing Diagrams (continued) VIN_ IN_ V+ VL V+ VL VL VIN NO_ OR NC_ 50Ω 0V MAX4554 MAX4555 MAX4556 COM_ GND EN VOUT V- ∆VOUT VOUT CL 1000pF ∆VOUT IS THE MEASURED VOLTAGE DUE TO CHARGE TRANSFER ERROR Q WHEN THE CHANNEL TURNS OFF. V- Q = ∆VOUT x CL V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION. Figure 13. Charge Injection VL V+ VL MAX4554 MAX4555 MAX4556 VL ADDRESS SELECT V+ NO_ NC_ 1MHz CAPACITANCE ANALYZER COM_ IN_ GND EN VV- Figure 14. COM_, NO_, NC_ Capacitance V+ 10nF VL 10nF V+ VL COM_ NETWORK ANALYZER VIN 50Ω MAX4554 MAX4555 MAX4556 VL ADDRESS SELECT IN_ EN GND VOUT VOUT VIN ON LOSS = 20 log VOUT VIN CROSSTALK = 20 log VOUT VIN 50Ω MEAS. REF NO_, NC_ V50Ω OFF ISOLATION = 20 log 50Ω 10nF VMEASUREMENTS ARE STANDARDIZED AGAINST SHORT AT SOCKET TERMINALS. OFF ISOLATION IS MEASURED BETWEEN COM_ AND "OFF" NO_ OR NC_ TERMINALS. ON LOSS IS MEASURED BETWEEN COM_ AND "ON" NO_ OR NC_ TERMINALS. CROSSTALK IS MEASURED BETWEEN COM_ TERMINALS WITH ALL SWITCHES ON. SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED. V- IS CONNECTED TO GND (0V) FOR SINGLE-SUPPLY OPERATION. Figure 15. Frequency Response, Off-Isolation, and Crosstalk 26 ______________________________________________________________________________________ Force-Sense Switches TOP VIEW MAX4555 MAX4556 16 IN2 IN1 1 15 COM2* COM1 2 14 NC2* NC1 3 NO3 1 16 COM3 N02 2 15 COM2 NO1* 3 14 COM1* V- 4 13 V+ V- 4 13 V+ GND 5 12 VL GND 5 12 VL NC4 6 11 NC3* NC1* 6 11 IN1 10 COM3 NC2 7 10 IN2 9 IN3 NC3 8 9 IN3 COM4 7 IN4 8 DIP/SO DIP/SO MAX4555 IN_ SWITCH MAX4556 IN_ COM_ 0 1 ON OFF 0 1 NC_ NO_ SWITCH POSITIONS SHOWN WITH IN_ = LOW *INDICATES HIGH-CURRENT, LOW-RESISTANCE FORCE SWITCH Ordering Information (continued) PART TEMP. RANGE PIN-PACKAGE MAX4555CPE 0°C to +70°C 16 Plastic DIP MAX4555CSE 0°C to +70°C 16 Narrow SO MAX4555C/D MAX4555EPE MAX4555ESE 0°C to +70°C -40°C to +85°C -40°C to +85°C Dice* 16 Plastic DIP 16 Narrow SO MAX4556CPE 0°C to +70°C 16 Plastic DIP MAX4556CSE 0°C to +70°C 16 Narrow SO MAX4556C/D MAX4556EPE MAX4556ESE 0°C to +70°C -40°C to +85°C -40°C to +85°C Dice* 16 Plastic DIP 16 Narrow SO *Contact factory for availability. ______________________________________________________________________________________ 27 MAX4554/MAX4555/MAX4556 __________Pin Configurations/Functional Diagrams/Truth Tables (continued) MAX4554/MAX4555/MAX4556 Force-Sense Switches _________________________________________________________________________Chip Topographies MAX4554 NOG1 MAX4555 IN1 COMG NOS1 COM1 COMS NOF1 IN2 COM2 NC1 NC2 COMF V+ V- 0.190" (4.83mm) GND V+ V- 0.190" (4.83mm) GND VL VL NC3 IN1 COM3 NC4 IN2 NOF2 COM4 NOS2 NOG2 IN4 EN 0.086" (2.18mm) IN3 0.086" (2.18mm) MAX4556 NO3 COM3 NO2 COM2 NO1 COM1 V+ V- 0.190" (4.83mm) GND VL IN1 IN2 NC1 NC2 NC3 IN3 0.086" (2.18mm) TRANSISTOR COUNT: 197 SUBSTRATE IS INTERNALLY 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. 28 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.