19-2230; Rev 2; 2/05 Digitally Programmable Precision Voltage Divider for PGAs Features Four Precision Divider Ratios For Noninverting Gains of 1, 2, 4, and 8 in PGAs 0.025%, 0.09%, or 0.5% Ratio Accuracy Guaranteed Over -40C to +85C On-Chip Matching Resistor for Op Amp BiasCurrent Compensation (MAX5421) 5V Single or 5V Dual Supply Operation Low 3A Supply Current CMOS/TTL Logic Compatible 2-Wire Parallel Interface Small 8-Pin and 10-Pin MAX Packages Applications General-Purpose Programmable Noninverting Amplifiers Programmable Instrumentation Amplifiers Ordering Information TEMP. RANGE PART PINPACKAGE GAIN ACCURACY MAX5420AEUA -40C to +85C 8 MAX 0.025% MAX5420BEUA 0.09% -40C to +85C 8 MAX MAX5420CEUA -40C to +85C 8 MAX 0.5% MAX5421AEUB -40C to +85C 10 MAX 0.025% MAX5421BEUB -40C to +85C 10 MAX 0.09% MAX5421CEUB -40C to +85C 10 MAX 0.5% Pin Configurations Functional Diagram TOP VIEW VDD 1 VDD 8 H 7 W 3 6 L D0 4 5 D1 H VSS 2 MAX5420 MAX5421 GND W D0 MAX5420 DECODER MAX-8 D1 MATCH_H VDD 1 MATCH_L VSS GND L MAX5421 ONLY VSS 10 H 2 MAX5421 9 W GND 3 8 L D0 4 7 MATCH_H D1 5 6 MATCH_L MAX-10 ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. 1 MAX5420/MAX5421 General Description The MAX5420 and MAX5421 are digitally programmable precision voltage dividers optimized for use in digitally programmable gain amplifier configurations. The MAX5420/ MAX5421 operate from a single +5V supply or dual 5V supply, and consume only 3A supply current. These devices consist of a digitally selectable resistor array that provides four precision noninverting gains of 1, 2, 4, and 8 for PGAs. The MAX5420 and MAX5421 achieve a resistor ratio accuracy of 0.025% (MAX542_A), 0.09% (MAX542_B), and 0.5% (MAX542_C). The MAX5421 includes an on-chip matching resistor for op amp bias-current compensation. The MAX5420 and MAX5421 are available in 8-pin and 10-pin MAX packages. The devices are specified over the extended temperature range (-40C to +85C). MAX5420/MAX5421 Digitally Programmable Precision Voltage Divider for PGAs ABSOLUTE MAXIMUM RATINGS VDD to GND ..............................................................-0.3V to +6V VSS to GND...............................................................+0.3V to -6V D0, D1 to GND ...........................................-0.3V to (VDD + 0.3V) H, L, W, MATCH_ to GND ................(VSS - 0.3V) to (VDD + 0.3V) Input and Output Latchup Immunity.................................50mA Continuous Power Dissipation (TA = +70C) 8-Pin MAX (derate 4.1mW/C above +70C) .............333mW 10-Pin MAX (derate 5.6mW/C above +70C) ...........444mW Operating Temperature Range ...........................-40C to +85C Storage Temperature Range .............................-60C to +150C Lead Temperature (soldering, 10s) .................................+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 (VDD = +5V 5%, VSS = -5V 5% or VSS = GND, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SYMBOL Divider Ratio Accuracy H-to-L Resistance RHL Input Resistance at H RH Input Resistance at W RW CONDITIONS MIN MAX542_B 0.09 MAX542_C 0.5 (Figure 1) 15 Ratio = 1 300 VSS = 0 500 MAX5421 Ratio = 1 % 8 k 5 pF VSS = -5V 300 VSS = 0 500 Ratio = 2, 4, 8 UNITS k k 15 VSS = -5V CANALOG Matching Resistor MAX 0.025 Ratio = 2, 4, 8 Capacitance at H, L, W, MATCH_H, MATCH_L TYP MAX542_A 8 k 0.5 s DYNAMIC PERFORMANCE Switching Time tS VDD = +5V, VSS = -5V, digital input 0 to +3V, VW settles to 0.02% of final value with 2pF capacitive load. Circuit of Figure 2. DIGITAL INPUTS Input High Voltage VIH Input Low Voltage VIL Input Leakage Current Input Capacitance 2 2.4 0.8 D1, D0 = VDD or GND 1 5 _______________________________________________________________________________________ V A pF Digitally Programmable Precision Voltage Divider for PGAs (VDD = +5V 5%, VSS = -5V 5% or VSS = GND, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER SUPPLIES Positive Supply Voltage VDD 4.75 5.25 Negative Supply Voltage VSS 0 -5.25 Positive Supply Current IDD Negative Supply Current ISS D1, D0 = VDD or GND 3 7 D1, D0 = 3V 15 25 D1, D0 = VDD or GND 3 7 D1, D0 = 3V 15 25 W, H, L, MATCH_L, MATCH_H Voltage Range V A A VDD VSS V Typical Operating Characteristics (VDD = +5V, VSS = -5V, or VSS = GND, TA = +25C, unless otherwise noted.) (Note 1) 0.0046 0.0004 0.0042 0.0038 0.0034 0.0001 -15 10 35 TEMPERATURE (C) 60 85 VH = +5V VL = -5V RATIO = 4 0.004 0.003 0.002 0.001 0.0030 -40 0.005 RATIO ACCURACY (%) 0.0007 VH = +5V VL = -5V RATIO = 2 MAX542_A DIVIDER RATIO ACCURACY vs. TEMPERATURE MAX5420/21 toc02 0.0050 RATIO ACCURACY (%) RATIO ACCURACY (%) VH = +5V VL = -5V RATIO = 1 MAX5420/21 toc01 0.0010 MAX542_A DIVIDER RATIO ACCURACY vs. TEMPERATURE MAX5420/21 toc03 MAX542_A DIVIDER RATIO ACCURACY vs. TEMPERATURE 0 -40 -15 10 35 TEMPERATURE (C) 60 85 -40 -15 10 35 60 85 TEMPERATURE (C) _______________________________________________________________________________________ 3 MAX5420/MAX5421 ELECTRICAL CHARACTERISTICS (continued) MAX5420/MAX5421 Digitally Programmable Precision Voltage Divider for PGAs Typical Operating Characteristics (continued) (VDD = +5V, VSS = -5V, or VSS = GND, TA = +25C, unless otherwise noted.) (Note 1) VH = +5V VL = -5V RATIO = 1 0.004 0.003 0.002 0.0015 VH = +5V VL = -5V RATIO = 2 -0.0225 RATIO ACCURACY (%) RATIO ACCURACY (%) RATIO ACCURACY (%) 0.005 -0.0200 MAX5420/21 toc05 VH = +5V VL = -5V RATIO = 8 0.006 0.0020 MAX5420/21 toc04 0.007 MAX542_B DIVIDER RATIO ACCURACY vs. TEMPERATURE MAX542_B DIVIDER RATIO ACCURACY vs. TEMPERATURE MAX5420/21 toc06 MAX542_A DIVIDER RATIO ACCURACY vs. TEMPERATURE 0.0010 -0.0250 -0.0275 0.0005 0.001 10 35 60 85 -40 -15 10 35 60 85 -15 MAX542_B DIVIDER RATIO ACCURACY vs. TEMPERATURE MAX542_B DIVIDER RATIO ACCURACY vs. TEMPERATURE -0.050 VH = +5V VL = -5V RATIO = 8 RATIO ACCURACY (%) -0.035 -0.040 35 60 85 -0.055 MAX542_A RATIO ACCURACY vs. POSITIVE SUPPLY VOLTAGE 0.01 RATIO = 4 RATIO ACCURACY (%) VH = +5V VL = -5V RATIO = 4 MAX5420/21 toc07 -0.030 10 TEMPERATURE (C) TEMPERATURE (C) MAX5420/21 toc08 -15 TEMPERATURE (C) -0.060 RATIO = 8 RATIO = 2 0.001 -0.065 -0.045 RATIO = 1 VH = +3V, VL = 0 0.0001 -0.070 10 35 60 -40 85 -15 MAX542_B RATIO ACCURACY vs. POSITIVE SUPPLY VOLTAGE 60 4.75 85 5.00 0.01 RATIO ACCURACY (%) RATIO = 2 RATIO = 8 0.001 RATIO = 8 RATIO = 2 RATIO = 4 5.25 POSITIVE SUPPLY VOLTAGE (V) MAX542_A RATIO ACCURACY vs. NEGATIVE SUPPLY VOLTAGE MAX5420/21 toc10 RATIO = 4 0.01 35 TEMPERATURE (C) TEMPERATURE (C) 0.1 10 MAX542_B RATIO ACCURACY vs. NEGATIVE SUPPLY VOLTAGE 0.1 RATIO ACCURACY (%) -15 MAX5420/21 toc11 -40 0.001 MAX5420/21 toc12 -0.050 RATIO ACCURACY (%) RATIO ACCURACY (%) -0.0300 -40 0 -40 MAX5420/21 toc09 0 RATIO = 4 RATIO = 2 0.01 RATIO = 8 VH = 5V, VL = 0 0.001 RATIO = 1 0.0001 VH = +3V, VL = 0 4.75 RATIO = 1 5.00 POSITIVE SUPPLY VOLTAGE (V) 4 VH = 5V, VL = 0 5.25 0.0001 -5.25 -4.00 RATIO = 1 -2.75 -1.50 NEGATIVE SUPPLY VOLTAGE (V) -0.25 0.0001 -5.25 -4.00 -2.75 -1.50 NEGATIVE SUPPLY VOLTAGE (V) _______________________________________________________________________________________ -0.25 Digitally Programmable Precision Voltage Divider for PGAs SWITCHING TIME (RATIO 2-TO-4) SWITCHING TIME (RATIO 1-TO-2) MAX5420/21 toc14 MAX5420/21 toc13 D0, 5V/div 0 D1, 5V/div 0 VW 2V/div VW 1V/div 100ns/div VH = +5V, VL = -5V 100ns/div VH = +5V, VL = -5V SUPPLY CURRENT vs. TEMPERATURE SWITCHING TIME (RATIO 4-TO-8) MAX5420/21 toc15 MAX5420/21 toc16 5 D1, D0 = GND or VDD VW 500mV/div 4 SUPPLY CURRENT (A) 5V D0, 5V/div 0 3 2 1 0 100ns/div VH = +5V, VL = -5V -40 -15 10 35 60 85 TEMPERATURE (C) Note 1: For MAX542_C accuracy Typical Operating Characteristics, refer to MAX542_B accuracy Typical Operating Characteristics. _______________________________________________________________________________________ 5 MAX5420/MAX5421 Typical Operating Characteristics (continued) (VDD = +5V, VSS = -5V, or VSS = GND, TA = +25C, unless otherwise noted.) (Note 1) MAX5420/MAX5421 Digitally Programmable Precision Voltage Divider for PGAs Pin Description PIN NAME FUNCTION MAX5420 MAX5421 1 1 VDD Positive Supply Voltage 2 2 VSS Negative Supply Voltage 3 3 GND Ground 4, 5 4, 5 D0, D1 6 8 L 7 9 W Resistor-Divider Output 8 10 H High Terminal of Resistor-Divider -- 6 MATCH_L Matching Resistor Low Terminal -- 7 MATCH_H Matching Resistor High Terminal Digital Control Inputs. Drive D0 and D1 logic high or logic low to set the divider ratio. See Logic Control Truth Table. Low Terminal of Resistor-Divider Detailed Description The MAX5420/MAX5421 are digitally programmable precision voltage dividers for programmable-gain amplifiers. Operationally, these devices consist of digitally selectable precision resistor-dividers providing noninverting gains of 1, 2, 4, and 8 for PGA applications (see Functional Diagram and Figure 1). Ratio = 1 + R_B R_ A The MAX5420/MAX5421 achieve divider ratio accuracy of 0.025% (MAX5420A/MAX5421A), 0.09% (MAX5420B/ MAX5421B) or 0.5% (MAX5420C/MAX5421C). The end-to-end resistance from H to L is 15k. The impedance seen at W is designed to be the same 8k for divider ratios 2, 4, and 8, ensuring excellent impedance matching and constant switching times. In gain of +1 configuration, H is internally connected to W with a typical resistance of 500. Matching Resistor (MAX5421) The MAX5421 includes a matching resistor to compensate for offset voltage due to input bias current of the op amp. The resistance from MATCH_H to MATCH_L, equals the resistance seen at W for gains of 2, 4, and 8. In the gain of +1, an internal switch connects MATCH_H and MATCH_L. This internal switch matches the impedance of the switch between H and W. 6 Table 1. Logic Control Truth Table DIGITAL INPUTS D1 D0 DIVIDER RATIO 0 0 1 0 1 2 1 0 4 1 1 8 Digital Interface Operation The MAX5420/MAX5421 feature a simple two-bit parallel programming interface. D1 and D0 program the divider ratio setting according to the Logic Control Truth Table (Table 1). The digital interface is CMOS/TTL logic compatible. Applications Information Programmable-Gain Amplifier The MAX5420/MAX5421 are ideally suited for high-precision PGA applications. The typical application circuit of Figure 3 uses the MAX5421 with matching resistor to compensate for voltage offset due to op amp input bias currents. Use the MAX5420 with an ultra-low input bias current op amp such as the MAX4237 (Figure 4). Power Supplies and Bypassing The MAX5420/MAX5421 operate from dual 5V supplies, or a single +5V supply. For dual supplies, bypass VDD and VSS with 0.1F ceramic capacitors to GND. For single supply, connect VSS to GND and bypass VDD with a 0.1F ceramic capacitor to GND. _______________________________________________________________________________________ Digitally Programmable Precision Voltage Divider for PGAs VDD RATIO = 1 +5V MATCH_H MATCH_L VIN VOUT MAX5421 MAX4493 L R2B R3B MAX5420/MAX5421 +5V H H R1B GND VSS W RATIO = 2 RATIO = 4 RATIO = 8 W R3A R2A Figure 3. Programmable-Gain Amplifier with Op Amp BiasCurrent Matching R1A +5V ( RATIO = 1+ R_B R_A VIN ) MAX4237 VOUT L +5V Figure 1. Simplified Functional Diagram VDD W H +5V 0.1F MAX5420 VDD H VSS RATIO = 1 R2B R3B L GND Figure 4. Programmable-Gain Amplifier R1B RATIO = 2 RATIO = 4 RATIO = 8 W ( RATIO = 1+ R3A R2A R_B R_A R1A ) TEKTRONIX P6245 OSCILLOSCOPE FET PROBE CL < 1pF 1M Switching Time and Layout Concerns The switching time of the MAX5420/MAX5421 depends on the capacitive loading at W. For best performance, reduce parasitic board capacitance by minimizing the circuit board trace from W to the op amp inverting input, and choose an op amp with low input capacitance. MAX5421 VSS L D1 0.1F -5V GND D0 Chip Information TRANSISTOR COUNT: 118 PROCESS: CMOS PULSE GENERATOR Figure 2. Switching Time Test Circuit _______________________________________________________________________________________ 7 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 4X S 8 8 INCHES DIM A A1 A2 b E O0.500.1 H c D e E H 0.60.1 L 1 1 0.60.1 S BOTTOM VIEW D MIN 0.002 0.030 MAX 0.043 0.006 0.037 0.014 0.010 0.007 0.005 0.120 0.116 0.0256 BSC 0.120 0.116 0.198 0.188 0.026 0.016 6 0 0.0207 BSC 8LUMAXD.EPS MAX5420/MAX5421 Digitally Programmable Precision Voltage Divider for PGAs MILLIMETERS MAX MIN 0.05 0.75 1.10 0.15 0.95 0.25 0.36 0.13 0.18 2.95 3.05 0.65 BSC 2.95 3.05 4.78 5.03 0.41 0.66 0 6 0.5250 BSC TOP VIEW A1 A2 A c e FRONT VIEW b L SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 8L uMAX/uSOP APPROVAL DOCUMENT CONTROL NO. 21-0036 8 _______________________________________________________________________________________ REV. J 1 1 Digitally Programmable Precision Voltage Divider for PGAs 10LUMAX.EPS e 4X S 10 10 INCHES H O0.500.1 0.60.1 1 1 0.60.1 BOTTOM VIEW TOP VIEW D2 MILLIMETERS MAX DIM MIN 0.043 A 0.006 A1 0.002 A2 0.030 0.037 0.120 D1 0.116 0.118 0.114 D2 0.116 0.120 E1 0.118 E2 0.114 0.199 H 0.187 L 0.0157 0.0275 L1 0.037 REF b 0.007 0.0106 e 0.0197 BSC c 0.0035 0.0078 0.0196 REF S 0 6 MAX MIN 1.10 0.15 0.05 0.75 0.95 3.05 2.95 3.00 2.89 3.05 2.95 2.89 3.00 4.75 5.05 0.40 0.70 0.940 REF 0.177 0.270 0.500 BSC 0.090 0.200 0.498 REF 0 6 E2 GAGE PLANE A2 c A b A1 E1 D1 L L1 FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 10L uMAX/uSOP APPROVAL DOCUMENT CONTROL NO. 21-0061 REV. 1 1 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX5420/MAX5421 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)