DS1666, DS1666S DS1666, DS1666S Audio Digital Resistor FEATURES PIN ASSIGNMENT • 128 position, digitally controlled potentiometer • Operates from a +5 volts power supply with TTL signal inputs • Wide analog voltage range of ±5 volts • Resistive elements are temperature compensated to ±20 percent end to end • Low–power CMOS 1 14 2 13 VCC INC 3 12 VB CS 4 11 VW GND 5 10 VH NC 6 9 VL NC 7 8 NC 14–PIN DIP (300 MIL) See Mech. Drawings Section • 14–pin DIP or 16–pin SOIC for surface mount applications U/D NC NC INC NC CS NC GND • Default position on power up sets wiper position at 10% • Operating temperature range – –40°C to +85°C; industrial Resolution/Step Resistance values Low End High End –3dB Point DS1666–10 10KΩ 24Ω 152Ω 1.1 MHz DS1666–50 50KΩ 122Ω 759Ω 200 KHz DS1666–100100KΩ 243Ω 1.519KΩ 100 KHz NC NC U/D 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VCC NC VB VW VH NC NC VL 16–PIN SOIC (300 MIL) See Mech. Drawings Section PIN DESCRIPTION VH VL VW U/D INC CS NC VCC GND VB – – – – – – – – – – High Terminal of Resistor Low Terminal of Resistor Wiper Terminal of Resistor Up/Down Control Wiper Movement Control Chip Select for Wiper Movement No Connection +5 Volts Ground 0 to –5 Volts DESCRIPTION The DS1666 is a solid–state potentiometer which is set to value by digitally controlled resistive elements. The potentiometer is composed of 127 resistive sections. Between each resistive section and both ends of the potentiometer are TAP points accessible to the wiper. The position of the wiper on the resistance array is controlled by the CS, U/D and INC inputs. The position of the wiper defaults to the 10% position on power up. The resolution of the DS1666 is shown in Figure 1. The DS1666 Digital Audio Resistor is uniquely designed to provide a potentiometer that is logarithmic rather than linear across its entire range. The lower half of the potentiometer advances 1% of total resistance for each 3% of scale advanced, providing for precise amplification of low volume signals. The upper half of the potentiometer advances 2% of resistance for every 1% of scale advanced, providing for the lower resolution gain required for high volume amplification. 022698 1/7 DS1666, DS1666S GRAPH OF AUDIO TAPER Figure 1 100 90 80 PERCENT TOTAL RESISTANCE 70 60 1 2 50 40 30 20 3 1 10 0 0 5 10 LOW TERMINAL 15 20 25 30 35 40 45 55 60 65 70 The CS, U/D and INC inputs control the position of the wiper along the resistor array (Figure 1). When CS is active (low), a high to low transition on the INC will increment or decrement an internal counter depending on the level of the U/D pin. When the U/D pin is low, the counter will decrement. When the U/D pin is high, the counter will increment. The state of the U/D pin can be changed while CS is active allowing for precise adjustment during calibration. The output of the counter is decoded to set the position of the wiper. When the CS input transitions to the high (inactive) level, the value of the counter is stored and the wiper position is maintained until power (VCC) is lost. When power is restored, the DS1666 returns to the default setting and positions the wiper to 10 percent. The value of the end–to–end and end–to–wiper position is indeterminate while VCC is not applied. The DS1666 has a resistor array that resembles an audio taper potentiometer as shown in Figure 1 1. Since the taper is not linear, exact resistance values for each of the 128 positions of the resistor is not specified. However, the end-to-end resistance is specified to be within ±20 percent of the stated resistor value over an industrial temperature range of –40°C to +85°C. 75 80 85 90 95 100 HIGH TERMINAL % OF ACTIVE DIGITAL TAPS OPERATION 022698 2/7 50 ANALOG CHARACTERISTICS End–to–End Resistance Tolerance = ±20 percent Typical Noise = <120 dB/Hz REF:IV Temperature Coefficient = ±800 PPM/°C typical Resistance at tap #74=18% ± 2% of total resistance. PIN DESCRIPTIONS VH The high end of the potentiometer. This terminal is capable of handling input voltages between ±5 volts. VL The Low end of the potentiometer. This terminal is capable of handling input voltages between ±5 volts. VW The wiper terminal of the potentiometer. The value of the wiper is controlled by the U/D and the INC pins. Up/Down (U/D) The U/D input controls the direction of the wiper movement when setting the potentiometer. Increment (INC) Toggling INC will move the potentiometer wiper by either incrementing or decrementing the counter. Chip Select The device is selected when CS input is (CS) low. The current counter value is stored when CS is returned high. DS1666, DS1666S BLOCK DIAGRAM Figure 2 TRANSFER LOGIC ARRAY VH WIPER POSITION DECODE U/D INC 7 BIT COUNTER CS 1 OF 128 VL VW MODE SELECTION Figure 3 CS INC U/D MODE L H WIPER UP L L WIPER DOWN X STORE WIPER POSITION H 022698 3/7 DS1666, DS1666S ABSOLUTE MAXIMUM RATINGS* Voltage on CS, INC, U/D, and VCC Relative to Ground Voltage on VH, VL, and VW Relative to Ground Voltage on VB Operating Temperature Storage Temperature Soldering Temperature –0.5V to +7.0V –6.5V to +6.5V –6.5V to Ground –40°C to +85°C –55°C to +125°C 260°C for 10 seconds * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. (–40°C to +85°C) RECOMMENDED DC OPERATING CONDITIONS PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Supply Voltage VCC +4.5 5.0 5.5 V 1 Input Logic 1 VIH 2.0 VCC+0.5 V 1 Input Logic 0 VIL –0.5 +0.8 V 1 VH, VL, VW Voltage VR VB–0.3 VCC+0.3 V 1 VB Voltage VB –5.5 GND V 1 (–40°C to +85°C; VCC = 5.0V ± 10%) DC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL Supply Current ICC Input Leakage ILI Wiper Resistance RW Wiper Current IW MIN TYP 0.1 –1 350 MAX UNITS NOTES 5 mA 3 +1 µA 2 650 Ω 1 mA (tA = 25°C) CAPACITANCE PARAMETER Capacitance 022698 4/7 3 SYMBOL CONDITION TYP MAX UNITS NOTES CIN tA=25°C 6 10 pF 2 DS1666, DS1666S (tA=–40°C to +85°C; VCC=+5V ± 10%) AC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL MIN CS to INC Setup tCI 100 ns INC High to U/D Change tID 100 ns U/D to INC Setup tDI 1 µs INC Low Period tIL 500 ns INC High Period tIH 1 µs INC Inactive to CS Inactive tIC 500 ns tCPH 100 ns CS Deselect Time TYP MAX UNITS NOTES AC TIMING Figure 4 CS tCPH tCI tIL tIC tIH INC tID tDI U/D tIW VW VVH VVL NOTES: 1. All voltages are referenced to ground. 2. This parameter is periodically sampled and not 100% tested. 3. Typical values are for tA = 25°C and nominal supply voltages. 4. Wiper output open circuited. AC TEST CONDITIONS Input Pulse Levels Input Rise and Fall Times Input Level 0V to 3V 10 ns 1.5V 022698 5/7 DS1666, DS1666S DS1666 ORDERING INFORMATION ORDERING NUMBER PACKAGE OPERATING TEMPERATURE VERSION DS1666–010 14L DIP –40°C TO +85°C 10KΩ DS1666–050 14L DIP –40°C TO +85°C 50KΩ DS1666–100 14L DIP –40°C TO +85°C 100KΩ DS1666S–010 16L SOIC (300 MIL) –40°C TO +85°C 10KΩ DS1666S–050 16L SOIC (300 MIL) –40°C TO +85°C 50KΩ DS1666S–100 16L SOIC (300 MIL) –40°C TO +85°C 100KΩ 022698 6/7 DS1666, DS1666S DATA SHEET REVISION SUMMARY The following represent the key differences between 07/26/93 and 06/18/97 version of the DS1666 data sheet. Please review this summary carefully. 1. Remove commercial temp grade reference 2. Add order info table 022698 7/7