Datasheet

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General Description

The DS1882 is a dual, nonvolatile (NV) digital poten-

tiometer designed to operate in audio systems that

accomodate up to ±7V signal levels. The potentiometer

settings can be stored in EEPROM so that they are

retained when the power is cycled. The DS1882 has

separate supplies for the potentiometers (V

) and the

communication circuitry (V

). For clickless/popless

operation, a zero-crossing detector allows the wiper

position to change when there is no voltage across the

potentiometer. The DS1882 is also designed to mini-

mize crosstalk, and the two digital potentiometers pro-

vide 0.5dB channel-to-channel matching to prevent

volume differences between channels. Total harmonic

distortion (THD) is also minimal as long as the wiper

drives a high-impedance load.

Two attenuation configuration options provide optimum

flexibility for the specific application. Configuration

Option 1 provides 63 logarithmic tapered steps (0dB to

-62dB, 1dB/step) plus a mute setting. Configuration

Option 2 has 32 logarithmic steps plus mute and pro-

vides software compatibility with the DS1808. When

Configuration Option 2 is used in combination with the

16-pin SO package, the DS1882 is both software and pin

compatible with the DS1808 in 5V applications.

Applications

Notebook and PC Audio

Portable Audio Equipment

Car Stereo

Consumer Audio/Video

Features

♦ Dual, Audio Log Taper Potentiometers

♦ Low THD+N and Crosstalk

♦ ±7V Analog Supply (Independent of Digital

Supply)

♦ 5V Digital Supply

♦ Potentiometer Settings Configurable as

Nonvolatile or Volatile

♦ Zero-Crossing Detector Eliminates Switching

Noise

♦ Two User-Configurable Attenuation Options

♦ Configuration Option 1: 63 Positions Provide 1dB

Attenuation Steps from 0dB to -62dB Plus Mute

♦ Configuration Option 2: (Software-Compatible

with the DS1808): 33 Positions Plus Mute as

Follows

Positions 0–12: 1dB per Step for 12 Steps

Positions 13–24: 2dB per Step for 12 Steps

Positions 25–32: 3dB per Step for 8 Steps

♦ I

C*-Compatible Serial Interface

♦ Three Address Pins Allow Up to 8 Devices on

C Bus

♦ 45kΩ Potentiometer End-to-End Resistance

♦ Industrial Temperature Range (-40°C to +85°C)

♦ 16-Pin TSSOP or SO Package

DS1882

Dual Log Audio Digital Potentiometer

______________________________________________ Maxim Integrated Products 1

SCL

SDAV-

GND

TOP VIEW

H1L0

98L1H0

TSSOP/SO

DS1882

Pin Configuration

Rev 0; 6/06

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.

+Denotes lead-free package.

Ordering Information

PART

TEMP

RANGE

VERSION

(kΩ)

PIN-

PACKAGE

DS1882E-050+

-40°C to +85°

16 TSSOP

(173 mils)

DS1882E-050+T&R

-40°C to +85°

16 TS S O P

( 173 m i l s)

Tap e- and - Reel

DS1882Z-050+

-40°C to +85°

16 S O

( 150 m i l s)

DS1882Z-050+T&R

-40°C to +85°

16 S O

( 150 m i l s)

Tap e- and - Reel

Typical Operating Circuit appears at end of data sheet.

Summary of content (15 pages)

PAGE 1
Rev 0; 6/06 Dual Log Audio Digital Potentiometer The DS1882 is a dual, nonvolatile (NV) digital potentiometer designed to operate in audio systems that accomodate up to ±7V signal levels. The potentiometer settings can be stored in EEPROM so that they are retained when the power is cycled. The DS1882 has separate supplies for the potentiometers (VCC) and the communication circuitry (VDD).
PAGE 2
DS1882 Dual Log Audio Digital Potentiometer ABSOLUTE MAXIMUM RATINGS Voltage on VDD, SDA, and SCL Relative to GND .....-0.5V to +6.0V Voltage on A2, A1, A0, and CE Relative to GND .................-0.5V to (VDD + 0.5V), not to exceed +6.0V Voltage on VCC Relative to GND ...........................-0.5V to +8.0V Voltage on H1, H0, W1, W0, L1, and L0 Relative to GND ............................................(V- - 0.5V) to (VCC + 0.5V) Voltage on V- Relative to GND ..............................-8.0V to +0.
PAGE 3
Dual Log Audio Digital Potentiometer (VDD = +4.5V to +5.5V, VCC = +4.5V to +7.0V, V- = -4.5V to -7.0V, TA = -40°C to +85°C.) PARAMETER End-to-End Resistance SYMBOL REE CONDITIONS MIN +25°C TYP MAX 45 kΩ End-to-End Resistance Tolerance +25°C Ratiometric Temperature Coefficient (Note 6) 30 ppm/°C End-to-End Resistance Temperature Coefficient (Note 6) 750 ppm/°C Wiper Resistance -20 UNITS 250 Ω dB -0.25 +0.25 dB -0.5 +0.5 dB 160 (Note 7) -0.
PAGE 4
NV MEMORY CHARACTERISTICS (VDD = +4.5V to +5.5V, VCC = +4.5V to +7.0V, V- = -4.5V to -7.0V, TA = 0°C to +70°C.) PARAMETER SYMBOL CONDITIONS Writes MIN +70°C (Note 6) TYP MAX UNITS 50,000 All voltages are referenced to ground. The value of VDD should never exceed VCC, including during power-ups. VCC must be applied before VDD. IDD is specified with SDA = SCL = CE = VDD, resistor pins floating, and digital inputs connected to VDD or GND.
PAGE 5
Dual Log Audio Digital Potentiometer END-TO-END RESISTANCE PERCENT CHANGE FROM +25°C vs. TEMPERATURE -80.0 -100.0 20 -20 SETTING (DEC) 0 20 40 TEMPERATURE (°C) RESISTANCE vs. POWER-DOWN VOLTAGE HIGH IMPEDANCE 80 80 0 1 2 3 4 DS1882 toc06 5 POWER-UP VOLTAGE (V) 1000 900 800 700 ICC (µA) 60 PROGRAMMED RESISTANCE (6dBh) 20 60 ICC vs.
PAGE 6
Dual Log Audio Digital Potentiometer DS1882 Pin Description PIN NAME 1 GND FUNCTION 2 A2 3 A1 4 V- Negative Analog Voltage Supply 5 A0 I2C Address Input. Inputs A0, A1, and A2 determine the I2C slave address of the device.
PAGE 7
Dual Log Audio Digital Potentiometer The DS1882 is a dual-channel, digitally controlled, audio potentiometer. The Block Diagram illustrates the features of the DS1882. The following sections discuss these features in detail. Potentiometer Configurations The DS1882 potentiometers have two possible attenuation configuration options. The Configuration Register section discusses how to change between the two options. Note that both potentiometers are always set to the same option.
PAGE 8
DS1882 Dual Log Audio Digital Potentiometer Command Byte Table 2. Configuration Option 2 8 TAP POSITION ATTENUATION (dB) 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13 14 14 16 15 18 16 20 17 22 18 24 19 26 20 28 21 30 22 32 23 34 24 36 25 39 26 42 27 45 28 48 29 51 30 54 31 57 32 60 33 90 The Command Byte determines both the potentiometer wiper settings and the configuration of both potentiometers.
PAGE 9
Dual Log Audio Digital Potentiometer the Command Byte are then used to store the wiper settings for the selected potentiometer. See below for the potentiometer wiper setting details. POTENTIOMETER WIPER REGISTER Factory Default: XX111111b Memory Type: NV (EEPROM) 0 X b7 b6 WIPER SETTING b5 b4 b3 b2 b1 b0 bits 7, 6 Configuration Selection: Selects which potentiometer will be programmed. 00 = Potentiometer 0 will be programmed. 01 = Potentiometer 1 will be programmed.
PAGE 10
DS1882 Dual Log Audio Digital Potentiometer Configuration Register If 10 is entered as the value of the two MSBs of the Command Byte, then the Configuration Register is to be modified. The three LSBs of the Configuration Register control the NV/volatile wiper setting, the zerocrossing detection feature, and the potentiometer attenuation configuration.
PAGE 11
Dual Log Audio Digital Potentiometer Three pins, A0, A1, A2, serve as slave address inputs. For multidrop configurations, they allow eight such devices to be addressed by the same I2C bus. If the I2C address matches the hardware levels of these bits, the DS1882 is allowed to receive communications from the I2C bus. The I2C slave address byte is shown below. This is the first byte transmitted from the master to the DS1882. The upper nibble value is fixed to 0101.
PAGE 12
Writing Command Byte Values I2C Definitions An example of writing to the DS1882 is shown in Figure 2. The DS1882 has one write command that is used to change the Potentiometer Wiper Setting Registers and the Configuration Register. All write operations begin with a START from the master, followed by a slave address byte. The R/W bit should be written to 0, which initiates a write command.
PAGE 13
Dual Log Audio Digital Potentiometer receiving data (the master during a read or the slave during a write operation) performs an ACK by transmitting a zero during the 9th bit. A device performs a NACK by transmitting a one during the 9th bit. Timing (Figure 4) for the ACK and NACK is identical to all other bit writes. An ACK is the acknowledgment that the device is properly receiving data. A NACK is used to terminate a read sequence or as an indication that the device is not receiving data.
PAGE 14
DS1882 Dual Log Audio Digital Potentiometer Byte Write: A byte write consists of 8 bits of information transferred from the master to the slave (most significant bit first) plus a 1-bit acknowledgement from the slave to the master. The 8 bits transmitted by the master are done according to the bit write definition and the acknowledgement is read using the bit read definition.
PAGE 15
Dual Log Audio Digital Potentiometer Power-Supply Decoupling To achieve best results, it is recommended that the power supplies are decoupled with a 0.01µF or a 0.1µF capacitor. Use high-quality, ceramic, surface-mount capacitors, and mount the capacitors as close as possible to the voltage supplies and GND pins to minimize lead inductance. SDA and SCL Pullup Resistors SDA is an open-collector output on the DS1882 that requires a pullup resistor to realize high logic levels.