概要

The MAX5481–MAX5484 10-bit (1024-tap) nonvolatile,linear-taper, programmable voltage-dividers and variable resistors perform the function of a mechanical potentiometer, but replace the mechanics with a pinconfigurable 3-wire serial SPI™-compatible interface or up/down digital interface. The MAX5481/MAX5482 are 3-terminal voltage-dividers and the MAX5483/MAX5484 are 2-terminal variable resistors.

The MAX5481–MAX5484 feature an internal, nonvolatile, electrically erasable programmable read-only memory (EEPROM) that stores the wiper position for initialization during power-up. The 3-wire SPI-compatible serial interface allows communication at data rates up to 7MHz. A pin-selectable up/down digital interface is also available.

The MAX5481–MAX5484 are ideal for applications requiring digitally controlled potentiometers. Two end-toend resistance values are available (10kΩ and 50kΩ) in a voltage-divider or a variable-resistor configuration (see the Selector Guide). The nominal resistor temperature coefficient is 35ppm/°C end-to-end, and only 5ppm/°C ratiometric, making these devices ideal for applications requiring low-temperature-coefficient voltage-dividers, such as low-drift, programmable gain-amplifiers.

The MAX5481–MAX5484 operate with either a +2.7V to +5.25V single power supply or ±2.5V dual power supplies. These devices consume 400µA (max) of supply current when writing data to the nonvolatile memory and 1.0µA (max) of standby supply current. The MAX5481–MAX5484 are available in a space-saving (3mm x 3mm), 16-pin TQFN, or a 14-pin TSSOP package and are specified over the extended (-40°C to +85°C) temperature range.

 

アプリケーション

Gain and Offset

Adjustment

LCD Contrast Adjustment

Pressure Sensors

Low-Drift Programmable

Gain Amplifiers

Mechanical Potentiometer

Replacement

 

特徴

1024 Tap Positions

Power-On Recall of Wiper Position from Nonvolatile Memory

16-Pin (3mm x 3mm x 0.8mm) TQFN or 14-Pin TSSOP Package

35ppm/°C End-to-End Resistance Temperature

Coefficient

5ppm/°C Ratiometric Temperature Coefficient

10kΩ and 50kΩ End-to-End Resistor Values

Pin-Selectable SPI-Compatible Serial Interface or Up/Down Digital Interface

1µA (max) Standby Current

Single +2.7V to +5.25V Supply Operation

Dual ±2.5V Supply Operation

 

詳細

The MAX5481/MAX5482 linear programmable voltagedividers and the MAX5483/MAX5484 variable resistors feature 1024 tap points (10-bit resolution) (see the Functional Diagrams). These devices consist of multiple strings of equal resistor segments with a wiper contact that moves among the 1024 points through a pin-selectable 3-wire SPI-compatible serial interface or up/down interface. The MAX5481/MAX5483 provide a total end-to-end resistance of 10kΩ, and the MAX5482/MAX5484 have an end-to-end resistance of 50kΩ. The MAX5481/MAX5482 allow access to the high, low, and wiper terminals for a standard voltagedivider configuration.

MAX5482 Programmable Voltage-Dividers

The MAX5482 programmable voltagedividers provide a weighted average of the voltage between the H and L inputs at the W output. Both devices feature 10-bit resolution and provide up to 1024 tap points between the H and L voltages. Ideally, the VL voltage occurs at the wiper terminal (W) when all data bits are zero and the VH voltage occurs at the wiper terminal when all data bits are one. The step size (1 LSB) voltage is equal to the voltage applied across terminals H and L divided by 210.

スタンバイモード

The MAX5481–MAX5484 feature a low-power standby mode. When the device is not being programmed, it enters into standby mode and supply current drops to 0.5µA (typ).

Nonvolatile Memory

The internal EEPROM consists of a nonvolatile register that retains the last value stored prior to power-down.

The nonvolatile register is programmed to midscale at the factory. The nonvolatile memory is guaranteed for 50 years of wiper data retention and up to 200,000 wiper write cycles.

Power-Up

Upon power-up, the MAX5481–MAX5484 load the data stored in the nonvolatile wiper register into the volatile wiper register, updating the wiper position with the data stored in the nonvolatile wiper register.

アプリケーション情報

The MAX5481–MAX5484 are ideal for circuits requiring digitally controlled adjustable resistance, such as LCD contrast control (where voltage biasing adjusts the display contrast), or programmable filters with adjustable gain and/or cutoff frequency.