WM2613 Ver la hoja de datos (PDF) - Wolfson Microelectronics plc
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WM2613 Datasheet PDF : 11 Pages
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WM2613
DEVICE DESCRIPTION
Production Data Rev 1.0
GENERAL FUNCTION
The device uses a resistor string network buffered with an op amp to convert 12-bit digital data to
analogue voltage levels (see Block Diagram). The output voltage is determined by the reference input
voltage and the input code according to the following relationship:
Output voltage = ( ) 2 VREF CODE
4096
INPUT
OUTPUT
1111
1111
1111
( ) 2 VREF 4095
4096
:
:
1000
0000
0001
( ) 2049
2 VREF
4096
1000
0000
0000
( ) 2 VREF 2048 = VREf
4096
0111
1111
1111
( ) 2 VREF 2047
4096
:
:
0000
0000
0001
( )1
2 VREF
4096
0000
0000
0000
0V
Table 1 Binary Code Table (0V to 2VREF Output), Gain = 2
POWER ON RESET
An internal power-on-reset circuit resets the DAC register to all 0s on power-up.
BUFFER AMPLIFIER
The output buffer has a near rail-to-rail output with short circuit protection and can reliably drive a 2kΩ
load with a 100pF load capacitance.
EXTERNAL REFERENCE
The reference voltage input is buffered which makes the DAC input resistance independent of code. The
REFIN pin has an input resistance of 10MΩ and an input capacitance of typically 5pF. The reference
voltage determines the DAC full-scale output.
HARDWARE CONFIGURATION OPTIONS
The device has three configuration options that are controlled by device pins.
DEVICE POWER DOWN
The device can be powered-down by pulling pin NPD (pin 15) low. This powers down the DAC. This will
reduce power consumption significantly. The NPD pin overrides the software control bit PWR. When the
power down function is released the device reverts to the DAC code set prior to power down.
SETTLING TIME
The settling time of the device can be controlled by pin SPD (pin 9). A ONE on pin SPD will ensure a
FAST settling time; a ZERO will ensure a SLOW settling time. The SPD pin high overrides the software
control bit SPD.
SIMULTANEOUS DAC UPDATE
The NLDAC pin (Pin 16) can be held high to prevent word writes from updating the DAC latch. By writing
the new value to the DAC then pulling NLDAC low, the new DAC code is loaded into the DAC latch.
WOLFSON MICROELECTRONICS LTD
Production Data Rev 1.0 June 1999
8
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