DAC8552 Datasheet, PDF (18/22 Pages) Burr-Brown (TI) – 16-BIT, DUAL CHANNEL, ULTRA-LOW GLITCH VOLTAGE OUTPUT DIGITAL-TO-ANALOG CONVERTER

DAC8552
SLAS430 – JULY 2006
APPLICATION INFORMATION
www.ti.com
CURRENT CONSUMPTION
The DAC8552 typically consumes 170µA at V_DD =
5 V and 155µA at V_DD = 2.7V for each active
channel, excluding reference current consumption.
Additional current consumption can occur at the
digital inputs if V_IH<< V_DD. For most efficient power
operation, CMOS logic levels are recommended at
the digital input to the DAC.
In power-down mode, typical current consumption is
700nA. A delay time of 10ms to 20ms after a
power-down command is issued to the DAC is
typically sufficient for the power-down current to drop
below 10µA.
DRIVING RESISTIVE AND CAPACITIVE
LOADS
The DAC8552 output stage is capable of driving
loads of up to 1000 pF while remaining stable. Within
the offset and gain error margins, the DAC8552 can
operate rail-to-rail when driving a capacitive load.
Resistive loads of 2kΩ can be driven by the
DAC8552 while achieving good load regulation.
When the outputs of the DAC are driven to the
positive rail under resistive loading, the PMOS
transistor of each Class-AB output stage can enter
into the linear region. When this occurs, the added
IR voltage drop deteriorates the linearity
performance of the DAC. This only occurs within
approximately the top 100mV of the DACs output
voltage characteristic. Under resistive loading
conditions, good linearity is preserved as long as the
output voltage is at least 100 mV below the VDD
voltage.
CROSSTALK AND AC PERFORMANCE
The DAC8552 architecture uses separate resistor
strings for each DAC channel in order to achieve
ultra-low crosstalk performance. DC crosstalk seen
at one channel during a full-scale change on the
neighboring channel is typically less than 0.5 LSBs.
The AC crosstalk measured (for a full-scale, 1kHz
sine wave output generated at one channel, and
measured at the remaining output channel) is
typically under –100dB.
In addition, the DAC8552 can achieve typical AC
performance of 96dB signal-to-noise ratio (SNR) and
-85dB total harmonic distortion (THD), making the
DAC8552 a solid choice for applications requiring
high SNR at output frequencies at or below 10kHz.
OUTPUT VOLTAGE STABILITY
The DAC8552 exhibits excellent temperature stability
of 5ppm/°C typical output voltage drift over the
specified temperature range of the device. This
enables the output voltage of each channel to stay
within a ±25µV window for a ±1°C ambient
temperature change.
Good power-supply rejection ratio (PSRR)
performance reduces supply noise present on V_DD
from appearing at the outputs. Combined with good
DC noise performance and true 16-bit differential
linearity, the DAC8552 becomes an ideal choice for
closed-loop control applications.
SETTLING TIME AND OUTPUT GLITCH
PERFORMANCE
The DAC8552 settles to ±0.003% of its full-scale
range within 10µs, driving a 200pF, 2kΩ load. For
good settling performance the outputs should not
approach the top and bottom rails. Small signal
settling time is under 1µs, enabling data update rates
exceeding 1MSPS for small code changes.
Many applications are sensitive to undesired
transient signals such as glitch. The DAC8552 has a
proprietary, ultra-low glitch architecture addressing
such applications. Code-to-code glitches rarely
exceed 1mV and they last under 0.3µs. Typical glitch
energy is an outstanding 0.15nV-s. Theoretical worst
cast glitch should occur during a 256LSB step, but it
is so low, it cannot be detected.
DIFFERENTIAL AND INTERGRAL
NONLINEARITY
The DAC8552 uses precision, thin-film resistors to
achieve monotonicity and good linearity. Typical
linearity error is ±4LSBs; ±0.3mV error for a 5V
range. Differential linearity is typically ±0.35LSBs,
±27µV error for a consecutive code change.
USING REF02 AS A POWER SUPPLY FOR
DAC8552
Due to the extremely low supply current required by
the DAC8552, a possible configuration is to use a
REF02 +5V precision voltage reference to supply the
required voltage to the DAC8552s supply input as
well as the reference input, as shown in Figure 50.
This is especially useful if the power supply is quite
noisy or if the system supply voltages are at some
value other than 5V. The REF02 will output a steady
supply voltage for the DAC8552. If the REF02 is
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