Datasheet

V
R
REF
REF
· Gain; = 5V, = 30k nominalWV R
REF REF
I = IOUTP IOUTN = 7.5
FS
- ± ·
DAC1280
www.ti.com SBAS432A –APRIL 2010–REVISED SEPTEMBER 2010
ELECTRICAL CHARACTERISTICS
Minimum/maximum specifications at –40°C to +85°C, typical specifications at +25°C, AVDD = +2.5V, AVSS = –2.5V, DVDD =
3.3V, CLK = 4.096MHz, V
REF
= 5V, and R
REF
= 30kΩ, unless otherwise noted. Refer to circuit configuration shown in
Figure 35.
DAC1280
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ANALOG OUTPUTS
Full-scale output current I
FS
= (IOUTP – IOUTN)
(1)
Gain = 1/1 to 1/64 ±1250 ● Gain mA
Output common-mode voltage
(2)
– 0.15 0 + 0.15 V
DC PERFORMANCE
(3)
Gain error Gain = 1/1 ±0.02 ±0.25 %
Gain match Relative to Gain = 1/1 ±0.1 ±0.5 %
Gain drift
(4)
4 ppm/°C
Offset Gain = 1/1 to 1/64 ±50 ±800 ppm of FS
Offset drift
(4)
0.2 ppm of FS/°C
Gain = 1/1 1.2 mV
RMS
Gain = 1/2 1.4 mV
RMS
Gain = 1/4 1.8 mV
RMS
DC noise
(5)
Gain = 1/8 2.9 mV
RMS
Gain = 1/16 5.5 mV
RMS
Gain = 1/32 10 mV
RMS
Gain = 1/64 19 mV
RMS
AC PERFORMANCE
Gain = 1/1 –125 –118 dB
Gain = 1/2, 1/4, 1/8 –125 dB
Total harmonic
THD Gain = 1/16 –124 dB
distortion
(6)
Gain = 1/32 –118 dB
Gain = 1/64 –113 dB
Gain = 1/1 116 120 dB
Gain = 1/2 119 dB
Gain = 1/4 117 dB
Signal-to-noise ratio
(7)
SNR Gain = 1/8 114 dB
Gain = 1/16 109 dB
Gain = 1/32 105 dB
Gain = 1/64 99 dB
AVDD, AVSS 60Hz ac, gain = 1/8 85 dB
Power-supply rejection PSR
DVDD 60Hz ac 115 dB
–3dB bandwidth 8.2 kHz
REFERENCE VOLTAGE INPUT (VREF)
Reference voltage V
REF
= VREF – AVSS 2.4 5 AVDD + 0.25 V
Operating 220 kΩ
Input impedance
Power-down 10 MΩ
(1) TDATA modulated 75% and 25% yielding positive full-scale output and negative full-scale output, respectively. Full-scale positive and
negative output current is given by:
Gain can be trimmed by adjusting V
REF
/R
REF
ratio over the range of 40% to 105% of nominal.
(2) Output common-mode voltage is regulated by the external I/V converter. The specified output common-mode voltage range is: (AVDD +
AVSS)/2 ±0.15V.
(3) Excludes the tolerances of external components.
(4) Drift is calculated over the specified temperature range using the box calculation method.
(5) DC noise measured by ADS1282 with complementing gain over 413Hz bandwidth with DAC output = 0V.
(6) THD = Total harmonic distortion; measured by ADS1282 with complementing gain including first nine harmonics, DAC output =
–0.5dBFS, 31.25Hz.
(7) SNR = Signal-to-noise ratio; measured by ADS1282 with complementing gain over 413Hz bandwidth, DAC output = –0.5dBFS,
31.25Hz.
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