ad5331bru-reel7 Analog Devices, Inc., ad5331bru-reel7 Datasheet - Page 13

• Manufacturer Part Number: ad5331bru-reel7
• Description: 2.5 V To 5.5 V, 115 Ua, Parallel Interface Single Voltage-output 8-/10-/12-bit Dacs
• Manufacturer: Analog Devices, Inc.

FUNCTIONAL DESCRIPTION
The AD5330/AD5331/AD5340/AD5341 are single resistor-string
DACs fabricated on a CMOS process with resolutions of 8, 10,
12, and 12 bits, respectively. They are written to using a parallel
interface. They operate from single supplies of 2.5 V to 5.5 V and
the output buffer amplifiers offer rail-to-rail output swing. The
AD5330, AD5340, and AD5341 have a reference input that may
be buffered to draw virtually no current from the reference
source. The reference input of the AD5331 is unbuffered. The
devices have a power-down feature that reduces current con-
sumption to only 80 nA @ 3 V.
Digital-to-Analog Section
The architecture of one DAC channel consists of a reference
buffer and a resistor-string DAC followed by an output buffer
amplifier. The voltage at the V
voltage for the DAC. Figure 27 shows a block diagram of the
DAC architecture. Since the input coding to the DAC is straight
binary, the ideal output voltage is given by:
–0.2
0.4
0.2
80
0
0
90
V
V
T
DD
DD
A
100
= 25 C
= 3V
= 5V
110
1
120
130
I
DD
V
V
2
REF
OUT
140
– A
– Volts
150
=
3
160
V
V
170
REF
DD
180
= 5V
REF
4
×
190
2
pin provides the reference
D
N
200
5
×
Gain
0.917
0.916
0.915
0.914
0.913
0.912
0.911
0.910
0.909
0.908
0.907
0.906
0.905
0.904
0.903
250ns/DIV
where:
D = decimal equivalent of the binary code which is loaded to the
DAC register:
N = DAC resolution
Gain = Output Amplifier Gain (1 or 2)
0–255 for AD5330 (8 Bits)
0–1023 for AD5331 (10 Bits)
0–4095 for AD5340/AD5341 (12 Bits)
REGISTER
INPUT
AD5330/AD5331/AD5340/AD5341
REGISTER
DAC
REFERENCE
–10
–20
–30
–40
–50
–60
10
0.01
0
BUFFER
0.1
RESISTOR
STRING
V
REF
FREQUENCY – kHz
1
10
BUFFER AMPLIFIER
OUTPUT
100
GAIN
1k
BUF
10k
V
OUT