MAX5380-MAX5382 MAXIM [Maxim Integrated Products], MAX5380-MAX5382 Datasheet - Page 8

• Manufacturer Part Number: MAX5380-MAX5382
• Description: Low-Cost, Low-Power, 8-Bit DACs with 2-Wire Serial Interface in SOT23
• Manufacturer: MAXIM [Maxim Integrated Products]

Low-Cost, Low-Power, 8-Bit DACs with
2-Wire Serial Interface in SOT23
Figure 1. Functional Diagram
The MAX5380/MAX5381/MAX5382 voltage-output, 8-bit
digital-to-analog converters (DACs) offer full 8-bit perfor-
mance with less than 1LSB integral nonlinearity error
and less than 1LSB differential nonlinearity error, ensur-
ing monotonic performance. The devices use a simple
2-wire, fast-mode I
operates at up to 400kHz. The MAX5380/MAX5381/
MAX5382 include an internal reference, an output
buffer, and a low-current shutdown mode, which make
these devices ideal for low-power, highly integrated
applications (See Figure 1. Functional Diagram).
The MAX5380/MAX5381/MAX5382 employ a current-
steering DAC topology as shown in Figure 2. At the core
of the DAC is a reference voltage-to-current converter
(V/I) that generates a reference current. This current is
mirrored to 255 equally weighted current sources. DAC
switches control the outputs of these current mirrors so
that only the desired fraction of the total current-mirror
8
Table 1. Unipolar Code Output Voltage
SDA
SCL
_______________________________________________________________________________________
DAC CODE
CONTROL
1111 1111
1000 0000
0000 0001
0000 0000
LOGIC
REF
2
C-compatible serial interface that
Detailed Description
CURRENT-
STEERING
SERIAL INPUT
DATA LATCH
REGISTER
DAC
255
8
GND
V
MAX5380
MAX5381
MAX5382
Analog Section
DD
2V x (255 / 256)
MAX5380
7.8mV
+1V
0
10k
OUT
currents is steered to the DAC output. The current is
then converted to a voltage across a resistor, and this
voltage is buffered by the output buffer amplifier.
Table 1 shows the relationship between the DAC code
and the analog output voltage. The 8-bit DAC code is
binary unipolar with 1LSB = V
MAX5381 have a full-scale output voltage of (+2V -
1LSB) and (+4V - 1LSB), respectively, set by the internal
references. The MAX5382 has a full-scale output volt-
age of (0.9
The DAC voltage output is an internally buffered unity-
gain follower that typically slews at ±0.4V/µs. The out-
put can swing from 0 to full scale. With a 1/4 FS to 3/4
FS output transition, the amplifier outputs typically settle
to 1/2LSB in less than 5µs when loaded with 10kΩ in
parallel with 50pF. The buffer amplifiers are stable with
any combination of resistive loads >10kΩ and capaci-
tive loads <50pF.
Figure 2. Current-Steering Topology
OUTPUT VOLTAGE
4V x (255 / 256)
MAX5381
15.6mV
SW1
+2V
x
0
V
DD
SW2
- 1LSB).
SW255
REF
0.9 x V
0.9 x V
/ 256. The MAX5380/
V
0.9 x V
REF
MAX5382
DD
Output Voltage
x (255 / 256)
DD
0
Output Buffer
DD
/ 256
/ 2
OUT