19-0378; Rev 1; 6/95
Octal, 2-Wire Serial 8-Bit DAC
with Rail-to-Rail Outputs
________________________Applications
Minimum Component Analog Systems
Digital Offset/Gain Adjustment
Industrial Process Control
Automatic Test Equipment
Programmable Attenuators
____________________________Features
o
o
o
o
o
o
o
Single +5V Supply
Simple 2-Wire Serial Interface
I2C Compatible
Output Buffer Amplifiers Swing Rail-to-Rail
Reference Input Range Includes Both Supply Rails
Power-On Reset Clears All Latches
4µA Power-Down Mode
______________Ordering Information
TEMP. RANGE
MAX521ACPP
0°C to +70°C
20 Plastic DIP
1
MAX521BCPP
MAX521ACWG
MAX521BCWG
0°C to +70°C
0°C to +70°C
0°C to +70°C
20 Plastic DIP
24 Wide SO
24 Wide SO
2
1
2
MAX521ACAG
0°C to +70°C
24 SSOP
MAX521BCAG
0°C to +70°C
24 SSOP
MAX521BC/D
0°C to +70°C
Dice*
Ordering Information continued at end of data sheet.
*Dice are specified at TA = +25°C, DC parameters only.
SDA
SCL
REF2
OUT0
INPUT
LATCH 0
1
OUTPUT
LATCH 0
DAC0
8
INPUT
LATCH 1
1
OUTPUT
LATCH 1
DAC1
8
INPUT
LATCH 2
1
OUTPUT
LATCH 2
DAC2
8
INPUT
LATCH 3
1
OUTPUT
LATCH 3
DAC3
OUTPUT
LATCH 4
DAC4
OUTPUT
LATCH 5
DAC5
OUTPUT
LATCH 6
DAC6
OUTPUT
LATCH 7
DAC7
MAX521
OUT1
OUT1 1
20 OUT2
OUT0 2
19 OUT3
START/STOP
DETECTOR
REF1 3
OUT2
ADDRESS
COMPARATOR
18 REF2
REF0 4
MAX521
OUT3
17 REF3
16 REF4
AGND 6
1
14 AD1
SDA 8
8
11 OUT6
OUT4
INPUT
LATCH 5
OUT5
1
8
INPUT
LATCH 6
OUT6
1
8
DIP
Pin Configurations continued at end of data sheet.
INPUT
LATCH 4
1
8
12 OUT7
OUT5 10
8
13 AD0
OUT4 9
8
DECODE
15 VDD
SCL 7
REF1 REF0
8
8-BIT
SHIFT REGISTER
DGND 5
1
2
2
________________Functional Diagram
_________________Pin Configurations
TOP VIEW
PIN-PACKAGE
TUE
(LSB)
PART
AD0
INPUT
LATCH 7
AD1
OUT7
REF3
REF4
________________________________________________________________ Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
1
MAX521
_______________General Description
The MAX521 is an octal, 8-bit voltage-output digital-toanalog converter (DAC) with a simple 2-wire serial interface that allows communication between multiple devices.
It operates from a single 5V supply and its internal precision buffers allow the DAC outputs to swing rail-to-rail.
The reference input range includes both supply rails.
The MAX521 has five reference inputs. The first four DACs
(DAC0–DAC3) each have a separate reference input
(REF0–REF3), allowing each DAC’s full-scale range to be
set independently. The remaining four DACs
(DAC4–DAC7) share the remaining reference input, REF4.
The MAX521 features a serial interface and internal
software protocol, allowing communication at data rates
up to 400kbps. The interface, combined with the double-buffered input configuration, allows the DAC registers to be updated individually or simultaneously. In
addition, the device can be put into a low-power shutdown mode that reduces supply current to 4µA. Poweron reset ensures the DAC outputs are at 0V when
power is initially applied.
The MAX521 is available in 20-pin DIP and 24-pin SO
package as well as a space-saving 24-pin SSOP package.
