19-0378; Rev 3; 9/96
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
_______________General Description
The MAX520/MAX521 are quad/octal, 8-bit voltage-output
digital-to-analog converters (DACs) with simple 2-wire ser-
ial interfaces that allow communication between multiple
devices. They operate from a single +5V supply and their
reference input range includes both supply rails.
The MAX521 includes rail-to-rail output buffer amplifiers for
reduced system size and component count when driving
loads. The MAX520’s unbuffered voltage outputs reduce
the device’s total supply current to 4µA and provide
increased accuracy at low output currents.
The MAX520/MAX521 feature 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
devices can be put into a low-power shutdown mode that
reduces supply current to 4µA. Power-on reset ensures the
DAC outputs are at 0V when power is initially applied.
The MAX520 is available in 16-pin DIP and wide SO pack-
ages, as well as a space-saving 20-pin SSOP. The
MAX521 comes in 20-pin DIP and 24-pin SO packages, as
well as a space-saving 24-pin SSOP.
____________________________Features
o
o
o
o
Single +5V Supply
Simple 2-Wire Serial Interface
I
2
C Compatible
Outputs Swing Rail to Rail:
Unbuffered Outputs (MAX520)
Buffered Outputs (MAX521)
1%-Accurate Trimmed Output Resistance (MAX520A)
Ultra-Low 4µA Supply Current (MAX520)
Individual DACs Have Separate Reference Inputs
Power-On Reset Clears All Latches
4µA Power-Down Mode
MAX520/MAX521
o
o
o
o
o
______________Ordering Information
PART
†
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
PIN-PACKAGE
16 Plastic DIP
16 Plastic DIP
16 Wide SO
16 Wide SO
TUE
(LSB)
1
1
1
1
MAX520ACPE
MAX520BCPE
MAX520ACWE
MAX520BCWE
________________________Applications
Minimum Component Analog Systems
Digital Offset/Gain Adjustment
Industrial Process Control
Automatic Test Equipment
Programmable Attenuators
Ordering Information continued at end of data sheet.
†
MAX520 “A” grade parts include a 1%-accurate, factory-trimmed
output resistance.
_______________Functional Diagrams
SDA
SCL
REF1
INPUT
LATCH 0
1
OUTPUT
LATCH 0
REF0
DAC0
OUT0
_________________Pin Configurations
TOP VIEW
MAX520
8
8-BIT
SHIFT REGISTER
OUT1
OUT0
1
2
16 OUT2
15 OUT3
14 REF2
ADDRESS
COMPARATOR
START/STOP
DETECTOR
INPUT
LATCH 1
1
OUTPUT
LATCH 1
DAC1
OUT1
REF1 3
REF0 4
AGND 5
DGND 6
SCL 7
SDA 8
MAX520
13 REF3
12 V
DD
11 AD2
10 AD1
9
AD0
AD0
AD1
AD2
DECODE
4
INPUT
LATCH 2
1
INPUT
LATCH 3
1
OUTPUT
LATCH 2
DAC2
OUT2
OUTPUT
LATCH 3
DAC3
OUT3
DIP/SO
REF2
REF3
Pin Configurations continued at end of data sheet.
Functional Diagrams continued at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
MAX520/MAX521
ABSOLUTE MAXIMUM RATINGS
V
DD
to DGND ...........................................................-0.3V to +6V
V
DD
to AGND............................................................-0.3V to +6V
OUT_ ..........................................................-0.3V to (V
DD
+ 0.3V)
REF_ ...........................................................-0.3V to (V
DD
+ 0.3V)
AD0, AD1, AD2...........................................-0.3V to (V
DD
+ 0.3V)
SCL, SDA to DGND ..................................................-0.3V to +6V
AGND to DGND.....................................................-0.3V to +0.3V
Maximum Current into Any Pin............................................50mA
Continuous Power Dissipation (T
A
= +70°C)
16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)....842mW
20-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW
16-Pin Wide SO (derate 9.52mW/°C above +70°C) ......762mW
24-Pin Wide SO (derate 11.76mW/°C above +70°C) ....941mW
20-Pin SSOP (derate 8.00mW/°C above +70°C) .........640mW
24-Pin SSOP (derate 8.00mW/°C above +70°C) .........640mW
16-Pin CERDIP (derate 10.00mW/°C above +70°C)....800mW
20-Pin CERDIP (derate 11.11mW/°C above +70°C)....889mW
Operating Temperature Ranges
MAX520_C_ _/MAX521_C_ _ ..............................0°C to +70°C
MAX520_E_ _/MAX521_E_ _ ...........................-40°C to +85°C
MAX520_MJE/MAX521BMJP ........................-55°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
DD
= 5V ±10%, V
REF_
= 4V, R
L
=
∞
(MAX520), R
L
= 10kΩ (MAX521), C
L
= 0pF (MAX520), C
L
= 100pF (MAX521), T
A
= T
MIN
to T
MAX,
unless otherwise noted. Typical values are at T
A
= +25°C)
PARAMETER
STATIC ACCURACY
Resolution
MAX520_
Total Unadjusted Error
Differential Nonlinearity
TUE
DNL
MAX521A
MAX521B
Guaranteed monotonic
MAX520_
Zero-Code Error
ZCE
Code = 00 hex
MAX521_C
MAX521_E
MAX521BM
Zero-Code-Error Supply Rejection
Zero-Code-Error Temperature Coefficient
Code = 00 hex
Code = 00 hex
MAX520_
Full-Scale Error
Code = FF hex
MAX521_C
MAX521_E
MAX521BM
Full-Scale-Error Supply Rejection
Full-Scale-Error Temperature Coefficient
Code = FF hex, V
DD
= 5V ±10%
±1
±10
±1
±10
8
18
20
20
mV
µV/°C
mV
8
±1
±1.5
±2
±1.0
8
18
20
20
mV
µV/°C
mV
LSB
LSB
Bits
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 5V ±10%, V
REF_
= 4V, R
L
=
∞
(MAX520), R
L
= 10kΩ (MAX521), C
L
= 0pF (MAX520), C
L
= 100pF (MAX521), T
A
= T
MIN
to T
MAX
,
unless otherwise noted. Typical values are at T
A
= +25°C)
PARAMETER
REFERENCE INPUTS
Input Voltage Range
Input Resistance
Input Current
Input Capacitance
R
IN
Code =
55 hex
(Note 1)
PD = 1
Code =
FF hex
(Note 2)
(Note 3)
(Note 4)
0
MAX520A
MAX520B
MAX521_, OUT_ = 4V,
0mA to 2.5mA
Output Load Regulation
MAX521_C/E, V
REF_
= V
DD
,
code = FF hex, 0µA to 500µA
MAX521BM, V
REF_
= V
DD
,
code = FF hex, 0µA to 500µA
Output Leakage Current
DIGITAL INPUTS SCL, SDA
Input High Voltage
Input Low Voltage
Input Current
Input Hysteresis
Input Capacitance
DIGITAL INPUTS AD0, AD1
Input High Voltage
Input Low Voltage
Input Leakage
DIGITAL OUTPUT SDA
(Note 6)
Output Low Voltage
Three-State Leakage Current
Three-State Output Capacitance
V
OL
I
L
C
OUT
I
SINK
= 3mA
I
SINK
= 6mA
V
IN
= 0V to V
DD
(Note 5)
0.4
0.6
±10
10
V
µA
pF
V
IH
V
IL
I
IN
V
IN
= 0V to V
DD
2.4
0.8
±10
V
V
µA
V
IH
V
IL
I
IN
V
HYST
C
IN
0V
≤
V
IN
≤
V
DD
(Note 5)
(Note 5)
0.05V
DD
10
0.7V
DD
0.3V
DD
±10
V
V
µA
V
pF
MAX521_, OUT_ = 0V to V
DD
,
PD = 1
T
A
= +25°C
T
A
= T
MIN
to T
MAX
15.8
15.6
8.4
0.25
1.5
2.0
±10
µA
LSB
16
16
MAX520_
MAX521_
MAX520_
MAX521_
REF4
REF0–REF3
30
120
30
-70
-60
-70
V
DD
16.2
16.4
16.4
kΩ
MAX520_
MAX521_
REF4
REF0–REF3
0
8
4
16
V
DD
12
6
24
±10
V
kΩ
µA
pF
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX520/MAX521
Channel-to-Channel Isolation
AC Feedthrough
DAC OUTPUTS
Full-Scale Output Voltage
Output Resistance (Note 5)
dB
dB
V
_______________________________________________________________________________________
3
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
MAX520/MAX521
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 5V ±10%, V
REF_
= 4V, R
L
=
∞
(MAX520), R
L
= 10kΩ (MAX521), C
L
= 0pF (MAX520), C
L
= 100pF (MAX521), T
A
= T
MIN
to T
MAX
,
unless otherwise noted. Typical values are at T
A
= +25°C)
PARAMETER
DYNAMIC PERFORMANCE
MAX521_C
Voltage Output Slew Rate
Positive and negative MAX521_E
MAX521BM
MAX520_, to 1/2LSB, no load
Output Settling Time
MAX521_, to 1/2LSB, 10kΩ and
100pF load (Note 7)
Code = 00 hex, all digital inputs from
0V to V
DD
Code 128 to 127
SINAD
V
REF_
= 4Vp-p at 1kHz, V
DD
= 5V,
code = FF hex
V
REF_
= 4Vp-p, 3dB bandwidth
MAX521_
V
DD
Operating mode, out- MAX520_
put unloaded, all dig- MAX521_C
ital inputs 0V or V
DD
MAX521_E/BM
Power-down mode (PD = 1)
4.5
4
10
10
4
1.0
0.7
0.5
2
µs
6
5
12
87
1
60
5.5
20
20
24
20
nV-s
nV-s
dB
MHz
µV
RMS
V
µA
mA
µA
V/µs
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Digital Feedthrough
Digital-Analog Glitch Impulse
Signal to Noise + Distortion Ratio
Multiplying Bandwidth
Wideband Amplifier Noise
POWER REQUIREMENTS
Supply Voltage
Supply Current
I
DD
Note 1:
Input resistance is code dependent. The lowest input resistance occurs at code = 55 hex.
Note 2:
Input capacitance is code dependent. The highest input capacitance occurs at code = FF hex.
Note 3:
V
REF_
= 4Vp-p, 10kHz. Channel-to-channel isolation is measured by setting the code of one DAC to FF hex and setting the
code of all other DACs to 00 hex.
Note 4:
V
REF_
= 4Vp-p, 10kHz, DAC code = 00 hex.
Note 5:
Guaranteed by design.
Note 6:
I
2
C-compatible mode.
Note 7:
Output settling time is measured by taking the code from 00 hex to FF hex, and from FF hex to 00 hex.
4
_______________________________________________________________________________________
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
TIMING CHARACTERISTICS
(V
DD
= 5V ±10%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Serial Clock Frequency
Bus Free Time Between a STOP and a
START Condition
Hold Time, (Repeated) Start Condition
Low Period of the SCL Clock
High Period of the SCL Clock
Setup Time for a Repeated START Condition
Data Hold Time
Data Setup Time
Rise Time of Both SDA and SCL Signals, Receiving
Fall Time of Both SDA and SCL Signals, Receiving
Fall Time of SDA Transmitting (Note 6)
Setup Time for STOP Condition
Capacitive Load for Each Bus Line
Pulse Width of Spike Suppressed
SYMBOL
f
SCL
t
BUF
t
HD, STA
t
LOW
t
HIGH
t
SU, STA
t
HD, DAT
t
SU, DAT
t
R
t
F
t
F
t
SU, STO
Cb
t
SP
(Notes 10, 11)
0
(Note 9)
(Note 9)
I
SINK
≤
6mA (Note 9)
(Note 8)
CONDITIONS
MIN
0
1.3
0.6
1.3
0.6
0.6
0
100
20 + 0.1Cb
20 + 0.1Cb
20 + 0.1Cb
0.6
400
50
300
300
250
0.9
TYP
MAX
400
UNITS
kHz
µs
µs
µs
µs
µs
µs
ns
ns
ns
ns
µs
pF
ns
MAX520/MAX521
Note 8:
A master device must provide a hold time of at least 300ns for the SDA signal (referred to V
IL
of the SCL signal) in order to
bridge the undefined region of SCL’s falling edge.
Note 9:
Cb = total capacitance of one bus line in pF. t
R
and t
f
measured between 0.3V
DD
and 0.7V
DD
.
Note 10:
An input filter on the SDA and SCL input suppresses noise spikes less than 50ns.
Note 11:
Guaranteed by design.
__________________________________________Typical Operating Characteristics
(V
DD
= 5V, DAC outputs unloaded, T
A
= +25°C, unless otherwise noted.)
MAX520
REFERENCE INPUT CURRENT vs.
TEMPERATURE (SHUTDOWN MODE)
MAX520/521-01
MAX520/521-02
MAX520
SUPPLY CURRENT vs. TEMPERATURE
10
9
8
7
I
DD
(µA)
6
5
4
3
2
1
0
-60
-30
0
30
60
90
120
150
TEMPERATURE (°C)
OPERATING MODE OR
SHUTDOWN MODE
40
SHUTDOWN REFERENCE CURRENT (nA)
35
30
25
20
15
10
5
0
-60
MAX520
REFERENCE VOLTAGE INPUT
FREQUENCY RESPONSE
0
RELATIVE OUTPUT (dB)
-2
-4
-6
-8
-10
-12
-14
-16
-18
V
DD
= 5V
V
REF
= 4Vp-p SINE WAVE
CENTERED AT 2.5V
MAX520/521-03
2
V
REF
= 4V
ONE REF INPUT DRIVEN
-30
0
30
60
90
120
150
1k
10k
100k
FREQUENCY (Hz)
1M
10M
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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