_______________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.
________________________Applications
Minimum Component Analog Systems
Digital Offset/Gain Adjustment
Industrial Process Control
Automatic Test Equipment
Programmable Attenuators
____________________________Features
o
Single +5V Supply
o
Simple 2-Wire Serial Interface
o
I
2
C Compatible
o
Outputs Swing Rail to Rail:
Unbuffered Outputs (MAX520)
Buffered Outputs (MAX521)
o
1%-Accurate Trimmed Output Resistance (MAX520A)
o
Ultra-Low 4µA Supply Current (MAX520)
o
Individual DACs Have Separate Reference Inputs
o
Power-On Reset Clears All Latches
o
4µA Power-Down Mode
MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
________________________________________________________________
Maxim Integrated Products
1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
OUT1
OUT2
OUT3
REF2
REF3
V
DD
AD2
AD1
AD0
OUT0
REF1
REF0
AGND
DGND
SCL
SDA
TOP VIEW
MAX520
DIP/SO
_________________Pin Configurations
INPUT
LATCH 0
8-BIT
SHIFT REGISTER
SCL
REF0
SDA
REF1
OUTPUT
LATCH 0
DAC0
OUT0
1
MAX520
ADDRESS
COMPARATOR
START/STOP
DETECTOR
DECODE
OUTPUT
LATCH 1
DAC1
OUT1
4
8
INPUT
LATCH 2
OUTPUT
LATCH 2
DAC2
OUT2
OUT3
INPUT
LATCH 3
OUTPUT
LATCH 3
DAC3
REF3
REF2
AD2
AD1
AD0
1
INPUT
LATCH 1
1
1
_______________Functional Diagrams
______________Ordering Information
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
19-0378; Rev 3; 9/96
PART
†
MAX520
ACPE
MAX520BCPE
MAX520ACWE
0°C to +70°C
0°C to +70°C
0°C to +70°C
TEMP. RANGE
PIN-PACKAGE
16 Plastic DIP
16 Plastic DIP
16 Wide SO
TUE
(LSB)
1
1
1
Pin Configurations continued at end of data sheet.
Functional Diagrams continued at end of data sheet.
MAX520BCWE
0°C to +70°C
16 Wide SO
1
Ordering Information continued at end of data sheet.
†
MAX520 “A” grade parts include a 1%-accurate, factory-trimmed
output resistance.
MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DD
= 5V ±10%, V
REF_
= 4V, R
L
=
∞
(MAX520), R
L
= 10k
Ω
(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)
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.
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
CONDITIONS
Bits
8
Resolution
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
±1.5
±1
18
Guaranteed monotonic
8
LSB
±1.0
DNL
LSB
±2
TUE
Total Unadjusted Error
Differential Nonlinearity
Code = 00 hex
Code = 00 hex
µV/°C
±10
mV
Code = 00 hex
±1
Zero-Code-Error Supply Rejection
Zero-Code-Error Temperature Coefficient
Code = FF hex
mV
20
20
Full-Scale Error
8
mV
20
ZCE
20
Zero-Code Error
Code = FF hex, V
DD
= 5V ±10%
µV/°C
±10
mV
±1
Full-Scale-Error Supply Rejection
Full-Scale-Error Temperature Coefficient
MAX520_
MAX520_
MAX521B
MAX521A
MAX521_C
MAX521_E
MAX521BM
MAX520_
18
MAX521_C
MAX521_E
MAX521BM
STATIC ACCURACY
MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 5V ±10%, V
REF_
= 4V, R
L
=
∞
(MAX520), R
L
= 10k
Ω
(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)
(Note 3)
30
CONDITIONS
Input Capacitance
16
24
R
IN
Input Resistance
REF4
MAX520_
MAX521_
Input Current
-60
V
0
V
DD
Input Voltage Range
dB
-70
µA
±10
REF4
PD = 1
4
6
Code =
55 hex
(Note 1)
k
Ω
8
12
MAX520_
REF0–REF3
Channel-to-Channel Isolation
dB
-70
AC Feedthrough
120
Code =
FF hex
(Note 2)
pF
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
30
MAX520_
REF0–REF3
15.8
16
16.2
V
0
V
DD
Full-Scale Output Voltage
k
Ω
8.4
16.4
Output Resistance (Note 5)
MAX521_, OUT_ = 4V,
0mA to 2.5mA
0.25
15.6
16
16.4
MAX521_, OUT_ = 0V to V
DD
,
PD = 1
µA
±10
Output Leakage Current
V
0.3V
DD
V
IL
Input Low Voltage
(Note 5)
V
0.05V
DD
V
HYST
Input Hysteresis
0V
≤
V
IN
≤
V
DD
µA
±10
I
IN
Input Current
V
0.7V
DD
V
IH
Input High Voltage
MAX521BM, V
REF_
= V
DD
,
code = FF hex, 0µA to 500µA
LSB
2.0
Output Load Regulation
(Note 5)
pF
10
C
IN
Input Capacitance
V
0.8
V
IL
Input Low Voltage
V
IN
= 0V to V
DD
µA
±10
I
IN
Input Leakage
V
2.4
V
IH
Input High Voltage
MAX520B
MAX521_C/E, V
REF_
= V
DD
,
code = FF hex, 0µA to 500µA
1.5
I
SINK
= 6mA
0.6
V
OL
Output Low Voltage
(Note 5)
pF
10
C
OUT
Three-State Output Capacitance
V
IN
= 0V to V
DD
µA
±10
I
L
Three-State Leakage Current
I
SINK
= 3mA
V
0.4
REFERENCE INPUTS
DIGITAL INPUTS SCL, SDA
DIGITAL INPUTS AD0, AD1
DIGITAL OUTPUT SDA
(Note 6)
(Note 4)
DAC OUTPUTS
MAX521_
MAX521_
MAX520A
T
A
= +25°C
T
A
= T
MIN
to T
MAX
MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
4
_______________________________________________________________________________________
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.
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 5V ±10%, V
REF_
= 4V, R
L
=
∞
(MAX520), R
L
= 10k
Ω
(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)
MAX521BM
MAX521_C
0.7
MAX521_E
MAX520_
1.0
MAX521_C
MAX521_E/BM
Power-down mode (PD = 1)
10
20
4
20
Positive and negative
CONDITIONS
V/µs
0.5
Voltage Output Slew Rate
Operating mode, out-
put unloaded, all dig-
ital inputs 0V or V
DD
mA
4
20
I
DD
10
24
Supply Current
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
MAX520_, to 1/2LSB, no load
µs
2
Output Settling Time
Code = 00 hex, all digital inputs from
0V to V
DD
nV-s
5
Digital Feedthrough
MAX521_, to 1/2LSB, 10k
Ω
and
100pF load (Note 7)
6
Code 128 to 127
nV-s
12
Digital-Analog Glitch Impulse
V
REF_
= 4Vp-p at 1kHz, V
DD
= 5V,
code = FF hex
dB
87
SINAD
Signal to Noise + Distortion Ratio
V
REF_
= 4Vp-p, 3dB bandwidth
MHz
1
Multiplying Bandwidth
MAX521_
µV
RMS
60
Wideband Amplifier Noise
V
4.5
5.5
V
DD
Supply Voltage
µA
µA
DYNAMIC PERFORMANCE
POWER REQUIREMENTS
MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
_______________________________________________________________________________________
5
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.
Hold Time, (Repeated) Start Condition
t
HD, STA
0.6
µs
Low Period of the SCL Clock
t
LOW
1.3
µs
High Period of the SCL Clock
t
HIGH
0.6
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Serial Clock Frequency
f
SCL
0
400
kHz
Bus Free Time Between a STOP and a
START Condition
t
BUF
1.3
µs
CONDITIONS
µs
Setup Time for a Repeated START Condition
t
SU, STA
0.6
µs
Data Hold Time
t
HD, DAT
0
0.9
µs
Data Setup Time
t
SU, DAT
100
(Note 8)
ns
Fall Time of SDA Transmitting (Note 6)
t
F
20 + 0.1Cb
250
ns
Setup Time for STOP Condition
t
SU, STO
0.6
µs
Capacitive Load for Each Bus Line
Cb
400
I
SINK
≤
6mA (Note 9)
pF
Rise Time of Both SDA and SCL Signals, Receiving
t
R
20 + 0.1Cb
300
ns
Fall Time of Both SDA and SCL Signals, Receiving
t
F
20 + 0.1Cb
300
(Note 9)
(Note 9)
ns
Pulse Width of Spike Suppressed
t
SP
0
50
(Notes 10, 11)
ns
TIMING CHARACTERISTICS
(V
DD
= 5V ±10%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
__________________________________________Typical Operating Characteristics
(V
DD
= 5V, DAC outputs unloaded, T
A
= +25°C, unless otherwise noted.)
10
9
0
-60
-30
30
90
120
150
MAX520
SUPPLY CURRENT vs. TEMPERATURE
2
1
8
7
MAX520/521-01
TEMPERATURE (°C)
I
DD
(
µ
A)
0
60
6
5
4
3
OPERATING MODE OR
SHUTDOWN MODE
40
0
-60
-30
30
90
120
150
MAX520
REFERENCE INPUT CURRENT vs.
TEMPERATURE (SHUTDOWN MODE)
5
35
30
MAX520/521-02
TEMPERATURE (°C)
SHUTDOWN REFERENCE CURRENT (nA)
0
60
25
20
15
10
V
REF
= 4V
ONE REF INPUT DRIVEN
0
1k
100k
10k
1M
10M
MAX520
REFERENCE VOLTAGE INPUT
FREQUENCY RESPONSE
-16
-18
MAX520/521-03
FREQUENCY (Hz)
RELATIVE OUTPUT (dB)
-14
-12
-10
-8
-6
-4
-2
2
V
DD
= 5V
V
REF
= 4Vp-p SINE WAVE
CENTERED AT 2.5V
MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
6
_______________________________________________________________________________________
______________________________Typical Operating Characteristics (continued)
(V
DD
= 5V, DAC outputs unloaded, T
A
= +25°C, unless otherwise noted.)
OUT2 = NO LOAD, REF2 = 4V,
DAC CODE = 00 HEX to FF HEX
1
µ
s/div
MAX520
POSITIVE SETTLING TIME
OUT2
1V/div
OUT2 = NO LOAD, REF2 = 4V,
DAC CODE = FF HEX to 00 HEX
1
µ
s/div
MAX520
NEGATIVE SETTLING TIME
OUT2
1V/div
REF2 = 4V, DAC CODE = 7F HEX to 80 HEX
500ns/div
MAX520
WORST-CASE 1LSB DIGITAL STEP CHANGE
(CAPACITIVE LOAD < 5pF)
OUT2
20mV/div
AC COUPLED
REF2 = 4V, DAC CODE = 7F HEX to 80 HEX
500ns/div
MAX520
WORST-CASE 1LSB DIGITAL STEP CHANGE
(CAPACITIVE LOAD = 25pF)
OUT2
20mV/div
AC COUPLED
MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
_______________________________________________________________________________________
7
12
0
-60
-20
60
140
MAX521
SUPPLY CURRENT vs. TEMPERATURE
2
8
10
MAX520/521-08
TEMPERATURE (°C)
I
CC
(mA)
20
100
6
4
V
DD
= 5.5V
ALL REF INPUTS = 0.6V
ALL DIGITAL INPUTS to V
DD
ALL DAC CODES FF HEX
ALL DAC CODES 00 HEX
6
0
-60
-20
60
140
MAX521
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
1
4
5
MAX520/521-09
TEMPERATURE (°C)
SHUTDOWN I
CC
(
µ
A)
20
100
3
2
V
DD
= 5.5V
ALL REF INPUTS = 0.6V
ALL DIGITAL INPUTS to V
DD
10
0
0
1
3
5
MAX521
SUPPLY CURRENT
vs. REFERENCE VOLTAGE
2
6
8
MAX520/521-10
REFERENCE VOLTAGE (V)
I
CC
(mA)
2
4
4
ALL REFERENCE
INPUTS DRIVEN
ALL DAC CODES = FF HEX
ALL DAC CODES = 00 HEX
1.0
0
0
2
6
10
12
14
16
MAX521
DAC OUTPUT HIGH VOLTAGE
vs. OUTPUT SOURCE CURRENT
0.2
0.8
MAX520/521-11
OUTPUT SOURCE CURRENT (mA)
V
DD
- V
OUT
(V)
4
8
0.6
0.4
V
REF
= 5V
DAC CODE = FF HEX
LOAD to AGND
V
OUT
= V
REF
x (255/256)
1.0
0
0
2
6
10
MAX521
DAC OUTPUT LOW VOLTAGE
vs. OUTPUT SINK CURRENT
0.2
0.8
MAX520/521-12
OUTPUT SINK CURRENT (mA)
V
OUT
(V)
4
8
0.6
0.4
V
REF
= 5V
DAC CODE = 00 HEX
LOAD to V
DD
0
1k
100k
10k
1M
10M
MAX521
REFERENCE VOLTAGE INPUT
FREQUENCY RESPONSE
-16
-18
MAX520/521-13
FREQUENCY (Hz)
RELATIVE OUTPUT (dB)
-14
-12
-10
-8
-6
-4
-2
2
V
REF
= SINE WAVE
CENTERED AT 2.5V
4V
p-p
SINE
2V
p-p
SINE
1V
p-p
SINE
0.5V
p-p
SINE
__________________________________________Typical Operating Characteristics
(V
DD
= 5V, DAC outputs unloaded, T
A
= +25°C, unless otherwise noted.)
OUT1 LOADED WITH 10k
Ω
II 100pF, REF1 = 4V,
DAC CODE = 00 HEX to FF HEX
1
µ
s/div
MAX521
POSITIVE SETTLING TIME
OUT1
1V/div
OUT1 LOADED WITH 10k
Ω
II 100pF, REF1 = 4V,
DAC CODE = FF HEX to 00 HEX
1
µ
s/div
MAX521
NEGATIVE SETTLING TIME
OUT1
1V/div
MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
8
_______________________________________________________________________________________
A = REF1, 1V/div (4V
P-P
)
B = OUT1, 50
µ
V/div, UNLOADED
FILTER PASSBAND = 1kHz to 100kHz, DAC CODE = 00 HEX
REFERENCE FEEDTHROUGH AT 10kHz
B
A
A = REF1, 1V/div (4V
P-P
)
B = OUT1, 50
µ
V/div, UNLOADED
FILTER PASSBAND = 10kHz to 1MHz, DAC CODE = 00 HEX
REFERENCE FEEDTHROUGH AT 100kHz
B
A
______________________________Typical Operating Characteristics (continued)
(V
DD
= 5V, DAC outputs unloaded, T
A
= +25°C, unless otherwise noted.)
REF1 = 5V, DAC CODE = 80 HEX to 7F HEX
500ns/div
MAX521
WORST-CASE 1LSB DIGITAL STEP CHANGE
OUT1
20mV/div
AC COUPLED
A = SCL, 400kHz, 5V/div
B = OUT1, 5mV/div
REF1 = 5V, DAC CODE = 7F HEX
CLOCK FEEDTHROUGH
B
A
A = REF1, 1V/div (4V
P-P
)
B = OUT1, 50
µ
V/div, UNLOADED
FILTER PASSBAND = 100Hz to 10kHz, DAC CODE = 00 HEX
REFERENCE FEEDTHROUGH AT 1kHz