19-1300; Rev 0; 10/97
8-Bit Parallel DAC in
QSOP-16 Package
_______________General Description
The MAX5480 is a CMOS, 8-bit digital-to-analog con-
verter (DAC) that interfaces directly with most micro-
processors. On-chip input latches make the DAC load
cycle interface similar to a RAM write cycle, where
CS
and
WR
are the only control inputs required.
Linearity of ±1/2LSB is guaranteed, and power con-
sumption is less than 500µW. Monotonicity is guaran-
teed over the full operating temperature range.
The MAX5480 can be operated in either voltage-output
or current-output mode. It is available in a small 16-pin
QSOP package.
____________________________Features
o
QSOP-16 Package (same footprint as SO-8)
o
Single +5V Supply Operation
o
V
OUT
or I
OUT
Operation
o
8-Bit Parallel Interface
o
Guaranteed Monotonic Over Temperature
o
Low Power Consumption—100µA max
o
±1/2LSB Linearity Over Temperature
MAX5480
________________________Applications
Digitally Adjusted Power Supplies
Programmable Gain
Automatic Test Equipment
Portable, Battery-Powered Instruments
VCO Frequency Control
RF Transmit Control in Portable Radios
______________Ordering Information
PART
MAX5480ACEE
MAX5480BCEE
MAX5480AEEE
MAX5480BEEE
TEMP. RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
16 QSOP
16 QSOP
16 QSOP
16 QSOP
ERROR
(LSB)
±1/2
±1/2
±1/2
±1/2
__________Typical Operating Circuit
__________________Pin Configuration
V
REF
V
DD
TOP VIEW
15
REF
DATA
INPUTS 4–11 D7–D0
12
13
R1
2k
14
V
DD
RFB
16
1
R2
1k
10pF
MAX4330
OUT1 1
OUT2 2
GND 3
D7 (MSB) 4
V
OUT
D6 5
D5 6
D4 7
D3 8
16 RFB
15 REF
14 V
DD
OUT1
OUT2
MAX5480
13 WR
12 CS
11 D0 (LSB)
10 D1
9
D2
CS
WR
MAX5480
GND
3
2
R1 AND R2 USED ONLY IF GAIN
ADJUSTMENT IS REQUIRED.
QSOP
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
8-Bit Parallel DAC in
QSOP-16 Package
MAX5480
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND ............................................................-0.3V to +17V
REF to GND .........................................................................±25V
RFB to GND .........................................................................±25V
Digital Inputs to GND .................................-0.3V to (V
DD
+ 0.3V)
OUT1, OUT2 to GND................................................-0.3V to V
DD
Operating Temperature Ranges
MAX5480_CEE....................................................0°C to +70°C
MAX5480_EEE .................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Continuous Power Dissipation (T
A
= +70°C)
MAX5480_ _EE (derate 8.3mW/°C above +70°C) ........667mW
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, V
REF
= +10V, V
OUT1
= V
OUT2
= 0V, Circuit of Figure 1, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
DC ACCURACY
Resolution
Relative Accuracy
Differential Nonlinearity
Gain Error (Note 1)
Gain Temperature
Coefficient (Note 2)
MAX5480A
(Note 3)
Supply Rejection
PSR
MAX5480B
Output Leakage Current
(I
OUT1
)
Output Leakage Current
(I
OUT2
)
REFERENCE INPUT
Input Resistance
DYNAMIC PERFORMANCE
D0–D7 = 0V to
V
DD
or V
DD
to 0V,
WR
=
CS
= 0V,
OUT1 load =
100Ω
||
13pF
V
REF
= ±10V,
100kHz sine
wave,
WR
=
CS
= 0V
MAX5480A
(Note 3)
T
A
= +25°C
T
A
= T
MIN
to T
MAX
250
0.25
0.5
0.1
120
30
30
120
ns
400
500
ns
R
REF
pin 15 to GND
5
10
20
kΩ
V
REF
= ±10V
DAC code = full scale
V
REF
= ±10V
DAC code = zero scale
T
A
= +25°C
T
A
= T
MIN
to T
MAX
T
A
= +25°C
T
A
= T
MIN
to T
MAX
T
A
= +25°C
T
A
= T
MIN
to T
MAX
T
A
= +25°C
T
A
= T
MIN
to T
MAX
INL
DNL
All grades guaranteed monotonic over temperature
T
A
= T
MIN
to T
MAX
±1
±2
0.002
0.01
0.002
0.01
±50
±400
±50
±400
nA
nA
0.08
0.16
%FSR/%
8
±1/2
±1
Bits
LSB
LSB
LSB
ppm/°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Output Current Settling Time
to 1/2LSB
MAX5480B T
A
= +25°C
MAX5480A T
A
= +25°C
(Note 3)
T
A
= T
MIN
to T
MAX
MAX5480B T
A
= +25°C
AC Feedthrough
(OUT1 or OUT2)
ANALOG OUTPUTS
OUT1 Capacitance (Note 3)
OUT2 Capacitance (Note 3)
C
OUT1
C
OUT2
D0–D7 = V
DD
,
WR
=
CS
= 0V
D0–D7 = 0V,
WR
=
CS
= 0V
D0–D7 = V
DD
,
WR
=
CS
= 0V
D0–D7 = 0V,
WR
=
CS
= 0V
pF
pF
2
_______________________________________________________________________________________
8-Bit Parallel DAC in
QSOP-16 Package
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +5V, V
REF
= +10V, V
OUT1
= V
OUT2
= 0V, Circuit of Figure 1, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
DIGITAL INPUTS
Input High Voltage
Input Low Voltage
Input Current
Input Capacitance (Note 3)
POWER REQUIREMENTS
Supply Current
I
DD
Digital inputs at 0V or V
DD
T
A
= +25°C
T
A
= T
MIN
to T
MAX
220
35
0
0
220
35
170
55
10
-7
100
500
µA
V
IH
V
IL
I
IN
C
IN
T
A
= +25°C; V
IN
= 0V to V
DD
T
A
= T
MIN
to T
MAX
D0–D7
WR, CS
2.4
0.8
±1
±10
8
20
V
V
µA
pF
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5480
SWITCHING CHARACTERISTICS
(Figure 4)
Chip-Select to Write-
Setup Time
Chip-Select to Write-
Hold Time
Write Pulse Width
Data-Setup Time
Data-Hold Time
t
CS
t
CH
t
WR
t
DS
t
DH
MAX5480A
MAX5480B
MAX5480A
MAX5480B
MAX5480A
MAX5480B
MAX5480A
MAX5480B
MAX5480A
MAX5480B
ns
ns
ns
ns
ns
Note 1:
Gain error is measured using internal feedback resistor. Full-scale range (FSR) = V
REF
.
Note 2:
Gain TempCo measured from +25°C to T
MAX
and from +25°C to T
MIN
.
Note 3:
Guaranteed by design.
______________________________________________________________Pin Description
PIN
1
2
3
4–11
12
13
14
15
16
NAME
OUT1
OUT2
GND
D7–D0
CS
WR
V
DD
REF
RFB
R-2R Ladder Output
R-2R Ladder Output, complement of OUT1
Ground
Data Inputs, D7 is the most significant bit.
Chip Select Input. Active Low.
Write Control Input. Active Low.
Power Supply Input, +5V
Reference Voltage Input
Feedback Resistor Connection
FUNCTION
_______________________________________________________________________________________
3
8-Bit Parallel DAC in
QSOP-16 Package
MAX5480
_______________Detailed Description
The MAX5480 is an 8-bit multiplying digital-to-analog
converter (DAC) that consists of a thin-film R-2R resistor
array with CMOS current steering switches. Figure 3
shows a simplified schematic of the DAC. The inverted
R-2R ladder divides the voltage or current reference in
a binary manner among the eight steering switches.
The magnitude of the current appearing at either OUT
terminal depends on the number of switches selected;
therefore, the output is an analog representation of the
digital input. The two OUT terminals must be held at the
same potential so a constant current is maintained in
each ladder leg. This makes the REF input current inde-
pendent of switch state and also ensures that the
MAX5480 maintains its excellent linearity performance.
V
REF
V
DD
15
REF
DATA
INPUTS 4–11 D7–D0
12
13
R1
2k
14
V
DD
R
FB
16
1
R2
1k
10pF
MAX4330
OUT1
OUT2
V
OUT
CS
WR
MAX5480
GND
3
2
Interface-Logic Information
Mode Selection
The inputs
CS
and
WR
control the MAX5480’s operat-
ing mode (see Table 1).
Write Mode
When
CS
and
WR
are both low, the MAX5480 is in write
mode, and its analog output responds to data activity at
the D0–D7 data-bus inputs. In this mode, the data
latches are transparent (see Tables 2 and 3).
Hold Mode
In hold mode, the MAX5480 retains the data that was
present on D0–D7 just prior to
CS
or
WR
assuming a
high state. The analog output remains at the value cor-
responding to the digital code locked in the data latch.
R1 AND R2 USED ONLY IF GAIN
ADJUSTMENT IS REQUIRED.
Figure 1. Unipolar Binary Operation (Two-Quadrant Multiplication)
16
REF
INPUT*
1
RFB
OUT1
+5V
14
V
DD
REF
15 OUTPUT
VOLTAGE
(10kΩ OUTPUT
RESISTANCE)
2
MAX5480
OUT2
WR CS
13
12
GND
3
D7–D0
4–11
DATA IN
__________Applications Information
Using the MAX5480 in Voltage-
Output Mode (Single Supply)
The MAX5480 can be used either as a current-output
DAC (Figures 1 and 6) or as a voltage-output DAC
(Figures 2 and 5).
To use the MAX5480 in voltage mode, connect OUT1 to
the reference input and connect OUT2 to ground. REF,
now the DAC output, is a voltage source with a con-
stant output resistance of 10kΩ (nominally). This output
is often buffered with an op amp (Figure 5).
An advantage of voltage-mode operation is single-
supply operation for the complete circuit; i.e., a nega-
tive reference is not required for a positive output. It is
important to note that the range of the reference is
restricted in voltage mode. The reference input (voltage
at OUT1) must always be positive and is limited to no
more than V
DD
- 3V. If the reference voltage exceeds
this value, linearity is degraded.
4
*(V
DD
- 3V, max)
Figure 2. Typical Operating Circuit (Voltage Mode—Unbuffered)
Table 1. Mode-Selection Table
CS
L
H
X
WR
L
X
H
MODE
Write
Hold
Hold
DAC Response
DAC responds to data bus
(D0–D7) inputs.
Data bus (D0–D7) is locked out;
DAC holds last data present
when
CS
or
WR
assumed high
state.
L = Low State, H = High State, X = Don’t Care
_______________________________________________________________________________________
8-Bit Parallel DAC in
QSOP-16 Package
MAX5480
Table 2. Unipolar Binary Code Table
DIGITAL INPUT
MSB
LSB
1 1 1 1 1 1 1 1
ANALOG OUTPUT
Table 3. Bipolar (Offset Binary) Code Table
DIGITAL INPUT
MSB
LSB
1 1 1 1 1 1 1 1
ANALOG OUTPUT
255
-V
REF
256
129
-V
REF
256
128
V
REF
-V
REF
= −
2
256
127
-V
REF
256
1
-V
REF
256
0
-V
REF
=
0
256
127
+V
REF
128
1
+V
REF
128
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0
0
1
-V
REF
128
127
-V
REF
128
128
-V
REF
128
0 1 1 1 1 1 1 1
0 1 1 1 1 1 1 1
0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
1
NOTE : 1 LSB
=
2
−
8
V
REF
=
V
REF
256
(
)
(
)
1
NOTE : 1 LSB
=
2
−
7
V
REF
=
V
REF
128
(
)
(
)
t
CS
10kΩ
REF
20kΩ
S8
20kΩ
S7
20kΩ
S6
20kΩ
S1
20kΩ
10kΩ
10kΩ
t
CH
V
DD
CS
0
t
WR
WR
0
OUT2
OUT1
RFB
V
DD
t
DS
t
DH
DATA IN
(D7–D0)
V
IH
V
IL
V
DD
DATA IN
STABLE
0
CS
WR
D7 (MSB)
10kΩ
INTERFACE LOGIC
D6
D5
D0 (LSB)
NOTES:
1. FOR THE MAX5480, ALL INPUT SIGNAL RISE AND FALL TIMES ARE MEASURED
FROM 10% TO 90% OF V
DD
. V
DD
= +5V, t
r
= t
f
= 20ns.
2. TIMING MEASUREMENT REFERENCE LEVEL IS (V
IH
+ V
IL
) / 2.
Figure 3. MAX5480 Functional Diagram
Figure 4. Write-Cycle Timing Diagram
_______________________________________________________________________________________
5
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