max552bcubt Maxim Integrated Products, Inc., max552bcubt Datasheet - Page 8

• Manufacturer Part Number: max552bcubt
• Description: +3v/+5v, 12-bit, Serial, Multiplying Dacs In 10-pin ?max Package
• Manufacturer: Maxim Integrated Products, Inc.

The MAX551/MAX552 digital-to-analog converter (DAC)
circuits consist of a laser-trimmed, thin-film R-2R resis-
tor array with NMOS current switches (Figure 1).
Binary-weighted currents are switched to either OUT or
AGND, depending on the status of each input data bit.
Although the currents at OUT and AGND depend on
the digital input code, the sum of the two output cur-
rents is always equal to the input current at REF.
The output current (I
age by adding an external output amplifier (Figure 3).
The REF input accepts a wide range of signals, includ-
ing fixed and time-varying voltage or current inputs. If a
current source is used at the reference input, use a
low-tempco, external feedback resistor in place of the
+3V/+5V, 12-Bit, Serial, Multiplying DACs
Figure 2. Write-Cycle Timing Diagram
8
Table 1. Unipolar Binary-Code Table
for Circuit of Figure 3
in 10-Pin µMAX Package
1 1 1 1
0 0 0 0
0 0 0 0
1000
MSB
_______________________________________________________________________________________
DIN
SCLK
LOAD
CLR
DIGITAL INPUT
t
DS
1 1 1 1
0 0 0 0
0 0 0 0
0000
1
1 1 1 1
0 0 0 1
0 0 0 0
0000
OUT
LSB
BIT 11
MSB
t
CH
Detailed Description
t
DH
) can be converted into a volt-
t
CL
−
V
REF
−
ANALOG OUTPUT
−
V
V
REF
REF
2



BIT 10
2048
4096






4096
4095
4096
0
LOAD SERIAL DATA INTO INPUT REGISTER
1

 = −







V
REF
2
internal feedback resistor (R
tion with temperature.
The internal feedback resistor (R
with an NMOS switch that matches the NMOS switches
used in the R-2R array, resulting in excellent supply
rejection and gain-temperature coefficient.
The OUT pin output capacitance (C
dependent. C
at FFFhex.
The MAX551/MAX552 serial interface is compatible
with the SPI/QSPI and MICROWIRE serial-interface
standards. These devices accept serial clocks up to
12.5MHz (50% duty cycle). If the SCLK input is not
Figure 3. Unipolar Operation
V
REF
LOAD
( ) ARE FOR MAX552
SCLK
DIN
100Ω
11
R1
BIT 1
OUT
REF
MAX551
MAX552
t
SL
+5V (+3V)
is typically
V
DD
AGND
OUT
GND
RFB
BIT 0
LSB
50Ω
R2
FB
14
15pF
C1
t
LD
) to minimize gain varia-
pF at 000hex and
FB
Serial Interface
) is compensated
2
3
OUT
t
CLR
t
LC
) is code
6
V
OUT
20
pF