Datasheet
®
12
DAC7715
THEORY OF OPERATION
The DAC7715 is a quad, serial input, 12-bit, voltage output
DAC. The architecture is a classic R-2R ladder configuration
followed by an operational amplifier that serves as a buffer,
as shown in Figure 1. Each DAC has its own R-2R ladder
network and output op amp, but all share the reference
voltage inputs. The minimum voltage output (“zero-scale”)
and maximum voltage output (“full-scale”) are set by external
voltage references (V
REFL
and V
REFH
, respectively). The
FIGURE 2. Basic Single-Supply Operation of the DAC7715.
NOTE: (1) As configured, RESET LOW sets all internal registers to code 000
H
(0V).
If RESETSEL is HIGH, RESET LOW sets all internal registers to code 800
H
(5.00V).
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
V
OUTD
V
OUTC
V
REFL
V
REFH
V
OUTB
V
OUTA
V
SS
RESETSEL
RESET
LOADREG
LOADDACS
CS
CLK
SDI
GND
Reset DACs
(1)
Update Selected Register
Update All DAC Registers
Chip Select
Clock
Serial Data In
DAC7715
0.1µF
0.1µF
0V to +10V
1µF to 10µF
+15V
+
0V to +10V
0V to +10V
0V to +10V
+10.00V
R
2R
2R2R 2R 2R 2R 2R 2R 2R
V
REF
H
V
OUT
RRRRRR
V
REF
L
R
F
FIGURE 1. DAC7715 Architecture.
digital input is a 16-bit serial word that contains the 12-bit
DAC code and a 2-bit address code that selects one of the four
DACs (the two remaining bits are unused). The converter can
be powered from a single +15V supply or a dual ±15V
supply. Each device offers a reset function which immedi-
ately sets all DAC output voltages and internal registers to
either zero-scale (code 000
H
) or mid-scale (code 800
H
). The
reset code is selected by the state of the RESETSEL pin
(LOW = 000
H
, HIGH = 800
H
). See Figures 2 and 3 for the
basic operation of the DAC7715.
FIGURE 3. Basic Dual-Supply Operation of the DAC7715.
NOTE: (1) As configured, RESET LOW sets all internal registers to code 800
H
(0V).
If RESETSEL is LOW, RESET LOW sets all internal registers to code 000
H
(–10 V).
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
V
OUTD
V
OUTC
V
REFL
V
REFH
V
OUTB
V
OUTA
V
SS
RESETSEL
RESET
LOADREG
LOADDACS
CS
CLK
SDI
GND
Reset DACs
(1)
Update Selected Register
Update All DAC Registers
Chip Select
Clock
Serial Data In
DAC7715
0.1µF
0.1µF
–10V to +10V
1µF to 10µF
+15V
–15V
+
0.1µF
1µF to 10µF
+
–10V to +10V
–10.00V
0.1µF
+10.00V
–10V to +10V
–10V to +10V
+5V