ltc1821 Linear Technology Corporation, ltc1821 Datasheet - Page 11

• Manufacturer Part Number: ltc1821
• Description: Ltc1821 - 16-bit, Ultra Precise, Fast Settling Vout Dac
• Manufacturer: Linear Technology Corporation

APPLICATIONS
Bipolar Mode
(4-Quadrant Multiplying, V
The LTC1821 contains on chip all the 4-quadrant resistors
necessary for bipolar operation. 4-quadrant multiplying
INPUTS
25 TO 36,
V
DATA
CLR
WR
3 TO 6
REF
LD
U
16
INFORMATION
Figure 2. Bipolar Operation (4-Quadrant Multiplication) V
WR
U
10
R1
24
OUT
R1
LD
23
= – V
R
9
LTC1821
3
2
COM
R2
CLR DNC* DNC*
+
–
W
LT1001
7
REF
18
to V
REF
1111
1000
1000
0111
0000
MSB
19
6
8
Bipolar Offset Binary Code Table
REF
U
DNC*
IN DAC REGISTER
BINARY NUMBER
V
DIGITAL INPUT
)
CC
1111 1111 1111
0000 0000 0001
0000 0000 0000
1111 1111 1111
0000 0000 0000
21
2
NC
R
11
R
22
OFS
OFS
16-BIT DAC
0.1 F
LSB
R
operation can be achieved with a minimum of external
components—a capacitor and a single op amp, as shown
in Figure 2. With a fixed 10V reference, the circuit shown
gives a precision bipolar – 10V to 10V output swing.
FB
DGND
5V
1
V
V
0V
–V
–V
R
12
ANALOG OUTPUT
REF
REF
FB
REF
REF
(32,767/32,768)
(1/32,768)
17
AGNDF AGNDS
(1/32,768)
V
OUT
1821 F02
16
14
I
OUT
OUT
–
+
*DO NOT CONNECT
= – V
V
+
22pF
V
–
REF
15
20
to V
13
V
OUT
REF
0.1 F
0.1 F
15V
–15V
V
–V
TO V
OUT
REF
LTC1821
REF
=
11