LT1679 Linear Technology, LT1679 Datasheet - Page 13

• Manufacturer Part Number: LT1679
• Description: Dual/Quad Low Noise Rail-to-Rail Precision Op Amps
• Manufacturer: Linear Technology

Bipolar Confi guration
Figure 3 shows a typical bipolar DAC application for the
LTC2642. The on-chip bipolar offset/gain resistors, R
and R
a bipolar output swing from –V
Table 2a. 16-Bit Bipolar Offset Binary
Code Table (LTC2642-16)
MSB
1111 1111 1111 1111 V
1000 0000 0000 0001 V
1000 0000 0000 0000 0V
0111 1111 1111 1111 –V
0000 0000 0000 0000 –V
APPLICATIONS INFORMATION
BINARY NUMBER
DIGITAL INPUT
IN DAC LATCH
INV
, are connected to an external amplifi er to produce
LSB
REF
REF
ANALOG OUTPUT
REF
REF
(32,767/32,768)
(1/32,768)
(1/32,768)
(V
2
3
4
5
OUT
CS
SCLK
DIN
CLR
LTC2642-16
)
Figure 3. 16-Bit Bipolar Output (LTC2642-16) V
REF
5V/3V
V
DD
to V
9
REF
0.1μF
16-BIT DAC
Table 2b. 14-Bit Bipolar Offset Binary
Code Table (LTC2642-14)
MSB
1111 1111 1111 11xx V
1000 0000 0000 01xx V
1000 0000 0000 00xx 0V
0111 1111 1111 11xx –V
0000 0000 0000 00xx –V
at the R
V
2.5V
REF
BINARY NUMBER
1
REF
DIGITAL INPUT
IN DAC LATCH
FB
0.1μF
pin.
FB
GND
V
LSB
R
OUT
INV
10
FB
4.7μF
26412 F02
8
7
6
The amplifi er circuit provides a gain of +2 from the V
pin, and gain of –1 from V
the bipolar offset binary code tables for 16-bit, 14-bit and
12-bit operation.
ANALOG OUTPUT
REF
REF
REF
REF
(8,191/8,192)
(1/8,192)
C1
10pF
OUT
(1/8,192)
(V
LT1019CS8-2.5
OUT
–
+
1/2 LT1678
GND
)
OUT
–5V
5V
= –V
IN
0.1μF
0.1μF
REF
LTC2641/LTC2642
5V
to V
Table 2c. 12-Bit Bipolar Offset Binary
Code Table (LTC2642-12)
MSB
1111 1111 1111 xxxx V
1000 0000 0001 xxxx V
1000 0000 0000 xxxx 0V
0111 1111 1111 xxxx –V
0000 0000 0000 xxxx –V
BINARY NUMBER
REF
BIPOLAR V
–2.5V TO 2.5V
DIGITAL INPUT
IN DAC LATCH
REF
. Tables 2a, 2b and 2c show
OUT
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LSB
ANALOG OUTPUT
REF
REF
REF
REF
(2,047/2,048)
(1/2,048)
(1/2048)
(V
OUT
13
)
26412f
OUT