ltc1428cs8-50-trpbf Linear Technology Corporation, ltc1428cs8-50-trpbf Datasheet - Page 7
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ltc1428cs8-50-trpbf
Manufacturer Part Number
ltc1428cs8-50-trpbf
Description
Micropower 8-bit Current Sink Output D/a Converter
Manufacturer
Linear Technology Corporation
Datasheet
1.LTC1428CS8-50-TRPBF.pdf
(8 pages)
APPLICATIONS
shifted in, a rising edge at CS transfers the data from the
input shift register into the DAC register. The DAC output
assumes the new value and the D
impedance state.
1-Wire Interface (Pulse Mode, Figure 4)
In 1-wire pulse mode, each rising edge at CLK increments
the upper six bits of the DAC register by one count. When
incremented beyond 11111100B, the counter rolls over
and sets the DAC to the minimum value (00000000B). In
this way, a single pulse applied to CLK increases the DAC
output by a single 4LSB step and 63 pulses decrease the
TYPICAL
I
OUT
= (B7 B6 B5 B4 B3 B2 B1 B0)I
V
0.1 F
CC
Figure 3. 3-Wire Mode; Serial Interface
(3-Wire Control by CS, CLK and D
V
0.1 F
D
FOR HALF-DUPLEX DATA TRANSFER
Figure 4. Pulse Mode: Increment Only
(1-Wire Control by CLK)
CC
IN
AND D
APPLICATION
OUT
SHDN
I
CLK
OUT
U
SHDN
CAN BE TIED TOGETHER
I
D
OUT
CLK
OUT
D
CS
IN
1
2
3
4
INFORMATION
1
2
3
4
I
V
SHDN
CLK
OUT
CC
V
V
U
I
V
Pulse Mode: Increment-Only (1-Wire Control by CLK) with Voltage Output
OUT
DD
SHDN
CLK
LTC1428-50
OUT
CC
LTC1428-50
= (I
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
V
OUT
V
OUT
OUT
OUT
D
GND
OUT
D
+ 1V, 2V V
)(R
CS
U
D
IN
GND
OUT
D
W
CS
FB
IN
pin returns to a high-
8
7
6
5
1428-50 F04
) + V
FULLSCALE
6
5
8
7
6
100k
BIAS
R
IN
FB
BIAS
1428-50 F03
)
V
LT1006
V
D
DD
10V
EE
OUT
7
4
U
/255
+
–
3
2
V
BIAS
SHDN
CLK
DAC output by one step. The last two LSBs are always zero
in pulse mode.
To configure the LTC1428-50 in 1-wire pulse mode, tie
both the CS and D
2-Wire Interface (Pulse Mode, Figure 5)
In 2-wire pulse mode, a logic high at UP/DN programs the
DAC register to increment and each rising edge at CLK
increments the upper six bits of the register by one count.
Similarly, a logic low at UP/DN programs the DAC register
to decrement and a rising edge at CLK decrements the
upper six bits of the register by one count. Each count in
2-wire mode changes the DAC output by a single 4LSB
step. The DAC register stops incrementing at 11111100B
and stops decrementing at 00000000B and will not roll
over in 2-wire pulse mode. The last two LSBs are always
zero in pulse mode.
To configure the LTC1428-50 in 2-wire pulse mode, tie CS
to V
power-up.
1
2
3
4
I
I
I
V
SHDN
CLK
OUT
OUT
OUT
CC
CC
LTC1428-50
and bring the UP/DN pin low at least once during
= (B7 B6 B5 B4 B3 B2 0 0)I
= (B7 B6 B5 B4 B3 B2 0 0)I
Figure 5. Pulse Mode; Increment/Decrement
(2-Wire Control by CLK and UP/DN)
D
V
0.1 F
GND
CC
OUT
D
CS
IN
6
5
8
7
1428-50 TA02
IN
UP/DN
SHDN
I
CLK
OUT
pins to V
V
D
CC
OUT
1
2
3
4
I
V
SHDN
CLK
OUT
CC
LTC1428-50
CC
.
D
GND
OUT
D
CS
IN
FULLSCALE
FULLSCALE
LTC1428-50
6
5
8
7
1428-50 F05
D
OUT
/255
/255
7