LTC6603 Linear Technology, LTC6603 Datasheet - Page 17

• Manufacturer Part Number: LTC6603
• Description: Dual Adjustable Lowpass Filter
• Manufacturer: Linear Technology

APPLICATIONS INFORMATION
LTC6078
CLR LOW WILL SET DAC TO MID-SCALE (WITH A –1 VERSION).
HAS ~100ms TC AT START-UP TO RESET TO ZERO SCALE.
Figure 7. Frequency Response Controlled by LTC2621-1
2
3
7
–IN
+IN
5V
V
OUT
OUT
V+
V–
–10
–20
–30
–40
–50
–60
–70
–80
10
V
0
REF
1k
1
LTC2621-1
C7
100nF
V
T
S
A
2
V
GND
= 3V
= 25°C
CC
5V
I RANGE = 6μA TO 38.4μA
10k
TRACES FOR MINIMUM
Q1
RK7002AT116CT
CS/LD
R1
30.5k
LDAC
USE NARROW SHORT
SDO
C8
100nF
SCK
CLR
SDI
FREQUENCY (Hz)
LTC6078
100k
R4
1
2
3
4
5
10
CAPACITANCE.
7
100k
OUT
V+
V–
5V
5V
–IN
+IN
1M
C9
1μF
–INB
Figure 6. Current Controlled Clock Frequency
6603 F07
R23
50k
C16
50pF
10M
+INB
DATA FORMAT
DATA IS SHIFTED FROM MOSI (MASTER OUT, SLAVE IN) THRU LTC6603 INTO THE LTC2621.
THE TOTAL PACKET IS 32 BITS. IT STARTS WITH A CONTROL BYTE (0011 XXXX) THEN MSB OF THE DAC,
WITH DUMMY BITS AT THE END, 16 BITS (24 BITS TOTAL). THEN 8 BITS TO THE FILTER.
D6 & D7 = GAIN, D4 & D5 = LPF , D1 = SHDN. D0 = GEN. PURPOSE OUTPUT.
R24
50k
C17
50pF
V
OCM
5V
V+
C1
100nF
IN
SPI INTERFACE
10
11
12
1
2
3
4
5
6
7
8
9
SDI
SCLK
CS
V+
V+
V
R
CLKCNTL
LPF1(CS)
+INB
–INB
LPF0(SCLK)
SDI
SDO
–OUTB
OCM
BIAS
IN
A
C2
2.2μF
Figure 8. Voltage Controlled Clock Frequency
f
CLK
LTC6603
= 247.2MHz • (10k/R
V+
GAIN0(D0)
C3
2.2μF
V
OCM
V
CLK IO
+OUTB
+OUTA
–OUTA
GAIN1
CONTROL
+INA
–INA
GND
6603 F06
CAP
SER
V+
R
3V
BIAS
D
24
23
22
21
20
19
18
17
16
15
14
13
C4
100nF
BIAS
–
+
) • (1 – V
+INA
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R25
50k
C18
50pF
CONTROL
C15
10nF
R
–INA
BIAS
LTC6603
/1.17V)
6603 F08
R26
50k
C19
50pF
+OUTA
–OUTA
+OUTB
–OUTB
17
6603f