LTC6990

22

Rev. D

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TYPICAL APPLICATIONS

Full Range VCO with Any NDIV Setting (fMAX to fMIN for VIN = 0V to VSET)

6990 TA03

LTC6990

5V

OE

GND

SET

OUT

V+

DIV

C1

0.1µF

R1

R2

RSET

826k

5V

5V

D1

IN4148

LT1490

RVCO1

26.1k

VIN

0V TO 1V

RVCO2

26.1k

Full Range VCO with Any NDIV Setting (Positive Frequency Control, fMIN to fMAX for VIN = 0V to VSET

6990 TA04

LTC6990

5V

OE

GND

SET

OUT

V+

DIV

C1

0.1µF

R1

R2

RSET2

412k

RSET1

412k

5V

5V

LT1490

R3

10k

VIN

0V TO 1V

R4

10k

RVCO

53.6k

Programming NDIV Using an 8-Bit DAC

6990 TA02

LTC6990

OE

GND

SET

OUT

V+

DIV

C1

0.1µF

RSET

619k

2.25V TO 5.5V

C2

0.1µF

µP

LTC2630-LZ8

SDI

SCK

CS/LD

VCC

GND

VOUT

DIVCODE

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

DAC CODE

0

24

40

56

72

88

104

120

136

152

168

184

200

216

232

255