AD835

REV. A

–8–

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

8-Pin Plastic DIP

(N Package)

8-Pin Plastic SOIC

(R Package)

PIN 1

0.280 (7.11)

0.240 (6.10)

4

5

8

1

0.325 (8.25)

0.300 (7.62)

0.015 (0.381)

0.008 (0.204)

0.195 (4.95)

0.115 (2.93)

SEATING

PLANE

0.060 (1.52)

0.015 (0.38)

0.130

(3.30)

MIN

0.210

(5.33)

MAX

0.160 (4.06)

0.115 (2.93)

0.430 (10.92)

0.348 (8.84)

0.100

(2.54)

BSC

0.070 (1.77)

0.045 (1.15)

0.022 (0.558)

0.014 (0.356)

PIN 1

0.1574 (4.00)

0.1497 (3.80)

0.2440 (6.20)

0.2284 (5.80)

4

5

1

8

8

°

0

°

0.0196 (0.50)

0.0099 (0.25)

x 45

°

0.0098 (0.25)

0.0075 (0.19)

0.0500 (1.27)

0.0160 (0.41)

0.0098 (0.25)

0.0040 (0.10)

0.1968 (5.00)

0.1890 (4.80)

0.102 (2.59)

0.094 (2.39)

0.0500

(1.27)

BSC

0.0192 (0.49)

0.0138 (0.35)

Figure 22 shows a frequency doubler which overcomes this limi-

tation and provides a relatively constant output over a moder-

ately wide frequency range, determined by the time-constant C1

and R1. The voltage applied to the X- and Y-inputs are exactly

in quadrature at a frequency f = 1/2

πC1R1 and their ampli-

tudes are equal. At higher frequencies, the X-input becomes

smaller while the Y-input increases in amplitude; the opposite

happens at lower frequencies. The result is a double frequency

output, centered on ground, whose amplitude of 1 V for a 1 V

input varies by only 0.5% over a frequency range of

±10%. Be-

cause there is no “squared” dc component at the output, sud-

den changes in the input amplitude do not cause a “bounce” in

the dc level.

Figure 22. Broadband “Zero-Bounce” Frequency Doubler

This circuit is based on the identity

cos

θ sinθ= 1

2

sin 2

θ

( 7)

At

ω

is attenuated by

√2, while the Y input lags the input signal by

45

°, and is also attenuated by √2. Since the X and Y inputs are

90

° out of phase, the response of the circuit will be

W

= 1

U

E

2

( sin

ωt –45° ) E

2

( sin

ωt + 45° ) = E

2

2U

( sin 2

ωt) (8)

which has no dc component, R2 and R3 are included to restore

the output to 1 V for an input amplitude of 1 V (the same gain

adjustment as mentioned earlier). Because the voltage across the

capacitor, C1, decreases with frequency, while that across the

resistor, R1, increases, the amplitude of the output varies only

slightly with frequency. In fact, it is only 0.5% below its full

value (at its center frequency

of this frequency.

R1

R3

301

Ω

VOLTAGE

OUTPUT

X1

X2

VP

W

Z

VN

Y2

Y1

X1

AD835

+5V

–5V

R2

97.6

Ω

3

4

2

1

5

6

7

8

C1