REV. A

–6–

AD8015

100

50

1

10

100

1000

FREQUENCY – MHz

0

5V, +25

°C

PIN 7

PIN 6

Figure 12. Output Impedance vs. Frequency

100

–100

20

0

0

10

TIME – ns

Figure 13. Small Signal Pulse Response

2

0

–12

10.0E+6

100.0E+6

1.0E+9

–2

–4

–6

–8

–10

0pF

1pF

3pF

5pF

8pF

FREQUENCY – Hz

Figure 14. Differential Gain vs. Input Capacitance

APPLICATION

155 Mbps Fiber Optic Receiver

The AD8015 and AD807 can be used together for a complete

155 Mbps Fiber Optic Receiver (Transimpedance Amplifier,

Post Amplifier with Signal Detect Output, and Clock Recovery

and Data Retiming) as shown in Figure 16.

The PIN diode front end is connected to a single mode, 1300 nm

laser source. The PIN diode has 3.3 V reverse bias, 0.8 A/W

responsivity, 0.7 pF capacitance, and 2.5 GHz bandwidth.

stant impedance (50

Ω) low-pass π filter with a 3 dB cutoff of

100 MHz. The outputs of the low-pass filter are ac coupled to

the AD807 inputs (PIN and NIN). The AD807 PLL damping

factor is set at 10 using a 0.22

µF capacitor.

The entire circuit was enclosed in a shielded box. Table I sum-

marizes results of tests performed using a 2

and varying the average power at the PIN diode.

The circuit acquires and maintains lock with an average input

power as low as –39.25 dBm.

80

0

20

10

40

30

50

60

70

80

0

20

10

40

30

50

60

70

90

100

30 DEVICES, 2 LOTS:

(+OUT, –OUT)

× (25°C, –40°C, 85°C) × (5V, 4.5V, 11.0V)

FREQUENCY – Hz

Figure 15. Bandwidth Distribution Matrix