ADN2531

Rev. 0 | Page 15 of 20

TYPICAL APPLICATION CIRCUIT

Figure 40 shows a typical application circuit for the ADN2531.

The dc voltages applied to the BSET and MSET pins control the

bias and modulation currents. The bias current can be monitored

as a voltage drop across the 750 Ω resistor connected between

the IBMON pin and GND. The dc voltage applied to the CPA

pin controls the crosspoint in the output eye diagram. By tying

allows the user to turn the bias and modulation currents on and

off, depending on the logic level applied to the pin. The data

signal source must be connected to the DATAP and DATAN

pins of the ADN2531 using 50 Ω transmission lines. The

modulation current outputs, IMODP and IMODN, must be

connected to the load (TOSA) using 100 Ω differential (50 Ω

single-ended) transmission lines.

Table 6 provides a list of recommended components for the ac

coupling interface between the ADN2531 and the TOSA. The

reference circuit can support up to 11.3 Gbps applications, and

the low frequency cutoff performance is dependent on the dc

blocking capacitance and the transmission line impedance. For

additional applications information and optical eye diagram

performance data, consult the relevant application notes on the

ADN2531 product page at www.analog.com.

Table 6. Recommended Components

Component

Value

Description

APPLICATIONS INFORMATION

R1, R2

110 Ω

0603 size resistor

R3, R4

300 Ω

0603 size resistor

R13, R14

Varies

The resistor value and size are TOSA

load impedance dependent

C3, C4

100 nF

0402 size capacitor,

Phycomp 223878719849

L6, L7

160 nH

0603 size inductor,

Murata LQW18ANR16

L2, L3

0603 size chip ferrite bead, Murata

BLM18HG601

L1, L4, L5, L8

10 μH

0805 size inductor,

Murata LQM21FN100M70L

MSET

ALS

GND

BSET IBMON IBIAS GND

VCC

DATAP

DATAN

VCC

VCC

IMODP

IMODN

VCC

DATAP

DATAN

C1

C2

MSET

BSET

R5

750

Ω

ADN2531

GND

GND

TOSA

C4

C7

20µF

L2

L1

R1

R14

+3.3V

TP1

C5

10nF

GND

GND

C6

10nF

GND

ALS

CPA

CPA

R13

L7

L8

R4

L6

L5

R3

L3

L4

R2

C3

GND

C8

100nF

Figure 40. Typical ADN2531 Application Circuit