ADL5903

Data Sheet

Rev. B | Page 16 of 20

The ENBL pin configures the device enable interface.

Connecting the ENBL pin to a logic high signal (2 V to 5.0 V)

enables the device, and connecting the pin to a logic low signal

(0 V to 0.6 V) disables the device. The exposed pad is internally

connected to GND and must be soldered to a low impedance

ground plane.

The output buffer of the ADL5903 features a PMOS common

source drive transistor and a resistive pull-down load. Under

typical operating conditions, the internal measurement range of

the device limits the output signal range to ≤2.2 V. Place a

100 Ω resistor on chip in series with the output to allow

additional filtering, if desired.

quickest response time to a pulsed waveform but leaves signifi-

cant output noise on the output voltage signal. However, a large

filter capacitor reduces output noise and improves the rms

measurement accuracy but at the expense of the response time.

In applications where the response time is not critical, place a

relatively large capacitor on the CRMS pin. In Figure 44, a value

of 0.1 µF is used. For most signal modulation schemes, this value

ensures excellent rms measurement compliance and low residual

when the ADL5903 is driven by a single carrier W-CDMA

(Test Model TM1-64, peak envelope power = 10.56 dB, bandwidth

= 3.84 MHz) and an LTE signal (Test Model TM1-20, peak

envelope power = 11.58 dB, bandwidth = 20 MHz), respectively.

the response time. This is measured by applying an RF burst at

2.14 GHz at 0 dBm to the ADL5903. The 10% to 90% rise time

and 90% to 10% fall time are then measured.

Figure 44. Basic Connections

0.1

1

10

100

1k

10k

100k

1M

0

100

200

300

400

500

600

700

0.1

1

10

100

1000

OUTPUT NOISE (mV p-p)

10% TO 90% RISE TIME (µs)

90% to 10% FALL TIME (µs)

0.1

1

10

100

1k

10k

100k

1M

10M

100M

0

50

100

150

200

250

300

350

400

450

0.1

1

10

100

1000

CFLT4 (nF)

OUTPUT NOISE (mV p-p)

10% TO 90% RISE TIME (µs)

90% to 10% FALL TIME (µs)

RFIN

VPOS

VRMS

GND

ADL5903

INTERNAL

FILTERING

CRMS

ENBL

RMS CORE

BUFFER

100

Ω

1k

Ω

CREG

NIC

630pF

EP

4pF

0.1μF

4.02Ω

0.1μF

VPOS

RFIN

VRMS

0.1μF

100pF

6

5

4

3

7

1

2

8