AD539 datasheet(13/20 Pages) AD

13 / 20 page

AD539

Rev. B | Page 13 of 20

Table 4. Summary of Operating Conditions and

Performance for the AD539 When Used with Various

External Op Amp Output Amplifiers

Operating Conditions

AD7111

LH00321

Op Amp Supply Voltages

±15 V

±10 V

Op Amp Compensation Capacitor

None

1 pF to 5 pF

Feedback Capacitor, CF

None

1 pF to 4 pF

−3 dB Bandwidth, VX = 1 V

900 kHz

25 MHz

Load Capacitance

<1 nF

<10 pF

HF Feedthrough

VX = −0.01 V, f = 5 MHz

N/A

−70 dB

RMS Output Noise

VX = 1 V, BW 10 Hz to10 kHz

50 μV

30 μV

VX = 1 V, BW 10 Hz to 5 MHz

120 μV

500 μV

1 For the circuit of Figure 20.

In all cases, 0.47 μF ceramic supply decoupling capacitors were

used at each IC pin, the AD539 supplies were ±5 V, and the

control compensation capacitor CC was 3 nF.

Minimal Wideband Configurations

The maximum bandwidth can be achieved using the AD539

with simple resistive loads to convert the output currents to

voltages. These currents (nominally ±1 mA FS, ±2.25 mA peak,

into short-circuit loads) are shunted by their source resistance

of 1.25 kΩ (each channel). Calculations of load power and

effective scaling-voltage must allow for this shunting effect

when using resistive loads. The output power is quite low in this

mode, and the device behaves more like a voltage-controlled

attenuator than a classical multiplier. The matching of gain and

phase between the two channels is excellent. From dc to 10 MHz,

the gains are typically within ±0.025 dB (measured using preci-

sion 50 Ω load resistors) and the phase difference within ±0.1°.

For a given load resistance, the output power can be quadrupled

by using both channels in parallel, as shown in Figure 21. The

small signal silicon diode, D, connected between ground and

BASE COMMON (Pin 12 and Pin 13) provides extra voltage

compliance at the output nodes in the negative direction (to

−1 V at 25°C); it is not required if the output swing does not

exceed −300 mV. Table 5 compares performance for various

load resistances, using this configuration.

AD539

VY1

VY2

HF COMP

+VS

–VS

INPUT

COMMON

OUTPUT

COMMON

BASE

COMMON

CHAN1

OUTPUT

CHAN2

OUTPUT

CC = 3nF

0.47µF

+VS

–VS

VW =

VXVY

REQUIRED IF LOAD

RESISTANCE >300Ω

Figure 21. Minimal Single-Channel Multiplier

(16-Lead SBDIP and PDIP Shown)

Figure 9 shows the high frequency response for Figure 21 with

the AD539 in a carefully shielded 50 Ω test environment; the

test system response was first characterized and this

background removed by digital signal processing to show the

inherent circuit response.

In many applications phase linearity over frequency is important.

Figure 10 shows the deviation from an ideal linear-phase response

for a typical AD539 over the frequency range dc to 10 MHz, for

VX = 3 V; the peak deviation is slightly more than 1°. Differen-

tial phase linearity (the stability of phase over the signal window

at a fixed frequency) is shown in Figure 11 for f = 3.579 MHz

and various values of VX. The most rapid variation occurs for

VY above 1 V; in applications where this characteristic is critical,

it is recommended that a ground-referenced, negative-going

signal be used.

Table 5. Summary of Performance for Minimal Configuration

Load Resistance

50 Ω

75 Ω

100 Ω

150 Ω

600 Ω

Open Circuit

FS Output Voltage

±92.6 mV

±134 mV

±172 mV

±242 mV

±612 mV

±1 V

AC (RMS)

65.5 mV rms

94.7 mV rms

122 mV rms

171 mV rms

433 mV rms

Note1

FS Output

0.086 mW

0.12 mW

0.15 mW

0.195 mW

0.312 mW

N/A2

Power in Load

−10.5 dBm

−9.2 dBm

−8.3 dBm

−7.1 dBm

−5.05 dBm

N/A

Peak Output Voltage

±210 mV

±300 mV

±388 mV

±544 mV

±1 mV

±1 V

AC (RMS)

148 mV rms

212 mV rms

274 mV rms

385 mV rms

Note1

Peak Output

0.44 mW

0.6 mW

0.75 mW

1 mW

±1 V

Power in Load

−7 dBm

−4.4 dBm

−2.5 dBm

0 dBm

Note1

Effective Scaling Voltage, VU’

67.5 V

46.7 V

36.3 V

25.8 V

10.2 V

5 V

1 Peak negative voltage swing limited by output compliance.

2 N/A means not applicable.

AD539 Datasheet(PDF) 13 Page - Analog Devices

AD539 Datasheet(HTML) 13 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Datasheet Download

Link URL