Rainbow Electronics MAX2055 User Manual

General Description

The MAX2055 high-performance, digitally controlled,
variable-gain, differential analog-to-digital converter
(ADC) driver/amplifier (DVGA) is designed for use from
30MHz to 300MHz in base station receivers.

The device integrates a digitally controlled attenuator
and a high-linearity single-ended-to-differential output
amplifier, which can either eliminate an external trans­former, or can improve the even-order distortion perfor­mance of a transformer-coupled circuit, thus relaxing
the requirements of the anti-alias filter preceding an
ADC. Targeted for ADC driver applications to adjust
gain either dynamically or as a one-time channel gain
setting, the MAX2055 is ideal for applications requiring
high performance. The attenuator provides 23dB of
attenuation range with ±0.2dB accuracy.

The MAX2055 is available in a thermally enhanced 20­pin TSSOP-EP package and operates over the -40°C to
+85°C temperature range.

Applications

Cellular Base Stations

PHS/PAS Infrastructure

Receiver Gain Control

Broadband Systems

Automatic Test Equipment

Terrestrial Links

High-Performance ADC Drivers

Features

♦ 30MHz to 300MHz Frequency Range

♦ Single-Ended-to-Differential Conversion

♦ -3dB to +20dB Variable Gain

♦ 40dBm Output IP3 (at All Gain States and 70MHz)

♦ 2nd Harmonic -76dBc

♦ 3rd Harmonic -69dBc

♦ Noise Figure: 5.8dB at Maximum Gain

♦ Digitally Controlled Gain with 1dB Resolution and

±0.2dB Accuracy

♦ Adjustable Bias Current

MAX2055

Digitally Controlled, Variable-Gain, Differential

ADC Driver/Amplifier

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

GND

ATTN

OUT

GND

I

SET

B4

GND

RF_IN

V

CC

C

C

AMP

IN

L

E

C

BP

B0

B1

B2

B3

12

11

9

10

I

BIAS

RF_OUT+

RF_OUT-

ATTENUATION

LOGIC

CONTROL

V

CC

TSSOP

MAX2055

TOP VIEW

19-2799; Rev 0; 4/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

*EP = Exposed paddle.

Pin Configuration/

Functional Diagram

PART TEMP RANGE PIN-PACKAGE

MAX2055EUP-T -40°C to +85°C 20 TSSOP-EP*

MAX2055

Digitally Controlled, Variable-Gain, Differential
ADC Driver/Amplifier

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1; VCC= +4.75V to +5.25V, GND = 0V. No input signals applied, and input and output ports are terminated with
50Ω. R1 = 1.13kΩ, T

A

= -40°C to +85°C. Typical values are at VCC= +5V and TA= +25°C, unless otherwise noted.) (Notes 1, 2)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

All Pins to GND. .....................................-0.3V to +(VCC+ 0.25V)

Input Signal (RF_IN)............................…………………….20dBm

Output Power (RF_OUT) ...................................................24dBm

Continuous Power Dissipation (T

A

= +70°C)

20-Pin TSSOP (derate 21.7mW/°C above +70°C) ...........2.1W

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +165°C

Lead Temperature (soldering, 10s) .................................+300°C

AC ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1; VCC= +4.75V to +5.25V, GND = 0V, max gain (B0 = B1 = B2 = B3 = B4 = 0), R1= 1.13kΩ, P

OUT

= 5dBm,

f

IN

= 70MHz, 50Ω system impedance. Typical values are at VCC= +5V and TA= +25°C, unless otherwise noted.) (Notes 1, 2)

SUPPLY

Supply Voltage V

Supply Current I

I

SET

CONTROL INPUTS

Control Bits Parallel 5 Bits

Input Logic High 2V

Input Logic Low 0.6 V

Input Leakage Current -1.2 +1.2 µA

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Current I

CC

CC

SET

4.75 5.0 5.25 V

240 290 mA

1.1 mA

Frequency Range f

Gain G 19.9 dB

Amplitude Unbalance (Note 3) 0.06 dB

Phase Unbalance (Note 3) 0.7 D eg r ees

Minimum Reverse Isolation 29 dB

Noise Figure NF 5.8 dB

Output 1dB Compression Point P

2nd-Order Output Intercept Point OIP2

3rd-Order Output Intercept Point OIP3 All gain conditions, 5dBm/tone at RF_OUT 40 dBm

2nd Harmonic 2f

3rd Harmonic 3f

RF Gain-Control Range 23 dB

Gain-Control Resolution 1dB

Attenuation Absolute Accuracy Compared to the ideal expected attenuation ±0.2 dB

Attenuation Relative Accuracy Between adjacent states

Gain Drift Over Temperature TA = -40°C to +85°C ±0.3 dB

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

R

1dB

IN

IN

f

+ f2, f1 = 70MHz, f2 = 71MHz, 5dBm/tone

1

at RF_OUT

30 300 MHz

25.7 dBm

75 dBm

-76 dBc

-69 dBc

+0.05/

-0.2

dB

MAX2055

Digitally Controlled, Variable-Gain, Differential

ADC Driver/Amplifier

_______________________________________________________________________________________ 3

Note 1: Guaranteed by design and characterization.
Note 2: All limits reflect losses of external components. Output measurements are taken at RF_OUT using the application circuit

shown in Figure 1.

Note 3: The amplitude and phase unbalance are tested with 50Ω resistors connected from OUT+/OUT- to GND.

AC ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1; VCC= +4.75V to +5.25V, GND = 0V, max gain (B0 = B1 = B2 = B3 = B4 = 0), R1= 1.13kΩ, P

OUT

= 5dBm,

f

IN

= 70MHz, 50Ω system impedance. Typical values are at VCC= +5V and TA= +25°C, unless otherwise noted.) (Notes 1, 2)

Typical Operating Characteristics

(Circuit of Figure 1, VCC= 5.0V, R1= 1.13kΩ, max gain (B0 = B1 = B2 = B3 = B4 = 0), P

OUT

= 5dBm, TA= +25°C, unless other-

wise noted.)

SUPPLY CURRENT vs. TEMPERATURE

MAX2055 toc01

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

603510-15

220

230

240

250

260

270

210

-40 85

VCC = 5.25V

VCC = 5.0V

VCC = 4.75V

INPUT RETURN LOSS vs. RF FREQUENCY

(ALL STATES)

MAX2055 toc02

FREQUENCY (MHz)

INPUT RETURN LOSS (dB)

27024060 90 120 180150 210

35

30

25

20

15

10

5

0

40

30 300

OUTPUT RETURN LOSS vs. RF FREQUENCY

(ALL STATES)

MAX2055 toc03

FREQUENCY (MHz)

OUTPUT RETURN LOSS (dB)

27024060 90 120 180150 210

35

30

25

20

15

10

5

0

40

30 300

GAIN vs. RF FREQUENCY (ALL STATES)

MAX2055 toc04

FREQUENCY (MHz)

GAIN (dB)

27024060 90 120 180150 210

-5

0

5

10

15

20

25

-10
30 300

GAIN vs. RF FREQUENCY

MAX2055 toc05

FREQUENCY (MHz)

GAIN (dB)

27024060 90 120 180150 210

12

14

16

18

20

22

24

10

30 300

TA = +85°C

TA = +25°C

TA = -40°C

GAIN vs. RF FREQUENCY

MAX2055 toc06

FREQUENCY (MHz)

GAIN (dB)

27024060 90 120 180150 210

12

14

16

18

20

22

24

10

30 300

VCC = 5.25V

VCC = 5.0V

VCC = 4.75V

Gain Flatness Over 50MHz
Bandwidth

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Peak-to-peak for all settings 0.5 dB

Attenuator Switching Time 50% control to 90% RF 40 ns

Input Return Loss fR = 30MHz to 300MHz, all gain conditions 15 dB

Output Return Loss

fR = 30MHz to 250MHz, all gain conditions 15

= 250MHz to 300MHz, all gain conditions 12

f

R

dB

MAX2055

Digitally Controlled, Variable-Gain, Differential
ADC Driver/Amplifier

4 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(Circuit of Figure 1, VCC= 5.0V, R1= 1.13kΩ, max gain (B0 = B1 = B2 = B3 = B4 = 0), P

OUT

= 5dBm, TA= +25°C, unless other-

wise noted.)

ATTENUATION ABSOLUTE ACCURACY

(ALL STATES)

1.0

0.8

0.6

0.4

0.2

0

-0.2

-0.4

ABSOLUTE ACCURACY (dB)

-0.6

-0.8

-1.0
30 300

FREQUENCY (MHz)

MAX2055 toc07

27024060 90 120 180150 210

ATTENUATION RELATIVE ACCURACY

(ALL STATES)

1.0

0.8

0.6

0.4

0.2

0

-0.2

-0.4

RELATIVE ACCURACY (dB)

-0.6

-0.8

-1.0
30 300

FREQUENCY (MHz)

27024060 90 120 180150 210

MAX2055 toc08

REVERSE ISOLATION vs. RF FREQUENCY

40

36

32

28

REVERSE ISOLATION (dB)

24

20

30 300

FREQUENCY (MHz)

MAX2055 toc09

27024060 90 120 180150 210

NOISE FIGURE vs. FREQUENCY

8.0

7.5

7.0

6.5

6.0

5.5

NOISE FIGURE (dB)

5.0

4.5

4.0

TA = +85°C

TA = -40°C

30 300

FREQUENCY (MHz)

OUTPUT IP3 vs. FREQUENCY

44

42

40

38

TA = +85°C

36

OIP3 (dBm)

34

32

30

30 300

TA = +25°C

P

= P

RF1

AT OUTPUT, ∆f = 1MHz

FREQUENCY (MHz)

TA = +25°C

TA = -40°C

= 5dBm

RF2

OUTPUT P-1dB vs. FREQUENCY

27

26

MAX2055 toc10

25

24

23

OUTPUT P-1dB (dBm)

22

27024060 90 120 180150 210

21

30 300

TA = +85°C

TA = -40°C

FREQUENCY (MHz)

TA = +25°C

MAX2055 toc11

OUTPUT P-1dB (dBm)

27024060 90 120 180150 210

OUTPUT IP3 vs. FREQUENCY

44

42

MAX2055 toc13

40

38

36

OIP3 (dBm)

34

32

27024060 90 120 180150 210

30

VCC = +5.25V

VCC = +5V

VCC = +4.75V

P

= P

= 5dBm

RF1

RF2

AT OUTPUT, ∆f = 1MHz

30 300

FREQUENCY (MHz)

27024060 90 120 180150 210

MAX2055 toc14

IIP3 (dBm)

OUTPUT P-1dB vs. FREQUENCY

27

26

25

24

VCC = +5V

23

22

21

30 300

VCC = +5.25V

VCC = +4.75V

FREQUENCY (MHz)

MAX2055 toc12

27024060 90 120 180150 210

INPUT IP3 vs. ATTENUATION STATE

55

50

45

40

35

30

25

20

15

024

P

= P

RF1

AT OUTPUT, ∆f = 1MHz,

= 70MHz

f

IN

ATTENUATION STATE

RF2

= 5dBm

MAX2055 toc15

20164 8 12