MAX19790ETX+T - Hytronics

_______________________________________________________________ Maxim Integrated Products 1

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

19-5165; Rev 0; 3/10

General Description

The MAX19790 dual, general-purpose analog voltage

variable attenuator (VVA) is designed to interface with

50I systems operating in the 250MHz to 4000MHz fre-

quency range. Each attenuator includes a control circuit

that provides 22dB of attenuation range with a linear

control slope of 10dB/V.

Both attenuators share a common analog control and

can be cascaded together to yield 44dB of total dynamic

range, with a combined linear control slope of 20dB/V.

The IC is a monolithic device designed on one of Maxim’s

proprietary SiGe BiCMOS processes. The device oper-

ates from a single +5.0V supply and is available in a com-

pact, 36-pin thin QFN package (6mm x 6mm x 0.8mm)

with an exposed pad. Electrical performance is guaran-

teed over the extended -40° to +85°C temperature range.

Applications

Broadband System Applications, Including

Wireless Infrastructure Digital and Spread-

Spectrum Communication Systems

WCDMA/LTE, TD-SCDMA/TD-LTE, WiMAX™,

cdma2000®, GSM/EDGE, and MMDS Base

Stations

VSAT/Satellite Modems

Microwave Terrestrial Links

Lineup Gain Trim

Temperature Compensation Circuits

Automatic Level Control (ALC)

Transmitter Gain Control

Receiver Gain Control

General Test Equipment

Features

S 250MHz to 4000MHz RF Frequency Range

S Integrates Two Analog Attenuators in One

Monolithic Device

S Flexible Attenuation-Control Ranges

22dB (per Attenuator)

44dB (Both Attenuators Cascaded)

S 2.4dB 1500MHz Insertion Loss (per Attenuator)

S Linear dB/V Analog Control Response Curve

Simplifies Automatic Leveling Control and

Gain-Trim Algorithms

S Excellent Attenuation Flatness Over Wide

Frequency Ranges and Attenuation Settings

S Low 7.3mA Supply Current

S Single +5.0V Supply Voltage

Ordering Information

+Denotes a lead(Pb)-free/RoHS-compliant package.

*EP = Exposed pad.

T = Tape and reel.

WiMAX is a trademark of WiMAX Forum.

cdma2000 is a registered trademark of Telecommunications

Industry Association.

PART TEMP RANGE PIN-PACKAGE

MAX19790ETX+ -40NC to +85NC36 Thin QFN-EP*

MAX19790ETX+T -40NC to +85NC36 Thin QFN-EP*

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

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.

VCC to GND ..........................................................-0.3V to +5.5V

CTRL to GND (with VCC = +5.0V applied) ............ 0V to +4.75V

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

RF Input ......................................................................... +20dBm

Current into CTRL Pin (VCC grounded) .............................40mA

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

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

Storage Temperature Range ........................….-65°C to +150°C

Continuous Power Dissipation (TC = +85°C) (Note 1) .......2.1W

θJC (Notes 2, 4) ............................................................ +10°C/W

θJA (Notes 3, 4) ............................................................ +35°C/W

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

Soldering Temperature (reflow) ......................................+260°C

DC ELECTRICAL CHARACTERISTICS

(VCC = +4.75V to +5.25V, VCTRL = +1.0V to +4.0V, no RF signals applied, all input and output ports terminated with 50I, TC =

-40°C to +85°C, unless otherwise noted. Typical values are at VCC = +5.0V, VCTRL = +1.0V, TC = +25°C, unless otherwise noted.)

RECOMMENDED AC OPERATING CONDITIONS

ABSOLUTE MAXIMUM RATINGS

Note 1: TC is the temperature on the exposed pad of the package. TA is the ambient temperature of the device and PCB.

Note 2: Based on junction temperature TJ = TC + (θJC x VCC x ICC). This formula can be used when the temperature of the exposed

pad is known while the device is soldered down to a PCB. See the Applications Information section for details. The junction

temperature must not exceed +150°C.

Note 3: Junction temperature TJ = TA + (θJA x VCC x ICC). This formula can be used when the ambient temperature of the PCB is

known. The junction temperature must not exceed +150°C.

Note 4: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.

CAUTION! ESD SENSITIVE DEVICE

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SUPPLY

Supply Voltage VCC 4.75 5.0 5.25 V

Supply Current ICC 7.3 9.5 mA

CONTROL INPUT

Control Voltage Range VCTRL (Note 5) 1.0 4.0 V

Control Input Resistance RCTRL 50 kI

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

RF Frequency Range fRF (Note 6) 250 4000 MHz

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

AC ELECTRICAL CHARACTERISTICS

(MAX19790 Evaluation Kit, line and connector losses included, two attenuators in cascade, VCC = 4.75V to 5.25V, RF ports are

driven from 50I sources, input PRF = -10dBm, fRF = 950MHz to 2150MHz, VCTRL = +1.0V, TC = -40°C to +85°C. Typical values are

for TC = +25°C, VCC = +5.0V, input PRF = -10dBm, fRF = 1500MHz, VCTRL = +1.0V, unless otherwise noted.)

Note 5: Operating outside this range for extended periods may affect device reliability. Limit pin input current to 40mA when VCC

is not present (see Table 1 for R4 value).

Note 6: Operation outside this range is possible, but with degraded performance of some parameters. See the Typical Operating

Characteristics.

Note 7: f1 = 1500MHz, f2 = 1501MHz, -10dBm/tone at attenuator input.

Note 8: Guaranteed by design and characterization.

Note 9: Switching time is measured from 50% of the control signal to when the RF output settles to Q1dB.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Insertion Loss IL TC = +25NC950MHz to 1500MHz 4.4 6.3 dB

950MHz to 2150MHz 4.4 7.0

Loss Variation Over Temperature TC = -40NC to +85NC 0.6 dB

Input P1dB IP1dB 23.1 dBm

Input Second-Order Intercept

Point IIP2 fRF1 + fRF2 term, fRF1 - fRF2 = 1MHz

(Note 7) 69.6 dBm

Input Third-Order Intercept Point IIP3 fRF1 - fRF2 = 1MHz (Note 7) 36.3 dBm

Second Harmonic 2fIN 72 dBc

Third Harmonic 3fIN 77 dBc

Attenuation-Control Range AR

One attenuator, VCTRL = +1.0V

to +4.0V, TC = +25NC22

Two attenuators,

VCTRL = +1.0V

to +4.0V,

TC = +25NC

950MHz to 1500MHz 36 44.7

950MHz to 2150MHz 33 44.7

Average Attenuation-Control

Slope VCTRL = +1.0V to +3.5V 20.0 dB/V

Maximum Attenuation-Control

Slope VCTRL = +1.0V to +3.5V 30.4 dB/V

Attenuation Flatness Over

125MHz Bandwidth (Note 8)

Peak-to-peak for VCTRL = +1.0V to +3.1V,

TC = +25NC0.13 0.89 dB

Switching Time From 15dB to 0dB attenuation (Note 9) 500 ns

Input Return Loss All gain settings 25 dB

Output Return Loss All gain settings 21 dB

Group Delay Input/output 50I lines deembedded 190 ps

Group-Delay Flatness Over

125MHz Bandwidth Peak-to-peak 10 ps

Group-Delay Change vs.

Attenuation Control VCTRL = +1.0V to +4.0V -175 ps

Insertion Phase Change vs.

Attenuation Control VCTRL = +1.0V to +4.0V 82 Degrees

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

Typical Operating Characteristics

(MAX19790 Evaluation Kit, two attenuators in cascade, VCC = +5.0V, PRF = -10dBm, TC = +25NC, VCTRL = +1.0V, unless otherwise noted.)

SUPPLY CURRENT vs. VCC

MAX19790 toc01

VCC (V)

SUPPLY CURRENT (mA)

5.1255.0004.875

7.0

7.5

8.0

6.5

4.750 5.250

TC = +25°C

TC = +85°C

TC = -40°C

INPUT MATCH vs. RF FREQUENCY

MAX19790 toc02

RF FREQUENCY (MHz)

S11 (dB)

300020001000

-30

-20

-10

-40

0 4000

TC = -40°C

TC = +25°C

TC = +85°C

OUTPUT MATCH vs. RF FREQUENCY

MAX19790 toc03

RF FREQUENCY (MHz)

S22 (dB)

300020001000

-30

-20

-10

-40

0 4000

TC = -40°C

TC = +25°C

TC = +85°C

INSERTION LOSS vs. RF FREQUENCY

MAX19790 toc04

RF FREQUENCY (MHz)

INSERTION LOSS (dB)

300020001000

0 4000

TC = -40°C

TC = +25°C

TC = +85°C

INPUT MATCH vs. VCTRL

MAX19790 toc05

VCTRL (V)

4000MHz

500MHz

2150MHz

950MHz

S11 (dB)

-30

-20

-10

-40

1 4

250MHz

OUTPUT MATCH vs. VCTRL

MAX19790 toc06

VCTRL (V)

4000MHz

500MHz

2150MHz

950MHz

S22 (dB)

250MHz

-30

-20

-10

-40

1 4

ATTENUATION vs. VCTRL

MAX19790 toc07

VCTRL (V)

4000MHz

2150MHz

S21 (dB)

-50

-40

-30

-20

-10

-60

1 4

250MHz, 500MHz, 950MHz

ATTENUATION vs. VCTRL

MAX19790 toc08

VCTRL (V)

fRF = 950MHz

S21 (dB)

-50

-40

-30

-20

-10

-60

1 4

TC = -40°C, +25°C, +85°C

S21 PHASE CHANGE vs. VCTRL

MAX19790 toc09

VCTRL (V)

4000MHz

950MHz

500MHz

2150MHz

S21 PHASE CHANGE (DEGREES)

100

150

200

-50

1 4

REFERENCED TO INSERTION-LOSS STATE.

POSITIVE PHASE = ELECTRICALLY

SHORTER.

250MHz

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

Typical Operating Characteristics (continued)

(MAX19790 Evaluation Kit, two attenuators in cascade, VCC = +5.0V, PRF = -10dBm, TC = +25NC, VCTRL = +1.0V, unless otherwise noted.)

INPUT IP3 vs. VCTRL

MAX19790 toc11

VCTRL (V)

INPUT IP3 (dBm)

1 4

PIN = -10dBm/TONE

950MHz

1500MHz

2150MHz

INPUT IP2 vs. VCTRL

MAX19790 toc12

VCTRL (V)

INPUT IP2 (dBm)

1 4

fRF = 950MHz

PIN = -10dBm/TONE

TC = +25°C

TC = +85°C

TC = -40°C

INPUT IP2 vs. VCTRL

MAX19790 toc13

VCTRL (V)

INPUT IP2 (dBm)

1 4

PIN = -10dBm/TONE

2150MHz

950MHz

1500MHz

INPUT P1dB vs. RF FREQUENCY

MAX19790 toc14

RF FREQUENCY (MHz)

INPUT P1dB (dBm)

17501350

950 2150

TC = +85°C

TC = +25°C

TC = -40°C

INPUT IP3 vs. VCTRL

MAX19790 toc10

VCTRL (V)

INPUT IP3 (dBm)

1 4

fRF = 950MHz

PIN = -10dBm/TONE

TC = +25°C

TC = +85°C

TC = -40°C

INPUT P1dB vs. RF FREQUENCY

MAX19790 toc15

RF FREQUENCY (MHz)

INPUT P1dB (dBm)

17501350

950 2150

VCC = 4.75V

VCC = 5.25V VCC = 5.0V

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

Typical Operating Characteristics (continued)

(MAX19790 Evaluation Kit, one attenuator connected, VCC = +5.0V, PRF = -10dBm, TC = +25NC, VCTRL = +1.0V, unless otherwise noted.)

ATTENUATION vs. VCTRL

MAX19790 toc23

VCTRL (V)

S21 (dB)

-25

-20

-15

-10

-5

-30

1 4

fRF = 950MHz

TC = -40°C, +25°C, +85°C

OUTPUT MATCH vs. RF FREQUENCY

MAX19790 toc18

RF FREQUENCY (MHz)

S22 (dB)

300020001000

-40

-30

-20

-10

-50

0 4000

TC = -40°C

TC = +85°C

TC = +25°C

SUPPLY CURRENT vs. VCC

MAX19790 toc16

VCC (V)

SUPPLY CURRENT (mA)

5.1255.0004.875

7.0

7.5

8.0

6.5

4.750 5.250

TC = -40°C

TC = +25°C

TC = +85°C

S21 PHASE CHANGE vs. VCTRL

MAX19790 toc24

VCTRL (V)

S21 PHASE CHANGE (DEGREES)

-25

100

-50

1 4

2150MHz

500MHz

250MHz

4000MHz

950MHz

REFERENCED TO INSERTION-LOSS STATE.

POSITIVE PHASE = ELECTRICALLY SHORTER.

INSERTION LOSS vs. RF FREQUENCY

MAX19790 toc19

RF FREQUENCY (MHz)

INSERTION LOSS (dB)

300020001000

0 4000

TC = -40°C

TC = +85°C

TC = +25°C

INPUT MATCH vs. RF FREQUENCY

MAX19790 toc17

RF FREQUENCY (MHz)

S11 (dB)

300020001000

-40

-30

-20

-10

-50

0 4000

TC = +25°C

TC = +85°C

TC = -40°C

INPUT MATCH vs. VCTRL

MAX19790 toc20

VCTRL (V)

S11 (dB)

-40

-30

-20

-10

-50

1 4

4000MHz

950MHz

250MHz 2150MHz

500MHz

OUTPUT MATCH vs. VCTRL

MAX19790 toc21

VCTRL (V)

S22 (dB)

-40

-30

-20

-10

-50

1 4

4000MHz

950MHz

250MHz

2150MHz

500MHz

ATTENUATION vs. VCTRL

MAX19790 toc22

VCTRL (V)

S21 (dB)

-25

-20

-15

-10

-5

-30

1 4

250MHz, 500MHz, 950MHz

2150MHz

4000MHz

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

Typical Operating Characteristics (continued)

(MAX19790 Evaluation Kit, one attenuator connected, VCC = +5.0V, PRF = -10dBm, TC = +25NC, VCTRL = +1.0V, unless otherwise noted.)

INPUT IP3 vs. VCTRL

MAX19790 toc26

VCTRL (V)

INPUT IP3 (dBm)

1 4

PIN = -10dBm/TONE

950MHz

2150MHz

1500MHz

INPUT IP2 vs. VCTRL

MAX19790 toc27

VCTRL (V)

INPUT IP2 (dBm)

100

1 4

fRF = 950MHz

PIN = -10dBm/TONE

TC = -40°C

TC = +25°C

TC = +85°C

INPUT IP3 vs. VCTRL

MAX19790 toc25

VCTRL (V)

INPUT IP3 (dBm)

1 4

fRF = 950MHz

PIN = -10dBm/TONE

TC = +25°C

TC = -40°C

TC = +85°C

INPUT IP2 vs. VCTRL

MAX19790 toc28

VCTRL (V)

INPUT IP2 (dBm)

100

1 4

PIN = -10dBm/TONE

950MHz

2150MHz

1500MHz

INPUT P1dB vs. RF FREQUENCY

MAX19790 toc29

RF FREQUENCY (MHz)

INPUT P1dB (dBm)

17501350

950 2150

TC = +25°C

TC = +85°C

TC = -40°C

INPUT P1dB vs. RF FREQUENCY

MAX19790 toc30

RF FREQUENCY (MHz)

INPUT P1dB (dBm)

17501350

950 2150

VCC = 4.75V

VCC = 5.0V

VCC = 5.25V

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

Pin Description

Pin Configuration/Functional Diagram

GND

CTRL

GND

VCC

GND

VCC

GND

IN_B

GND

*EXPOSED PAD.

GND

123456789

192021222324252627

ATTEN_B

ATTEN_A

VCC

GND

OUT_A

GND

THIN QFN

TOP VIEW

GND

IN_A

OUT_B

ATTENUATION-

CONTROL

CIRCUITRY

*EP

MAX19790

PIN NAME FUNCTION

1, 3, 4, 6, 7, 9, 10,

12, 14–28, 30, 31,

33, 34, 36

GND Ground. Connect to the board’s ground plane using low-inductance layout techniques.

2 OUT_A Attenuator A Output. Internally matched to 50I over the operating frequency band. This pin,

if used, requires a DC block. If this attenuator is not used, the pin can be left unconnected.

5, 13, 32 VCC Power Supply. Bypass to GND with capacitors and resistors as shown in the Typical

Application Circuit.

8 IN_A Attenuator A Input. Internally matched to 50I over the operating frequency band. This pin,

if used, requires a DC block. If this attenuator is not used, the pin can be left unconnected.

11 CTRL

Analog Attenuator Control Input. VCC must be present unless using a current-limiting resis-

tor, as noted in the Applications Information section. Limit voltages applied to this pin to a

+1.0V to +4.0V range with VCC present to ensure device reliability.

29 OUT_B Attenuator B Output. Internally matched to 50I over the operating frequency band. This pin,

if used, requires a DC block. If this attenuator is not used, the pin can be left unconnected.

35 IN_B Attenuator B Input. Internally matched to 50I over the operating frequency band. This pin,

if used, requires a DC block. If this attenuator is not used, the pin can be left unconnected.

— EP Exposed Pad. Internally connected to GND. Solder evenly to the board’s ground plane for

proper operation.

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

Detailed Description

The MAX19790 is a dual, general-purpose analog volt-

age variable attenuator (VVA) designed to interface

with 50I systems operating in the 250MHz to 4000MHz

frequency range. Each attenuator includes a control

circuit that provides 22dB of attenuation range with a

linear control slope of 10dB/V. Both attenuators share a

common analog control and can be cascaded together

to yield 44dB of total dynamic range, with a combined

linear control slope of 20dB/V.

Applications Information

Analog Attenuation Control

A single input voltage at the CTRL pin adjusts the attenu-

ation of the device. Up to 22dB of attenuation-control

range is provided per attenuator. At the insertion-loss

setting, the attenuator’s loss is approximately 2.4dB.

If a larger attenuation-control range is desired, the

second on-chip attenuator can be connected in series to

provide an additional 22dB of gain-control range.

Note that the CTRL pin simultaneously adjusts both

on-chip attenuators. The CTRL input voltage drives a

high-impedance load (> 50kI). It is suggested that a

current-limiting resistor be included in series with this

connection, to limit the input current to less than 40mA,

should the control voltage be applied when VCC is not

present. A series resistor of greater than 200I provides

complete protection for +5.0V control voltage ranges.

Note: To ensure the reliability of the device, limit CTRL

input voltages to a +1.0V to +4.0V range when VCC is

present.

Layout Considerations

A properly designed PCB is an essential part of any

RF/microwave circuit. Keep RF signal lines as short as

possible to reduce losses, radiation, and inductance.

For best performance, route the ground-pin traces

directly to the exposed pad underneath the package.

This pad MUST be connected to the ground plane of

the board by using multiple vias under the device to

provide the best RF and thermal conduction path. Solder

the exposed pad on the bottom of the device package

to a PCB.

Power-Supply Bypassing

Proper voltage-supply bypassing is essential for high-

frequency circuit stability. Bypass each VCC pin with

capacitors placed as close as possible to the device.

Place the smallest capacitor closest to the device. See

the Typical Application Circuit and Table 1 for details.

Table 1. Typical Application Circuit Component Values

*C8 can be used to provide additional filtering. Depending on the external driver used on the CTRL line, this capacitance could

slow down the response time.

DESIGNATION QTY DESCRIPTION

C1, C3, C5 3

220pF Q5%, 50V C0G ceramic

capacitors (0402)

Murata GRM1555C1H221J

C2, C4 2

0.01FF Q10%, 25V X7R ceramic

capacitors (0402)

Murata GRM155R71E103K

C6 1

1000pF Q5%, 50V C0G ceramic

capacitor (0402)

Murata GRM1555C1H102J

C7 1

0.1FF Q10%, 16V X7R ceramic

capacitor (0603)

Murata GRM188R71C104K

C8* 0 Not installed, ceramic capacitor

(0603)

DESIGNATION QTY DESCRIPTION

C9 1

22pF Q5%, 50V C0G ceramic

capacitor (0402)

Murata GRM1555C1H220J

R1, R2 2 10I Q5% resistors (0402)

Any

R3, R4 2

0I resistors (0402)

Note: In cases where VCTRL is

applied before or removed after

VCC, use R4 = 200I.

U1 1

Analog attenuator IC

Maxim MAX19790ETX+

Note: U1 has an exposed pad

conductor, which requires it to be

solder-attached to a grounded

pad on the PCB to ensure a

proper electrical/thermal design.

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

Typical Application Circuit

Exposed Pad RF and Thermal

Considerations

The exposed pad (EP) of the device’s 36-pin thin QFN

package provides a low thermal-resistance path to

the die. It is important that the PCB on which the IC is

mounted be designed to conduct heat from this contact.

In addition, provide the EP with a low-inductance RF

ground path for the device.

The EP MUST be soldered to a ground plane on the

PCB, either directly or through an array of plated via

holes. Soldering the pad to ground is also critical

for efficient heat transfer. Use a solid ground plane

wherever possible.

RFA

CTRL

VCC

IN_B

GND

2 3 4 5 6 7 8 9

192021222324252627

ATTEN_B

ATTEN_A

OUT_A

GND

IN_A

OUT_B

ATTENUATION-

CONTROL

CIRCUITRY

*SCHEMATIC SHOWS CONFIGURATION FOR TWO CASCADED ATTENUATORS. TO USE ATTENUATOR A ONLY MOVE C3

TO CONNECT OUT_A TO RFB. TO USE ATTENUATOR B ONLY MOVE C3 TO CONNECT RFB TO IN_B.

GND

VCC

CTRL C9

VCC

GND

RFB*

VCC

RFOUT

VCC

GND

MAX19790

250MHz to 4000MHz Dual,

Analog Voltage Variable Attenuator

MAX19790

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.

Maxim reserves the right to change the circuitry and specifications without notice at any time.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 11

Package Information

For the latest package outline information and land patterns,

go to www.maxim-ic.com/packages. Note that a “+”, “#”, or

“-” in the package code indicates RoHS status only. Package

drawings may show a different suffix character, but the drawing

pertains to the package regardless of RoHS status.

Chip Information

PROCESS: BiCMOS

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

36 Thin QFN-EP T3666+2 21-0141