VIN

1

8

3

2

5

4

7

6

RF

1 k:

RL

100:

RG

100:

V

-

V

+

VG

-0.5

0

0.5

1

1.5

VG (V)

2

-90

-70

-50

30

-30

-10

10

0

2

4

12

6

8

10

11

9

7

5

3

1

dB

V/V

125°C

25°C

-55°C

125°C

25°C

-55°C

LMH6505

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SNOSAT4E – DECEMBER 2005 – REVISED APRIL 2013

LMH6505 Wideband, Low Power, Linear-in-dB, Variable Gain Amplifier

Check for Samples: LMH6505

Near ideal input characteristics (i.e. low input bias

1

FEATURES

current, low offset, low pin 3 resistance) enable the

2

•

VS = ±5V, TA = 25°C, RF = 1 kΩ, RG = 100Ω, RL =

device to be easily configured as an inverting

100

Ω, AV = AVMAX = 9.4 V/V, Typical Values

amplifier as well.

Unless Specified.

To provide ease of use when working with a single

•

−3 dB BW 150 MHz

supply, the VG range is set to be from 0V to +2V

•

Gain Control BW 100 MHz

relative to the ground pin potential (pin 4). VG input

impedance is high in order to ease drive requirement.

•

Adjustment Range (<10 MHz) 80 dB

In single supply operation, the ground pin is tied to a

•

Gain Matching (Limit) ±0.50 dB

"virtual" half supply.

•

Supply Voltage Range 7V to 12V

The LMH6505’s gain control is linear in dB for a large

•

Slew Rate (Inverting) 1500 V/

μs

portion of the total gain control range from 0 dB down

•

Supply Current (No Load) 11 mA

to

−85 dB at 25°C, as shown below. This makes the

device suitable for AGC applications. For linear gain

•

Linear Output Current ±60 mA

control applications, see the LMH6503 datasheet.

•

Output Voltage Swing ±2.4V

The LMH6505 is available in either the 8-Pin SOIC or

•

Input Noise Voltage 4.4 nV/

√Hz

the 8-Pin VSSOP package. The combination of

•

Input Noise Current 2.6 pA/

√Hz

minimal external components and small outline

•

THD (20 MHz, RL = 100Ω, VO = 2 VPP) −45 dBc

packages allows the LMH6505 to be used in space-

constrained applications.

APPLICATIONS

•

Variable Attenuator

•

AGC

•

Voltage Controlled Filter

•

Video Imaging Processing

DESCRIPTION

The LMH6505 is a wideband DC coupled voltage

controlled gain stage followed by a high speed

current feedback operational amplifier which can

directly drive a low impedance load. The gain

adjustment range is 80 dB for up to 10 MHz which is

accomplished by varying the gain control input

Figure 1. Gain vs. VG

voltage, VG.

Maximum gain is set by external components, and

the gain can be reduced all the way to cutoff. Power

Typical Application

consumption is 110 mW with a speed of 150 MHz

and a gain control bandwidth (BW) of 100 MHz.

Output referred DC offset voltage is less than 55 mV

over the entire gain control voltage range. Device-to-

device gain matching is within ±0.5 dB at maximum

gain. Furthermore, gain is tested and ensured over a

wide range. The output current feedback op amp

allows high frequency large signals (Slew Rate =

1500 V/

μs) and can also drive a heavy load current

(60 mA) ensured.

Figure 2. AVMAX = 9.4 V/V

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2005–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.