MAXIM MAX4104, MAX4105, MAX4304, MAX4305 User Manual

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.

General Description

The MAX4104/MAX4105/MAX4304/MAX4305 op amps feature ultra-high speed, low noise, and low distortion in a SOT23 package. The unity-gain-stable MAX4104 requires only 20mA of supply current while delivering 625MHz bandwidth and 400V/µs slew rate. The MAX4304, compensated for gains of +2V/V or greater, delivers a 730MHz bandwidth and a 1000V/µs slew rate. The MAX4105 is compensated for a minimum gain of +5V/V and delivers a 410MHz bandwidth and a 1400V/sec slew rate. The MAX4305 has +10V/V minimum gain compensation and delivers a 340MHz bandwidth and a 1400V/µs slew rate.

Low voltage noise density of 2.1nV/√Hz and -88dBc spurious-free dynamic range make these devices ideal for low-noise/low-distortion video and telecommunications applications. These op amps also feature a wide output voltage swing of ±3.7V and ±70mA output currentdrive capability. For space-critical applications, they are available in a miniature 5-pin SOT23 package.

________________________Applications

Video ADC Preamp Pulse/RF Telecom Applications Video Buffers and Cable Drivers Ultrasound Active Filters ADC Input Buffers

Features

♦ Low 2.1nV/√Hz Voltage Noise Density ♦ Ultra-High 740MHz -3dB Bandwidth (MAX4304,

VCL

= 2V/V)

♦ 100MHz 0.1dB Gain Flatness (MAX4104/4105) ♦ 1400V/µs Slew Rate (MAX4105/4305) ♦ -88dBc SFDR (5MHz, R

= 100Ω) (MAX4104/4304)

♦ High Output Current Drive: ±70mA ♦ Low Differential Gain/Phase Error: 0.01%/0.01°

(MAX4104/4304)

♦ Low ±1mV Input Offset Voltage ♦ Available in Space-Saving 5-Pin SOT23 Package

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion

Op Amps in SOT23-5

________________________________________________________________

Maxim Integrated Products

MAX4304

8 to 16-BIT

HIGH-SPEED

ADC

INPUT

330Ω

ADC BUFFER WITH GAIN (A

VCL

= 2V/V)

330Ω

Typical Application Circuit

19-4757; Rev 3; 10/98

PART

MAX4104ESA

MAX4104EUK-T -40°C to +85°C

-40°C to +85°C

TEMP. RANGE

PIN-

PACKAGE

8 SO 5 SOT23-5

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

Ordering Information

Selector Guide

SOT

TOP MARK

—

ACCO

PART

MAX4104 MAX4304 MAX4105 5

MINIMUM

STABLE

GAIN (V/V)

BANDWIDTH

(MHz)

625 740 410

MAX4305 10 340

PIN-PACKAGE

5-pin SOT23, 8-pin SO 5-pin SOT23, 8-pin SO 5-pin SOT23, 8-pin SO 5-pin SOT23, 8-pin SO

Pin Configurations

Pin Configurations continued at end of data sheet.

Ordering Information continued at end of data sheet.

TOP VIEW

15V

OUT

SOT23-5

MAX4104 MAX4105 MAX4304 MAX4305

IN-IN+

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(VCC= +5V, VEE= -5V, VCM= 0, RL= 100kΩ, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

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.

Supply Voltage (VCCto VEE)................................................+12V

Voltage on Any Pin to Ground..........(V

- 0.3V) to (VCC+ 0.3V)

Short-Circuit Duration (V

OUT

to GND)........................Continuous

Continuous Power Dissipation (T

= +70°C)

5-pin SOT23 (derate 7.1mW/°C above +70°C)...........571mW

8-pin SO (derate 5.9mW/°C above +70°C).................471mW

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

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

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

OUT

= 0

RL= short to ground

Guaranteed by PSRR test

RL= 30Ω

RL= 100kΩ

VCC= 3.5V to 5.5V

-2.8V ≤ VCM≤ 4.1V

-2.8V ≤ V

OUT

≤ 2.8V, RL= 100Ω

OUT

= 0

Guaranteed by CMRR test

Either input

-0.8V ≤ VIN≤ 0.8V

VEE= -3.5V to -5.5V

CONDITIONS

Ω9Z

OUT

Open-Loop Output Impedance

mA80I

Short-Circuit Output Current

mA±53 ±70I

OUT

Output Current Drive

±3.0 -3.5 to +3.4

±3.5 -3.7 to +3.8

OUT

Output Voltage Swing

dB55 65A

VOL

Open-Loop Gain

mA20 27I

Quiescent Supply Current

dB55 65PSRR-

Negative Power-Supply Rejection Ratio

1 6

V±3.5 ±5 ±5.5VCC/V

Operating Supply Voltage Range

dB75 85PSSR+

Positive Power-Supply Rejection Ratio

dB80 95CMRRCommon-Mode Rejection Ratio

V-2.8 +4.1V

Input Common-Mode Voltage Range

MΩ1.5R

Common-Mode Input Resistance

1 8

µV/°CTCV

Input Offset-Voltage Drift

µA32 70I

kΩ6R

Differential Input Resistance

UNITSMIN TYP MAXSYMBOLPARAMETER

Input Offset Voltage

Input Bias Current

MAX4_0_EUK

2.5

MAX4_0_ESA

Input Offset Current µA0.5 5.0I

RL= 100Ω

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion

Op Amps in SOT23-5

_______________________________________________________________________________________ 3

AC ELECTRICAL CHARACTERISTICS

(VCC= +5V, VEE= -5V, VCM= 0, RL= 100Ω; AV= +1V/V for MAX4104, +2V/V for MAX4304, +5V/V for MAX4105, +10V/V for MAX4305; T

= +25°C; unless otherwise noted.)

CONDITIONS

MHz

625

(-3dB)

-3dB Bandwidth

UNITSMIN TYP MAXSYMBOLPARAMETER

OUT

= 2Vp-p

f = 1MHz

f = 10MHz

f = 1MHz

Ω1Z

OUT

Output Impedance

pA/√Hz

3.1i

Input Current Noise Density

nV/√Hz

2.1e

Input Voltage Noise Density

nst

Settling Time to 0.1%

0.01

DGDifferential Gain Error

OUT

= 100mVp-p

MAX4104 MAX4304 MAX4105 MAX4305 340

410

740

MAX4305

MHz

100

(0.1)

0.1dB Bandwidth

MAX4104

OUT

= 100mVp-p

MAX4304 MAX4105

MAX4305

MHz

115

FPBWFull-Power Bandwidth

MAX4104

OUT

= 2Vp-p

MAX4304 MAX4105

320

370

285

MAX4305

V/µs

400

SRSlew Rate

MAX4104

OUT

= 2Vp-p

MAX4304 MAX4105

1400

1000

to 0.1%

25to 0.01%

-88

OUT

=2Vp-p

fC = 5MHz

-67fC = 20MHz dBcSFDR

Spurious-Free Dynamic Range

-74fC = 5MHz

-61fC = 20MHz

MAX4104/ MAX4304

MAX4105/ MAX4305

MAX4104/MAX4304

NTSC, RL= 150Ω

MAX4105/MAX4305 0.02

MAX4105/MAX4305

MAX4104/MAX4304

NTSC, RL= 150Ω degrees

0.02

0.01

DPDifferential Phase Error

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(VCC= +5V, V

= -5V, RF= 330Ω, RL= 100Ω, TA= +25°C, unless otherwise noted.)

5 4

-5 100k 1M 10M 100M 1G

MAX4104

SMALL-SIGNAL GAIN

vs. FREQUENCY (A

VCL

= +1)

-3

-4

FREQUENCY (Hz)

GAIN (dB)

-1

-2

1 0

3 2

MAX4104 TOC01

OUT

= 100mVp-p

5 4

-5 100k 1M 10M 100M 1G

MAX4304

SMALL-SIGNAL GAIN

vs. FREQUENCY (A

VCL

= +2)

-3

-4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-1

-2

1 0

3 2

MAX4104 TOC 2

OUT

= 100mVp-p

5 4

-5 100k 1M 10M 100M 1G

MAX4105

SMALL-SIGNAL GAIN

vs. FREQUENCY (A

VCL

= +5)

-3

-4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-1

-2

1 0

3 2

MAX4104 TOC 3

OUT

= 100mVp-p

5 4

-5 100k 1M 10M 100M 1G

MAX4305

SMALL-SIGNAL GAIN

vs. FREQUENCY (A

VCL

= +10)

-3

-4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-1

-2

1 0

3 2

MAX4104 TOC 4

OUT

= 100mVp-p

0.5

0.4

-0.5 100k 1M 10M 100M 1G

MAX4105

GAIN FLATNESS

vs. FREQUENCY (A

VCL

= +5)

-0.3

-0.4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-0.1

-0.2

0.1 0

0.3

0.2

MAX4104 TOC 7

OUT

= 100mVp-p

0.5

0.4

-0.5 100k 1M 10M 100M 1G

MAX4104

GAIN FLATNESS

vs. FREQUENCY (A

VCL

= +1)

-0.3

-0.4

FREQUENCY (Hz)

GAIN (dB)

-0.1

-0.2

0.1 0

0.3

0.2

MAX4104 TOC 5

OUT

= 100mVp-p

0.5

0.4

-0.5 100k 1M 10M 100M 1G

MAX4304

GAIN FLATNESS

vs. FREQUENCY (A

VCL

= +2)

-0.3

-0.4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-0.1

-0.2

0.1 0

0.3

0.2

MAX4104 TOC 6

OUT

= 100mVp-p

0.5

0.4

-0.5

100k 1M 10M 100M 1G

MAX4305

GAIN FLATNESS

vs. FREQUENCY (A

VCL

= +10)

-0.3

-0.4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-0.1

-0.2

0.1 0

0.3

0.2

MAX4104 TOC 8

OUT

= 100mVp-p

5 4

-5 100k 1M 10M 100M 1G

MAX4104

LARGE-SIGNAL GAIN

vs. FREQUENCY (A

VCL

= +1)

-3

-4

FREQUENCY (Hz)

GAIN (dB)

-1

-2

1 0

3 2

MAX4104 TOC9

OUT

= 2Vp-p

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion

Op Amps in SOT23-5

_______________________________________________________________________________________

5 4

-5 100k 1M 10M 100M 1G

MAX4304

LARGE-SIGNAL GAIN

vs. FREQUENCY (A

VCL

= +2)

-3

-4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-1

-2

1 0

3 2

MAX4104 TOC10

OUT

= 2Vp-p

5 4

-5 100k 1M 10M 100M 1G

MAX4105

LARGE-SIGNAL GAIN

vs. FREQUENCY (A

VCL

= +5)

-3

-4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-1

-2

1 0

3 2

MAX4104 TOC 11

OUT

= 2Vp-p

5 4

-5 100k 1M 10M 100M 1G

MAX4305

LARGE-SIGNAL GAIN

vs. FREQUENCY (A

VCL

= +10)

-3

-4

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-1

-2

1 0

3 2

MAX4104 TOC12

OUT

= 2Vp-p

-10

-100

-90

100k 1M 10M 100M 1G

POSITIVE POWER-SUPPLY REJECTION

vs. FREQUENCY

-80

-70

MAX4104 TOCM

FREQUENCY (Hz)

POWER-SUPPLY REJECTION (dB)

-50

-60

-30

-40

-20

10 100 100k 1M 10M

FREQUENCY (Hz)

1k 10k1

100

VOLTAGE NOISE DENSITY vs. FREQUENCY

(INPUT REFERRED)

MAX4104 TOC-P

VOLTAGE NOISE DENSITY (nV/√Hz)

20 10

-80

-70

100k 1M 10M 100M 1G

NEGATIVE POWER-SUPPLY REJECTION

vs. FREQUENCY

-60

-50

MAX4104 TOCN

FREQUENCY (Hz)

POWER-SUPPLY REJECTION (dB)

-30

-40

-10

-20

-10

-100 10k 1M 10M 100M100k 1G

COMMON-MODE REJECTION

vs. FREQUENCY

-80

-90

MAX4104 TOCO

FREQUENCY (Hz)

CMR (dB)

-60

-70

-40

-50

-20

-30

10 100 100k 1M 10M

FREQUENCY (Hz)

1k 10k1

100

CURRENT NOISE DENSITY vs. FREQUENCY

(INPUT REFERRED)

CURRENT NOISE DENSITY (pA/√Hz)

MAX4104 TOC-Q

1000

0.01 100k 1M 10M 100M 1G

CLOSED-LOOP OUTPUT IMPEDANCE

vs. FREQUENCY

0.1

MAX4104 TOC-R

FREQUENCY (Hz)

OUTPUT IMPEDANCE (Ω)

100

Typical Operating Characteristics (continued)

(VCC= +5V, V

= -5V, RF= 330Ω, RL= 100Ω, TA= +25°C, unless otherwise noted.)

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VCC= +5V, V

= -5V, RF= 330Ω, RL= 100Ω, TA= +25°C, unless otherwise noted.)

0 100

MAX4104/MAX4304

DIFFERENTIAL GAIN AND PHASE

-0.015

0.000

-0.010

0.005

-0.005

0.010

0.015

-0.005

0.000

0.005

IRE

DIFF PHASE (deg)

DIFF GAIN (%)

MAX4104 TOC-S

RL = 150Ω

-0.005 0 100

0 100

MAX4105/MAX4305

DIFFERENTIAL GAIN AND PHASE

-0.01

0.010

0.005

0.000

0.00

0.015

0.01

0.020

0.02

0.025

0.03

IRE

DIFF PHASE (deg)

DIFF GAIN (%)

MAX4104 TOC T

RL = 150Ω

-100 100k 1M 10M 100M

MAX4104/MAX4304

HARMONIC DISTORTION vs. FREQUENCY

-80

MAX4104 TOC-U

FREQUENCY (Hz)

HARMONIC DISTORTION (dBc)

-60

-40

-20

-10

-90

-70

-50

-30

3RD HARMONIC

2ND HARMONIC

OUT

= 2Vp-p

-100 100k 1M 10M 100M

MAX4105/MAX4305

HARMONIC DISTORTION vs. FREQUENCY

-80

MAX4104 TOC-V

FREQUENCY (Hz)

DISTORTION (dBc)

-60

-40

-20

-10

-90

-70

-50

-30

3RD HARMONIC

2ND HARMONIC

OUT

= 2Vp-p

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0.5 1.5 2.0 2.51.0 3.0 3.5 4.0

MAX4104/MAX4304

HARMONIC DISTORTION

vs. OUTPUT SWING

MAX4104 TOC-Y

OUTPUT SWING (Vp-p)

HARMONIC DISTORTION (dBc)

3RD HARMONIC

2ND HARMONIC

f = 5MHz

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0 200 300 400100 500 600 700 900800 1k

MAX4104/MAX4304

HARMONIC DISTORTION vs. LOAD

MAX4104 TOC-W

LOAD (Ω)

HARMONIC DISTORTION (dBc)

3RD HARMONIC

2ND HARMONIC

f = 5MHz V

OUT

= 2Vp-p

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0 200 300 400100 500 600 700 900800 1k

MAX4105/MAX4305

HARMONIC DISTORTION vs. LOAD

MAX4104 TOC-X

LOAD (Ω)

HARMONIC DISTORTION (dBc)

3RD HARMONIC

2ND HARMONIC

f = 5MHz V

OUT

= 2Vp-p

-100

-80

-90

-60

-70

-40

-50

-30

-10

-20

0.5 1.5 2.0 2.51.0 3.0 3.5 4.0

MAX4105/MAX4305

HARMONIC DISTORTION

vs. OUTPUT SWING

MAX4104 TOC-Z

OUTPUT SWING (Vp-p)

HARMONIC DISTORTION (dBc)

3RD HARMONIC

2ND HARMONIC

f = 5MHz

0 100 15050 200 250 300 350 400

OUTPUT SWING vs. LOAD RESISTANCE

MAX4104 TOCAA

LOAD RESISTANCE (Ω)

OUTPUT SWING (Vp-p)

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion

Op Amps in SOT23-5

_______________________________________________________________________________________

-3.0

-2.0

0.0

-1.0

1.5

2.0

3.0

-2.5

-0.5

-1.5

1.0

0.5

2.5

-40 10-15 35 60 85

INPUT OFFSET VOLTAGE

vs. TEMPERATURE

MAX4104 TOCBB

TEMPERATURE (°C)

INPUT OFFSET VOLTAGE (mV)

-3

-1

-2

-40 10-15 35 60 85

INPUT OFFSET CURRENT

vs. TEMPERATURE

MAX4104 TOC-CC

TEMPERATURE (°C)

INPUT OFFSET CURRENT (µA)

-40 10-15 35 60 85

INPUT BIAS CURRENT

vs. TEMPERATURE

MAX4104 TOC-DD

TEMPERATURE (°C)

INPUT BIAS CURRENT (µA)

18 17 16

9.0 9.5 10.0 10.5 11.0

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX4104 TOC-FF

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

18 17 16

-40 10-15 35 60 85

SUPPLY CURRENT

vs. TEMPERATURE

MAX4104 TOC-EE

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

-50mV

+50mV

OUT

-25mV

GND

+25mV

10ns/div

MAX4304

SMALL-SIGNAL PULSE RESPONSE

= +2)

MAX4104 TOCII

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

4.0

-40 -15 10 35 60 85

POSITIVE OUTPUT VOLTAGE SWING

vs. TEMPERATURE

MAX4104 TOC-GG

TEMPERATURE (°C)

VOLTAGE SWING (V)

RL = 100kΩ

-50mV

OUT

+50mV

-50mV

GND

10ns/div

MAX4104

SMALL-SIGNAL PULSE RESPONSE

= +1)

MAX4104 TOCHH

-50mV

OUT

+50mV

-10mV

GND

+10mV

10ns/div

MAX4105

SMALL-SIGNAL PULSE RESPONSE

= +5)

MAX4104 TOCJJ

Typical Operating Characteristics (continued)

(VCC= +5V, V

= -5V, RF= 330Ω, RL= 100Ω, TA= +25°C, unless otherwise noted.)

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5

8 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VCC= +5V, V

= -5V, RF= 330Ω, RL= 100Ω, TA= +25°C, unless otherwise noted.)

-1V

OUT

+1V

-1V

GND

10ns/div

MAX4104

LARGE-SIGNAL PULSE RESPONSE

= +1)

MAX4104 TOCLL

-1V

OUT

+1V

+500mV

-500mV

GND

10ns/div

MAX4305

LARGE-SIGNAL PULSE RESPONSE

= +2)

MAX4104 TOCMM

-1V

OUT

+1V

+200mV

-200mV

GND

10ns/div

MAX4105

LARGE-SIGNAL PULSE RESPONSE

= +5)

MAX4104 TOCNN

-1V

+1V

OUT

+100mV

-100mV

GND

10ns/div

MAX4305

LARGE-SIGNAL PULSE RESPONSE

= +10)

MAX4104 TOCOO

-50mV

+50mV

OUT

-5mV

GND

+5mV

10ns/div

MAX4305

SMALL-SIGNAL PULSE RESPONSE

= +10)

MAX4104 TOCKK

_______________Detailed Description

The MAX4104/MAX4105/MAX4304/MAX4305 are ultrahigh-speed, low-noise amplifiers featuring -3dB bandwidths up to 880MHz, 0.1dB gain flatness up to 100MHz, and low differential gain and phase errors of

0.01% and 0.01°, respectively. These devices operate on dual power supplies ranging from ±3.5V to ±5.5V and require only 20mA of supply current.

The MAX4104/MAX4304/MAX4105/MAX4305 are optimized for minimum closed-loop gains of +1V/V, +2V/V, +5V/V and +10V/V (respectively) with corresponding

-3dB bandwidths of 880MHz, 730MHz, 430MHz, and 350MHz. Each device in this family features a low input voltage noise density of only 2.1nV/√Hz (at 1MHz), an output current drive of ±70mA, and spurious-free dynamic range as low as -88dBc (5MHz, RL= 100Ω).

___________Applications Information

Layout and Power-Supply Bypassing

The MAX4104/MAX4105/MAX4304/MAX4305 have an extremely high bandwidth, and consequently require careful board layout, including the possible use of constant-impedance microstrip or stripline techniques.

To realize the full AC performance of these high-speed amplifiers, pay careful attention to power-supply bypassing and board layout. The PC board should have at least two layers: a signal and power layer on one side, and a large, low-impedance ground plane on the other side. The ground plane should be as free of voids as possible. With multilayer boards, locate the ground plane on a layer that incorporates no signal or power traces.

Regardless of whether or not a constant-impedance board is used, it is best to observe the following guidelines when designing the board:

1) Do not use wire-wrapped boards (they are much too inductive) or breadboards (they are much too capacitive).

2) Do not use IC sockets. IC sockets increase reac tances.

3) Keep signal lines as short and straight as possible. Do not make 90° turns; round all corners.

4) Observe high-frequency bypassing techniques to maintain the amplifier’s accuracy and stability.

5) Bear in mind that, in general, surface-mount components have shorter bodies and lower parasitic reactance, resulting in greatly improved high-frequency performance over through-hole components.

The bypass capacitors should include 1nF and 0.1µF ceramic surface-mount capacitors between each supply pin and the ground plane, located as close to the package as possible. Optionally, place a 10µF tantalum capacitor at the power supply pins’ point of entry to the PC board to ensure the integrity of incoming supplies. The power-supply trace should lead directly from the tantalum capacitor to the V

and VEEpins. To minimize parasitic inductance, keep PC traces short and use surface-mount components.

Input termination resistors and output back-termination resistors, if used, should be surface-mount types, and should be placed as close to the IC pins as possible.

DC and Noise Errors

The MAX4104/MAX4105/MAX4304/MAX4305 output offset voltage, V

OUT

(Figure 1), can be calculated with

the following equation: V

OUT

= [VOS+ (IB+x RS) + (IB-x (R

RG))] [1 + RF/ RG] where: VOS= input offset voltage (in volts)

1 + RF/RG= amplifier closed-loop gain (dimensionless) IB+= noninverting input bias current (in amps) IB-= inverting input bias current (in amps) RG= gain-setting resistor (in ohms) RF= feedback resistor (in ohms) RS= source resistor at noninverting input (in ohms)

The following equation represents output noise density:

e 1

i x R i x R R e

n(OUT)

n S

n F G

||= +

 

 

 

 

( )

 



 



MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion

Op Amps in SOT23-5

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_____________________Pin Description

SOT23-5 SO

OUT

IN+

IN-

N.C.

NAME

Amplifier Output61 Positive Power Supply75

Negative Power Supply 42

Amplifier Noninverting Input

Amplifier Inverting Input24

Not internally connected.1, 5, 8

—

FUNCTION

MAX4104/MAX4105/MAX4304/MAX4305

where: in= input current noise density (in pA/√Hz)

en= input voltage noise density (in nV/√Hz) The MAX4104/MAX4105/MAX4304/MAX4305 have a

very low, 2.1nV/√Hz input voltage noise density and

3.1pA/√Hz input current noise density. An example of DC-error calculations, using the

MAX4304 typical data and the typical operating circuit with RF= RG= 330Ω (RF|| RG= 165Ω) and RS= 50Ω gives:

Calculating total output noise in a similar manner yields the following:

With a 200MHz system bandwidth, this calculates to

60.8µV

RMS

(approximately 365µVp-p, using the six-

sigma calculation).

ADC Input Buffers

Input buffer amplifiers can be a source of significant error in high-speed ADC applications. The input buffer is usually required to rapidly charge and discharge the ADC’s input, which is often capacitive. In addition, the input impedance of a high-speed ADC often changes

very rapidly during the conversion cycle—a condition that demands an amplifier with very low output impedance at high frequencies to maintain measurement accuracy. The combination of high-speed, fast slew rate, low noise, and low-distortion available in the MAX4104/MAX4105/MAX4304/MAX4305 makes them ideally suited for use as buffer amplifiers in high-speed ADC applications.

Video Line Driver

The MAX4104/MAX4105/MAX4304/MAX4305 are optimized to drive coaxial transmission lines when the cable is terminated at both ends, as shown in Figure 2. To minimize reflections and maximize power transfer, select the termination resistors to match the characteristic impedance of the transmission line. Cable frequency response can cause variations in the flatness of the signal.

Driving Capacitive Loads

The MAX4104/MAX4105/MAX4304/MAX4305 provide maximum AC performance when driving no output load capacitance. This is the case when driving a correctly terminated transmission line (i.e., a back-terminated cable).

In most amplifier circuits, driving a large load capacitance increases the chance of oscillations occurring. The amplifier’s output impedance and the load capacitor combine to add a pole and excess phase to the loop response. If the pole’s frequency is low enough and phase margin is degraded sufficiently, oscillations may result.

A second concern when driving capacitive loads originates from the amplifier’s output impedance, which

x x x x x

e nV Hz

n OUT

( )

. . .

[ ]

 

 

 

 

 

 

− − −

1 1 3 1 10 50 3 1 10 165 2 1 10

4 3

V 32 x 10 50 32 x 10 165 1 x 10 1 1 V 15.8mV

OUT

6 6 3

OUT

 

 

( )

 

 

( )

 



 



[ ]

− − −

Ω

740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5

10 ______________________________________________________________________________________

MAX4104 MAX4105 MAX4304 MAX4305

B-

B+

OUT

Figure 1. Output Offset Voltage Figure 2. Video Line Driver

MAX4104 MAX4105 MAX4304 MAX4305

IN-

IN+

OUT

75Ω

75Ω CABLE

appears inductive at high frequencies. This inductance forms an L-C resonant circuit with the capacitive load, which causes peaking in the frequency response and degrades the amplifier’s phase margin.

The MAX4104/MAX4105/MAX4304/MAX4305 drive capacitive loads up to 10pF without oscillation. However, some peaking may occur in the frequency domain (Figure 3). To drive larger capacitance loads or to reduce ringing, add an isolation resistor between the amplifier’s output and the load (Figure 4).

The value of R

ISO

depends on the circuit’s gain and the capacitive load (Figure 5). Figure 6 shows the MAX4104/MAX4105/MAX4304/MAX4305 frequency response with the isolation resistor and a capacitive

load. With higher capacitive values, bandwidth is dominated by the RC network formed by R

ISO

and CL; the bandwidth of the amplifier itself is much higher. Also note that the isolation resistor forms a divider that decreases the voltage delivered to the load.

Maxim’s High-Speed Evaluation Boards

The MAX4104 evaluation kit manual shows a suggested layout for Maxim’s high-speed, single-amplifier evaluation boards. This board was developed using the techniques described previously (

see Layout and

Power-Supply Bypassing

section). The smallest available surface-mount resistors were used for the feedback and back-termination resistors to minimize the

MAX4104/MAX4105/MAX4304/MAX4305

740MHz, Low-Noise, Low-Distortion

Op Amps in SOT23-5

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Figure 3a. MAX4104 Frequency Response with Capacitive Load and No Isolation Resistor

30 25

-20 100k 1M 10M 100M 1G

-10

-15

FREQUENCY (Hz)

GAIN (dB)

-5

20 15

CL = 10pF

CL = 5pF

CL = 15pF

Figure 3b. MAX4304 Frequency Response with Capacitive Load and No Isolation Resistor

Figure 3d. MAX4305 Frequency Response with Capacitive Load and No Isolation Resistor

Figure 3c. MAX4105 Frequency Response with Capacitive Load and No Isolation Resistor

30 25

-20 100k 1M 10M 100M 1G

-10

-15

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-5

20 15

CL = 5pF

CL = 15pF

CL = 10pF

25 20 15 10

5 0

-5

-10

NORMALIZED GAIN (dB)

-15

-20

-25 100k 1M 10M 100M 1G

CL = 5pF

FREQUENCY (Hz)

CL = 15pF

CL = 10pF

25 20 15 10

5 0

-5

-10

NORMALIZED GAIN (dB)

-15

-20

-25 100k 1M 10M 100M 1G

FREQUENCY (Hz)

CL = 15pF

CL = 10pF

CL = 5pF

MAX4104/MAX4105/MAX4304/MAX4305

distance from the IC to these resistors, thus reducing the capacitance associated with longer lead lengths.

SMA connectors were used for best high-frequency performance. Because distances are extremely short, performance is unaffected by the fact that inputs and outputs do not match a 50Ω line. However, in applications that require lead lengths greater than 1/4 of the wavelength of the highest frequency of interest, constant-impedance traces should be used.

Fully assembled evaluation boards are available for the MAX4104 in an 8-pin SO package.

740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5

12 ______________________________________________________________________________________

MAX4104 MAX4105 MAX4304 MAX4305

IN-

IN+

ISO

OUT

Figure 5. Optimal Isolation Resistor (R

ISO

) vs. Capacitive

Load

4 3

-6 100k 1M 10M 100M 1G

-4

-5

FREQUENCY (Hz)

GAIN (dB)

-2

-3

-1

2 1

CL = 47pF

MAX4104/MAX4304 R

ISO

= 15Ω

CL = 83pF

CL = 68pF

Figure 6. Frequency Responses vs. Capacitive Load with 15

Ω

Isolation Resistor

Figure 4. Using an Isolation Resistor (R

ISO

) for High Capacitive

Loads

Chip Information

TRANSISTOR COUNT: 44 SUBSTRATE CONNECTED TO V

Ordering Information (continued)

Future product—contact factory for availability.

PART

MAX4105ESA

-40°C to +85°C

TEMP. RANGE

PIN-

PACKAGE

8 SO MAX4105EUK-T -40°C to +85°C 5 SOT23-5 MAX4304ESA MAX4304EUK-T MAX4305ESA*

-40°C to +85°C

-40°C to +85°C 8 SO 5 SOT23-5 8 SO

MAX4305EUK-T -40°C to +85°C 5 SOT23-5

SOT

TOP MARK

—

ACCP

—

ACCQ

—

ACCR

OUT

IN+

N.C.

N.C. V

IN-

N.C.

MAX4304 MAX4305

MAX4104 MAX4105

TOP VIEW

Pin Configurations (continued)

MAX4105/MAX4305

MAX4104/MAX4304

OPTIMAL ISLOATION RESISTOR (Ω)

0 10050 150 200 250

CAPACITIVE LOAD (pF)

MAXIM MAX4104, MAX4105, MAX4304, MAX4305 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual