Datasheet MAX4228EUB, MAX4228ESD, MAX4226ESDB, MAX4225ESA, MAX4224EUT-T Datasheet (Maxim)

...

_______________General Description

The MAX4223–MAX4228 current-feedback amplifiers combine ultra-high-speed performance, low distortion, and excellent video specifications with low-power operation. The MAX4223/MAX4224/MAX4226/MAX4228 have a shutdown feature that reduces power-supply current to 350µA and places the outputs into a highimpedance state. These devices operate with dual supplies ranging from ±2.85V to ±5.5V and provide a typical output drive current of 80mA. The MAX4223/ MAX4225/MAX4226 are optimized for a closed-loop gain of +1 (0dB) or more and have a -3dB bandwidth of 1GHz, while the MAX4224/MAX4227/MAX4228 are compensated for a closed-loop gain of +2 (6dB) or more, and have a -3dB bandwidth of 600MHz (1.2GHz gain-bandwidth product).

The MAX4223–MAX4228 are ideal for professional video applications, with differential gain and phase errors of

0.01% and 0.02°, 0.1dB gain flatness of 300MHz, and a 1100V/µs slew rate. Total harmonic distortion (THD) of

-60dBc (10MHz) and an 8ns settling time to 0.1% suit these devices for driving high-speed analog-to-digital inputs or for data-communications applications. The lowpower shutdown mode on the MAX4223/MAX4224/ MAX4226/MAX4228 makes them suitable for portable and battery-powered applications. Their high output impedance in shutdown mode is excellent for multiplexing applications.

The single MAX4223/MAX4224 are available in spacesaving 6-pin SOT23 packages. All devices are available in the extended -40°C to +85°C temperature range.

________________________Applications

ADC Input Buffers Data Communications Video Cameras Video Line Drivers Video Switches Video Multiplexing Video Editors XDSL Drivers RF Receivers Differential Line Drivers

____________________________Features

♦ Ultra-High Speed and Fast Settling Time:

1GHz -3dB Bandwidth (MAX4223, Gain = +1) 600MHz -3dB Bandwidth (MAX4224, Gain = +2) 1700V/µs Slew Rate (MAX4224) 5ns Settling Time to 0.1% (MAX4224)

♦ Excellent Video Specifications (MAX4223):

Gain Flatness of 0.1dB to 300MHz

0.01%/0.02° DG/DP Errors

♦ Low Distortion:

-60dBc THD (f

= 10MHz)

42dBm Third-Order Intercept (f = 30MHz)

♦ 6.0mA Quiescent Supply Current (per amplifier) ♦ Shutdown Mode:

350µA Supply Current (per amplifier) 100kΩ Output Impedance

♦ High Output Drive Capability:

80mA Output Current Drives up to 4 Back-Terminated 75Ω Loads to ±2.5V while Maintaining Excellent Differential Gain/Phase Characteristics

♦ Available in Tiny 6-Pin SOT23 and 10-Pin µMAX

Packages

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

________________________________________________________________

Maxim Integrated Products

IN-

IN+

SHDN

OUT

MAX4223 MAX4224

SOT23-6

TOP VIEW

_________________Pin Configurations

19-1230; Rev 2a; 6/97

PART

MAX4223EUT-T

MAX4223ESA -40°C to +85°C

-40°C to +85°C

TEMP. RANGE

PIN-

PACKAGE

6 SOT23 8 SO

EVALUATION KIT

AVAILABLE

______________Ordering Information

_____________________Selector Guide

Pin Configurations continued at end of data sheet.

Ordering Information continued at end of data sheet.

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 For small orders, phone 408-737-7600 ext. 3468.

SOT

TOP MARK

AAAD

—

10 µMAX,

14 SO

8 SO

10 µMAX,

14 SO

8 SO

6 SOT23, 8 SO

PIN-

PACKAGE

Yes

SHUTDOWN MODE

AMPS

PER

PKG.

2MAX4227

MAX4228

PART

1MAX4225

MAX4226

1MAX4223

MAX4224

MIN.

GAIN

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(VCC= +5V, VEE= -5V, SHDN = 5V, VCM= 0V, RL= ∞, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

= +25°C.) (Note 1)

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

Analog Input Voltage .......................(V

- 0.3V) to (VCC+ 0.3V)

Analog Input Current........................................................±25mA

SHDN Input Voltage.........................(V

- 0.3V) to (VCC+ 0.3V) Short-Circuit Duration

OUT to GND...........................................................Continuous

OUT to V

or VEE............................................................5sec

Continuous Power Dissipation (T

= +70°C)

6-Pin SOT23 (derate 7.1mW/°C above +70°C).............571mW

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

10-Pin µMAX (derate 5.6mW/°C above +70°C)............444mW

14-Pin SO (derate 8.3mW/°C above +70°C).................667mW

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

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

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

CONDITIONS

±0.5 ±4

UNITSMIN TYP MAXSYMBOLPARAMETER

±0.5 ±5

Input Offset Voltage

±2 ±10

Input Bias Current (Positive Input)

±7

TA= T

MIN

to T

MAX

µA

±15

TA= +25°C

Ω45R

IN-

Input Resistance (Negative Input)

kΩ700R

IN+

Input Resistance (Positive Input)

55 61

Inferred from CMRR test V±2.5 ±3.2V

Input Common-Mode Voltage Range

Inferred from PSRR test V±2.85 ±5.5VCC/V

VCM= ±2.5V

Operating Supply Voltage Range

68 74

CMRRCommon-Mode Rejection Ratio

VCC= 2.85V to 5.5V, VEE= -2.85V to -5.5V

PSRRPower-Supply Rejection Ratio

Shutdown mode (SHDN = 0V)

0.35 0.55

RL= 50Ω

Quiescent Supply Current (per Amplifier)

Normal mode (SHDN = 5V)

6.0 9.0

V±2.5 ±2.8V

OUT

Output Voltage Swing

OUT

= ±2.5V MΩ

0.3 0.8

Open-Loop Transresistance

OUT

= ±2.5V mA60 80I

OUT

Output Current (Note 2)

0.7 1.5

RL= short to ground mA140I

Short-Circuit Output Current

V0.8V

SHDN Logic Low

±4 ±20

TA= +25°C

µA

±4 ±25

B+

TA= +25°C TA= T

MIN

to T

MAX

TA= +25°C TA= T

MIN

to T

MAX

RL= ∞ RL= 50Ω

V2.0V

SHDN Logic High

±6

TA= T

MIN

to T

MAX

MAX4223/MAX4224

MAX4225–MAX4228

µV/°C±2TCV

Input Offset Voltage Drift

MAX4225–MAX4228

TA= T

MIN

to T

MAX

±30

Input Bias Current (Negative Input)

±35

B-

TA= +25°C

MAX4223/MAX4224 MAX4225–MAX4228 MAX4223/MAX4224 MAX4225–MAX4228

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

_______________________________________________________________________________________ 3

DC ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V, VEE= -5V, SHDN = 5V, VCM= 0V, RL= ∞, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

= +25°C.) (Note 1)

AC ELECTRICAL CHARACTERISTICS

(VCC= +5V, VEE= -5V, SHDN = 5V, VCM= 0V, AV= +1V/V for MAX4223/MAX4225/MAX4226, AV= +2V/V for MAX4224/MAX4227/ MAX4228, R

= 100Ω, TA= +25°C, unless otherwise noted.) (Note 4)

10 100

CONDITIONS

25 70

UNITSMIN TYP MAXSYMBOLPARAMETER

µAIIL/I

SHDN Input Current SHDN = 0V or 5V

SHDN = 0V, V

OUT

= -2.5V to +2.5V

(Note 3)

Shutdown Mode Output Impedance

kΩ

MAX4224/7/8 MAX4223/5/6

60 200

100 300

MAX4223/5/6

0.1

OUT

= 2V step

MAX4224/7/8

THD

850 1100

1.5

Total Harmonic Distortion

RL= 1kΩ

1400 1700

250

-65

OUT

= 4V step

625 800

CONDITIONS

Gain Peaking

OUT

= 2Vp-p MHz

330

Large-Signal Bandwidth

MAX4223/4/6/8

OUT

= 2V step

RL= 100Ω

MAX4223/5/6

µs2

0.02

Turn-On Time from Shutdown

SHDN = 0V, f = 10MHz, MAX4223/4/6/8

dB65Off Isolation

RL= 150Ω (Note 6)

0.01

degrees

0.01

VCC, VEE= 0V to ±5V step ns100t

MAX4223/4/6/8

Power-Up Time

RL= 150Ω (Note 6) %

0.02

DGDifferential Gain Error

ns300t

OFF

Turn-Off Time to Shutdown

f = 30MHz, RS= 50Ω

MAX4225/6

-60

325 600

dBc

-61

MAX4223/5/6

750 1000

MAX4224/7/8

-78

MAX4224/7/8

DPDifferential Phase Error

MAX4224/7/8

MAX4223/5/6

Rising edge

MAX4223/5/6

OUT

= 2Vp-p,

fC= 10MHz

MAX4224/7/8

MAX4223/5/6

1.0

Falling edge

1100 1400

V/µsSRSlew Rate (Note 5)

MAX4224/7/8

1.5

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX4224/7/8

tr, t

Rise and Fall Time

MAX4223/5/6

MAX4223/5/6 MAX4224/7/8

MAX4223/5/6

OUT

= 20mVp-p MHz

MAX4224/7/8

0.1dB

Bandwidth for ±0.1dB Gain Flatness (Note 5)

OUT

= 20mVp-p

-72

MAX4227/8

-68

TALK

Settling Time to 0.1%

Crosstalk

MHzBW

-3dB Small-Signal Bandwidth (Note 5)

MAX4224/7/8

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

4 _______________________________________________________________________________________

Note 1: The MAX422_EUT is 100% production tested at TA= +25°C. Specifications over temperature limits are guaranteed by design. Note 2: Absolute Maximum Power Dissipation must be observed. Note 3: Does not include impedance of external feedback resistor network. Note 4: AC specifications shown are with optimal values of R

and RG. These values vary for product and package type, and are

tabulated in the

Applications Information

section of this data sheet.

Note 5: The AC specifications shown are not measured in a production test environment. The minimum AC specifications given are

based on the combination of worst-case design simulations along with a sample characterization of units. These minimum specifications are for design guidance only and are not intended to guarantee AC performance (see

AC Testing/

Performance

). For 100% testing of these parameters, contact the factory.

Note 6: Input Test Signal: 3.58MHz sine wave of amplitude 40IRE superimposed on a linear ramp (0IRE to 100IRE). IRE is a unit of

video signal amplitude developed by the International Radio Engineers. 140IRE = 1V.

Note 7: Assumes printed circuit board layout similar to that of Maxim’s evaluation kit.

AC ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V, VEE= -5V, SHDN = 5V, VCM= 0V, AV= +1V/V for MAX4223/MAX4225/MAX4226, AV= +2V/V for MAX4224/MAX4227/ MAX4228, R

= 100Ω, TA= +25°C, unless otherwise noted.) (Note 4)

__________________________________________Typical Operating Characteristics

(VCC= +5V, VEE= -5V, RL= 100Ω, TA = +25°C, unless otherwise noted.)

4 3

-6 1 100 100010

MAX4223

SMALL-SIGNAL GAIN vs. FREQUENCY

VCL

= +1)

-4

-5

MAX4223-01

FREQUENCY (MHz)

GAIN (dB)

-2

-3

-1

2 1

VIN = 20mVp-p

SO-8 PACKAGE R

= 560Ω

SOT23-6 R

= 470Ω

4 3

-6 1 100 100010

MAX4223

SMALL-SIGNAL GAIN vs. FREQUENCY

VCL

= +2/+5)

-4

-5

MAX4223-02

FREQUENCY (MHz)

NORMALIZED GAIN (dB)

-2

-3

-1

2 1

VIN = 20mVp-p

AV = +2V/V R

= RG = 200Ω

AV = +5V/V R

= 100Ω

= 25Ω

4 3

-6 1 100 100010

MAX4223/MAX4225/MAX4226

LARGE-SIGNAL GAIN vs. FREQUENCY

VCL

= +1)

-4

-5

MAX4223-03

FREQUENCY (MHz)

GAIN (dB)

-2

-3

-1

2 1

= +1V/V

= 560Ω

OUT

= 2Vp-p

PARAMETER SYMBOL MIN TYP MAX UNITS

Input Capacitance (Note 7) C

0.8

Third-Order Intercept IP3

1.0

dBm

SO-8, SO-14 packages

f = 30kHz fz= 30.1MHz

SOT23-6, 10-pin µMAX packages

0.3

CONDITIONS

2Output Impedance Z

OUT

Ω

201dB Gain Compression

dBmf = 10kHz

f = 10kHz

Input Noise Current Density in+, in-

pA/√Hz

f = 10kHz

Input Noise Voltage Density

nV/√Hz

f = 10kHz

MAX4223/5/6 MAX4224/7/8

-61

Spurious-Free Dynamic Range SFDR

-62

dBf = 10kHz

MAX4223/5/6 MAX4224/7/8

IN+ INPin to pin Pin to GND Pin to pin Pin to GND

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

_______________________________________________________________________________________

4 3

-6 1 100 100010

MAX4224

SMALL-SIGNAL GAIN vs. FREQUENCY

VCL

= +2)

-4

-5

MAX4223-04

FREQUENCY (MHz)

NORMALIZED GAIN (dB)

-2

-3

-1

2 1

VIN = 20mVp-p

SO-8 PACKAGE R

= RG = 470Ω

SOT23-6 PACKAGE R

= RG = 470Ω

4 3

-6 1 100 100010

MAX4224

SMALL-SIGNAL GAIN vs. FREQUENCY

VCL

= +5/+10)

-4

-5

MAX4223-05

FREQUENCY (MHz)

NORMALIZED GAIN (dB)

-2

-3

-1

2 1

VIN = 20mVp-p

VCL

= +5V/V

= 240Ω

= 62Ω

VCL

= +10V/V

= 130Ω

= 15Ω

4 3

-6 1 100 100010

MAX4224/MAX4227/MAX4228

LARGE-SIGNAL GAIN vs. FREQUENCY

VCL

= +2)

-4

-5

MAX4223-06

FREQUENCY (MHz)

NORMALIZED GAIN (dB)

-2

-3

-1

2 1

VCL

= +2V/V

= RG = 470Ω

OUT

= 2Vp-p

4 3

-6 1 100 100010

MAX4225/MAX4226

SMALL-SIGNAL GAIN vs. FREQUENCY

VCL

= +1)

-4

-5

MAX4223-07

FREQUENCY (MHz)

GAIN (dB)

-2

-3

-1

2 1

VIN = 20mVp-p A

VCL

= +1V/V

= 560Ω

0.4

0.3

-0.6

0.1 10 1001

MAX4227/MAX4228

GAIN MATCHING vs. FREQUENCY

VCL

= +2)

-0.4

-0.5

MAX4223-10

FREQUENCY (MHz)

NORMALIZED GAIN (dB)

-0.2

-0.3

-0.1

0.2

0.1

VIN = 20mVp-p A

VCL

= +2V/V

= RG = 470Ω

10 100

MAX4225/MAX4226

GAIN MATCHING vs. FREQUENCY

VCL

= +1)

MAX4223-08

FREQUENCY (MHz)

GAIN (dB)

AMPLIFIER A

0.4

0.3

-0.6

-0.4

-0.5

-0.2

-0.3

-0.1

0.2

0.1

VIN = 2OmVp-p A

VCL

= +1V/V

= 560Ω

AMPLIFIER B

-10

-100 1 100 100010

MAX4225/MAX4226

CROSSTALK vs. FREQUENCY

-80

-90

MAX4223-11

FREQUENCY (MHz)

CROSSTALK (dB)

-60

-70

-40

-50

-20

-30

RS = 50Ω V

OUT

= 2Vp-p

-10

-100 1 100 100010

MAX4227/MAX4228

CROSSTALK vs. FREQUENCY

-80

-90

MAX4223-12

FREQUENCY (MHz)

CROSSTALK (dB)

-60

-70

-40

-50

-20

-30

RS = 50Ω V

OUT

= 2Vp-p

____________________________Typical Operating Characteristics (continued)

(VCC= +5V, VEE= -5V, RL= 100Ω, TA = +25°C, unless otherwise noted.)

4 3

-6 1 100 100010

MAX4227/MAX4228

SMALL-SIGNAL GAIN vs. FREQUENCY

VCL

= +2)

-4

-5

MAX4223-09

FREQUENCY (MHz)

NORMALIZED GAIN (dB)

-2

-3

-1

2 1

VIN = 20mVp-p A

VCL

= +2V/V

= RG = 470Ω

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

6 _______________________________________________________________________________________

____________________________Typical Operating Characteristics (continued)

(VCC= +5V, VEE= -5V, RL= 100Ω, TA = +25°C, unless otherwise noted.)

-90

0.01 1 10 1000.1

MAX4223/MAX4225/MAX4226

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY (A

VCL

= +1)

-70

-80

MAX4223-13

FREQUENCY (MHz)

PSRR (dB)

-50

-60

-30

-40

-10

-20

VCL

= +1V/V

= 560Ω

-90

0.01 1 10 1000.1

MAX4224/MAX4227/MAX4228

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY (A

VCL

= +2)

-70

-80

MAX4223-14

FREQUENCY (MHz)

PSRR (dB)

-50

-60

-30

-40

-10

-20

VCL

= +2V/V

= RG = 470Ω

0.01

0.01 0.1 1 10 100

OUTPUT IMPEDANCE vs. FREQUENCY

0.1

MAX4223-15

FREQUENCY (MHz)

OUTPUT IMPEDANCE (Ω)

100

MAX4224/7/8 A

VCL

= +2V/V

= RG = 470Ω

MAX4223/5/6 A

VCL

= +1V/V

= 560Ω

-180

0.01 10 1000.1 1 1000

SHUTDOWN MODE OUTPUT ISOLATION

vs. FREQUENCY

-140

-160

MAX4223-16

FREQUENCY (MHz)

SHUTDOWN MODE OUTPUT ISOLATION (dB)

-100

-120

-60

-20

-40

-80 MAX4224/7/8

VCL

= +2V/V

= RG = 470Ω

MAX4223/5/6 A

VCL

= +1V/V

= 560Ω

-30

-90

0.1 10 100

MAX4224/MAX4227/MAX4228

TOTAL HARMONIC DISTORTION

vs. FREQUENCY (R

= 150Ω)

-70

-50

-40

-60

-80

MAX4223-19

FREQUENCY (MHz)

THD (dBc)

3RD HARMONIC

2ND HARMONIC

THD

-30

-90

0.1 10 100

MAX4223/MAX4225/MAX4226

TOTAL HARMONIC DISTORTION

vs. FREQUENCY (R

= 150Ω)

-70

-50

-40

-60

-80

MAX4223-17

FREQUENCY (MHz)

THD (dBc)

VCL

= +1V/V

= 150Ω

= 560Ω

OUT

= 2Vp-p

3RD HARMONIC

2ND HARMONIC

THD

-30

-100

0.1 10 100

MAX4223/MAX4225/MAX4226

TOTAL HARMONIC DISTORTION

vs. FREQUENCY (R

= 1kΩ)

-80

-60

-40

-70

-50

-90

MAX4223-18

FREQUENCY (MHz)

THD (dBc)

VCL

= +1V/V

= 1kΩ

= 560Ω

OUT

= 2Vp-p

2ND HARMONIC

3RD HARMONIC

THD

-30

-100

0.1 10 100

MAX4224/MAX4227/MAX4228

TOTAL HARMONIC DISTORTION

vs. FREQUENCY (R

= 1kΩ)

-80

-60

-40

-70

-50

-90

MAX4223-20

FREQUENCY (MHz)

THD (dBc)

2ND HARMONIC

3RD HARMONIC

THD

10 30 4020 50 60 70 80 90 100

TWO-TONE THIRD-ORDER INTERCEPT

vs. FREQUENCY

MAX4223-21

FREQUENCY (MHz)

THIRD-ORDER INTERCEPT (dBm)

MAX4224/7/8

MAX4223/5/6

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

_______________________________________________________________________________________

____________________________Typical Operating Characteristics (continued)

(VCC= +5V, VEE= -5V, RL= 100Ω, TA = +25°C, unless otherwise noted.)

+100mV

-100mV

INPUT

+100mV

-100mV

OUTPUT

GND

TIME (10ns/div)

MAX4223/MAX4225/MAX4226

SMALL-SIGNAL PULSE RESPONSE

VCL

= +1)

MAX4223-22

+100mV

-100mV

INPUT

+100mV

-100mV

OUTPUT

GND

TIME (10ns/div)

MAX4223/MAX4225/MAX4226

SMALL-SIGNAL PULSE RESPONSE

VCL

= +1, CL = 25pF)

MAX4223-23

+50mV

-50mV

INPUT

+100mV

-100mV

OUTPUT

GND

TIME (10ns/div)

MAX4224/MAX4227/MAX4228

SMALL-SIGNAL PULSE RESPONSE

VCL

= +2)

MAX4223-24

+50mV

-50mV

INPUT

+100mV

-100mV

OUTPUT

GND

TIME (10ns/div)

MAX4224/MAX4227/MAX4228

SMALL-SIGNAL PULSE RESPONSE

VCL

= +2, CL = 10pF)

MAX4223-25

+1V

-1V

INPUT

+2V

-2V

OUTPUT

GND

TIME (10ns/div)

MAX4224/MAX4227/MAX4228

LARGE-SIGNAL PULSE RESPONSE

VCL

= +2)

MAX4223-28

+2V

-2V

INPUT

+2V

-2V

OUTPUT

GND

TIME (10ns/div)

MAX4223/MAX4225/MAX4226

LARGE-SIGNAL PULSE RESPONSE

VCL

= +1)

MAX4223-26

+2V

-2V

INPUT

+2V

-2V

OUTPUT

GND

TIME (10ns/div)

MAX4223/MAX4225/MAX4226

LARGE-SIGNAL PULSE RESPONSE

VCL

= +1, CL = 25pF)

MAX4223-27

+1V

-1V

INPUT

+2V

-2V

OUTPUT

GND

TIME (10ns/div)

MAX4224/MAX4227/MAX4228

LARGE-SIGNAL PULSE RESPONSE

VCL

= +2,CL = 10pF)

MAX4223-29

+400mV

-400mV

INPUT

+2V

-2V

OUTPUT

GND

TIME (10ns/div)

MAX4224/MAX4227/MAX4228

LARGE-SIGNAL PULSE RESPONSE

VCL

= +5)

MAX4223-30

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

8 _______________________________________________________________________________________

-50 0-25 25 50 75 100

POWER-SUPPLY CURRENT PER AMPLIFIER

vs. TEMPERATURE

MAX4223-31

TEMPERATURE (°C)

CURRENT (mA)

NORMAL MODE

SHUTDOWN MODE

-50

-25

25 50 75 100

INPUT BIAS CURRENT

vs. TEMPERATURE

MAX4223-32

TEMPERATURE (°C)

CURRENT (µA)

B-

B+

120

130

150

140

160

170

100

SHORT-CIRCUIT OUTPUT CURRENT

vs. TEMPERATURE

MAX4223-33

TEMPERATURE (°C)

CURRENT (mA)

-50

-25

25 50 75 100

SOURCING

SINKING

1.0

2.0

1.5

3.0

2.5

4.0

3.5

4.5

-50 0 25-25 50 75 100

POSITIVE OUTPUT SWING

vs. TEMPERATURE

MAX4223-34

TEMPERATURE (°C)

POSITIVE OUTPUT SWING (V)

RL = OPEN

RL = 50Ω

-4.5

-3.5

-4.0

-2.5

-3.0

-1.5

-2.0

-1.0

-50 0 25-25 50 75 100

NEGATIVE OUTPUT SWING

vs. TEMPERATURE

MAX4223-35

TEMPERATURE (°C)

NEGATIVE OUTPUT SWING (V)

RL = OPEN

RL = 50Ω

____________________________Typical Operating Characteristics (continued)

(VCC= +5V, VEE= -5V, RL= 100Ω, TA = +25°C, unless otherwise noted.)

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

_______________________________________________________________________________________ 9

FUNCTION

______________________________________________________________Pin Description

— —

— — 9— 6

SHDNB

Amplifier B Shutdown Input. Connect to +5V for normal operation. Connect to GND for low-power shutdown mode.

7 9

— 5

— —

OUTB Amplifier B Output

SHDNA

— —

Amplifier A Shutdown Input. Connect to +5V for normal operation. Connect to GND for low-power shutdown mode.

— — 11

5 7 6 8

INB+ Amplifier B Noninverting Input

INB-— — Amplifier B Inverting Input

2 3

2 2 3 3

INA- Amplifier A Inverting Input

INA+— — Amplifier A Noninverting Input

4 2

6 7 14

8 10

1 1

Positive Power-Supply Voltage. Connect to +5V.

OUTA— — Amplifier A Output

—

— —

IN- Amplifier Inverting Input

SHDN

5 8

Amplifier Shutdown. Connect to +5V for normal operation. Connect to GND for lowpower shutdown.

2 4 4

—

4 4

— —

Negative Power-Supply Voltage. Connect to -5V.

IN+3 3 Amplifier Noninverting Input

—— — OUT Amplifier Output1 6

5, 7, 8, 10— — N.C.

No Connect. Not internally connected. Tie to GND for optimum AC performance.

— 1, 5

MAX4225 MAX4227

SOµMAXSOSOSOT23

MAX4223/MAX4224 MAX4226/MAX4228

NAME FUNCTION

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

10 ______________________________________________________________________________________

_______________Detailed Description

The MAX4223–MAX4228 are ultra-high-speed, lowpower, current-feedback amplifiers featuring -3dB bandwidths up to 1GHz, 0.1dB gain flatness up to 300MHz, and very low differential gain and phase errors of 0.01% and 0.02°, respectively. These devices operate on dual ±5V or ±3V power supplies and require only 6mA of supply current per amplifier. The MAX4223/MAX4225/MAX4226 are optimized for closed-loop gains of +1 (0dB) or more and have -3dB bandwidths of 1GHz. The MAX4224/MAX4227/ MAX4228 are optimized for closed-loop gains of +2 (6dB) or more, and have -3dB bandwidths of 600MHz (1.2GHz gain-bandwidth product).

The current-mode feedback topology of these amplifiers allows them to achieve slew rates of up to 1700V/µs with corresponding large signal bandwidths up to 330MHz. Each device in this family has an output that is capable of driving a minimum of 60mA of output current to ±2.5V.

Theory of Operation

Since the MAX4223–MAX4228 are current-feedback amplifiers, their open-loop transfer function is expressed as a transimpedance:

The frequency behavior of this open-loop transimpedance is similar to the open-loop gain of a voltage-feedback amplifier. That is, it has a large DC value and decreases at approximately 6dB per octave.

Analyzing the current-feedback amplifier in a gain configuration (Figure 1) yields the following transfer function:

At low gains, (G x R

IN-

) << RF. Therefore, unlike traditional voltage-feedback amplifiers, the closed-loop bandwidth is essentially independent of the closedloop gain. Note also that at low frequencies, TZ>> [(G x R

IN-

) + RF], so that:

Low-Power Shutdown Mode

The MAX4223/MAX4224/MAX4226/MAX4228 have a shutdown mode that is activated by driving the SHDN input low. When powered from ±5V supplies, the SHDN input is compatible with TTL logic. Placing the amplifier in shutdown mode reduces quiescent supply current to 350µA typical, and puts the amplifier output into a highimpedance state (100kΩ typical). This feature allows these devices to be used as multiplexers in wideband systems. To implement the mux function, the outputs of multiple amplifiers can be tied together, and only the amplifier with the selected input will be enabled. All of the other amplifiers will be placed in the low-power shutdown mode, with their high output impedance presenting very little load to the active amplifier output. For gains of +2 or greater, the feedback network impedance of all the amplifiers used in a mux application must be considered when calculating the total load on the active amplifier output.

__________Applications Information

Layout and Power-Supply Bypassing

The MAX4223–MAX4228 have an extremely high bandwidth, and consequently require careful board layout, including the possible use of constant-impedance microstrip or stripline techniques.

OUT

= = + 1

G x

T S

T S G x R R

where G A

OUT

Z IN F

( )

+ +

= = +

−

∆∆V

or T

OUT

INZ−

MAX4223 MAX4224 MAX4225 MAX4226 MAX4227 MAX4228

IN-

OUT

IN+

Figure 1. Current-Feedback Amplifier

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

______________________________________________________________________________________ 11

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. The ground plane should be as free of voids as possible, with one exception: the inverting input pin (IN-) should have as low a capacitance to ground as possible. This means that there should be no ground plane under IN- or under the components (RFand RG) connected to it. With multilayer boards, locate the ground plane on a layer that incorporates no signal or power traces.

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 too inductive) or breadboards (they are too capacitive).

2) Do not use IC sockets. IC sockets increase reactance.

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) In general, surface-mount components have shorter bodies and lower parasitic reactance, giving better high-frequency performance than through-hole components.

The bypass capacitors should include a 10nF ceramic, surface-mount capacitor 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 powersupply trace should lead directly from the tantalum capacitor to the VCCand VEEpins. To minimize parasitic inductance, keep PC traces short and use surfacemount components. The N.C. pins should be connected to a common ground plane on the PC board to minimize parasitic coupling.

If input termination resistors and output back-termination resistors are used, they should be surface-mount types, and should be placed as close to the IC pins as possible. Tie all N.C. pins to the ground plane to minimize parasitic coupling.

Choosing Feedback and Gain Resistors

As with all current-feedback amplifiers, the frequency response of these devices depends critically on the value of the feedback resistor RF. RFcombines with an internal compensation capacitor to form the dominant pole in the feedback loop. Reducing RF’s value increases the pole frequency and the -3dB bandwidth, but also increases peaking due to interaction with other nondominant poles. Increasing RF’s value reduces peaking and bandwidth.

Table 1 shows optimal values for the feedback resistor (RF) and gain-setting resistor (RG) for the MAX4223– MAX4228. Note that the MAX4224/MAX4227/MAX4228 offer superior AC performance for all gains except unity gain (0dB). These values provide optimal AC response using surface-mount resistors and good layout techniques. Maxim’s high-speed amplifier evaluation kits provide practical examples of such layout techniques.

Stray capacitance at IN- causes feedback resistor decoupling and produces peaking in the frequencyresponse curve. Keep the capacitance at IN- as low as possible by using surface-mount resistors and by avoiding the use of a ground plane beneath or beside these resistors and the IN- pin. Some capacitance is unavoidable; if necessary, its effects can be counteracted by adjusting RF. Use 1% resistors to maintain consistency over a wide range of production lots.

Table 1. Optimal Feedback Resistor Networks

MAX4223/MAX4225/MAX4226

2 6 200 200 380 115

GAIN

(dB)

(Ω)

0.1dB BW

(MHz)

GAIN

(V/V)

-3dB BW

(MHz)

5 14 100 25 235 65

2 6 470 470 600 200 5 14 240 62 400 90

10 20 130 15 195 35

MAX4224/MAX4227/MAX4228

For the MAX4223EUT, this optimal value is 470Ω.

1 0 560* Open 1000 300

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

12 ______________________________________________________________________________________

DC and Noise Errors

The MAX4223–MAX4228 output offset voltage, V

OUT

(Figure 2), can be calculated with the following equation:

where: VOS= input offset voltage (in volts) 1 + RF / RG= amplifier closed-loop gain (dimensionless) IB+= input bias current (in amps) IB-= inverting input bias current (in amps) RG= gain-setting resistor (in Ω) RF= feedback resistor (in Ω) RS= source resistor (in Ω)

The following equation represents output noise density:

where: i

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

en= input noise voltage density (in nV/√Hz) The MAX4223–MAX4228 have a very low, 2nV/√Hz

noise voltage. The current noise at the noninverting input (in+) is 3pA/√Hz, and the current noise at the inverting input (in-) is 20pA/√Hz.

An example of DC-error calculations, using the MAX4224 typical data and the typical operating circuit with RF= RG= 470Ω (RF || RG= 235Ω) and RS= 50Ω, gives:

OUT

= [5 x 10-4x (1 + 1)] + [2 x 10-6x 50 x (1 + 1)] +

[4 x 10-6x 470]

OUT

= 3.1mV

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

With a 600MHz system bandwidth, this calculates to 250µV

RMS

(approximately 1.5mVp-p, using the six-

sigma calculation).

Communication Systems

Nonlinearities of components used in a communication system produce distortion of the desired output signal. Intermodulation distortion (IMD) is the distortion that results from the mixing of two input signals of different frequencies in a nonlinear system. In addition to the input signal frequencies, the resulting output signal contains new frequency components that represent the sum and difference products of the two input frequencies. If the two input signals are relatively close in frequency, the third-order sum and difference products will fall close to the frequency of the desired output and will therefore be very difficult to filter. The third-order intercept (IP3) is defined as the power level at which the amplitude of the largest third-order product is equal to the power level of the desired output signal. Higher third-order intercept points correspond to better linearity of the amplifier. The MAX4223–MAX4228 have a typical IP3 value of 42dBm, making them excellent choices for use in communications systems.

ADC Input Buffers

Input buffer amplifiers can be a source of significant errors in high-speed ADC applications. The input buffer is usually required to rapidly charge and discharge the ADC’s input, which is often capacitive (see the section

Driving Capacitive Loads

). In addition, a high-speed ADC’s input impedance often changes very rapidly during the conversion cycle, requiring an amplifier with

e x

x x

x x x

e nV Hz

n OUT

( )

−

− −

( )

= +

( )

 

 

 



 



 

 

 



 



 

 

. /

1 1

3 10 50

20 10 235 2 10

10 2

R R

i x R i x R R e

n OUT

n S n F G n

( )

+ −

= +

 



 



( )

[ ]

( )

V V x 1 R /R I x R

x 1

I x R

OUT OS F G B S

F G

B F

= +

( )

 



 



−

MAX4223 MAX4224 MAX4225 MAX4226 MAX4227 MAX4228

IN-

B-

B+

IN+

OUT

Figure 2. Output Offset Voltage

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

______________________________________________________________________________________ 13

very low output impedance at high frequencies to maintain measurement accuracy. The combination of high speed, fast slew rate, low noise, and low distortion makes the MAX4223–MAX4228 ideally suited for use as buffer amplifiers in high-speed ADC applications.

Video Line Driver

The MAX4223–MAX4228 are optimized to drive coaxial transmission lines when the cable is terminated at both ends, as shown in Figure 3. Note that cable frequency response may cause variations in the signal’s flatness.

Driving Capacitive Loads

A correctly terminated transmission line is purely resistive and presents no capacitive load to the amplifier. Although the MAX4223–MAX4228 are optimized for AC performance and are not designed to drive highly capacitive loads, they are capable of driving up to 25pF without excessive ringing. Reactive loads decrease phase margin and may produce excessive ringing and oscillation (see

Typical Operating

Characteristics

). Figure 4’s circuit reduces the effect of large capacitive loads. The small (usually 5Ω to 20Ω) isolation resistor R

ISO

, placed before the reactive load,

prevents ringing and oscillation at the expense of a

small gain error. At higher capacitive loads, AC performance is limited by the interaction of load capacitance with the isolation resistor.

Maxim’s High-Speed

Evaluation Board Layout

Figures 7 and 8 show a suggested layout for Maxim’s high-speed, single-amplifier evaluation boards. These boards were developed using the techniques described above. The smallest available surface-mount resistors were used for the feedback and back-termination resistors to minimize the 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 MAX4223 in an SO-8 package.

MAX4223 MAX4224 MAX4225 MAX4226 MAX4227 MAX4228

IN-

IN+

OUT

75Ω

75Ω CABLE

Figure 3. Video Line Driver

MAX4223 MAX4224 MAX4225 MAX4226 MAX4227 MAX4228

IN-

IN+

ISO

OUT

Figure 4. Using an Isolation Resistor (R

ISO

) for High

Capacitive Loads

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

14 ______________________________________________________________________________________

AC Testing/Performance

AC specifications on high-speed amplifiers are usually guaranteed without 100% production testing. Since these high-speed devices are sensitive to external parasitics introduced when automatic handling equipment is used, it is impractical to guarantee AC parameters through volume production testing. These parasitics are greatly reduced when using the recommended PC board layout (like the Maxim evaluation kit). Characterizing the part in this way more accurately represents the amplifier’s true AC performance. Some

manufacturers guarantee AC specifications without clearly stating how this guarantee is made. The MAX4223–MAX4228 AC specifications are derived from worst-case design simulations combined with a sample characterization of 100 units. The AC performance distributions along with the worst-case simulation limits are shown in Figures 5 and 6. These distributions are repeatable provided that proper board layout and power-supply bypassing are used (see

Layout

and Power-Supply Bypassing

section).

0–600

650–700

750–800

850–900

950–1000

1050–1100

1150–1200

1250–1300

1350–1400

1450–1500

MAX4223-fig5a

-3dB BANDWIDTH (MHz)

NUMBER OF UNITS

100 UNITS

SIMULATION

LOWER LIMIT

Figure 5a. MAX4223 -3dB Bandwidth Distribution

0–60

80–100

120–140

160–180

200–220

240–260

280–300

320–340

360–380

400–420

MAX4223-fig5b

±0.1dB BANDWIDTH (MHz)

NUMBER OF UNITS

100 UNITS

SIMULATION LOWER LIMIT

Figure 5b. MAX4223 ±0.1dB Bandwidth Distribution

0–800

825–850

875–900

925–950

975–1000

1025–1050

1075–1100

1125–1150

1175–1200

1225–1250

MAX4223-fig5c

RISING-EDGE SLEW RATE (V/µs)

NUMBER OF UNITS

100 UNITS

SIMULATION

LOWER LIMIT

Figure 5c. MAX4223 Rising-Edge Slew-Rate Distribution

0–500

525–550

575–600

625–650

675–700

725–750

775–800

825–850

875–900

925–950

MAX4223-fig5d

FALLING-EDGE SLEW RATE (V/µs)

NUMBER OF UNITS

100 UNITS

SIMULATION

LOWER LIMIT

Figure 5d. MAX4223 Falling-Edge Slew-Rate Distribution

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

______________________________________________________________________________________ 15

0–200

250–300

350–400

450–500

550–600

650–700

750–800

850–900

950–1000

1050–1100

MAX4223-fig6a

-3dB BANDWIDTH (MHz)

NUMBER OF UNITS

100 UNITS

SIMULATION LOWER LIMIT

Figure 6a. MAX4224 -3dB Bandwidth Distribution

0–40

60–80

100–120

140–160

180–200

220–240

260–280

300–320

340–360

380–400

MAX4223-fig6b

±0.1dB BANDWIDTH (MHz)

NUMBER OF UNITS

100 UNITS

SIMULATION

LOWER LIMIT

Figure 6b. MAX4224 ±0.1dB Bandwidth Distribution

0–1400

1425–1450

1475–1500

1525–1550

1575–1600

1625–1650

1675–1700

1725–1750

1775–1800

1825–1850

MAX4223-fig6c

RISING-EDGE SLEW RATE (V/µs)

NUMBER OF UNITS

100 UNITS

SIMULATION

LOWER LIMIT

Figure 6c. MAX4224 Rising-Edge Slew-Rate Distribution

0–1100

1125–1150

1175–1200

1225–1250

1275–1300

1325–1350

1375–1400

1425–1450

1475–1500

1525–1550

MAX4223-fig6d

FALLING-EDGE SLEW RATE (V/µs)

NUMBER OF UNITS

100 UNITS

SIMULATION

LOWER LIMIT

Figure 6d. MAX4224 Falling-Edge Slew-Rate Distribution

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

16 ______________________________________________________________________________________

Figure 7a. Maxim SOT23 High-Speed Evaluation Board Component Placement Guide—Component Side

Figure 7c. Maxim SOT23 High-Speed Evaluation Board PC Board Layout—Back Side

Figure 7b. Maxim SOT23 High-Speed Evaluation Board PC Board Layout—Component Side

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

______________________________________________________________________________________ 17

Figure 8a. Maxim SO-8 High-Speed Evaluation Board Component Placement Guide—Component Side

Figure 8c. Maxim SO-8 High-Speed Evaluation Board PC Board Layout—Back Side

Figure 8b. Maxim SO-8 High-Speed Evaluation Board PC Board Layout—Component Side

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

18 ______________________________________________________________________________________

_____________________________________________Pin Configurations (continued)

OUT

N.C.

87SHDN

IN-

IN+

N.C.

TOP VIEW

MAX4223 MAX4224

MAX4226 MAX4228

INB-

INB+

87V

OUTB

INA-

INA+

OUTA

MAX4225 MAX4227

1 2 3 4 5

9 8 7 6

OUTB INBINB+V

INA+

INA-

OUTA

µMAX

SHDNBSHDNA

14 13 12 11 10

9 8

1 2 3 4 5 6 7

OUTB INBINB+V

INA+

INA-

OUTA

N.C. SHDNB N.C.N.C.

SHDNA

N.C.

MAX4223–MAX4228

1GHz, Low-Power, SOT23,

Current-Feedback Amplifiers with Shutdown

______________________________________________________________________________________ 19

MAX4223/MAX4224 TRANSISTOR COUNT: 87 MAX4225–MAX4228 TRANSISTOR COUNT: 171 SUBSTRATE CONNECTED TO V

PART

MAX4224EUT-T

MAX4224ESA

SOT

TOP MARK

AAAE

-40°C to +85°C

TEMP. RANGE

PIN-

PACKAGE

6 SOT23 8 SO —

_Ordering Information (continued) ___________________Chip Information

MAX4225ESA MAX4226EUB

—

-40°C to +85°C

-40°C to +85°C 8 SO 10 µMAX —

MAX4226ESD —-40°C to +85°C 14 SO MAX4227ESA

-40°C to +85°C 8 SO —

MAX4228EUB MAX4228ESD—-40°C to +85°C

-40°C to +85°C 10 µMAX 14 SO —

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

MAX4223–MAX4228

1GHz, Low-Power, SOT23, Current-Feedback Amplifiers with Shutdown

________________________________________________________Package Information

10LUMAXB.EPS

6LSOT.EPS

Datasheet MAX4228EUB, MAX4228ESD, MAX4226ESDB, MAX4225ESA, MAX4224EUT-T Datasheet (Maxim)

Specifications and Main Features

Frequently Asked Questions

User Manual