Datasheet MAX4200ESA, MAX4204ESA, MAX4203EUA, MAX4203ESA, MAX4202EUK-T Datasheet (Maxim)

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________________General Description

The MAX4200–MAX4205 are ultra-high-speed, open­loop buffers featuring high slew rate, high output cur­rent, low noise, and excellent capacitive-load-driving
capability. The MAX4200/MAX4201/MAX4202 are sin­gle buffers, while the MAX4203/MAX4204/MAX4205 are
dual buffers. The MAX4201/MAX4204 have integrated
50Ω termination resistors, making them ideal for driv­ing 50Ω transmission lines. The MAX4202/MAX4205
include 75Ω back-termination resistors for driv­ing 75Ω transmission lines. The MAX4200/MAX4203
have no internal termination resistors.

The MAX4200–MAX4205 use a proprietary architecture
to achieve up to 780MHz -3dB bandwidth, 280MHz

0.1dB gain flatness, 4200V/µs slew rate, and ±90mA
output current drive capability. They operate from ±5V
supplies and draw only 2.2mA of quiescent current.
These features, along with low-noise performance, make
these buffers suitable for driving high-speed analog-to­digital converter (ADC) inputs or for data-communica­tions applications.

________________________Applications

High-Speed DAC Buffers
Wireless LANs
Digital-Transmission Line Drivers
High-Speed ADC Input Buffers
IF/Communications Systems

____________________________Features

♦ 2.2mA Supply Current
♦ High Speed

780MHz -3dB Bandwidth (MAX4201/MAX4202)
280MHz 0.1dB Gain Flatness (MAX4201/MAX4202)

4200V/µs Slew Rate

♦ Low 2.1nV/√Hz Voltage-Noise Density
♦ Low 0.8pA/√Hz Current-Noise Density
♦ High ±90mA Output Drive (MAX4200/MAX4203)
♦ Excellent Capacitive-Load-Driving Capability
♦ Available in Space-Saving SOT23 or µMAX

Packages

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,

SOT23 Open-Loop Buffers

________________________________________________________________

Maxim Integrated Products

1

19-1338; Rev 2; 4/99

_______________Ordering Information

___________Typical Application Circuit

PART

NO. OF

BUFFERS

INTERNAL

OUTPUT

TERMINATION

(Ω)

PIN-PACKAGE

MAX4204 2 50 8 SO/µMAX

MAX4200 1 — 8 SO, 5 SOT23

MAX4201 1 50 8 SO, 5 SOT23

MAX4205 2 75 8 SO/µMAX

MAX4202 1 75 8 SO, 5 SOT23

MAX4203 2 — 8 SO/µMAX

PART

TOP

MARK

MAX4200ESA

—

TEMP. RANGE

PIN-

PACKAGE

-40°C to +85°C 8 SO

MAX4200EUK-T AABZ-40°C to +85°C 5 SOT23-5
MAX4201ESA

—

-40°C to +85°C 8 SO

MAX4201EUK-T ABAA-40°C to +85°C 5 SOT23-5
MAX4202ESA

—

-40°C to +85°C 8 SO

MAX4205EUA—-40°C to +85°C 8 µMAX

MAX4202EUK-T ABAB
MAX4203ESA

—

-40°C to +85°C 5 SOT23-5

-40°C to +85°C 8 SO

MAX4203EUA—-40°C to +85°C 8 µMAX
MAX4204ESA

—

-40°C to +85°C 8 SO

MAX4204EUA—-40°C to +85°C 8 µMAX
MAX4205ESA

—

-40°C to +85°C 8 SO

___________________________Selector Guide

Pin Configurations appear at end of data sheet.

R

*

T

50Ω

MAX4201

50Ω CABLE

R

EXT

50Ω

OUTIN

*

*R

= RT + R

L

EXT

COAXIAL CABLE DRIVER

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(VCC= +5V, VEE= -5V, RL= ∞, 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 GND..............(V

EE

- 0.3V) to (VCC+ 0.3V)

Output Short-Circuit Duration to GND........................Continuous

Continuous Power Dissipation (T

A

= +70°C)

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

8-Pin µMAX (derate 4.1mW/°C above +70°C) ..............330mW

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

VIN= 0V

Sinking or sourcing

Per buffer, VIN= 0V

Guaranteed by PSR test

RL= 30Ω

VS= ±4V to ±5.5V

-3.0V ≤
V

OUT

≤

3.0V

f = DC

VIN= 0V

MAX4203/MAX4204/MAX4205

CONDITIONS

mA

75

I

SC

Short-Circuit Output
Current

90

150

mA

±44

I

OUT

Output Current

±52

±90

Ω

75

R

OUT

Output Resistance 50

8

mV115V

OS

Input Offset Voltage

mA2.2 4I

S

V±4 ±5.5V

S

Operating Supply Voltage
Quiescent Supply Current

dB55 72PSRPower-Supply Rejection

V/V

0.41 0.50 0.59

A

V

Voltage Gain

0.42 0.50 0.58

0.9 0.96 1.1

µV/°C20TCV

OS

Input Offset Voltage Drift

mV0.4

Input Offset Voltage
Matching

µA0.8 10I

B

Input Bias Current

kΩ500R

IN

Input Resistance

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX4200/MAX4203, R

EXT

= 150Ω

MAX4201/MAX4204, R

EXT

= 50Ω

MAX4202/MAX4205, R

EXT

= 75Ω

MAX4200/MAX4203
MAX4201/MAX4204
MAX4202/MAX4205
MAX4200/MAX4203
MAX4201/MAX4204
MAX4202/MAX4205
MAX4200/MAX4203
MAX4201/MAX4204
MAX4202/MAX4205

MAX4200/MAX4203

RL= 150Ω

VV

OUT

Output Voltage Swing

±3.3 ±3.8
RL= 100Ω ±3.2 ±3.7
RL= 37.5Ω ±3.3

MAX4201/MAX4204 RL= 50Ω ±1.9 ±2.1
MAX4202/MAX4205 RL= 75Ω ±2.0 ±2.3

V

OUT

= 2Vp-p

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,

SOT23 Open-Loop Buffers

_______________________________________________________________________________________ 3

V

OUT

=

2Vp-p

V

OUT

≤ 100mV

RMS

V

OUT

≤ 100mV

RMS

V

OUT

= 2V step

CONDITIONS

dBc

-32

SFDR

Spurious-Free Dynamic
Range

-44

-47

-34

-45

-48

ns12t

S

Settling Time to 0.1%

ps405Group Delay Time

530

780

660

MHz

310

FPBWFull-Power Bandwidth

490

MHz

230

BW

(0.1dB)

0.1dB Bandwidth

MHz

720

BW

(-3dB)

-3dB Bandwidth

220
280
130

UNITSMIN TYP MAXSYMBOLPARAMETER

AC ELECTRICAL CHARACTERISTICS

(VCC= +5V, VEE= -5V, RL= 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL= 150Ω for MAX4202/MAX4205, TA= T

MIN

to

T

MAX

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

f = 1MHz

MAX4200/MAX4201/
MAX4202, f = 500kHz,
V

OUT

= 2Vp-p

pA/√Hz

0.8i

n

Input Current Noise Density

-48

-48

-72

pF2C

IN

Input Capacitance

V

OUT

= 2Vp-p

f = 10MHz

-65

X

TALK

Amplifier Crosstalk dB

-87

Ω6Z

OUT

Output Impedance

MAX4200
MAX4201/MAX4202
MAX4203
MAX4204/MAX4205
MAX4200
MAX4201/MAX4202
MAX4203
MAX4204/MAX4205

MAX4200/MAX4201/MAX4202

MAX4200/MAX4201/
MAX4202

f = 5MHz
f = 20MHz
f = 100MHz
f = 5MHz
f = 20MHz
f = 100MHz

MAX4203/MAX4204/
MAX4205

V

OUT

≤ 2Vp-p

V

OUT

= 2V step V/µs4200SRSlew Rate

MAX4203/MAX4204/MAX4205

f = 1MHz

NTSC, RL= 150Ω

NTSC, RL= 150Ω

nV/√Hz

2.1e

n

Input Voltage Noise Density

degrees0.15DPDifferential Phase Error

%1.3DGDifferential Gain Error

Second harmonic
Third harmonic
Total harmonic
Second harmonic
Third harmonic
Total harmonic

MAX4203/MAX4204/|
MAX4205, f = 500kHz,
V

OUT

= 2Vp-p

dBc

-47

HDHarmonic Distortion

-47

-83

f = 10MHz
f = 100MHz

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(VCC= +5V, VEE= -5V, RL= 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL= 150Ω for MAX4202/MAX4205, unless
otherwise noted.)

4

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

MAX4200

SMALL-SIGNAL GAIN vs. FREQUENCY

-4

-5

-3

MAX4200/25-01

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-2

-1

0

2

1

3

V

OUT

= 100mVp-p

4

-6
100k

1M

10M 100M 1G

MAX4201/MAX4202

SMALL-SIGNAL GAIN vs. FREQUENCY

-4

-5

-3

MAX4200/25-02

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-2

-1

0

2

1

3

V

OUT

= 100mVp-p

4

-6
100k

1M

10M 100M 1G

MAX4200/MAX4201/MAX4202

LARGE-SIGNAL GAIN vs. FREQUENCY

-4

-5

-3

MAX4200/25-03

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-2

-1

0

2

1

3

V

OUT

= 2Vp-p

4

-6
100k 1M 10M

100M

1G

MAX4203

SMALL-SIGNAL GAIN vs. FREQUENCY

-4

-5

-3

MAX4200/25-04

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-2

-1

0

2

1

3

V

OUT

= 100mVp-p

5

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

GROUP DELAY vs. FREQUENCY

-3

-4

-2

MAX4200/25-07

FREQUENCY (Hz)

GROUP DELAY (ns)

-1

0

1

3

2

4

4

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

MAX4204/MAX4205

SMALL-SIGNAL GAIN vs. FREQUENCY

-4

-5

-3

MAX4200/25-05

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-2

-1

0

2

1

3

V

OUT

= 100mVp-p

4

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

MAX4203/MAX4204/MAX4205

LARGE-SIGNAL GAIN vs. FREQUENCY

-4

-5

-3

MAX4200/25-06

FREQUENCY (Hz)

NORMALIZED GAIN (dB)

-2

-1

0

2

1

3

V

OUT

= 2Vp-p

0

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

POWER-SUPPLY REJECTION

vs. FREQUENCY

-80

-90

-70

MAX4200/25-08

FREQUENCY (Hz)

PSR (dB)

-60

-50

-40

-20

-30

-10

9000

0

0 1.0 3.02.5 5.0

SLEW RATE vs. OUTPUT VOLTAGE

3000

2000

1000

4000

7000

8000

MAX4200/4205-09

OUTPUT VOLTAGE (Vp-p)

SLEW RATE (V/µs)

1.5 2.00.5 3.5

5000

6000

4.0 4.5

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,

SOT23 Open-Loop Buffers

_______________________________________________________________________________________

5

_________________________________Typical Operating Characteristics (continued)

(VCC= +5V, VEE= -5V, RL= 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL= 150Ω for MAX4202/MAX4205, unless
otherwise noted.)

MAX4200/MAX4201/MAX4202

HARMONIC DISTORTION vs. FREQUENCY

0

VIN = 2Vp-p

-10

-20

-30

-40

-50

-60

-70

HARMONIC DISTORTION (dBc)

-80

-90

-100

THIRD HARMONIC

SECOND HARMONIC

100k 100M10M1M

FREQUENCY (Hz)

MAX4201/MAX4204

OUTPUT IMPEDANCE vs. FREQUENCY

100

OUTPUT IMPEDANCE (Ω)

10

100k 10M 100M1M 1G

FREQUENCY (Hz)

-10

-20

MAX4200/4205-10

-30

-40

-50

-60

-70

HARMONIC DISTORTION (dBc)

-80

-90

-100

100

MAX4200/4205-13

OUTPUT IMPEDANCE (Ω)

MAX4203/MAX4204/MAX4205

HARMONIC DISTORTION vs. FREQUENCY

0

V

= 2Vp-p

OUT

THIRD HARMONIC

SECOND HARMONIC

100k 100M10M1M

FREQUENCY (Hz)

MAX4202/MAX4205

OUTPUT IMPEDANCE vs. FREQUENCY

10

100k 10M 100M1M 1G

FREQUENCY (Hz)

MAX4200/4205-11

OUTPUT IMPEDANCE (Ω)

MAX4200/4205-14

CROSSTALK (dB)

MAX4200/MAX4203

OUTPUT IMPEDANCE vs. FREQUENCY

100

10

1

100k 10M 100M1M 1G

FREQUENCY (Hz)

MAX4203/MAX4204/MAX4205

CROSSTALK vs. FREQUENCY

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

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

FREQUENCY (Hz)

MAX4200/4205-12

MAX4200/4205-15

INPUT VOLTAGE NOISE DENSITY

vs. FREQUENCY

100

10

VOLTAGE NOISE DENSITY (nV/√Hz)

1

1 10 100 1k 10k 100k 1M 10M

FREQUENCY (Hz)

MAX4200/4205-16

CURRENT NOISE DENSITY (pA/√Hz)

INPUT CURRENT NOISE DENSITY

vs. FREQUENCY

10

1.0

0.1
1 10 100 1k 10k 100k 1M 10M

FREQUENCY (Hz)

MAX4200/4205-17

DIFFERENTIAL GAIN AND PHASE

= 150Ω)

(R

1.5

1.0

0.5

DIFF GAIN (%)

0

-0.5
0 100

0.20

0.15

0.10

0.05

0

DIFF PHASE (deg)

-0.05
0 100

L

IRE

MAX4200/4205-18

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers

6 _______________________________________________________________________________________

_________________________________Typical Operating Characteristics (continued)

(VCC= +5V, VEE= -5V, RL= 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL= 150Ω for MAX4202/MAX4205, unless
otherwise noted.)

0

4

2

8

6

12

10

14

-5 -3 -2-4 -1012345

GAIN ERROR vs. INPUT VOLTAGE

MAX4200-19

INPUT VOLTAGE (V)

GAIN ERROR (%)

R

L

= 100Ω

R

L

= 150Ω

1

3

2

6

5

4

9

8

7

10

0 150 20050 100 250 300 350 400

OUTPUT VOLTAGE SWING vs.

EXTERNAL LOAD RESISTANCE

MAX4200-20

EXTERNAL LOAD RESISTANCE (Ω)

OUTPUT VOLTAGE SWING (V

p-p

)

MAX4200/4203

MAX4201/4204

MAX4202/4205

IN

VOLTAGE
50mV/div

OUT

GND

GND

TIME (5ns/div)

SMALL-SIGNAL PULSE RESPONSE

MAX4200-21

IN

VOLTAGE
50mV/div

OUT

GND

GND

TIME (5ns/div)

MAX4200/MAX4203

SMALL-SIGNAL PULSE RESPONSE

MAX4200-22

C

LOAD

= 15pF

IN

VOLTAGE
50mV/div

OUT

GND

GND

TIME (5ns/div)

MAX4201/MAX4202/MAX4204/MAX4205

SMALL-SIGNAL PULSE RESPONSE

MAX4200-23

C

LOAD

= 22pF

IN

VOLTAGE

1V/div

OUT

GND

GND

TIME (5ns/div)

LARGE-SIGNAL PULSE RESPONSE

MAX4200-24

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,

SOT23 Open-Loop Buffers

_______________________________________________________________________________________

7

_________________________________Typical Operating Characteristics (continued)

(VCC= +5V, VEE= -5V, RL= 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL= 150Ω for MAX4202/MAX4205, unless
otherwise noted.)

IN

VOLTAGE

1V/div

OUT

GND

GND

TIME (5ns/div)

MAX4200/MAX4203

LARGE-SIGNAL PULSE RESPONSE

MAX4200-25

C

LOAD

= 15pF

IN

VOLTAGE

1V/div

OUT

GND

GND

TIME (5ns/div)

MAX4201/MAX4202/MAX4204/MAX4205

LARGE-SIGNAL PULSE RESPONSE

MAX4200-26

C

LOAD

= 22pF

1.0

2.0

1.5

3.0

2.5

3.5

4.0

-40 10-15 35 60 85

SUPPLY CURRENT (PER BUFFER)

vs. TEMPERATURE

MAX4200-27

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

INPUT OFFSET VOLTAGE

vs. TEMPERATURE

5

4

3

2

1

0

-1

-2

INPUT OFFSET VOLTAGE (mV)

-3

-4

-5

-40 10-15 35 60 85
TEMPERATURE (°C)

MAX4200-28

INPUT BIAS CURRENT

vs. TEMPERATURE

5

4

3

2

1

0

-1

-2

INPUT BIAS CURRENT (µA)

-3

-4

-5

-40 10-15 35 60 85
TEMPERATURE (°C)

MAX4200-29

VOLTAGE SWING (Vp-p)

4.0

3.8

3.6

3.4

3.2

3.0

-40 10-15 35 60 85

MAX4200/MAX4203

OUTPUT VOLTAGE SWING

vs. TEMPERATURE

R

= 150Ω

L

R

= 100Ω

L

TEMPERATURE (°C)

MAX4200-30

_______________Detailed Description

The MAX4200–MAX4205 wide-band, open-loop buffers
feature high slew rates, high output current, low

2.1nV√Hz voltage-noise density, and excellent capaci­tive-load-driving capability. The MAX4200/MAX4203
are single/dual buffers with up to 660MHz bandwidth,
230MHz 0.1dB gain flatness, and a 4200V/µs slew rate.
The MAX4201/MAX4204 single/dual buffers with inte­grated 50Ω output termination resistors, up to 780MHz
bandwidth, 280MHz gain flatness, and a 4200V/µs slew
rate, are ideally suited for driving high-speed signals
over 50Ω cables. The MAX4202/MAX4205 provide
bandwidths up to 720MHz, 230MHz gain flatness,
4200V/µs slew rate, and integrated 75Ω output termina­tion resistors for driving 75Ω cables.

With an open-loop gain that is slightly less than +1V/V,
these devices do not have to be compensated with the
internal dominant pole (and its associated phase shift)
that is present in voltage-feedback devices. This fea­ture allows the MAX4200–MAX4205 to achieve a nearly
constant group delay time of 405ps over their full fre­quency range, making them well suited for a variety of
RF and IF signal-processing applications.

These buffers operate with ±5V supplies and consume
only 2.2mA of quiescent supply current per buffer while
providing up to ±90mA of output current drive capability.

__________Applications Information

Power Supplies

The MAX4200–MAX4205 operate with dual supplies
from ±4V to ±5.5V. Both VCCand VEEshould be
bypassed to the ground plane with a 0.1µF capacitor
located as close to the device pin as possible.

Layout Techniques

Maxim recommends using microstrip and stripline tech­niques to obtain full bandwidth. To ensure that the PC
board does not degrade the amplifier’s performance,
design it for a frequency greater than 6GHz. Pay care­ful attention to inputs and outputs to avoid large para­sitic capacitance. Whether or not you use a
constant-impedance board, observe the following
guidelines when designing the board:

• Do not use wire-wrap boards, because they are too

inductive.

• Do not use IC sockets, because they increase para-

sitic capacitance and inductance.

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers

8 _______________________________________________________________________________________

______________________________________________________________Pin Description

Not Internally ConnectedN.C.1 1, 2, 5, 8 —
Buffer InputIN3 3 —
Buffer 1 InputIN1— — 1
Buffer 1 OutputOUT1— — 2
Negative Power SupplyV

EE

2 4 —

Negative Power Supply for Buffer 1V

EE1

— — 3

Negative Power Supply for Buffer 2V

EE2

— — 4

Buffer 2 InputIN2— — 5
Buffer 2 OutputOUT2— — 6
Buffer OutputOUT5 6 —
Positive Power SupplyV

CC

4 7 —

Positive Power Supply for Buffer 2V

CC2

— — 7

Positive Power Supply for Buffer 1V

CC1

— — 8

NAME FUNCTION

SOT23-5 SO

SO/µMAX

MAX4200/MAX4201/MAX4202

PIN

MAX4203
MAX4204
MAX4205

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,

SOT23 Open-Loop Buffers

_______________________________________________________________________________________ 9

• Use surface-mount instead of through-hole compo-

nents for better high-frequency performance.

• Use a PC board with at least two layers; it should be

as free from voids as possible.

• Keep signal lines as short and as straight as possi-

ble. Do not make 90° turns; round all corners.

Input Impedance

The MAX4200–MAX4205 input impedance looks like a
500kΩ resistor in parallel with a 2pF capacitor. Since
these devices operate without negative feedback, there
is no loop gain to transform the input impedance
upward, as in closed-loop buffers. Inductive input
sources (such as an unterminated cable) may react
with the input capacitance and produce some peaking
in the buffer’s frequency response. This effect can usu­ally be minimized by using a properly terminated trans­mission line at the buffer input, as shown in Figure 1.

Output Current and Gain Sensitivity

The absence of negative feedback means that open­loop buffers have no loop gain to reduce their effective
output impedance. As a result, open-loop devices usu­ally suffer from decreasing gain as the output current is
decreased. The MAX4200–MAX4205 include local
feedback around the buffer’s class-AB output stage to
ensure low output impedance and reduce gain sensitiv­ity to load variations. This feedback also produces
demand-driven current bias to the output transistors for
±90mA (MAX4200/MAX4203) drive capability that is rel­atively independent of the output voltage (see

Typical

Operating Characteristics

).

Output Capacitive Loading and Stability

The MAX4200–MAX4205 provide maximum AC perfor­mance with no load capacitance. This is the case when
the load is a properly terminated transmission line.
However, these devices are designed to drive any load
capacitance without oscillating, but with reduced AC per­formance.

Since the MAX4200–MAX4205 operate in an open-loop
configuration, there is no negative feedback to be
transformed into positive feedback through phase shift
introduced by a capacitive load. Therefore, these
devices will not oscillate with capacitive loading, unlike
similar buffers operating in a closed-loop configuration.
However, a capacitive load reacting with the buffer’s
output impedance can still affect circuit performance. A
capacitive load will form a lowpass filter with the
buffer’s output resistance, thereby limiting system
bandwidth. With higher capacitive loads, bandwidth is
dominated by the RC network formed by RTand CL;

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

Another concern when driving capacitive loads results
from the amplifier’s output impedance, which looks
inductive at high frequency. This inductance forms an
L-C resonant circuit with the capacitive load and caus­es peaking in the buffer’s frequency response.

Figure 2 shows the frequency response of the
MAX4200/MAX4203 under different capacitive loads.
To settle out some of the peaking, the output requires
an isolation resistor like the one shown in Figure 3.
Figure 4 is a plot of the MAX4200/MAX4203 frequency
response with capacitive loading and a 10Ω isolation
resistor. In many applications, the output termination
resistors included in the MAX4201/MAX4202/
MAX4204/MAX4205 will serve this purpose, reducing
component count and board space. Figure 5 shows the
MAX4201/MAX4202/MAX4204/MAX4205 frequency
response with capacitive loads of 47pF, 68pF, and
120pF.

Coaxial Cable Drivers

Coaxial cable and other transmission lines are easily dri­ven when properly terminated at both ends with their
characteristic impedance. Driving back-terminated
transmission lines essentially eliminates the line’s
capacitance. The MAX4201/MAX4204, with their inte­grated 50Ω output termination resistors, are ideal for dri­ving 50Ω cables. The MAX4202/MAX4205 include
integrated 75Ω termination resistors for driving 75Ω
cables. Note that the output termination resistor forms a
voltage divider with the load resistance, thereby
decreasing the amplitude of the signal at the receiving
end of the cable by one half (see the

Typical Application

Circuit)

.

Figure 1. Using a Properly Terminated Input Source

50Ω COAX

SOURCE

R

L

50Ω

*MAX4201/4202/4204/4205 ONLY

R

*

T

MAX42_ _

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers

10 ______________________________________________________________________________________

Figure 2. MAX4200/MAX4203 Small-Signal Gain vs.
Frequency with Load Capacitance and No Isolation Resistor

Figure 3. Driving a Capacitive Load Through an Isolation
Resistor

Figure 4. MAX4200/MAX4203 Small-Signal Gain vs.
Frequency with Load Capacitance and 10

Ω

Isolation Resistor

Figure 5. MAX4201/MAX4202/MAX4204/MAX4205 Small­Signal Gain vs. Frequency with Capacitive Load and No
External Isolation Resistor

5

V

= 100mVp-p

4

3

2

1

0

GAIN (dB)

-1

-2

-3

-4

-5

OUT

CL = 220pF

100k 1M

FREQUENCY (Hz)

CL = 68pF

CL = 120pF

10M

CL = 47pF

100M 1G

MAX4200-FIG02

V

IN

MAX4200
MAX4203

R

ISO

V

OUT

C

L

5

R

= 10Ω

ISO

4

3

2

1

0

GAIN (dB)

-1

-2

-3

-4

-5

= 100mVp-p

V

OUT

100k 1M

CL = 120pF

10M

FREQUENCY (Hz)

MAX4200-FIG04

CL = 47pF

CL = 68pF

100M 1G

5

V

= 100mVp-p

OUT

4

3

2

1

0

GAIN (dB)

-1

-2

-3

-4

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

CL = 47pF

FREQUENCY (Hz)

CL = 68pF

CL = 120pF

MAX4200-FIG05

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,

SOT23 Open-Loop Buffers

______________________________________________________________________________________ 11

__________________________________________________________Pin Configurations

___________________Chip Information

TRANSISTOR COUNTS:

MAX4200/MAX4201/MAX4202: 33
MAX4203/MAX4204/MAX4205: 67

SUBSTRATE CONNECTED TO V

EE

TOP VIEW

1

2

3

4

MAX4203
MAX4204
MAX4205

*R

T

SO/µMAX

8

V

CC1

7

V

*R

CC2

T

6

OUT2

5

IN2V

MAX4200
MAX4201
MAX4202

1

N.C.

2

V

EE

3

IN

SOT23-5

N.C. = NOT INTERNALLY CONNECTED

MAX4200
MAX4201
MAX4202

5

OUT

*R

T

V

4

CC

N.C.

N.C.

V

1

2

3

IN

4

EE

8

N.C.

7

V

CC

*R

T

6

OUT

5

N.C.

IN1

OUT1

V

EE2

EE1

SO

= 0Ω (MAX4200/MAX4203)

* R

T

= 50Ω (MAX4201/MAX4204)

R

T

= 75Ω (MAX4202/MAX4205)

R

T

MAX4200–MAX4205

Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers

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.

12

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© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

________________________________________________________Package Information

SOT5L.EPS

8LUMAXD.EPS