MAXIM MAX4200ESA

19-1338; Rev 2; 4/99
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
____________________________Features
♦ 2.2mA Supply Current
________________________Applications
High-Speed DAC Buffers
Wireless LANs
♦ 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
_______________Ordering Information
TEMP. RANGE
PINPACKAGE
MAX4200ESA
-40°C to +85°C
8 SO
MAX4200EUK-T
-40°C to +85°C
5 SOT23-5
MAX4201ESA
-40°C to +85°C
8 SO
MAX4201EUK-T
-40°C to +85°C
5 SOT23-5
PART
TOP
MARK
—
AABZ
—
ABAA
—
MAX4202ESA
-40°C to +85°C
8 SO
Digital-Transmission Line Drivers
MAX4202EUK-T
-40°C to +85°C
5 SOT23-5
High-Speed ADC Input Buffers
MAX4203ESA
-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
—
MAX4205EUA
-40°C to +85°C
8 µMAX
—
IF/Communications Systems
___________________________Selector Guide
PART
INTERNAL
NO. OF
OUTPUT
BUFFERS TERMINATION
(Ω)
ABAB
PIN-PACKAGE
___________Typical Application Circuit
MAX4200
1
—
8 SO, 5 SOT23
MAX4201
1
50
8 SO, 5 SOT23
MAX4202
1
75
8 SO, 5 SOT23
MAX4203
2
—
8 SO/µMAX
MAX4204
2
50
8 SO/µMAX
MAX4205
2
75
8 SO/µMAX
Pin Configurations appear at end of data sheet.
RT*
50Ω
50Ω CABLE
IN
OUT
MAX4201
*RL = RT + REXT
REXT*
50Ω
COAXIAL CABLE DRIVER
________________________________________________________________ Maxim Integrated Products
1
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.
MAX4200–MAX4205
________________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.
MAX4200–MAX4205
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC to VEE)................................................+12V
Voltage on Any Pin to GND..............(VEE - 0.3V) to (VCC + 0.3V)
Output Short-Circuit Duration to GND........................Continuous
Continuous Power Dissipation (TA = +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
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.
DC ELECTRICAL CHARACTERISTICS
(VCC = +5V, VEE = -5V, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
Operating Supply Voltage
VS
Guaranteed by PSR test
Quiescent Supply Current
IS
Per buffer, VIN = 0V
Input Offset Voltage
Input Offset Voltage Drift
Input Resistance
Voltage Gain
Power-Supply Rejection
Output Resistance
Output Current
Short-Circuit Output
Current
2
MAX
UNITS
±5.5
V
2.2
4
mA
15
VOS
VIN = 0V
1
VIN = 0V
20
µV/°C
MAX4203/MAX4204/MAX4205
0.4
mV
IB
0.8
RIN
500
AV
PSR
ROUT
IOUT
ISC
-3.0V ≤
VOUT ≤
3.0V
10
0.9
0.96
1.1
MAX4201/MAX4204, REXT = 50Ω
0.42
0.50
0.58
MAX4202/MAX4205, REXT = 75Ω
0.41
0.50
0.59
55
72
VS = ±4V to ±5.5V
f = DC
RL = 30Ω
Sinking or sourcing
VOUT
MAX4200/MAX4203
8
MAX4201/MAX4204
50
MAX4202/MAX4205
75
MAX4200/MAX4203
±90
MAX4201/MAX4204
±52
MAX4202/MAX4205
±44
MAX4200/MAX4203
150
MAX4201/MAX4204
90
MAX4202/MAX4205
75
RL = 150Ω
±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
_______________________________________________________________________________________
mV
µA
kΩ
MAX4200/MAX4203, REXT = 150Ω
MAX4200/MAX4203
Output Voltage Swing
TYP
±4
TCVOS
Input Offset Voltage
Matching
Input Bias Current
MIN
V/V
dB
Ω
mA
mA
V
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
(VCC = +5V, VEE = -5V, RL = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL = 150Ω for MAX4202/MAX4205, TA = TMIN to
TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
-3dB Bandwidth
SYMBOL
BW(-3dB)
0.1dB Bandwidth
BW(0.1dB)
Full-Power Bandwidth
Slew Rate
FPBW
SR
CONDITIONS
VOUT ≤ 100mVRMS
VOUT ≤ 100mVRMS
VOUT ≤ 2Vp-p
MIN
660
MAX4201/MAX4202
780
MAX4203
530
MAX4204/MAX4205
720
MAX4200
220
MAX4201/MAX4202
280
MAX4203
130
MAX4204/MAX4205
230
MAX4200/MAX4201/MAX4202
490
MAX4203/MAX4204/MAX4205
310
VOUT = 2V step
Group Delay Time
Settling Time to 0.1%
tS
VOUT = 2V step
MAX4200/MAX4201/
MAX4202
Spurious-Free Dynamic
Range
SFDR
VOUT =
2Vp-p
MAX4203/MAX4204/
MAX4205
Harmonic Distortion
TYP
MAX4200
UNITS
MHz
MHz
MHz
4200
V/µs
405
ps
12
ns
f = 5MHz
-48
f = 20MHz
-45
f = 100MHz
-34
f = 5MHz
-47
f = 20MHz
-44
f = 100MHz
-32
MAX4200/MAX4201/
MAX4202, f = 500kHz,
VOUT = 2Vp-p
Second harmonic
-72
Third harmonic
-48
Total harmonic
-48
MAX4203/MAX4204/|
MAX4205, f = 500kHz,
VOUT = 2Vp-p
Second harmonic
-83
Third harmonic
-47
Total harmonic
-47
HD
MAX
dBc
dBc
Differential Gain Error
DG
NTSC, RL = 150Ω
1.3
%
Differential Phase Error
DP
NTSC, RL = 150Ω
0.15
degrees
Input Voltage Noise Density
en
f = 1MHz
2.1
nV/√Hz
Input Current Noise Density
in
f = 1MHz
0.8
pA/√Hz
2
pF
6
Ω
Input Capacitance
CIN
Output Impedance
ZOUT
f = 10MHz
XTALK
VOUT = 2Vp-p
VOUT = 2Vp-p
Amplifier Crosstalk
f = 10MHz
-87
f = 100MHz
-65
dB
_______________________________________________________________________________________
3
MAX4200–MAX4205
AC ELECTRICAL CHARACTERISTICS
__________________________________________Typical Operating Characteristics
(VCC = +5V, VEE = -5V, RL = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL = 150Ω for MAX4202/MAX4205, unless
otherwise noted.)
0
-1
-2
-3
2
0
-1
-2
-3
1
0
-1
-2
-3
-4
-4
-4
-5
-5
-6
100k
1M
10M
100M
1G
-6
100k
1M
10M
100M
1G
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
MAX4203
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4204/MAX4205
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4203/MAX4204/MAX4205
LARGE-SIGNAL GAIN vs. FREQUENCY
0
-1
-2
-3
1
0
-1
-2
-3
2
0
-1
-2
-3
-4
-4
-5
-5
-5
-6
1M
100M
10M
-6
100k
1G
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
GROUP DELAY vs. FREQUENCY
POWER-SUPPLY REJECTION
vs. FREQUENCY
3
-10
-20
-30
1
-40
PSR (dB)
2
0
7000
-50
5000
4000
-70
-3
-80
2000
-4
-90
1000
-5
-100
100M
FREQUENCY (Hz)
1G
10G
1G
6000
-2
10M
100M
8000
-60
1M
10M
SLEW RATE vs. OUTPUT VOLTAGE
-1
100k
1M
9000
SLEW RATE (V/µs)
4
100k
FREQUENCY (Hz)
0
MAX4200/25-07
5
10G
MAX4200/25-08
100k
VOUT = 2Vp-p
1
-4
-6
MAX4200/25-06
4
3
MAX4200/4205-09
1
VOUT = 100mVp-p
2
NORMALIZED GAIN (dB)
2
3
NORMALIZED GAIN (dB)
VOUT = 100mVp-p
MAX4200/25-05
4
MAX4200/25-04
4
3
NORMALIZED GAIN (dB)
1
VOUT = 2Vp-p
3
-5
-6
4
4
NORMALIZED GAIN (dB)
2
NORMALIZED GAIN (dB)
NORMALIZED GAIN (dB)
2
1
VOUT = 100mVp-p
3
MAX4200/MAX4201/MAX4202
LARGE-SIGNAL GAIN vs. FREQUENCY
MAX4200/25-02
VOUT = 100mVp-p
3
4
MAX4200/25-01
4
MAX4201/MAX4202
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4200/25-03
MAX4200
SMALL-SIGNAL GAIN vs. FREQUENCY
GROUP DELAY (ns)
MAX4200–MAX4205
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
3000
0
100k
1M
10M
100M
FREQUENCY (Hz)
1G
10G
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT VOLTAGE (Vp-p)
_______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
-30
-40
THIRD HARMONIC
-50
-60
-70
SECOND HARMONIC
-80
-30
-40
-60
-70
-90
-100
10M
10
-80
-100
1M
THIRD HARMONIC
-50
100
MAX4200/4205-12
-20
-90
100k
VOUT = 2Vp-p
MAX4200/MAX4203
OUTPUT IMPEDANCE vs. FREQUENCY
OUTPUT IMPEDANCE (Ω)
-20
0
-10
HARMONIC DISTORTION (dBc)
VIN = 2Vp-p
SECOND HARMONIC
1
100k
100M
1M
10M
100k
100M
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
MAX4201/MAX4204
OUTPUT IMPEDANCE vs. FREQUENCY
MAX4202/MAX4205
OUTPUT IMPEDANCE vs. FREQUENCY
MAX4203/MAX4204/MAX4205
CROSSTALK vs. FREQUENCY
0
1G
MAX4200/4205-15
100
MAX4200/4205-14
-10
-20
-30
CROSSTALK (dB)
OUTPUT IMPEDANCE (Ω)
MAX4200/4205-13
100
OUTPUT IMPEDANCE (Ω)
HARMONIC DISTORTION (dBc)
MAX4200/4205-10
0
-10
MAX4200/4205-11
MAX4203/MAX4204/MAX4205
HARMONIC DISTORTION vs. FREQUENCY
MAX4200/MAX4201/MAX4202
HARMONIC DISTORTION vs. FREQUENCY
-40
-50
-60
-70
-80
-90
10
100k
1M
10M
100M
1M
10M
100M
100k
1G
1M
10M
100M
1G
FREQUENCY (Hz)
INPUT VOLTAGE NOISE DENSITY
vs. FREQUENCY
INPUT CURRENT NOISE DENSITY
vs. FREQUENCY
DIFFERENTIAL GAIN AND PHASE
(RL = 150Ω)
1
10
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M
1.5
10G
MAX4200/4205-18
MAX4200/4205-17
1.0
0.5
0
-0.5
0
1.0
DIFF PHASE (deg)
CURRENT NOISE DENSITY (pA/√Hz)
10
10
DIFF GAIN (%)
FREQUENCY (Hz)
MAX4200/4205-16
VOLTAGE NOISE DENSITY (nV/√Hz)
100k
FREQUENCY (Hz)
100
1
-100
10
1G
100
0.20
0.15
0.10
0.05
0
-0.05
0.1
1
10
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M
0
100
IRE
_______________________________________________________________________________________
5
MAX4200–MAX4205
_________________________________Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, RL = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL = 150Ω for MAX4202/MAX4205, unless
otherwise noted.)
_________________________________Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, RL = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL = 150Ω for MAX4202/MAX4205, unless
otherwise noted.)
OUTPUT VOLTAGE SWING vs.
EXTERNAL LOAD RESISTANCE
GAIN ERROR vs. INPUT VOLTAGE
10
8
6
RL = 100Ω
4
MAX4200/4203
GND
OUT
GND
MAX4201/4204
7
6
VOLTAGE
50mV/div
5
4
MAX4202/4205
3
2
1
0
-5
-4
-3
-2
-1
0
1
2
3
4
0
5
50
100 150 200 250 300 350 400
MAX4200/MAX4203
SMALL-SIGNAL PULSE RESPONSE
MAX4201/MAX4202/MAX4204/MAX4205
SMALL-SIGNAL PULSE RESPONSE
MAX4200-22
IN
LARGE-SIGNAL PULSE RESPONSE
MAX4200-23
GND
VOLTAGE
50mV/div
IN
MAX4200-24
GND
VOLTAGE
50mV/div
OUT
GND
CLOAD = 15pF
TIME (5ns/div)
EXTERNAL LOAD RESISTANCE (Ω)
INPUT VOLTAGE (V)
IN
GND
OUT
GND
VOLTAGE
1V/div
OUT
GND
CLOAD = 22pF
TIME (5ns/div)
6
IN
8
RL = 150Ω
2
MAX4200-20
9
OUTPUT VOLTAGE SWING (Vp-p)
12
SMALL-SIGNAL PULSE RESPONSE
MAX4200-21
10
MAX4200-19
14
GAIN ERROR (%)
MAX4200–MAX4205
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
TIME (5ns/div)
TIME (5ns/div)
_______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
MAX4200-26
4.0
IN
VOLTAGE
1V/div
VOLTAGE
1V/div
OUT
OUT
GND
3.5
GND
GND
SUPPLY CURRENT (mA)
GND
MAX4200-27
MAX4200-25
IN
SUPPLY CURRENT (PER BUFFER)
vs. TEMPERATURE
MAX4201/MAX4202/MAX4204/MAX4205
LARGE-SIGNAL PULSE RESPONSE
MAX4200/MAX4203
LARGE-SIGNAL PULSE RESPONSE
3.0
2.5
2.0
1.5
CLOAD = 22pF
CLOAD = 15pF
1.0
-40
TIME (5ns/div)
TIME (5ns/div)
-15
10
35
60
85
TEMPERATURE (°C)
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
1
0
-1
-2
3
2
1
0
-1
-2
-3
-3
-4
-4
-5
-15
10
35
TEMPERATURE (°C)
60
85
RL = 100Ω
3.6
3.4
3.2
-5
-40
RL = 150Ω
3.8
VOLTAGE SWING (Vp-p)
2
MAX4200-30
4
INPUT BIAS CURRENT (µA)
3
4.0
MAX4200-29
4
INPUT OFFSET VOLTAGE (mV)
5
MAX4200-28
5
MAX4200/MAX4203
OUTPUT VOLTAGE SWING
vs. TEMPERATURE
INPUT BIAS CURRENT
vs. TEMPERATURE
3.0
-40
-15
10
35
TEMPERATURE (°C)
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
7
MAX4200–MAX4205
_________________________________Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, RL = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, RL = 150Ω for MAX4202/MAX4205, unless
otherwise noted.)
MAX4200–MAX4205
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
______________________________________________________________Pin Description
PIN
MAX4200/MAX4201/MAX4202
MAX4203
MAX4204
MAX4205
FUNCTION
SOT23-5
SO
1
1, 2, 5, 8
—
N.C.
3
3
—
IN
Buffer Input
—
—
1
IN1
Buffer 1 Input
—
—
2
OUT1
2
4
—
VEE
Negative Power Supply
—
—
3
VEE1
Negative Power Supply for Buffer 1
—
—
4
VEE2
Negative Power Supply for Buffer 2
—
—
5
IN2
Buffer 2 Input
—
—
6
OUT2
Buffer 2 Output
5
6
—
OUT
Buffer Output
4
7
—
VCC
Positive Power Supply
—
—
7
VCC2
Positive Power Supply for Buffer 2
—
—
8
VCC1
Positive Power Supply for Buffer 1
SO/µMAX
_______________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.
8
NAME
Not Internally Connected
Buffer 1 Output
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 V CC and V EE should 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 parasitic capacitance and inductance.
_______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
50Ω COAX
RT*
SOURCE
RL
50Ω
MAX42_ _
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 RT and CL;
*MAX4201/4202/4204/4205 ONLY
Figure 1. Using a Properly Terminated Input Source
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).
_______________________________________________________________________________________
9
MAX4200–MAX4205
• Use surface-mount instead of through-hole components 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 possible. Do not make 90° turns; round all corners.
5
4
VOUT = 100mVp-p
MAX4200-FIG02
MAX4200–MAX4205
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
CL = 47pF
CL = 68pF
3
GAIN (dB)
2
RISO
CL = 120pF
1
VIN
VOUT
0
CL
-1
MAX4200
MAX4203
-2
-3
CL = 220pF
-4
-5
100k
10M
1M
100M
1G
FREQUENCY (Hz)
RISO = 10Ω
VOUT = 100mVp-p
3
GAIN (dB)
2
CL = 68pF
0
-1
3
-1
-3
-3
-4
-5
10M
CL = 68pF
0
-4
1M
CL = 47pF
1
CL = 120pF
-2
CL = 120pF
100k
VOUT = 100mVp-p
2
CL = 47pF
1
-2
-5
100M
1G
FREQUENCY (Hz)
Figure 4. MAX4200/MAX4203 Small-Signal Gain vs.
Frequency with Load Capacitance and 10Ω Isolation Resistor
10
5
4
MAX4200-FIG05
4
GAIN (dB)
5
Figure 3. Driving a Capacitive Load Through an Isolation
Resistor
MAX4200-FIG04
Figure 2. MAX4200/MAX4203 Small-Signal Gain vs.
Frequency with Load Capacitance and No Isolation Resistor
100k
1M
10M
100M
1G
FREQUENCY (Hz)
Figure 5. MAX4201/MAX4202/MAX4204/MAX4205 SmallSignal Gain vs. Frequency with Capacitive Load and No
External Isolation Resistor
______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
TOP VIEW
N.C. 1
VEE 2
5
OUT
N.C. 1
N.C. 2
*RT
*RT
IN 3
IN 3
MAX4203
MAX4204
MAX4205
MAX4200
MAX4201
MAX4202
MAX4200
MAX4201
MAX4202
4
VCC
VEE 4
SO
SOT23-5
N.C. = NOT INTERNALLY CONNECTED
8
N.C.
IN1 1
7
VCC
OUT1 2
*RT
6
OUT
VEE1 3
5
N.C.
VEE2
*RT
4
8
VCC1
7
VCC2
6
OUT2
5
IN2
SO/µMAX
* RT = 0Ω (MAX4200/MAX4203)
RT = 50Ω (MAX4201/MAX4204)
RT = 75Ω (MAX4202/MAX4205)
___________________Chip Information
TRANSISTOR COUNTS:
MAX4200/MAX4201/MAX4202: 33
MAX4203/MAX4204/MAX4205: 67
SUBSTRATE CONNECTED TO VEE
______________________________________________________________________________________
11
MAX4200–MAX4205
__________________________________________________________Pin Configurations
SOT5L.EPS
________________________________________________________Package Information
8LUMAXD.EPS
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 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.