MAX4205ESA [MAXIM]
Ultra-High-Speed, Low-Noise, Low-Power, SOT23 Open-Loop Buffers; 超高速，低噪声，低功耗， SOT23封装的开环缓冲器
| 型号： | MAX4205ESA |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Ultra-High-Speed, Low-Noise, Low-Power, SOT23 Open-Loop Buffers |
| 文件： | 总12页 (文件大小：177K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
1±-1338; Rev 2; 4/±±
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
–MAX4205
________________General Description
____________________________Features
The MAX4200–MAX4205 are ultra-high-speed, open-
loop buffers featuring high slew rate, high output cur-
rent, low noise, and excellent capacitive-load-driving
capability. The MAX4200/MAX4201/MAX4202 are sin-
gle buffers, while the MAX4203/MAX4204/MAX4205 are
dual buffers. The MAX4201/MAX4204 have integrated
50Ω termination resistors, making them ideal for driv-
ing 50Ω transmission lines. The MAX4202/MAX4205
include 75Ω back-termination resistors for driv-
ing 75Ω transmission lines. The MAX4200/MAX4203
have no internal termination resistors.
♦ 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
The MAX4200–MAX4205 use a proprietary architecture
to achieve up to 780MHz -3dB bandwidth, 280MHz
0.1dB gain flatness, 4200V/µs slew rate, and ±±0mA
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-to-
digital converter (ADC) inputs or for data-communica-
tions applications.
♦ Available in Space-Saving SOT23 or µMAX
Packages
_______________Ordering Information
PIN-
PACKAGE
TOP
MARK
PART
TEMP. RANGE
MAX4200ESA
-40°C to +85°C 8 SO
—
AABZ
—
________________________Applications
High-Speed DAC Buffers
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
MAX4202ESA -40°C to +85°C 8 SO
MAX4202EUK-T -40°C to +85°C 5 SOT23-5
ABAA
—
Wireless LANs
Digital-Transmission Line Drivers
High-Speed ADC Input Buffers
IF/Communications Systems
ABAB
—
MAX4203ESA
MAX4203EUA
MAX4204ESA
MAX4204EUA
MAX4205ESA
MAX4205EUA
-40°C to +85°C 8 SO
-40°C to +85°C 8 µMAX
-40°C to +85°C 8 SO
-40°C to +85°C 8 µMAX
-40°C to +85°C 8 SO
-40°C to +85°C 8 µMAX
—
—
—
—
___________________________Selector Guide
—
INTERNAL
NO. OF
BUFFERS TERMINATION
OUTPUT
PART
PIN-PACKAGE
___________Typical Application Circuit
(Ω)
MAX4200
MAX4201
MAX4202
MAX4203
MAX4204
MAX4205
1
1
1
2
2
2
—
50
75
—
50
75
8 SO, 5 SOT23
8 SO, 5 SOT23
8 SO, 5 SOT23
8 SO/µMAX
R *
T
50Ω CABLE
50Ω
IN
OUT
R
*
EXT
50Ω
MAX4201
8 SO/µMAX
8 SO/µMAX
COAXIAL CABLE DRIVER
*R = R + R
EXT
L
T
Pin Configurations appear at end of data sheet.
________________________________________________________________ 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.
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
Voltage on Any Pin to GND..............(V - 0.3V) to (V
Output Short-Circuit Duration to GND........................Continuous
to V )................................................+12V
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
CC
EE
+ 0.3V)
EE
CC
Continuous Power Dissipation (T = +70°C)
A
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.±mW/°C above +70°C)...................471mW
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
(V
CC
= +5V, V = -5V, R = ∞, T = T
to T , unless otherwise noted. Typical values are at T = +25°C.)
MAX A
EE
L
A
MIN
PARAMETER
SYMBOL
CONDITIONS
Guaranteed by PSR test
Per buffer, V = 0V
MIN
TYP
MAX
±5.5
4
UNITS
V
Operating Supply Voltage
Quiescent Supply Current
Input Offset Voltage
V
S
±4
–MAX4205
I
S
2.2
1
mA
IN
V
OS
V
IN
IN
= 0V
= 0V
15
mV
Input Offset Voltage Drift
TCV
V
20
µV/°C
OS
Input Offset Voltage
Matching
MAX4203/MAX4204/MAX4205
0.4
mV
Input Bias Current
Input Resistance
I
0.8
500
0.±6
0.50
0.50
72
10
µA
B
R
kΩ
IN
MAX4200/MAX4203, R
= 150Ω
= 50Ω
= 75Ω
0.±
0.42
0.41
55
1.1
EXT
EXT
EXT
-3.0V ≤
Voltage Gain
A
V
OUT
≤
MAX4201/MAX4204, R
MAX4202/MAX4205, R
0.58
0.5±
V/V
dB
Ω
V
3.0V
Power-Supply Rejection
Output Resistance
PSR
V = ±4V to ±5.5V
S
MAX4200/MAX4203
MAX4201/MAX4204
MAX4202/MAX4205
MAX4200/MAX4203
MAX4201/MAX4204
MAX4202/MAX4205
MAX4200/MAX4203
MAX4201/MAX4204
MAX4202/MAX4205
8
R
f = DC
50
OUT
75
±±0
±52
±44
150
±0
Output Current
I
R = 30Ω
L
mA
mA
OUT
Short-Circuit Output
Current
I
Sinking or sourcing
MAX4200/MAX4203
SC
75
R = 150Ω
L
±3.3
±3.2
±3.8
±3.7
±3.3
±2.1
±2.3
R = 100Ω
L
Output Voltage Swing
V
R = 37.5Ω
L
V
OUT
MAX4201/MAX4204
MAX4202/MAX4205
R = 50Ω
±1.±
±2.0
L
R = 75Ω
L
2
_______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
–MAX4205
AC ELECTRICAL CHARACTERISTICS
(V
CC
= +5V, V = -5V, R = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, R = 150Ω for MAX4202/MAX4205, T = T
to
EE
L
L
A
MIN
T
MAX
, unless otherwise noted. Typical values are at T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MAX4200
MIN
TYP
660
780
530
720
220
280
130
230
4±0
310
4200
405
12
MAX
UNITS
MAX4201/MAX4202
MAX4203
-3dB Bandwidth
BW
V
V
≤ 100mV
MHz
(-3dB)
OUT
RMS
MAX4204/MAX4205
MAX4200
MAX4201/MAX4202
MAX4203
0.1dB Bandwidth
BW
≤ 100mV
≤ 2Vp-p
MHz
MHz
(0.1dB)
OUT
RMS
MAX4204/MAX4205
MAX4200/MAX4201/MAX4202
MAX4203/MAX4204/MAX4205
Full-Power Bandwidth
FPBW
SR
V
V
OUT
Slew Rate
= 2V step
= 2V step
V/µs
ps
OUT
Group Delay Time
Settling Time to 0.1%
t
S
V
OUT
ns
f = 5MHz
-48
-45
-34
-47
-44
-32
-72
-48
-48
-83
-47
-47
1.3
MAX4200/MAX4201/
MAX4202
f = 20MHz
f = 100MHz
f = 5MHz
Spurious-Free Dynamic
Range
V
=
OUT
SFDR
dBc
dBc
2Vp-p
MAX4203/MAX4204/
MAX4205
f = 20MHz
f = 100MHz
Second harmonic
MAX4200/MAX4201/
MAX4202, f = 500kHz,
Third harmonic
Total harmonic
Second harmonic
Third harmonic
Total harmonic
V
OUT
= 2Vp-p
Harmonic Distortion
HD
MAX4203/MAX4204/|
MAX4205, f = 500kHz,
V
OUT
= 2Vp-p
Differential Gain Error
DG
DP
NTSC, R = 150Ω
%
L
Differential Phase Error
Input Voltage Noise Density
NTSC, R = 150Ω
0.15
2.1
degrees
nV/√Hz
L
e
n
f = 1MHz
f = 1MHz
Input Current Noise Density
Input Capacitance
i
n
0.8
2
pA/√Hz
pF
C
IN
Output Impedance
Z
OUT
f = 10MHz
6
Ω
f = 10MHz
-87
-65
Amplifier Crosstalk
X
TALK
V
= 2Vp-p
dB
OUT
f = 100MHz
_______________________________________________________________________________________
3
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
__________________________________________Typical Operating Characteristics
(V
= +5V, V
= -5V, R = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, R = 150Ω for MAX4202/MAX4205, unless
EE L L
CC
otherwise noted.)
MAX4200
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4201/MAX4202
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4200/MAX4201/MAX4202
LARGE-SIGNAL GAIN vs. FREQUENCY
4
3
4
3
4
3
V
OUT
= 100mVp-p
V
OUT
= 100mVp-p
V
= 2Vp-p
OUT
2
1
2
1
2
1
0
0
0
-1
-2
-3
-4
-1
-2
-3
-4
-1
-2
-3
-4
-5
-6
-5
-6
-5
-6
1M
1M
100k
1M
10M
100M
1G
100k
10M
100M
1G
100k
10M
100M
1G
–MAX4205
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
MAX4204/MAX4205
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4203
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4203/MAX4204/MAX4205
LARGE-SIGNAL GAIN vs. FREQUENCY
4
3
4
3
4
3
V
OUT
= 100mVp-p
V
OUT
= 100mVp-p
V
OUT
= 2Vp-p
2
1
2
1
2
1
0
0
0
-1
-2
-3
-4
-1
-2
-3
-4
-1
-2
-3
-4
-5
-6
-5
-6
-5
-6
100k
1M
10M
100M
1G
10G
100M
100k
1M
10M
FREQUENCY (Hz)
1G
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
POWER-SUPPLY REJECTION
vs. FREQUENCY
SLEW RATE vs. OUTPUT VOLTAGE
GROUP DELAY vs. FREQUENCY
0
9000
8000
7000
6000
5000
4000
5
4
-10
-20
-30
-40
-50
-60
-70
-80
3
2
1
0
-1
-2
-3
3000
2000
1000
0
-90
-4
-5
-100
100k
1M
10M
100M
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)
100k
1M
10M
100M
1G
10G
FREQUENCY (Hz)
FREQUENCY (Hz)
4
_______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
–MAX4205
_________________________________Typical Operating Characteristics (continued)
(V
= +5V, V
= -5V, R = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, R = 150Ω for MAX4202/MAX4205, unless
EE L L
CC
otherwise noted.)
MAX4203/MAX4204/MAX4205
HARMONIC DISTORTION vs. FREQUENCY
MAX4200/MAX4203
OUTPUT IMPEDANCE vs. FREQUENCY
MAX4200/MAX4201/MAX4202
HARMONIC DISTORTION vs. FREQUENCY
0
100
0
V
= 2Vp-p
V
IN
= 2Vp-p
OUT
-10
-20
-30
-40
-50
-60
-70
-80
-90
-10
-20
-30
-40
-50
-60
-70
-80
-90
THIRD HARMONIC
THIRD HARMONIC
10
SECOND HARMONIC
1M
SECOND HARMONIC
1M
-100
1
-100
100k
10M
100M
100k
1M
10M
100M
1G
100k
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
MAX4201/MAX4204
OUTPUT IMPEDANCE vs. FREQUENCY
MAX4203/MAX4204/MAX4205
CROSSTALK vs. FREQUENCY
MAX4202/MAX4205
OUTPUT IMPEDANCE vs. FREQUENCY
100
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
100
10
-100
10
10
100k
1M
10M
100M
1G
100k
1M
10M
100M
1G
10G
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
DIFFERENTIAL GAIN AND PHASE
INPUT VOLTAGE NOISE DENSITY
vs. FREQUENCY
INPUT CURRENT NOISE DENSITY
vs. FREQUENCY
(R = 150Ω)
L
100
1.5
1.0
0.5
0
-0.5
0
100
10
1.0
0.1
0.20
0.15
0.10
0.05
0
1
-0.05
1
10 100
1k 10k 100k 1M 10M
FREQUENCY (Hz)
0
100
1
10 100
1k 10k 100k 1M 10M
FREQUENCY (Hz)
IRE
_______________________________________________________________________________________
5
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
_________________________________Typical Operating Characteristics (continued)
(V
= +5V, V
= -5V, R = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, R = 150Ω for MAX4202/MAX4205, unless
CC
EE
L
L
otherwise noted.)
OUTPUT VOLTAGE SWING vs.
EXTERNAL LOAD RESISTANCE
SMALL-SIGNAL PULSE RESPONSE
GAIN ERROR vs. INPUT VOLTAGE
MAX4200-21
10
9
14
12
10
8
MAX4200/4203
MAX4201/4204
IN
GND
GND
8
7
6
VOLTAGE
50mV/div
5
6
R = 100Ω
L
4
OUT
4
MAX4202/4205
3
R = 150Ω
L
2
2
1
0
–MAX4205
0
50 100 150 200 250 300 350 400
TIME (5ns/div)
-5 -4 -3 -2 -1
0
1
2
3
4
5
EXTERNAL LOAD RESISTANCE (Ω)
INPUT VOLTAGE (V)
MAX4200/MAX4203
SMALL-SIGNAL PULSE RESPONSE
MAX4201/MAX4202/MAX4204/MAX4205
SMALL-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
MAX4200-22
MAX4200-23
MAX4200-24
IN
GND
GND
IN
GND
GND
IN
GND
GND
VOLTAGE
50mV/div
VOLTAGE
50mV/div
VOLTAGE
1V/div
OUT
OUT
OUT
C
LOAD
= 15pF
C
LOAD
= 22pF
TIME (5ns/div)
TIME (5ns/div)
TIME (5ns/div)
6
_______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
–MAX4205
_________________________________Typical Operating Characteristics (continued)
(V
= +5V, V
= -5V, R = 100Ω for MAX4200/MAX4201/MAX4203/MAX4204, R = 150Ω for MAX4202/MAX4205, unless
EE L L
CC
otherwise noted.)
SUPPLY CURRENT (PER BUFFER)
vs. TEMPERATURE
MAX4201/MAX4202/MAX4204/MAX4205
MAX4200/MAX4203
LARGE-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
MAX4200-26
MAX4200-25
4.0
3.5
3.0
2.5
2.0
1.5
1.0
IN
GND
IN
GND
GND
VOLTAGE
1V/div
VOLTAGE
1V/div
OUT
GND
OUT
C
LOAD
= 22pF
C
LOAD
= 15pF
-40
-15
10
35
60
85
TIME (5ns/div)
TIME (5ns/div)
TEMPERATURE (°C)
MAX4200/MAX4203
OUTPUT VOLTAGE SWING
vs. TEMPERATURE
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
INPUT BIAS CURRENT
vs. TEMPERATURE
5
4
5
4
4.0
3.8
3.6
3.4
3.2
3.0
3
3
R = 150Ω
L
2
2
R = 100Ω
L
1
1
0
0
-1
-2
-3
-4
-5
-1
-2
-3
-4
-5
-40
-15
10
35
60
85
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
7
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
______________________________________________________________Pin Description
PIN
MAX4203
MAX4204
MAX4205
MAX4200/MAX4201/MAX4202
NAME
FUNCTION
SOT23-5
SO
SO/µMAX
1
3
1, 2, 5, 8
—
N.C.
IN
Not Internally Connected
3
—
1
Buffer Input
—
—
2
—
—
4
IN1
Buffer 1 Input
2
OUT1
Buffer 1 Output
—
3
V
EE
Negative Power Supply
Negative Power Supply for Buffer 1
Negative Power Supply for Buffer 2
Buffer 2 Input
—
—
—
—
5
—
—
—
—
6
V
EE1
V
EE2
4
–MAX4205
5
IN2
OUT2
OUT
6
Buffer 2 Output
—
—
7
Buffer Output
4
7
V
CC
Positive Power Supply
Positive Power Supply for Buffer 2
Positive Power Supply for Buffer 1
—
—
—
—
V
CC2
V
CC1
8
These buffers operate with ±5V supplies and consume
only 2.2mA of quiescent supply current per buffer while
providing up to ±±0mA of output current drive capability.
_______________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 capaci-
tive-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 inte-
grated 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 termina-
tion resistors for driving 75Ω cables.
__________Applications Information
Power Supplies
The MAX4200–MAX4205 operate with dual supplies
from ±4V to ±5.5V. Both V
and V
should be
EE
CC
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 tech-
niques 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 care-
ful attention to inputs and outputs to avoid large para-
sitic capacitance. Whether or not you use a
constant-impedance board, observe the following
guidelines when designing the board:
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 fea-
ture allows the MAX4200–MAX4205 to achieve a nearly
constant group delay time of 405ps over their full fre-
quency range, making them well suited for a variety of
RF and IF signal-processing applications.
• Do not use wire-wrap boards, because they are too
inductive.
• Do not use IC sockets, because they increase para-
sitic capacitance and inductance.
8
_______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
–MAX4205
• 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
50Ω COAX
R *
T
as free from voids as possible.
SOURCE
• Keep signal lines as short and as straight as possi-
R
50Ω
L
ble. Do not make ±0° turns; round all corners.
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 usu-
ally be minimized by using a properly terminated trans-
mission line at the buffer input, as shown in Figure 1.
*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.
Output Current and Gain Sensitivity
The absence of negative feedback means that open-
loop buffers have no loop gain to reduce their effective
output impedance. As a result, open-loop devices usu-
ally 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 sensitiv-
ity to load variations. This feedback also produces
demand-driven current bias to the output transistors for
±±0mA (MAX4200/MAX4203) drive capability that is rel-
atively independent of the output voltage (see Typical
Operating Characteristics).
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 caus-
es 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.
Output Capacitive Loading and Stability
The MAX4200–MAX4205 provide maximum AC perfor-
mance 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 per-
formance.
Coaxial Cable Drivers
Coaxial cable and other transmission lines are easily dri-
ven 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 inte-
grated 50Ω output termination resistors, are ideal for dri-
ving 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).
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 R and C ;
T
L
_______________________________________________________________________________________
9
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
5
V
OUT
= 100mVp-p
C = 47pF
L
4
C = 68pF
L
3
2
R
ISO
C = 120pF
L
1
V
V
OUT
IN
0
C
L
-1
-2
-3
MAX4200
MAX4203
C = 220pF
L
-4
-5
100k
1M
10M
100M
1G
FREQUENCY (Hz)
–MAX4205
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
5
5
R
V
= 10Ω
V
OUT
= 100mVp-p
ISO
4
4
= 100mVp-p
OUT
3
2
3
2
C = 47pF
L
C = 47pF
L
1
1
C = 68pF
L
C = 68pF
L
0
0
-1
-2
-3
-1
-2
-3
C = 120pF
L
C = 120pF
L
-4
-5
-4
-5
10M
100k
1M
100M
1G
100k
1M
10M
FREQUENCY (Hz)
100M
1G
FREQUENCY (Hz)
Figure 4. MAX4200/MAX4203 Small-Signal Gain vs.
Frequency with Load Capacitance and 10Ω Isolation Resistor
Figure 5. MAX4201/MAX4202/MAX4204/MAX4205 Small-
Signal Gain vs. Frequency with Capacitive Load and No
External Isolation Resistor
10 ______________________________________________________________________________________
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
–MAX4205
__________________________________________________________Pin Configurations
TOP VIEW
MAX4203
MAX4204
MAX4205
MAX4200
MAX4201
MAX4202
MAX4200
MAX4201
MAX4202
1
2
3
4
8
7
6
5
1
2
3
5
4
1
2
3
4
8
7
6
5
OUT
N.C.
V
V
N.C.
IN1
N.C.
N.C.
IN
CC1
CC2
OUT1
V
CC
*R
T
*R
T
*R
T
V
EE
*R
T
OUT
N.C.
V
EE1
OUT2
IN2
V
V
EE
EE2
IN
V
CC
SO/µMAX
SO
SOT23-5
* R = 0Ω (MAX4200/MAX4203)
T
R = 50Ω (MAX4201/MAX4204)
R = 75Ω (MAX4202/MAX4205)
T
T
N.C. = NOT INTERNALLY CONNECTED
___________________Chip Information
TRANSISTOR COUNTS:
MAX4200/MAX4201/MAX4202: 33
MAX4203/MAX4204/MAX4205: 67
SUBSTRATE CONNECTED TO V
EE
______________________________________________________________________________________ 11
Ultra-High-Speed, Low-Noise, Low-Power,
SOT23 Open-Loop Buffers
________________________________________________________Package Information
–MAX4205
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
© 1±±± Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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