19-4757; Rev 3; 10/98
L
MANUA
ION KIT HEET
T
A
U
L
EVA
TA S
WS DA
FOLLO
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
The MAX4104/MAX4105/MAX4304/MAX4305 op amps
feature ultra-high speed, low noise, and low distortion in
a SOT23 package. The unity-gain-stable MAX4104
requires only 20mA of supply current while delivering
625MHz bandwidth and 400V/µs slew rate. The
MAX4304, compensated for gains of +2V/V or greater,
delivers a 730MHz bandwidth and a 1000V/µs slew
rate. The MAX4105 is compensated for a minimum gain
of +5V/V and delivers a 410MHz bandwidth and a
1400V/sec slew rate. The MAX4305 has +10V/V minimum gain compensation and delivers a 340MHz bandwidth and a 1400V/µs slew rate.
Low voltage noise density of 2.1nV/√Hz and -88dBc
spurious-free dynamic range make these devices ideal
for low-noise/low-distortion video and telecommunications applications. These op amps also feature a wide
output voltage swing of ±3.7V and ±70mA output currentdrive capability. For space-critical applications, they
are available in a miniature 5-pin SOT23 package.
Features
♦ Low 2.1nV/√Hz Voltage Noise Density
♦ Ultra-High 740MHz -3dB Bandwidth (MAX4304,
AVCL = 2V/V)
♦ 100MHz 0.1dB Gain Flatness (MAX4104/4105)
♦ 1400V/µs Slew Rate (MAX4105/4305)
♦ -88dBc SFDR (5MHz, RL = 100Ω) (MAX4104/4304)
♦ High Output Current Drive: ±70mA
♦ Low Differential Gain/Phase Error: 0.01%/0.01°
(MAX4104/4304)
♦ Low ±1mV Input Offset Voltage
♦ Available in Space-Saving 5-Pin SOT23 Package
Selector Guide
PART
________________________Applications
Video ADC Preamp
Pulse/RF Telecom Applications
Video Buffers and Cable Drivers
MINIMUM
BANDWIDTH
STABLE
(MHz)
GAIN (V/V)
PIN-PACKAGE
MAX4104
1
625
5-pin SOT23, 8-pin SO
MAX4304
MAX4105
MAX4305
2
5
10
740
410
340
5-pin SOT23, 8-pin SO
5-pin SOT23, 8-pin SO
5-pin SOT23, 8-pin SO
Ultrasound
Ordering Information
Active Filters
ADC Input Buffers
Typical Application Circuit
PART
TEMP. RANGE
PINPACKAGE
MAX4104ESA
-40°C to +85°C
8 SO
MAX4104EUK-T -40°C to +85°C
SOT
TOP MARK
—
5 SOT23-5
ACCO
Ordering Information continued at end of data sheet.
Pin Configurations
INPUT
MAX4304
8 to 16-BIT
HIGH-SPEED
ADC
TOP VIEW
OUT
1
5
VCC
MAX4104
MAX4105
MAX4304
MAX4305
VEE 2
330Ω
IN+ 3
330Ω
4
IN-
SOT23-5
ADC BUFFER WITH GAIN (AVCL = 2V/V)
Pin Configurations continued 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.
MAX4104/MAX4105/MAX4304/MAX4305
General Description
MAX4104/MAX4105/MAX4304/MAX4305
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC to VEE)................................................+12V
Voltage on Any Pin to Ground..........(VEE - 0.3V) to (VCC + 0.3V)
Short-Circuit Duration (VOUT to GND)........................Continuous
Continuous Power Dissipation (TA = +70°C)
5-pin SOT23 (derate 7.1mW/°C above +70°C)...........571mW
8-pin SO (derate 5.9mW/°C above +70°C).................471mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
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, VCM = 0, RL = 100kΩ, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Operating Supply Voltage
Range
Input Offset Voltage
Input Offset-Voltage Drift
Input Bias Current
SYMBOL
VCC/VEE
VOS
CONDITIONS
MIN
TYP
MAX
UNITS
±3.5
±5
±5.5
V
MAX4_0_ESA
1
6
MAX4_0_EUK
1
8
Guaranteed by PSRR test
VOUT = 0
TCVOS
2.5
mV
µV/°C
IB
32
70
Input Offset Current
IOS
0.5
5.0
Differential Input Resistance
RIN
-0.8V ≤ VIN ≤ 0.8V
Common-Mode Input
Resistance
RIN
Either input
Input Common-Mode Voltage
Range
VCM
Guaranteed by CMRR test
µA
µA
6
kΩ
1.5
MΩ
-2.8
+4.1
V
Common-Mode Rejection Ratio
CMRR
-2.8V ≤ VCM ≤ 4.1V
80
95
dB
Positive Power-Supply Rejection
Ratio
PSSR+
VCC = 3.5V to 5.5V
75
85
dB
Negative Power-Supply
Rejection Ratio
PSRR-
VEE = -3.5V to -5.5V
55
65
dB
55
65
Quiescent Supply Current
Open-Loop Gain
IS
AVOL
Output Voltage Swing
VOUT
Output Current Drive
IOUT
Short-Circuit Output Current
Open-Loop Output Impedance
2
ISC
ZOUT
VOUT = 0
-2.8V ≤ VOUT ≤ 2.8V, RL = 100Ω
20
RL = 100kΩ
±3.5 -3.7 to +3.8
RL = 100Ω
±3.0 -3.5 to +3.4
RL = 30Ω
±53
RL = short to ground
27
mA
dB
V
±70
mA
80
mA
9
Ω
_______________________________________________________________________________________
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
(VCC = +5V, VEE = -5V, VCM = 0, RL = 100Ω; AV = +1V/V for MAX4104, +2V/V for MAX4304, +5V/V for MAX4105, +10V/V for MAX4305;
TA = +25°C; unless otherwise noted.)
PARAMETER
-3dB Bandwidth
SYMBOL
BW(-3dB)
0.1dB Bandwidth
BW(0.1)
Full-Power Bandwidth
Slew Rate
FPBW
SR
Settling Time to 0.1%
Spurious-Free
Dynamic Range
tS
SFDR
CONDITIONS
VOUT = 100mVp-p
VOUT = 100mVp-p
VOUT = 2Vp-p
VOUT = 2Vp-p
TYP
MAX4104
625
MAX4304
740
MAX4105
410
MAX4305
340
MAX4104
100
MAX4304
60
MAX4105
80
MAX4305
70
MAX4104
115
MAX4304
285
MAX4105
370
MAX4305
320
MAX4104
400
MAX4304
1000
MAX4105
1400
MAX4305
1400
to 0.1%
20
to 0.01%
25
MAX4104/
MAX4304
fC = 5MHz
-88
fC = 20MHz
-67
MAX4105/
MAX4305
fC = 5MHz
-74
fC = 20MHz
-61
VOUT = 2Vp-p
VOUT = 2Vp-p
MIN
MAX4104/MAX4304
0.01
MAX4105/MAX4305
0.02
MAX4104/MAX4304
0.01
MAX4105/MAX4305
0.02
MAX
UNITS
MHz
MHz
MHz
V/µs
ns
dBc
Differential Gain Error
DG
NTSC, RL = 150Ω
Differential Phase Error
DP
NTSC, RL = 150Ω
Input Voltage Noise Density
en
f = 1MHz
2.1
nV/√Hz
Input Current Noise Density
in
f = 1MHz
3.1
pA/√Hz
ZOUT
f = 10MHz
1
Ω
Output Impedance
%
degrees
_______________________________________________________________________________________
3
MAX4104/MAX4105/MAX4304/MAX4305
AC ELECTRICAL CHARACTERISTICS
__________________________________________Typical Operating Characteristics
(VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.)
MAX4304
SMALL-SIGNAL GAIN
vs. FREQUENCY (AVCL = +2)
1
0
-1
-2
3
4
2
1
0
-1
-2
2
1
0
-1
-2
-3
-4
-4
-4
-5
-5
-5
100M
1G
100k
1M
10M
100M
1G
100k
MAX4304
GAIN FLATNESS
vs. FREQUENCY (AVCL = +2)
0.5
0.4
0.1
GAIN (dB)
1
-1
0.5
0
-0.1
0.3
0.2
0.1
0
-0.1
-2
-0.2
-3
-0.3
-4
-0.4
-0.4
-5
-0.5
-0.5
1M
10M
100M
1G
VOUT = 100mVp-p
0.4
NORMALIZED GAIN (dB)
0.3
0.2
0
VOUT = 100mVp-p
-0.2
-0.3
100k
1M
10M
100M
100k
1G
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
MAX4105
GAIN FLATNESS
vs. FREQUENCY (AVCL = +5)
MAX4305
GAIN FLATNESS
vs. FREQUENCY (AVCL = +10)
MAX4104
LARGE-SIGNAL GAIN
vs. FREQUENCY (AVCL = +1)
0.2
0.1
0
-0.1
VOUT = 100mVp-p
0.3
NORMALIZED GAIN (dB)
0.3
0.4
5
4
2
0.1
1
0
-0.1
0
-1
-0.2
-2
-0.3
-0.3
-3
-0.4
-0.4
-4
-0.5
-0.5
-5
-0.2
1M
10M
FREQUENCY (Hz)
100M
1G
100k
1M
10M
FREQUENCY (Hz)
100M
1G
VOUT = 2Vp-p
3
0.2
GAIN (dB)
VOUT = 100mVp-p
1G
MAX4104 TOC9
0.5
MAX4104 TOC 7
0.5
1G
MAX4104 TOC 6
MAX4104
GAIN FLATNESS
vs. FREQUENCY (AVCL = +1)
2
100k
100M
MAX4305
SMALL-SIGNAL GAIN
vs. FREQUENCY (AVCL = +10)
3
0.4
10M
FREQUENCY (Hz)
VOUT = 100mVp-p
100k
1M
FREQUENCY (Hz)
MAX4104 TOC 5
4
10M
-3
FREQUENCY (Hz)
MAX4104 TOC 4
5
1M
VOUT = 100mVp-p
3
-3
100k
NORMALIZED GAIN (dB)
5
MAX4104 TOC 8
GAIN (dB)
2
VOUT = 100mVp-p
4
NORMALIZED GAIN (dB)
3
4
5
NORMALIZED GAIN (dB)
VOUT = 100mVp-p
MAX4104 TOC 2
4
MAX4104 TOC01
5
MAX4105
SMALL-SIGNAL GAIN
vs. FREQUENCY (AVCL = +5)
MAX4104 TOC 3
MAX4104
SMALL-SIGNAL GAIN
vs. FREQUENCY (AVCL = +1)
NORMALIZED GAIN (dB)
MAX4104/MAX4105/MAX4304/MAX4305
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
100k
1M
10M
FREQUENCY (Hz)
_______________________________________________________________________________________
100M
1G
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
0
-1
-2
3
1
0
-1
-2
2
1
0
-1
-2
-3
-3
-4
-4
-4
-5
-5
-5
1M
10M
100M
1G
-3
100k
1M
10M
100M
1G
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
POSITIVE POWER-SUPPLY REJECTION
vs. FREQUENCY
NEGATIVE POWER-SUPPLY REJECTION
vs. FREQUENCY
COMMON-MODE REJECTION
vs. FREQUENCY
-40
-50
-60
-70
-80
0
-10
-20
-10
-30
-20
-40
-30
-50
-40
-60
-50
-70
-60
-80
-90
-70
-90
-100
-80
-100
100k
1M
10M
100M
1G
100k
1M
10M
100M
10k
1G
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
VOLTAGE NOISE DENSITY vs. FREQUENCY
(INPUT REFERRED)
CURRENT NOISE DENSITY vs. FREQUENCY
(INPUT REFERRED)
CLOSED-LOOP OUTPUT IMPEDANCE
vs. FREQUENCY
1
10
10
100
1k
10k 100k
FREQUENCY (Hz)
1M
10M
MAX4104 TOC-R
1G
100
10
1
0.1
1
1
1000
OUTPUT IMPEDANCE (Ω)
10
100
MAX4104 TOC-Q
MAX4104 TOC-P
100
1G
MAX4104 TOCO
10
CMR (dB)
-30
0
MAX4104 TOCN
-20
20
POWER-SUPPLY REJECTION (dB)
MAX4104 TOCM
0
-10
POWER-SUPPLY REJECTION (dB)
2
VOUT = 2Vp-p
4
NORMALIZED GAIN (dB)
1
100k
VOLTAGE NOISE DENSITY (nV/√Hz)
3
NORMALIZED GAIN (dB)
2
CURRENT NOISE DENSITY (pA/√Hz)
NORMALIZED GAIN (dB)
3
VOUT = 2Vp-p
4
5
MAX4104 TOC 11
VOUT = 2Vp-p
4
MAX4305
LARGE-SIGNAL GAIN
vs. FREQUENCY (AVCL = +10)
5
MAX4104 TOC10
5
MAX4105
LARGE-SIGNAL GAIN
vs. FREQUENCY (AVCL = +5)
MAX4104 TOC12
MAX4304
LARGE-SIGNAL GAIN
vs. FREQUENCY (AVCL = +2)
0.01
1
10
100
1k
10k 100k
FREQUENCY (Hz)
1M
10M
100k
1M
10M
100M
1G
FREQUENCY (Hz)
_______________________________________________________________________________________
5
MAX4104/MAX4105/MAX4304/MAX4305
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.)
-0.010
RL = 150Ω
RL = 150Ω
0
DIFF PHASE (deg)
0.015
RL = 150Ω
0.005
0.000
0
0.025
0.020
0.015
0.010
0.005
0.000
-0.005
100
RL = 150Ω
MAX4104 TOC-U
VOUT = 2Vp-p
-20
-30
-40
-50
-60
-70
2ND HARMONIC
-80
-90
3RD HARMONIC
-100
0
100
0
-10
100
100k
1M
10M
IRE
IRE
FREQUENCY (Hz)
MAX4105/MAX4305
HARMONIC DISTORTION vs. FREQUENCY
MAX4104/MAX4304
HARMONIC DISTORTION vs. LOAD
MAX4105/MAX4305
HARMONIC DISTORTION vs. LOAD
-40
-50
2ND HARMONIC
-60
3RD HARMONIC
-80
-30
-40
-50
-60
2ND HARMONIC
-70
3RD HARMONIC
-80
-40
-50
-60
-90
-100
-100
0 100 200 300 400 500 600 700 800 900 1k
0 100 200 300 400 500 600 700 800 900 1k
FREQUENCY (Hz)
LOAD (Ω)
LOAD (Ω)
MAX4104/MAX4304
HARMONIC DISTORTION
vs. OUTPUT SWING
MAX4105/MAX4305
HARMONIC DISTORTION
vs. OUTPUT SWING
100M
MAX4104 TOC-Y
0
f = 5MHz
-20
-30
-40
-50
-60
2ND HARMONIC
-70
3RD HARMONIC
-90
OUTPUT SWING vs. LOAD RESISTANCE
0
f = 5MHz
-10
-20
-30
-40
-50
2ND HARMONIC
-60
-70
-80
3RD HARMONIC
2.0
2.5
3.0
OUTPUT SWING (Vp-p)
3.5
4.0
6
5
4
3
1
-100
1.5
7
2
-90
-100
8
OUTPUT SWING (Vp-p)
10M
MAX4104 TOC-Z
1M
HARMONIC DISTORTION (dBc)
100k
1.0
3RD HARMONIC
-80
-100
0.5
2ND HARMONIC
-70
-90
-80
MAX4104 TOC-X
-30
-90
-10
f = 5MHz
VOUT = 2Vp-p
-20
MAX4104 TOCAA
-70
-20
100M
0
-10
HARMONIC DISTORTION (dBc)
-30
MAX4104 TOC-W
-20
f = 5MHz
VOUT = 2Vp-p
-10
HARMONIC DISTORTION (dBc)
VOUT = 2Vp-p
-10
0
MAX4104 TOC-V
0
DISTORTION (dBc)
0.00
100
-0.005
6
0.01
-0.01
0
0.010
0.02
HARMONIC DISTORTION (dBc)
-0.005
0.03
MAX4104/MAX4304
HARMONIC DISTORTION vs. FREQUENCY
MAX4104 TOC T
0.000
DIFF GAIN (%)
0.005
-0.015
DIFF PHASE (deg)
MAX4105/MAX4305
DIFFERENTIAL GAIN AND PHASE
MAX4104 TOC-S
DIFF GAIN (%)
MAX4104/MAX4304
DIFFERENTIAL GAIN AND PHASE
HARMONIC DISTORTION (dBc)
MAX4104/MAX4105/MAX4304/MAX4305
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
0.5
1.0
1.5
2.0
2.5
3.0
OUTPUT SWING (Vp-p)
3.5
4.0
0
50
100 150 200 250 300 350 400
LOAD RESISTANCE (Ω)
_______________________________________________________________________________________
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
INPUT OFFSET CURRENT
vs. TEMPERATURE
2
1
0
-1
MAX4104 TOC-DD
3
INPUT BIAS CURRENT (µA)
MAX4104 TOC-CC
35
34
33
32
31
-2
-3
-15
10
35
60
30
-40
85
-15
10
TEMPERATURE (°C)
35
60
85
-40
22
21
20
19
18
24
23
22
21
20
19
18
17
17
16
16
-15
10
35
60
3.6
3.5
RL = 100kΩ
3.2
9.5
10.0
10.5
11.0
-40
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
+50mV
-50mV
35
60
85
MAX4104 TOCJJ
IN
+25mV
GND
10
MAX4105
SMALL-SIGNAL PULSE RESPONSE
(AV = +5)
MAX4104 TOCII
MAX4104 TOCHH
-15
TEMPERATURE (°C)
MAX4304
SMALL-SIGNAL PULSE RESPONSE
(AV = +2)
MAX4104
SMALL-SIGNAL PULSE RESPONSE
(AV = +1)
IN
3.7
3.3
9.0
85
RL = 100kΩ
3.8
3.4
15
15
85
3.9
VOLTAGE SWING (V)
23
60
4.0
MAX4104 TOC-FF
24
35
POSITIVE OUTPUT VOLTAGE SWING
vs. TEMPERATURE
25
SUPPLY CURRENT (mA)
MAX4104 TOC-EE
25
10
TEMPERATURE (°C)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. TEMPERATURE
-40
-15
TEMPERATURE (°C)
MAX4104 TOC-GG
-40
SUPPLY CURRENT (mA)
INPUT BIAS CURRENT
vs. TEMPERATURE
4
INPUT OFFSET CURRENT (µA)
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
MAX4104 TOCBB
INPUT OFFSET VOLTAGE (mV)
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
IN
GND +10mV
-25mV
-10mV
+50mV
+50mV
GND
+50mV
GND
OUT
OUT
GND
OUT
GND
-50mV
-50mV
10ns/div
-50mV
10ns/div
10ns/div
_______________________________________________________________________________________
7
MAX4104/MAX4105/MAX4304/MAX4305
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.)
MAX4104/MAX4105/MAX4304/MAX4305
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.)
MAX4305
SMALL-SIGNAL PULSE RESPONSE
(AV = +10)
MAX4104
LARGE-SIGNAL PULSE RESPONSE
(AV = +1)
MAX4104 TOCKK
IN
+5mV
-5mV
MAX4104 TOCLL
+1V
GND
IN
GND
-1V
+50mV
+1V
OUT
OUT
GND
GND
-1V
-50mV
10ns/div
10ns/div
MAX4305
LARGE-SIGNAL PULSE RESPONSE
(AV = +2)
MAX4105
LARGE-SIGNAL PULSE RESPONSE
(AV = +5)
MAX4104 TOCNN
MAX4104 TOCMM
IN
+200mV
IN
+500mV
GND
GND
-200mV
-500mV
+1V
+1V
OUT
OUT
GND
GND
-1V
-1V
10ns/div
10ns/div
MAX4305
LARGE-SIGNAL PULSE RESPONSE
(AV = +10)
MAX4104 TOCOO
IN
+100mV
GND
-100mV
+1V
OUT
GND
-1V
10ns/div
8
_______________________________________________________________________________________
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
PIN
NAME
FUNCTION
1, 5, 8
N.C.
Not internally connected.
4
2
IN-
Amplifier Inverting Input
3
3
IN+
Amplifier Noninverting
Input
2
4
VEE
Negative Power Supply
1
6
OUT
Amplifier Output
5
7
VCC
Positive Power Supply
SOT23-5
SO
—
_______________Detailed Description
The MAX4104/MAX4105/MAX4304/MAX4305 are ultrahigh-speed, low-noise amplifiers featuring -3dB bandwidths up to 880MHz, 0.1dB gain flatness up to
100MHz, and low differential gain and phase errors of
0.01% and 0.01°, respectively. These devices operate
on dual power supplies ranging from ±3.5V to ±5.5V
and require only 20mA of supply current.
The MAX4104/MAX4304/MAX4105/MAX4305 are optimized for minimum closed-loop gains of +1V/V, +2V/V,
+5V/V and +10V/V (respectively) with corresponding
-3dB bandwidths of 880MHz, 730MHz, 430MHz, and
350MHz. Each device in this family features a low input
voltage noise density of only 2.1nV/√Hz (at 1MHz), an
output current drive of ±70mA, and spurious-free
dynamic range as low as -88dBc (5MHz, RL = 100Ω).
___________Applications Information
Layout and Power-Supply Bypassing
The MAX4104/MAX4105/MAX4304/MAX4305 have an
extremely high bandwidth, and consequently require
careful board layout, including the possible use of
constant-impedance microstrip or stripline techniques.
To realize the full AC performance of these high-speed
amplifiers, pay careful attention to power-supply
bypassing and board layout. The PC board should
have at least two layers: a signal and power layer on
one side, and a large, low-impedance ground plane on
the other side. The ground plane should be as free of
voids as possible. With multilayer boards, locate the
ground plane on a layer that incorporates no signal or
power traces.
Regardless of whether or not a constant-impedance
board is used, it is best to observe the following guidelines when designing the board:
1) Do not use wire-wrapped boards (they are much too
inductive) or breadboards (they are much too
capacitive).
2) Do not use IC sockets. IC sockets increase reactances.
3) Keep signal lines as short and straight as possible.
Do not make 90° turns; round all corners.
4) Observe high-frequency bypassing techniques to
maintain the amplifier’s accuracy and stability.
5) Bear in mind that, in general, surface-mount components have shorter bodies and lower parasitic reactance, resulting in greatly improved high-frequency
performance over through-hole components.
The bypass capacitors should include 1nF and 0.1µF
ceramic surface-mount capacitors between each supply pin and the ground plane, located as close to the
package as possible. Optionally, place a 10µF tantalum
capacitor at the power supply pins’ point of entry to the
PC board to ensure the integrity of incoming supplies.
The power-supply trace should lead directly from the
tantalum capacitor to the VCC and VEE pins. To minimize parasitic inductance, keep PC traces short and
use surface-mount components.
Input termination resistors and output back-termination
resistors, if used, should be surface-mount types, and
should be placed as close to the IC pins as possible.
DC and Noise Errors
The MAX4104/MAX4105/MAX4304/MAX4305 output
offset voltage, VOUT (Figure 1), can be calculated with
the following equation:
VOUT = [VOS + (IB+ x RS) + (IB- x (RF || RG))] [1 + RF / RG]
where:
VOS = input offset voltage (in volts)
1 + RF/RG = amplifier closed-loop gain (dimensionless)
IB+ = noninverting input bias current (in amps)
IB- = inverting input bias current (in amps)
RG = gain-setting resistor (in ohms)
RF = feedback resistor (in ohms)
RS = source resistor at noninverting input (in ohms)
The following equation represents output noise density:
R
en(OUT) = 1 + F
RG
(i
n x RS
)
2
(
)
2
2
+ in x RF || RG + en
_______________________________________________________________________________________
9
MAX4104/MAX4105/MAX4304/MAX4305
_____________________Pin Description
MAX4104/MAX4105/MAX4304/MAX4305
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
RG
RF
RG
RF
IN-
FB
IB-
OUT
OUT
VOUT
75Ω CABLE
IB+
RT
75Ω
IN+
IN
MAX4104
MAX4105
MAX4304
MAX4305
RS
75Ω CABLE
RL
75Ω
MAX4104
MAX4105
MAX4304
MAX4305
RT
75Ω
Figure 1. Output Offset Voltage
Figure 2. Video Line Driver
where:
in = input current noise density (in pA/√Hz)
en = input voltage noise density (in nV/√Hz)
very rapidly during the conversion cycle—a condition
that demands an amplifier with very low output impedance at high frequencies to maintain measurement
accuracy. The combination of high-speed, fast slew
rate, low noise, and low-distortion available in the
MAX4104/MAX4105/MAX4304/MAX4305 makes them
ideally suited for use as buffer amplifiers in high-speed
ADC applications.
The MAX4104/MAX4105/MAX4304/MAX4305 have a
very low, 2.1nV/√Hz input voltage noise density and
3.1pA/√Hz input current noise density.
An example of DC-error calculations, using the
MAX4304 typical data and the typical operating circuit
with RF = RG = 330Ω (RF || RG = 165Ω) and RS = 50Ω
gives:
[
]
VOUT = 32 x 10−6 50 + 32 x 10−6 165Ω + 1 x 10−3 1 + 1
( )
(
)
VOUT = 15.8mV
Calculating total output noise in a similar manner yields
the following:
Driving Capacitive Loads
en(OUT) =
[1+ 1]
2
2
3.1 x 10−12 x 50 + 3.1 x 10 −12 x 165 + 2.1 x 10 −9
2
en(OUT) = 4.3nV Hz
With a 200MHz system bandwidth, this calculates to
60.8µVRMS (approximately 365µVp-p, using the sixsigma calculation).
ADC Input Buffers
Input buffer amplifiers can be a source of significant
error in high-speed ADC applications. The input buffer
is usually required to rapidly charge and discharge the
ADC’s input, which is often capacitive. In addition, the
input impedance of a high-speed ADC often changes
10
Video Line Driver
The MAX4104/MAX4105/MAX4304/MAX4305 are optimized to drive coaxial transmission lines when the
cable is terminated at both ends, as shown in Figure 2.
To minimize reflections and maximize power transfer,
select the termination resistors to match the characteristic impedance of the transmission line. Cable frequency response can cause variations in the flatness of the
signal.
The MAX4104/MAX4105/MAX4304/MAX4305 provide
maximum AC performance when driving no output load
capacitance. This is the case when driving a correctly
terminated transmission line (i.e., a back-terminated
cable).
In most amplifier circuits, driving a large load capacitance increases the chance of oscillations occurring.
The amplifier’s output impedance and the load capacitor combine to add a pole and excess phase to the
loop response. If the pole’s frequency is low enough
and phase margin is degraded sufficiently, oscillations
may result.
A second concern when driving capacitive loads originates from the amplifier’s output impedance, which
______________________________________________________________________________________
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
25
25
CL = 15pF
GAIN (dB)
15
CL = 10pF
10
5
0
-5
CL = 5pF
CL = 15pF
20
NORMALIZED GAIN (dB)
20
15
CL = 10pF
10
5
0
-5
-10
-10
-15
-15
CL = 5pF
-20
-20
100k
1M
10M
100M
100k
1G
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 3a. MAX4104 Frequency Response with Capacitive
Load and No Isolation Resistor
Figure 3b. MAX4304 Frequency Response with Capacitive
Load and No Isolation Resistor
25
25
20
20
CL = 15pF
10
CL = 10pF
5
0
-5
CL = 5pF
-10
15
NORMALIZED GAIN (dB)
15
NORMALIZED GAIN (dB)
MAX4104/MAX4105/MAX4304/MAX4305
30
30
CL = 15pF
10
CL = 10pF
5
0
-5
-10
-15
-15
-20
-20
CL = 5pF
-25
-25
100k
1M
10M
100M
1G
FREQUENCY (Hz)
100k
1M
10M
100M
1G
FREQUENCY (Hz)
Figure 3c. MAX4105 Frequency Response with Capacitive
Load and No Isolation Resistor
Figure 3d. MAX4305 Frequency Response with Capacitive
Load and No Isolation Resistor
appears inductive at high frequencies. This inductance
forms an L-C resonant circuit with the capacitive load,
which causes peaking in the frequency response and
degrades the amplifier’s phase margin.
The MAX4104/MAX4105/MAX4304/MAX4305 drive
capacitive loads up to 10pF without oscillation.
However, some peaking may occur in the frequency
domain (Figure 3). To drive larger capacitance loads or
to reduce ringing, add an isolation resistor between the
amplifier’s output and the load (Figure 4).
The value of RISO depends on the circuit’s gain and the
capacitive load (Figure 5). Figure 6 shows the
MAX4104/MAX4105/MAX4304/MAX4305 frequency
response with the isolation resistor and a capacitive
load. With higher capacitive values, bandwidth is dominated by the RC network formed by RISO and CL; the
bandwidth of the amplifier itself is much higher. Also
note that the isolation resistor forms a divider that
decreases the voltage delivered to the load.
Maxim’s High-Speed Evaluation Boards
The MAX4104 evaluation kit manual shows a suggested layout for Maxim’s high-speed, single-amplifier evaluation boards. This board was developed using the
techniques described previously ( see Layout and
Power-Supply Bypassing section). The smallest available surface-mount resistors were used for the feedback and back-termination resistors to minimize the
______________________________________________________________________________________
11
4
RF
RG
3
2
CL = 47pF
1
GAIN (dB)
MAX4104
MAX4105
MAX4304
MAX4305
IN-
CL = 68pF
0
-1
-2
CL = 83pF
-3
RISO
OUT
-4
CL
IN+
-5
RL
MAX4104/MAX4304
RISO = 15Ω
-6
100k
1M
10M
100M
1G
FREQUENCY (Hz)
Figure 4. Using an Isolation Resistor (RISO) for High Capacitive
Loads
Figure 6. Frequency Responses vs. Capacitive Load with 15Ω
Isolation Resistor
distance from the IC to these resistors, thus reducing
the capacitance associated with longer lead lengths.
30
OPTIMAL ISLOATION RESISTOR (Ω)
MAX4104/MAX4105/MAX4304/MAX4305
740MHz, Low-Noise, Low-Distortion
Op Amps in SOT23-5
SMA connectors were used for best high-frequency
performance. Because distances are extremely short,
performance is unaffected by the fact that inputs and
outputs do not match a 50Ω line. However, in applications that require lead lengths greater than 1/4 of the
wavelength of the highest frequency of interest,
constant-impedance traces should be used.
Fully assembled evaluation boards are available for the
MAX4104 in an 8-pin SO package.
25
MAX4105/MAX4305
20
15
10
MAX4104/MAX4304
5
0
0
50
100
150
200
250
Ordering Information (continued)
CAPACITIVE LOAD (pF)
Figure 5. Optimal Isolation Resistor (RISO) vs. Capacitive
Load
Pin Configurations (continued)
TOP VIEW
N.C. 1
8
N.C.
IN- 2
7
VCC
IN+ 3
6
OUT
5
N.C.
VEE 4
MAX4104
MAX4105
MAX4304
MAX4305
PART
TEMP. RANGE
PINPACKAGE
SOT
TOP MARK
MAX4105ESA
MAX4105EUK-T
MAX4304ESA
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
8 SO
5 SOT23-5
8 SO
—
ACCP
—
MAX4304EUK-T
MAX4305ESA*
MAX4305EUK-T
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
5 SOT23-5
8 SO
5 SOT23-5
ACCQ
—
ACCR
*Future product—contact factory for availability.
Chip Information
TRANSISTOR COUNT: 44
SUBSTRATE CONNECTED TO VEE
SO
12
______________________________________________________________________________________
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