MAXIM MAX4269ESD

19-1552; Rev 0; 10/99
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
Features
♦ +4.5V to +8.0V Single-Supply Operation
The MAX4265 single and MAX4268 dual unity-gain-stable
amplifiers have up to a 300MHz gain-bandwidth product.
The MAX4266 single and MAX4269 dual amplifiers have
up to a 350MHz bandwidth at a minimum stable gain of
+2V/V. The MAX4267 single and MAX4270 dual amplifiers
have a 200MHz bandwidth at a minimum stable gain of
+5V/V.
For additional power savings, these amplifiers feature a
low-power disable mode that reduces supply current to
1.6mA and places the outputs in a high-impedance state.
The MAX4265/MAX4266/MAX4267 are available in a
space-saving 8-pin µMAX package, and the MAX4268/
MAX4269/MAX4270 are available in a 16-pin QSOP package.
♦ Shutdown Mode Places Outputs in HighImpedance State
♦ Superior SFDR with 100Ω Load
-90dBc (fC = 5MHz )
-60dBc (fC = 100MHz)
♦ 35dBm IP3 (fC = 20MHz)
♦ 8nV/√Hz Voltage Noise Density
♦ 100MHz 0.1dB Gain Flatness (MAX4268)
♦ 900V/µs Slew Rate
♦ ±45mA Output Driving Capability
Ordering Information
PART
MAX4265EUA*
MAX4265ESA*
MAX4266EUA*
MAX4266ESA*
MAX4267EUA*
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 µMAX
8 SO
8 µMAX
8 SO
-40°C to +85°C
8 µMAX
MAX4267ESA*
-40°C to +85°C
8 SO
MAX4268EEE
-40°C to +85°C
16 QSOP
MAX4268ESD
MAX4269EEE
-40°C to +85°C
14 SO
-40°C to +85°C
16 QSOP
Base-Station Amplifiers
MAX4269ESD
-40°C to +85°C
14 SO
IF Amplifiers
MAX4270EEE
-40°C to +85°C
16 QSOP
High-Frequency ADC Drivers
MAX4270ESD
-40°C to +85°C
14 SO
Applications
*Future product—contact factory for availability.
High-Speed DAC Buffers
RF Telecom Applications
SFDR vs. Input Frequency
High-Frequency Signal Processing
-30
BANDWIDTH
(MHz)
SFDR (dBc)
PART
MIN GAIN
(V/V)
-50
-60
MAX4265
1
1
300
-70
MAX4266
1
2
350
-80
MAX4267
1
5
200
-90
MAX4268
2
1
300
MAX4269
2
2
350
MAX4270
2
5
200
VOUT = 1Vp-p
RL = 100Ω to VCC/2
-40
Selector Guide
NO. OF
OP AMPS
MAX4268/70 toc10
-20
Pin Configurations appear at end of data sheet.
-100
0.1M
MAX4270
MAX4269
MAX4268
1M
10M
100M
FREQUENCY (Hz)
________________________________________________________________ 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.
MAX4265–MAX4270
General Description
The MAX4265–MAX4270 single-supply, voltage-feedback
op amps are capable of driving a 100Ω load while maintaining ultra-low distortion over a wide bandwidth. They
offer superior spurious-free dynamic range (SFDR) performance: -90dBc or better at frequencies below 5MHz and
-60dBc at a 100MHz frequency. Additionally, input voltage
noise density is 8nV/√Hz while operating from a single
+4.5V to +8.0V supply or from dual ±2.25V to ±4.0V supplies. These features make the MAX4265–MAX4270 ideal
for use in high-performance communications and signalprocessing applications that require low distortion and
wide bandwidth.
MAX4265–MAX4270
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC to VEE)...............................................+8.5V
Voltage on Any Other Pin .................(VEE - 0.3V) to (VCC + 0.3V)
Short-Circuit Duration (VOUT to VCC or VEE) ..............Continuous
Continuous Power Dissipation (TA = +70°C)
16-Pin QSOP (derate 8.33mW/°C above +70°C)........667mW
8-Pin µMAX (derate 4.10mW/°C above +70°C) ..........330mW
8-Pin SO (derate 5.9mW/°C above +70°C).................471mW
14-Pin SO (derate 8.33mW/°C above +70°C).............667mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) .................................+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 = 0, RL = 100Ω to VCC/2, VCM = VCC/2, TA = TMIN to TMAX, typical values are at TA = +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
8.0
V
Operating Supply Voltage
Range
VCC
Inferred from PSRR test
4.5
Common-Mode Input Voltage
VCM
Inferred from CMRR test
VEE + 1.6
Input Offset Voltage
VOS
1
TCVOS
1.5
µV/°C
1
mV
Input Offset Voltage Drift
Input Offset Voltage Channel
Matching
Input Bias Current
Input Offset Current
MAX4268/MAX4269/MAX4270
VCC - 1.6
9
V
mV
IB
3.5
40
µA
IOS
0.1
5.5
µA
Common-Mode Input
Resistance
RINCM
Either input, (VEE + 1.6) ≤ VCM ≤ (VCC - 1.6)
Differential Input Resistance
RINDIFF
-10mV ≤ VIN ≤ 10mV
40
kΩ
Common-Mode Rejection Ratio
CMRR
(VEE + 1.6V) ≤ VCM ≤ (VCC - 1.6V), no load
60
85
dB
Power-Supply Rejection Ratio
PSRR
VCC = 4.5V to 8.0V
60
85
dB
60
Open-Loop Voltage Gain
AOL
1.75V ≤ VOUT ≤ 3.25V
Output Voltage Swing
VOUT
VCC - VOH, VOL - VEE
Output Current Drive
IOUT
RL = 20Ω
Output Short-Circuit Current
Closed-Loop Output Resistance
Power-Up Time
Quiescent Supply Current
Disable Output Leakage Current
ISC
1
Sinking or sourcing to VCC or VEE
ROUT
tPWRUP
IS
95
1.1
±30
VO = 1V step, 0.1% settling time
MΩ
dB
1.5
mA
100
mA
0.035
Ω
10
µs
Normal mode, EN_ = 5V or floating
28
32
Disable mode, EN_ = 0
1.6
5
VEN_ = 0, VEE ≤ VOUT ≤ VCC
0.2
5
VCC - 3.5
EN_ Logic Low Threshold
VCC - 1.5
EN_ Logic High Threshold
dB
±45
mA
µA
V
V
EN_ Logic Input Low Current
VEN_ = 0
5
100
µA
EN_ Logic Input High Current
VEN_ = 5V
1
30
µA
2
_______________________________________________________________________________________
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
(VCC = +5V, VEE = 0, RL = 100Ω to VCC/2, VCM = VCC/2, MAX4265/MAX4268 AV = +1V/V, MAX4266/MAX4269 AV = +2V/V,
MAX4267/MAX4270 AV = +5V/V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Small-Signal -3dB Bandwidth
Full-Power Bandwidth
0.1dB Gain Flatness
SYMBOL
BW-3dB
FPBW
BW0.1dB
All-Hostile Crosstalk
CONDITIONS
VOUT = 100mVp-p
VOUT = 1Vp-p
VOUT = 100mVp-p
MIN
TYP
MAX4265/MAX4268
300
MAX4266/MAX4269
350
MAX4267/MAX4270
200
MAX4265/MAX4268
175
MAX4266/MAX4269
200
MAX4267/MAX4270
200
MAX4265/MAX4268
100
MAX4266/MAX4269
35
MAX4267/MAX4270
35
MAX
UNITS
MHz
MHz
MHz
f = 10MHz
85
dB
SR
VOUT = 1V step
900
V/µs
Rise/Fall Times
tR, tF
VOUT = 1V step
Settling Time (0.1%)
tS,0.1
VOUT = 1V step
Slew Rate
Spurious-Free Dynamic
Range
Second Harmonic
Distortion
Third Harmonic
Distortion
SFDR
VOUT = 1Vp-p
(MAX4269)
VOUT = 1Vp-p
(MAX4269)
VOUT = 1Vp-p
(MAX4269)
1
ns
VOUT = 1V step
15
ns
fC = 1MHz
88
fC = 5MHz
90
fC = 10MHz
87
fC = 20MHz
78
fC = 60MHz
68
fC = 100MHz
60
fC = 1MHz
88
fC = 5MHz
90
fC = 10MHz
87
fC = 20MHz
78
fC = 60MHz
68
fC = 100MHz
60
fC = 1MHz
96
fC = 5MHz
95
fC = 10MHz
92
fC = 20MHz
86
fC = 60MHz
72
fC = 100MHz
68
dBc
dBc
dBc
_______________________________________________________________________________________
3
MAX4265–MAX4270
AC ELECTRICAL CHARACTERISTICS
AC ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V, VEE = 0, RL = 100Ω to VCC/2, VCM = VCC/2, MAX4265/MAX4268 AV = +1V/V, MAX4266/MAX4269 AV = +2V/V,
MAX4267/MAX4270 AV = +5V/V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
Two-Tone, Third-Order
Intercept Distortion
CONDITIONS
MIN
TYP
VOUT = 1Vp-p, fCA = 20MHz,
fCB = 21.25MHz (MAX4269)
IP3
Input -1dB Compression Point
fC = 20MHz
MAX
UNITS
35
dBm
12
dBm
DG
NTSC, f = 3.58MHz, RL = 150Ω to VCC/2
0.015
%
Differential Phase
DP
NTSC, f = 3.58MHz, RL = 150Ω to VCC/2
0.03
degrees
Input Capacitance
CIN
2
pF
Output Impedance
ROUT
1
Ω
Differential Gain
f = 10MHz
Disabled Output Capacitance
VEN_ = 0
5
pF
Enable Time
tEN
VIN = 1V
100
ns
Disable Time
tDIS
VIN = 1V
750
µs
No sustained
oscillation
Capacitive Load Stability
MAX4265/MAX4268
15
MAX4266/MAX4269
15
MAX4267/MAX4270
22
pF
Input Voltage Noise Density
en
f = 1kHz
8
nV/√Hz
Input Current Noise Density
in
f = 1kHz
1
pA/√Hz
Typical Operating Characteristics
(VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C,
unless otherwise noted.)
LARGE-SIGNAL GAIN
vs. FREQUENCY
2
GAIN (dB)
MAX4269
-2
-3
0.3
0.2
MAX4268
1
0
-1
VOUT = 1Vp-p
2
MAX4268
1
0.1
0
-1
MAX4269
-2
MAX4270
-0.2
-0.3
-0.4
-5
-5
-0.5
-6
-6
0.1M
1M
10M
FREQUENCY (Hz)
100M
1G
MAX4269
-0.1
-4
MAX4270
MAX4268
0
-3
-4
4
3
MAX4268/70 toc3
VOUT = 100mVp-p
GAIN FLATNESS vs. FREQUENCY
0.4
GAIN (dB)
3
4
MAX4268/70 toc01a
4
MAX4268/70 toc02a
SMALL-SIGNAL BANDWIDTH
GAIN (dB)
MAX4265–MAX4270
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
MAX4270
-0.6
0.1M
1M
10M
FREQUENCY (Hz)
100M
1G
0.1M
1M
10M
FREQUENCY (Hz)
_______________________________________________________________________________________
100M
1G
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
-30
-40
DISTORTION (dBc)
-40
VOUT = 1Vp-p
-50
-60
-70
-70
2ND HARMONIC
-90
3RD HARMONIC
-90
VOUT = 1Vp-p
-30
-40
2ND HARMONIC
10M
1M
100M
-90
0.1M
10M
1M
3RD HARMONIC
-100
0.1M
100M
10M
1M
100M
MAX4268
DISTORTION vs. LOAD
MAX4269
DISTORTION vs. LOAD
MAX4270
DISTORTION vs. LOAD
-70
-80
-60
-70
-90
3RD HARMONIC
-100
200
300
400
500
600
-50
-60
-70
2ND HARMONIC
-80
-90
3RD HARMONIC
-100
100
MAX4268/70 toc09
-40
2ND HARMONIC
-80
2ND HARMONIC
-90
-50
fO = 5MHz
VOUT = 1Vp-p
-30
DISTORTION (dBc)
-40
DISTORTION (dBc)
-60
fO = 5MHz
VOUT = 1Vp-p
-30
-20
MAX4268/70 toc08
-20
MAX4268/70 toc07
-50
3RD HARMONIC
-100
0
100
200
300
400
500
600
0
100
200
300
400
500
RESISTIVE LOAD (Ω)
RESISTIVE LOAD (Ω)
MAX4268
DISTORTION vs. VOLTAGE SWING
MAX4269
DISTORTION vs. VOLTAGE SWING
MAX4270
DISTORTION vs. VOLTAGE SWING
-40
-60
-70
2ND HARMONIC
-80
-50
-60
-70
2ND HARMONIC
-80
-90
-100
1.0
1.5
VOLTAGE SWING (Vp-p)
2.0
2.5
-50
-60
-70
2ND HARMONIC
-90
3RD HARMONIC
-100
-100
0.5
-40
-80
3RD HARMONIC
-90
3RD HARMONIC
fO = 5MHz
-30
DISTORTION (dBc)
-50
fO = 5MHz
-30
DISTORTION (dBc)
-40
-20
MAX4268/70 toc11
-20
MAX4268/70 toc10
fO = 5MHz
600
MAX4268/70 toc12
RESISTIVE LOAD (Ω)
-30
0
2ND HARMONIC
FREQUENCY (Hz)
-40
-20
-70
FREQUENCY (Hz)
fO = 5MHz
VOUT = 1Vp-p
0
-60
FREQUENCY (Hz)
-20
-30
-50
-80
3RD HARMONIC
-100
0.1M
DISTORTION (dBc)
-60
-80
-100
DISTORTION (dBc)
-50
-80
-20
DISTORTION (dBc)
-30
MAX4270
DISTORTION vs. FREQUENCY
MAX4268/70 toc05
VOUT = 1Vp-p
DISTORTION (dBc)
-20
MAX4268/70 toc04
-20
MAX4269
DISTORTION vs. FREQUENCY
MAX4268/70 toc06
MAX4268
DISTORTION vs. FREQUENCY
0
0.5
1.0
1.5
VOLTAGE SWING (Vp-p)
2.0
2.5
0
0.5
1.0
1.5
2.0
2.5
VOLTAGE SWING (Vp-p)
_______________________________________________________________________________________
5
MAX4265–MAX4270
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C,
unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C,
unless otherwise noted.)
SPURIOUS-FREE DYNAMIC RANGE
vs. FREQUENCY
-30
-50
-60
MAX4270
-70
50
MAX4269
-80
MAX4268
MAX4269
55
INTERCEPT (dBm)
-40
SFDR (dBc)
MAX4270
0.01
60
MAX4268/70 toc14
VOUT = 1Vp-p
10M
1M
10M
1M
100M
0.1M
FREQUENCY (Hz)
VOLTAGE NOISE vs. FREQUENCY
OUTPUT IMPEDANCE vs. FREQUENCY
MAX4268/MAX4269/MAX4290
CROSSTALK vs. FREQUENCY
10
1
100
1k
10k 100k
1M
0.01
0.1M
10M
FREQUENCY (Hz)
IRE
10M
100M
10
0.1M
1G
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
MAX4269
DIFFERENTIAL GAIN AND PHASE
MAX4270
DIFFERENTIAL GAIN AND PHASE
0.020
0.010
0.000
-0.010
-0.020
-0.030
100
-80
-120
1M
MAX4268/70 toc20
DIFF GAIN (%)
MAX4268/70 toc19
MAX4268
DIFFERENTIAL GAIN AND PHASE
0.020
0.015
0.010
0.005
0.000
-0.005
-60
IRE
MAX4268/70 toc21
10
-40
-100
DIFF GAIN (%)
1
MAX4268/70 toc18
-20
CROSSTALK (dB)
100
100M
0
MAX4268/70 toc17
MAX4268/70 toc16
1000
0.1
DIFF GAIN (%)
10M
1M
FREQUENCY (Hz)
10
10
MAX4268
FREQUENCY (Hz)
100
1
MAX4270
35
20
0.1M
100M
40
25
MAX4268
-100
0.001
0.1M
MAX4269
45
30
-90
OUTPUT IMPEDANCE (Ω)
THD + NOISE (%)
VOUT = 1Vp-p
VOLTAGE NOISE (nV/√Hz)
-20
MAX4268/70 toc13
0.1
TWO-TONE THIRD-ORDER
INTERCEPT vs. FREQUENCY
MAX4268/70 toc15
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
0.006
0.004
0.002
0.000
-0.002
-0.004
-0.006
100
10
IRE
100
10
IRE
100
0.010
10
RL = 150Ω
6
IRE
100
0.012
0.008
0.004
0.000
-0.004
-0.008
DIFF PHASE (°)
0.04
0.03
0.02
0.01
0.00
-0.01
DIFF PHASE (°)
DIFF PHASE (°)
MAX4265–MAX4270
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
10
RL = 150Ω
IRE
100
0.000
-0.010
-0.020
-0.030
RL = 150Ω
_______________________________________________________________________________________
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
-10
-20
CMRR (dB)
-30
-40
-50
-60
-40
-50
-60
-70
3.5
3.0
2.5
2.0
1.5
-70
-90
-80
0.5
-100
-90
0
1M
10M
100M
10k
1G
100k
1M
10M
100M
1.0
1G
VOL
0
200
400
FREQUENCY (Hz)
FREQUENCY (Hz)
800
1000
SHUTDOWN/ENABLE RESPONSE
MAX4268/70 toc26
MAX4268/70 toc25
INPUT TO
SHUTDOWN
5V
VCC
2.5V/div
600
LOAD (Ω)
POWER-UP/POWER-DOWN RESPONSE
0V
5V
OUTPUT
500mV/div
0V
OUTPUT
500mV/div
ENABLED
SHUT
DOWN
5µs/div
250ns/div
INPUT OFFSET VOLTAGE
vs. SUPPLY VOLTAGE
INPUT BIAS CURRENT
vs. SUPPLY VOLTAGE
-1.00
-1.05
-1.10
MAX4268/70 toc28
-0.95
-5.0
-4.5
INPUT BIAS CURRENT (µA)
-0.90
MAX4268/70 toc27
0.1M
VOH
4.0
-80
INPUT OFFSET VOLTAGE (mV)
PSRR (dB)
-30
4.5
OUTPUT VOLTAGE SWING (V)
-20
5.0
MAX14268/70 toc23
0
MAX4268/70 toc22
0
-10
OUTPUT VOLTAGE SWING
vs. RESISTIVE LOAD
MAX4268/70 toc24
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-1.15
-0.5
-1.20
-0
4.5
5.0
5.5
6.0
6.5
7.0
SUPPLY VOLTAGE (V)
7.5
8.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
7
MAX4265–MAX4270
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C,
unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C,
unless otherwise noted.)
SUPPLY CURRENT (PER AMPLIFIER)
vs. SUPPLY VOLTAGE
32
31
30
29
28
27
4
26
3
2
1
0
-1
-2
-3
-4
25
-5
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
-50 -35 -20 -5
10
25
40
55
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
INPUT BIAS CURRENT vs. TEMPERATURE
INPUT OFFSET CURRENT
vs. TEMPERATURE
3
2
1
85
70
85
MAX4268/70 toc32
4
70
500
400
INPUT OFFSET CURRENT (nA)
MAX4268/70 toc31
5
INPUT BIAS CURRENT (µA)
MAX4268/70 toc30
33
5
INPUT OFFSET VOLTAGE (mV)
34
SUPPLY CURRENT (mA)
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
MAX4268/70 toc29
35
300
200
100
0
-100
-200
-300
-400
-500
0
10
25
40
55
70
-50 -35 -20 -5
85
10
25
40
55
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY CURRENT (PER AMPLIFIER)
vs. TEMPERATURE
VOLTAGE SWING vs. TEMPERATURE
5
MAX4268/70 toc33
35
34
4
VOLTAGE SWING (V)
33
32
31
30
29
28
VOH
3
2
1
27
MAX4268/70 toc34
-50 -35 -20 -5
SUPPLY CURRENT (mA)
MAX4265–MAX4270
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
VOL
26
0
25
-50 -35 -20 -5
10
25
40
TEMPERATURE (°C)
8
55
70
85
-50 -35 -20 -5
10
25
40
55
TEMPERATURE (°C)
_______________________________________________________________________________________
70
85
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
MAX4269
SMALL-SIGNAL PULSE RESPONSE
MAX4268/70 toc35
MAX4268/70 toc36
MAX4268
SMALL-SIGNAL PULSE RESPONSE
INPUT
50mV/div
INPUT
25mV/div
OUTPUT
50mV/div
OUTPUT
50mV/div
5ns/div
MAX4270
SMALL-SIGNAL PULSE RESPONSE
MAX4268
LARGE-SIGNAL PULSE RESPONSE
MAX4268/70 toc37
MAX4268/70 toc38
5ns/div
INPUT
10mV/div
INPUT
500mV/div
OUTPUT
50mV/div
OUTPUT
500mV/div
5ns/div
MAX4269
LARGE-SIGNAL PULSE RESPONSE
MAX4270
LARGE-SIGNAL PULSE RESPONSE
MAX4268/70 toc39
MAX4268/70 toc40
5ns/div
INPUT
250mV/div
INPUT
100mV/div
OUTPUT
500mV/div
OUTPUT
500mV/div
5ns/div
5ns/div
_______________________________________________________________________________________
9
MAX4265–MAX4270
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C,
unless otherwise noted.)
MAX4265–MAX4270
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
Pin Description
PIN
MAX4265
MAX4266
MAX4267
MAX4268
MAX4269
MAX4270
NAME
FUNCTION
8 µMAX/SO
14 SO
16 QSOP
FUNCTION
1
—
—
EN
Enable Input. Active high. Connect to VCC for normal operation.
—
4, 5
4, 5
ENA, ENB
Enable Input. Active high. Connect to VCC for normal operation.
2
—
—
IN-
Inverting Input
—
2, 9
2, 11
INA-, INB-
Inverting Input
3
—
—
IN+
Noninverting Input
—
3, 10
3, 12
INA+, INB+
Noninverting Input
4, 5
6, 7
6, 7
VEE
Negative Power Supply
6
—
—
OUT
Amplifier Output
—
1, 8
1, 10
OUTA, OUTB
Amplifier Output
7, 8
13, 14
15, 16
VCC
Positive Power Supply. Connect to a +4.5V to +8.0V supply and
bypass with a 0.1µF capacitor for single-supply operation.
—
11, 12
8, 9, 13, 14
N.C.
No Connection. Not internally connected.
_______________Detailed Description
The MAX4265–MAX4270 single-supply operational
amplifiers feature ultra-low distortion and wide bandwidth. Their low distortion and low noise make them
ideal for driving high-speed analog-to-digital converters
(ADCs) up to 16 bits in telecommunications applications and high-performance signal processing.
These devices can drive loads as low as 100Ω and
deliver 45mA while maintaining DC accuracy and AC
performance. The input common-mode voltage ranges
from (V EE + 1.6V) to (V CC - 1.6V), while the output
swings to within 1.1V of the rails.
Low Distortion
The MAX4265–MAX4270 use proprietary bipolar technology to achieve minimum distortion in single-supply
systems—a feature typically available only in dual-supply op amps.
Several factors can affect the noise and distortion that a
device contributes to the input signal. The following
guidelines explain how various design choices impact
the total harmonic distortion (THD).
10
• Choose the proper feedback-resistor and gain-resistor values for the application. In general, the smaller
the closed-loop gain, the smaller the THD generated—especially when driving heavy resistive loads.
Large-value feedback resistors can significantly
improve distortion. The MAX4265–MAX4270’s THD
normally increases at approximately 20dB per
decade at frequencies above 1MHz; this is a lower
rate than that of comparable dual-supply op amps.
• Operating the device near or above the full-power
bandwidth significantly degrades distortion (see the
Total Harmonic Distortion vs. Frequency graph in the
Typical Operating Characteristics).
• The decompensated devices (MAX4266/MAX4267/
MAX4269/MAX4270) deliver the best distortion performance since they have a slightly higher slew rate
and provide a higher amount of loop gain for a given
closed-loop gain setting.
______________________________________________________________________________________
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
Driving Capacitive Loads
Unity-Gain Configurations
The MAX4265 and MAX4268 are internally compensated for unity gain. When configured for unity gain, they
require a small resistor (RF) in series with the feedback
path (Figure 1). This resistor improves AC response by
reducing the Q of the tank circuit, which is formed by
parasitic feedback inductance and capacitance.
The MAX4265–MAX4270 are not designed to drive
highly reactive loads; stability is maintained with loads
up to 15pF with less than 2dB peaking in the frequency
response. To drive higher capacitive loads, place a
small isolation resistor in series between the amplifier’s
output and the capacitive load (Figure 1). This resistor
improves the amplifier’s phase margin by isolating the
capacitor from the op amp’s output.
To ensure a load capacitance that limits peaking to less
than 2dB, select a resistance value from Figure 2. For
example, if the capacitive load is 100pF, the corresponding isolation resistor is 6Ω (MAX4269). Figures 3
and 4 show the peaking that occurs in the frequency
response with and without an isolation resistor.
Inverting and Noninverting Configurations
The values of the gain-setting feedback and input resistors are important design considerations. Large resistor
values will increase voltage noise and interact with the
amplifier’s input and PC board capacitance to generate
undesirable poles and zeros, which can decrease
bandwidth or cause oscillations. For example, a noninverting gain of +2V/V (Figure 1) using RF = RG = 1kΩ
combined with 2pF of input capacitance and 0.5pF of
board capacitance will cause a feedback pole at
128MHz. If this pole is within the anticipated amplifier
bandwidth, it will jeopardize stability. Reducing the 1kΩ
resistors to 100Ω extends the pole frequency to
1.28GHz, but could limit output swing by adding 200Ω
in parallel with the amplifier’s load. Clearly, the selection of resistor values must be tailored to the specific
application.
Distortion Considerations
The MAX4265–MAX4270 are ultra-low-distortion, highbandwidth op amps. Output distortion will degrade as
the total load resistance seen by the amplifier decreases. To minimize distortion, keep the input and gain-setting resistor values relatively large. A 500Ω feedback
resistor combined with an appropriate input resistor to
set the gain will provide excellent AC performance without significantly increasing distortion.
Noise Considerations
The amplifier’s input-referred noise-voltage density is
dominated by flicker noise at lower frequencies and by
thermal noise at higher frequencies. Because the thermal noise contribution is affected by the parallel combination of the feedback resistive network, those resistor
values should be reduced in cases where the system
bandwidth is large and thermal noise is dominant. This
noise-contribution factor decreases, however, with
increasing gain settings. For example, the input noise
voltage density at the op amp input with a gain of
+10V/V using R F = 100kΩ and R G = 11kΩ is e n =
18nV/√Hz. The input noise can be reduced to 8nV/√Hz
by choosing RF = 1kΩ, RG = 110Ω.
Coaxial cable and other transmission lines are easily
driven when terminated at both ends with their characteristic impedance. When driving back-terminated
transmission lines, the capacitive load of the transmission line is essentially eliminated.
ADC Input Buffer
Input buffer amplifiers can be a source of significant
errors in high-speed ADC applications. The input buffer
is usually required to rapidly charge and discharge the
ADC’s input, which is often capacitive (see Driving
Capacitive Loads). In addition, since a high-speed
ADC’s input impedance often changes very rapidly during the conversion cycle, measurement accuracy must
RG
RF
RS*
VIN
CL
MAX4265
MAX4266
MAX4267
PART
RF (Ω)
RG (Ω)
GAIN (V/V)
MAX4265
MAX4266
24
500
∞
500
1
2
MAX4267
500
125
5
RL
*OPTIONAL, USED TO MINIMIZE PEAKING FOR CL > 15pF.
Figure 1. Noninverting Configuration
______________________________________________________________________________________
11
MAX4265–MAX4270
Choosing Resistor Values
Low-Power Disable Mode
The MAX4265–MAX4270 feature an active-high enable
pin that can be used to save power and place the outputs in a high-impedance state. Drive EN_ with logic
levels or connect EN_ to VCC for normal operation. In
the dual versions (MAX4268/MAX4269/MAX4270),
each individual op amp is enabled separately, allowing
the devices to be used in a multiplex configuration. The
supply current in low-power mode is reduced to 1.6mA
per device. Enable time is typically 100ns, and disable
time is typically 750µs.
15
MAX4268
0
0
40
4
3
CL = 5.1pF
80
100
120
CL = 7.3pF
2
GAIN (dB)
1
0
CL = 7.3pF
CL = 5.1pF
1
0
-1
CL = 2.2pF
-2
CL = 2.2pF
-3
-4
-4
-5
-5
0.1M
1M
10M
100M
0.1M
1G
1M
Figure 3a. MAX4268 Small-Signal Gain vs. Frequency
Without Isolation Resistor
5
3
4
3
CL = 15pF
2
0
1
GAIN (dB)
1
-1
-2
CL = 10pF
-3
CL = 7.3pF
100M
1G
Figure 3b. MAX4269 Small-Signal Gain vs. Frequency
Without Isolation Resistor
4
2
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
CL = 10pF
RISO = 12Ω
CL = 10pF
RISO = 15Ω
0
CL = 10pF
RISO = 18Ω
-1
-2
-4
-3
-5
-4
-5
-6
0.1M
1M
10M
100M
1G
FREQUENCY (Hz)
Figure 3c. MAX4270 Small-Signal Gain vs. Frequency
Without Isolation Resistor
12
60
Figure 2. MAX4268/MAX4269/MAX4270 Isolation Resistance
vs. Capacitive Load
3
-3
20
CLOAD (pF)
5
-2
MAX4270
5
4
-1
MAX4269
10
5
2
GAIN (dB)
20
RISO (Ω)
be maintained using an amplifier with very low output
impedance at high frequencies. The combination of
high speed, fast slew rate, low noise, and a low and
stable distortion over load makes the MAX4265–
MAX4270 ideally suited for use as buffer amplifiers in
high-speed ADC applications.
GAIN (dB)
MAX4265–MAX4270
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
0.1M
1M
10M
100M
1G
FREQUENCY (Hz)
Figure 4a. MAX4268 Small-Signal Gain vs. Frequency
With Isolation Resistor
______________________________________________________________________________________
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
4
4
3
3
CL = 10pF
RISO = 12Ω
CL = 10pF
RISO = 15Ω
1
0
-1
CL = 10pF
RISO = 18Ω
-2
CL = 22pF
RISO = 3.9Ω
1
GAIN (dB)
GAIN (dB)
2
CL = 22pF
RISO = 22Ω
2
0
-1
CL = 22pF
RISO = 6Ω
-2
-3
-3
-4
-4
-5
-5
-6
0.1M
1M
10M
100M
1G
FREQUENCY (Hz)
Figure 4b. MAX4269 Small-Signal Gain vs. Frequency With
Isolation Resistor
Power Supplies and Layout
The MAX4265–MAX4270 operate from a single +4.5V
to +8.0V power supply or from dual ±2.25V to ±4.0V
supplies. For single-supply operation, bypass each
power-supply input with a 0.1µF ceramic capacitor
placed close to the VCC pins, and an additional 10µF to
VEE. When operating from dual supplies, bypass each
supply to ground.
0.1M
1M
10M
100M
1G
FREQUENCY (Hz)
Figure 4c. MAX4270 Small-Signal Gain vs. Frequency With
Isolation Resistor
Chip Information
TRANSISTOR COUNT: MAX4265/66/67: 132
MAX4268/69/70: 285
Good layout improves performance by decreasing the
amount of stray capacitance and noise at the op amp’s
inputs and output. To decrease stray capacitance, minimize PC board trace lengths and resistor leads, and
place external components close to the op amp’s pins.
______________________________________________________________________________________
13
MAX4265–MAX4270
5
MAX4265–MAX4270
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
Pin Configurations
TOP VIEW
EN 1
8
IN- 2
IN+
3
7
MAX4265
MAX4266
MAX4267
VEE 4
µMAX/SO
14
VCC
VCC
OUTA 1
16 VCC
OUTA 1
14 VCC
INA- 2
15 VCC
INA-
2
13 VCC
INA+ 3
14 N.C.
INA+
3
12 N.C.
ENA 4
ENB 5
6
OUT
5
VEE
MAX4268
MAX4269
MAX4270
11 N.C.
10 INB+
VEE 6
9
INB-
VEE 7
8
OUTB
SO
ENA 4
ENB 5
MAX4268
MAX4269
MAX4270
13 N.C.
12 INB+
VEE 6
11 INB-
VEE 7
10 OUTB
N.C. 8
9
QSOP
______________________________________________________________________________________
N.C.
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
8LUMAXD.EPS
SOICN.EPS
______________________________________________________________________________________
15
MAX4265–MAX4270
Package Information
Ultra-Low-Distortion, Single-Supply,
300MHz Op Amps with Enable
QSOP.EPS
MAX4265–MAX4270
Package Information (continued)
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.
16 ____________________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.