MAXIM MAX4014, MAX4017, MAX4019, MAX4022 Technical data

_______________General Description
The MAX4014/MAX4017/MAX4019/MAX4022 are preci­sion, closed-loop, gain of +2 (or -1) buffers featuring high slew rates, high output current drive, and low dif­ferential gain and phase errors. These single-supply devices operate from +3.15V to +11V, or from ±1.575V to ±5.5V dual supplies. The input voltage range extends 100mV beyond the negative supply rail and the outputs swing Rail-to-Rail®.
These devices require only 5.5mA of quiescent supply current while achieving a 200MHz -3dB bandwidth and a 600V/µs slew rate. In addition, the MAX4019 has a disable feature that reduces the supply current to 400µA. Input voltage noise for these parts is only 10nV/Hz and input current noise is only 1.3pA/Hz. This buffer family is ideal for low-power/low-voltage applications that require wide bandwidth, such as video, communications, and instrumentation systems. For space-sensitive applications, the MAX4014 comes in a tiny 5-pin SOT23 package.
________________________Applications
Portable/Battery-Powered Instruments
Video Line Driver
Analog-to-Digital Converter Interface
CCD Imaging Systems
Video Routing and Switching Systems
____________________________Features
Internal Precision Resistors for Closed-Loop
Gains of +2 or -1
High Speed:
200MHz -3dB Bandwidth 30MHz 0.1dB Gain Flatness (6MHz min) 600V/µs Slew Rate
Single 3.3V/5.0V Operation
Outputs Swing Rail-to-Rail
Input Voltage Range Extends Beyond V
EE
Low Differential Gain/Phase: 0.04%/0.02°
Low Distortion at 5MHz:
-78dBc Spurious-Free Dynamic Range
-75dB Total Harmonic Distortion
High Output Drive: ±120mA
Low, 5.5mA Supply Current
400µA Shutdown Supply Current
Space-Saving SOT23-5, µMAX, or QSOP Packages
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2
Buffers with Rail-to-Rail Outputs in SOT23
__________Typical Operating Circuit
19-1284; Rev 2; 8/01
______________Ordering Information
PART
NO. OF
AMPS
ENABLE PIN-PACKAGE
MAX4014 1 No 5-Pin SOT23
MAX4017 2 No 8-Pin SO/µMAX
MAX4019 3 Yes
14-Pin SO, 16-Pin QSOP
MAX4022 4 No
14-Pin SO, 16-Pin QSOP
_____________________Selector Guide
PART
SOT
TOP MARK
MAX4014EUK
ABZQ
TEMP. RANGE
PIN-
PACKAGE
-40°C to +85°C 5 SOT23-5
MAX4017ESA
-40°C to +85°C 8 SO
MAX4017EUA -40°C to +85°C 8 µMAX
MAX4019ESD
-40°C to +85°C 14 SO
MAX4019EEE -40°C to +85°C 16 QSOP
MAX4022ESD
MAX4022EEE
-40°C to +85°C 14 SO
-40°C to +85°C 16 QSOP
Rail-to-Rail is a registered trademark of Nippon Motorola Ltd.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
IN+
75
500
IN-
MAX4014
500
GAIN OF +2 VIDEO/RF CABLE DRIVER
75
V
OUT
mA
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2 Buffers with Rail-to-Rail Outputs in SOT23
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(VCC= +5V, VEE= 0V, IN_- =0V, EN_ = 5V, RL= to ground, V
OUT
= VCC/ 2, noninverting configuration, TA= T
MIN
to T
MAX
, unless
otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
Supply Voltage (V
CC
to VEE)..................................................12V
IN_-, IN_+, OUT_, EN_ ....................(V
EE
- 0.3V) to (VCC+ 0.3V)
Output Short-Circuit Duration to V
CC
or VEE..............Continuous
Continuous Power Dissipation (T
A
= +70°C)
5-pin SOT23 (derate 7.1mW/°C above+70°C)..............571mW
8-pin SO (derate 5.9mW/°C above +70°C)...................471mW
8-pin µMAX (derate 4.1mW/°C above +70°C) ..............330mW
14-pin SO (derate 8.3mW/°C above +70°C).................667mW
16-pin QSOP (derate 8.3mW/°C above +70°C)............667mW
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 at 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.
VEN_ Logic-High Threshold V
IH
MAX4019 VCC- 1.5
VEN_ Logic-Low Threshold V
IL
MAX4019 VCC- 2.6
kDisabled Output Resistance R
OUT(OFF)
MAX4019, EN_ = 0V, 0V ≤ V
OUT
5V 1
VOperating Supply-Voltage Range VCCto V
EE
3.15 11.0
dB
Power-Supply Rejection Ratio (Note 3)
PSRR
VCC= 5V, VEE= 0V, V
OUT
= 2V 46 57
Output Current I
OUT
±70 ±120
mA
RL= 20to VCCor V
EE
Output Resistance R
OUT
25
m
f = DC
Short-Circuit Output Current I
SC
±150 mASinking or sourcing
VEE- 0.1 VCC+ 0.1IN_-
VOL- V
EE
VCC- V
OH
VOL- V
EE
VCC- V
OH
VOL- V
EE
VCC- V
OH
0.06
0.06
RL= 2k
0.04 0.50
0.75 1.50
RL=150
0.04 0.50
Output Voltage Swing V
OUT
V
1.60 2.00
RL= 50
PARAMETER SYMBOL MIN TYP MAX UNITS
Input Resistance R
IN
3
M
Input Bias Current I
B
5.4 20 µA
Input Offset Voltage Matching ±1 mV
Voltage Gain A
V
1.9 2 2.1 V/V
Input Offset Voltage
Input Voltage Range V
IN
VEE- 0.1 VCC- 2.25
V
V
OS
420mV
Input Offset Voltage Drift TC
VOS
8 µV/°C
CONDITIONS
IN_+, over input voltage range
IN_+ (Note 2)
Any channels for MAX4017/MAX4019/MAX4022
RL≥ 50Ω, (VEE+ 0.5V) ≤ V
OUT
(VCC- 2.0V)
IN_+
RL= 50
µAEN_ Logic Input Low Current I
IL
0.5
VCC= 5V, VEE= -5V, V
OUT
= 0V 54 66
VCC= 3.3V, VEE= 0V, V
OUT
= 0.9V 45
MAX4019
(VEE+ 0.2V) EN_ ≤ V
CC
200 550EN_ = V
EE
µAEN_ Logic Input High Current I
IH
0.5 10MAX4019, EN_ = V
CC
mA
Quiescent Supply Current (per Buffer)
I
CC
5.5 8.0Enabled (EN_ = V
CC)
0.4 0.7MAX4019, disabled (EN_ = VEE)
±60
TA= +25°C
TA= T
MIN
to T
MAX
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2
Buffers with Rail-to-Rail Outputs in SOT23
_______________________________________________________________________________________ 3
Note 1: The MAX4014EUK is 100% production tested at TA= +25°C. Specifications over temperature limits are guaranteed by
design.
Note 2: Tested with V
OUT
= +2.5V.
Note 3: PSRR for single +5V supply tested with V
EE
= 0V, VCC= +4.5V to +5.5V; for dual ±5V supply with VEE= -4.5V to -5.5V,
V
CC
= +4.5V to +5.5V; and for single +3V supply with VEE= 0V, VCC= +3.15V to +3.45V.
Note 4: Guaranteed by design.
AC ELECTRICAL CHARACTERISTICS
(VCC= +5V, VEE= 0V, IN_- = 0V, EN_ = 5V, RL= 100to ground, noninverting configuration, TA= T
MIN
to T
MAX,
unless
otherwise noted. Typical values are at T
A
= +25°C.)
V
OUT
= 20mVp-p
MAX4017/MAX4019/MAX4022, f = 10MHz, V
OU
T
= 2Vp-p
dB-95X
TALK
Buffer Crosstalk
MAX4017/MAX4019/MAX4022, f = 10MHz, V
OUT
= 20mVp-p
dB0.1Buffer Gain Matching
MAX4019 µs1t
OFF
Buffer Disable Time
fC= 5MHz, V
OUT
= 2Vp-p dBc-78SFDR
Spurious-Free Dynamic Range
MAX4019
f = 10MHz
MAX4019, EN_ = 0V
f = 10kHz
f = 10kHz
NTSC, RL= 150
NTSC, RL= 150
fC= 10MHz, A
VCL
= +2V/V
V
OUT
= 2Vp-p,
fC= 5MHz
V
OUT
= 100mVp-p
f = 10.0MHz
V
OUT
= 2V step
V
OUT
= 2V step
V
OUT
= 2Vp-p
V
OUT
= 20mVp-p (Note 4)
CONDITIONS
ns100t
ON
Buffer Enable Time
6Z
OUT
Output Impedance
pF2C
OUT(OFF)
Disabled Output Capacitance
pF1C
IN
Input Capacitance
pA/Hz
1.3i
n
Input Noise Current Density
nV/Hz
10e
n
Input Noise Voltage Density
%0.04DGDifferential Gain Error
degrees0.02DPDifferential Phase Error
dBm11Input 1dB Compression Point
dBm35IP3Third-Order Intercept
-75
-82
HDHarmonic Distortion
MHz200BW
SS
Small-Signal -3dB Bandwidth
-78
ns1tR, t
F
Rise/Fall Time
ns45t
S
Settling Time to 0.1%
V/µs600SRSlew Rate
MHz140BW
LS
Large-Signal -3dB Bandwidth
MHz630BW
0.1dB
Bandwidth for 0.1dB Gain Flatness
UNITSMIN TYP MAXSYMBOLPARAMETER
dBc
Second harmonic
Total harmonic distortion
Third harmonic
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2 Buffers with Rail-to-Rail Outputs in SOT23
4 _______________________________________________________________________________________
__________________________________________Typical Operating Characteristics
(VCC= +5V, VEE= 0V, A
VCL
= +2, RL= 150to VCC/ 2, TA = +25°C, unless otherwise noted.)
SMALL-SIGNAL GAIN vs. FREQUENCY
8
7
6
5
GAIN (dB)
4
3
2
1
100k 1M 10M 100M 1G
FREQUENCY (Hz)
MAX4017/19/22
CROSSTALK vs. FREQUENCY
50
30
10
-10
-30
-50
-70
CROSSTALK (dB)
-90
-110
-130
-150 100k 1M 10M 100M 1G
FREQUENCY (Hz)
MAX4014-01
MAX4014-04
GAIN FLATNESS vs. FREQUENCY
6.8
6.7
6.6
6.5
6.4
6.3
GAIN (dB)
6.2
6.1
6.0
5.9 100k 1M 10M 100M 1G
FREQUENCY (Hz)
CLOSED-LOOP OUTPUT IMPEDANCE
vs. FREQUENCY
1000
100
10
IMPEDANCE ()
1
0.1
0.1M 1M 10M 100M
FREQUENCY (Hz)
LARGE-SIGNAL GAIN vs. FREQUENCY
8
MAX4014-02
7
6
5
4
GAIN (dB)
3
2
1
0
100k 1M 10M 100M 1G
0
V
-10
MAX4014-05
-20
-30
-40
-50
-60
-70
HARMONIC DISTORTION (dBc)
-80
-90
-100 100k 1M 10M 100M
FREQUENCY (Hz)
HARMONIC DISTORTION
vs. FREQUENCY
= 2Vp-p
OUT
2ND HARMONIC
FREQUENCY (Hz)
MAX4014-03
MAX4014-06
3RD HARMONIC
0
f = 5MHz
-10 V
OUT
-20
-30
-40
-50
-60
-70
HARMONIC DISTORTION (dBc)
-80
-90
3rd HARMONIC
-100 0 200 400 600 800 1000
= 2Vp-p
vs. LOAD
LOAD ()
2rd HARMONIC
0
-10
MAX4014-07
-20
-30
-40
-50
-60
-70
HARMONIC DISTORTION (dBc)
-80
-90
-100
HARMONIC DISTORTION
HARMONIC DISTORTION
vs. OUTPUT SWING
f = 5MHz
3RD HARMONIC
0.5
1.0
OUTPUT SWING (Vp-p)
2ND HARMONIC
1.5 2.0
MAX4014-08
-10
-20
-30
-40
-50
OFF ISOLATION (dB)
-60
-70
-80
-90
OFF ISOLATION vs. FREQUENCY
10
0
100k 10M 100M1M
MAX4019
FREQUENCY (Hz)
MAX4014-09
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2
Buffers with Rail-to-Rail Outputs in SOT23
_______________________________________________________________________________________ 5
)
__________________________________________Typical Operating Characteristics
(VCC= +5V, VEE= 0V, A
VCL
= +2, RL= 150to VCC/ 2, TA = +25°C, unless otherwise noted.)
POWER-SUPPLY REJECTION
vs. FREQUENCY
20
10
0
-10
-20
-30
-40
-50
-60
POWER-SUPPLY REJECTION (dB)
-70
-80
100k 1M 10M 100M
FREQUENCY (Hz)
OUTPUT SWING
vs. LOAD RESISTANCE
5
4
3
OUTPUT SWING (Vp-p)
2
10 100 1k 10k 100k 1M
LOAD RESISTANCE ()
CURRENT NOISE DENSITY
vs. FREQUENCY
10
MAX4014-10
NOISE (pA/ √Hz)
1
1 10 1k 10M1M
100 10k 100k
FREQUENCY (Hz)
OUTPUT SWING
4.5
4.0
MAX4014-13
3.5
3.0
2.5
OUTPUT SWING (Vp-p)
2.0
1.5
1.0
vs. LOAD RESISTANCE (R
25 50 75 100 125 150
LOAD RESISTANCE ()
)
L
MAX4014-11
NOISE (nV/Hz)
MAX4014-14
BANDWIDTH (MHz)
VOLTAGE NOISE DENSITY
vs. FREQUENCY
100
10
1
1 10 1k 10M1M
100 10k 100k
FREQUENCY (Hz)
BANDWIDTH
400
350
300
250
200
150
100
50
0
vs. LOAD RESISTANCE
1000 200 500400300 600
LOAD RESISTANCE ()
MAX4014-12
MAX4014-15
POWER-SUPPLY CURRENT (PER AMPLIFIER
7
6
5
4
POWER-SUPPLY CURRENT (mA)
3
vs. TEMPERATURE
-25-50 0 755025 100 TEMPERATURE (°C)
MAX4014-16
INPUT BIAS CURRENT
6.0
5.5
5.0
INPUT BIAS CURRENT (µA)
4.5
4.0
vs. TEMPERATURE
-25-50 0 755025 100 TEMPERATURE (°C)
MAX4014-17
0.20
0.16
0.12
0.08
INPUT OFFSET CURRENT (µA)
0.04
0
INPUT OFFSET CURRENT
vs. TEMPERATURE
MAX4014-18
-25-50 0 755025 100 TEMPERATURE (°C)
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2 Buffers with Rail-to-Rail Outputs in SOT23
6 _______________________________________________________________________________________
__________________________________________Typical Operating Characteristics
(VCC= +5V, VEE= 0V, A
VCL
= +2, RL= 150to VCC/ 2, TA = +25°C, unless otherwise noted.)
POWER-SUPPLY CURRENT (PER AMPLIFIER)
vs. POWER-SUPPLY VOLTAGE
10
8
6
4
2
POWER-SUPPLY CURRENT (mA)
0
43 567891011
POWER-SUPPLY VOLTAGE (V)
5
MAX4014-19
4
3
2
INPUT OFFSET VOLTAGE (mV)
1
0
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
-25-50 0 755025 100 TEMPERATURE (°C)
5.0
MAX4014-20
4.8
4.6
4.4
VOLTAGE SWING (Vp-p)
4.2
4.0
VOLTAGE SWING vs. TEMPERATURE
RL = 150TO V
-25-50 0 755025 100
SMALL-SIGNAL PULSE RESPONSE
DIFFERENTIAL GAIN AND PHASE
0.01
0.00
-0.01
-0.02
-0.03
DIFF. GAIN (%)
-0.04
-0.05 0 100
0.010
0.005
0.000
-0.005
-0.010
-0.015
-0.020
DIFF. PHASE (deg)
-0.025 0 100
IRE
IRE
MAX4014-22
VOLTAGE (25mV/div)
SMALL-SIGNAL PULSE RESPONSE
IN
OUT
TIME (20ns/div)
VCM = 1.25V, RL = 100to GROUND
MAX4014-23
OUT
VOLTAGE (25mV/div)
IN
LARGE-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
IN
MAX4014-25
IN
(C
= 5pF)
L
MAX4014-26
EN_
ENABLE RESPONSE TIME
/ 2
CC
TEMPERATURE (°C)
= 5pF)
(C
L
TIME (20ns/div)
MAX4014-24
MAX4014-27
MAX4014-21
5.0V (ENABLE)
0V (DISABLE)
OUT
VOLTAGE (500mV/div)
V
= 0.9V, RL = 100to GROUND
CM
TIME (20ns/div)
OUT
VOLTAGE (500mV/div)
V
= 1.75V, RL = 100to GROUND
CM
TIME (20ns/div)
OUT
TIME (1µs/div)
VIN = 0.5V
1V
0V
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2
Buffers with Rail-to-Rail Outputs in SOT23
_______________________________________________________________________________________ 7
______________________________________________________________Pin Description
53
87
96
105
14
4
485
71
62
3
1142
SOT23-5
1
SOSO/µMAX
3
2
1
12
13
335
7710
6611
5512
10816
444
117
226
131113
QSOP
8, 98, 9
QSOPSO
3
2
1614
1513
1412
1
121014
11915
INA+
OUTB
INB-
INB+
OUTC
IN-
V
CC
OUTA
INA-
IN+
V
EE
OUT
N.C.
ENB
ENC
OUTD
IND-
IND+
ENA
INC+
INC-
Amplifier A Noninverting Input
Amplifier B Output
Amplifier B Inverting Input
Amplifier B Noninverting Input
Amplifier C Output
Inverting Input
Positive Power Supply
Amplifier A Output
Amplifier A Inverting Input
Noninverting Input
Negative Power Supply or Ground (in single-supply operation)
Amplifier Output
No Connect. Not internally connected. Tie to ground or leave open.
Enable Input for Amplifier B
Enable Input for Amplifier C
Amplifier D Output
Amplifier D Inverting Input
Amplifier D Noninverting Input
Enable Input for Amplifier A
Amplifier C Noninverting Input
Amplifier C Inverting Input
MAX4014 MAX4017 MAX4019 MAX4022
PIN
NAME FUNCTION
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2 Buffers with Rail-to-Rail Outputs in SOT23
8 _______________________________________________________________________________________
_______________Detailed Description
The MAX4014/MAX4017/MAX4019/MAX4022 are sin­gle-supply, rail-to-rail output, voltage-feedback, closed­loop buffers that employ current-feedback techniques to achieve 600V/µs slew rates and 200MHz band­widths. These buffers use internal 500resistors to provide a preset closed-loop gain of +2V/V in the non­inverting configuration or -1V/V in the inverting configu­ration. Excellent harmonic distortion and differential gain/phase performance make these buffers an ideal choice for a wide variety of video and RF signal-pro­cessing applications.
Local feedback around the buffer’s output stage ensures low output impedance, which reduces gain sensitivity to load variations. This feedback also pro­duces demand-driven current bias to the output tran­sistors for ±120mA drive capability, while constraining total supply current to less than 7mA.
__________Applications Information
Power Supplies
These devices operate from a single +3.15V to +11V power supply or from dual supplies of ±1.575V to ±5.5V. For single-supply operation, bypass the VCCpin to ground with a 0.1µF capacitor as close to the pin as possible. If operating with dual supplies, bypass each supply with a 0.1µF capacitor.
Selecting Gain Configuration
Each buffer in the MAX4014 family can be configured for a voltage gain of +2V/V or -1V/V. For a gain of
+2V/V, ground the inverting terminal. Use the noninvert­ing terminal as the signal input of the buffer (Figure 1a). Grounding the noninverting terminal and using the inverting terminal as the signal input configures the buffer for a gain of -1V/V (Figure 1b).
Since the inverting input exhibits a 500input imped­ance, terminate the input with a 56resistor when the device is configured for an inverting gain in 50appli­cations (terminate with 88in 75applications). Terminate the input with a 49.9resistor in the nonin­verting case. Output terminating resistors should direct­ly match cable impedances in either configuration.
Layout Techniques
Maxim recommends using microstrip and stripline tech­niques to obtain full bandwidth. To ensure that the PC board does not degrade the buffer’s performance, design it for a frequency greater than 1GHz. 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:
• Don’t use wire-wrapped boards. They are too inductive.
• Don’t use IC sockets. They increase parasitic capac­itance and inductance.
• 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.
Figure 1a. Noninverting Gain Configuration (AV= +2V/V) Figure 1b. Inverting Gain Configuration (AV= -1V/V)
IN
R
*RL = 2R
IN+
*R
TIN
500
500
IN-
OUT
MAX40_ _
OUT
*R
IN
R
*R
IN+
*R
R
S
500
IN-
TIN
= 2R
L
500
OUT
MAX40_ _
OUT
*R
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2
Buffers with Rail-to-Rail Outputs in SOT23
_______________________________________________________________________________________ 9
Input Voltage Range and Output Swing
The input range for the MAX4014 family extends from (VEE- 100mV) to (VCC- 2.25V). Input ground sensing increases the dynamic range for single-supply applica­tions. The outputs drive a 2kload to within 60mV of the power-suply rails. With heavier loads, the output swing is reduced as shown in the Electrical Character- istics and the Typical Operating Characteristics. As the load increases, the input range is effectively limited by
the output-drive capability, since the buffers have a fixed voltage gain of +2 or -1.
For example, a 50load can typically be driven from 40mV above V
EE
to 1.6V below VCC, or 40mV to 3.4V when operating from a single +5V supply. If the buffer is operated in the noninverting, gain of +2 configuration with the inverting input grounded, the effective input voltage range becomes 20mV to 1.7V, instead of the
-100mV to 2.75V indicated by the Electrical Character- istics. Beyond the effective input range, the buffer out­put is a nonlinear function of the input, but it will not undergo phase reversal or latchup.
Enable
The MAX4019 has an enable feature (EN_) that allows the buffer to be placed in a low-power state. When the buffers are disabled, the supply current will not exceed 550µA per buffer.
As the voltage at the EN_ pin approaches the negative supply rail, the EN_ input current rises. Figure 2 shows a graph of EN_ input current versus EN_ pin voltage. Figure 3 shows the addition of an optional resistor in series with the EN pin, to limit the magnitude of the cur­rent increase. Figure 4 displays the resulting EN pin input current to voltage relationship.
Figure 2. Enable Logic-Low Input Current vs. Enable Logic­Low Threshold
Figure 3. Circuit to Reduce Enable Logic-Low Input Current
Figure 4. Enable Logic-Low Input Current vs. Enable Logic­Low Threshold with 10kSeries Resistor
20
0
-20
-40
-60
-80
-100
INPUT CURRENT (µA)
-120
-140
-160 0 100 300 500
200 400
V
(mV ABOVE VEE)
IL
0
-1
-2
-3
-4
-5
-6
INPUT CURRENT (µA)
-7
-8
-9
-10 0 100 300 500
200 400 (mV ABOVE VEE)
V
IL
ENABLE
10k
IN+
IN-
500 500
MAX40_ _
EN_
OUT
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2 Buffers with Rail-to-Rail Outputs in SOT23
10 ______________________________________________________________________________________
Disabled Output Resistance
The MAX4014/MAX4017/MAX4019/MAX4022 include internal protection circuitry that prevents damage to the precision input stage from large differential input volt­ages, as shown in Figure 5. This protection circuitry con­sists of five back-to-back Schottky diodes between IN_+ and IN_-. These diodes lower the disabled output resis­tance from 1kto 500when the output voltage is 3V greater or less than the voltage at IN_+. Under these
conditions, the input protection diodes will be forward biased, lowering the disabled output resistance to 500Ω.
Output Capacitive Loading and Stability
The MAX4014/MAX4017/MAX4019/MAX4022 provide maximum AC performance with no load capacitance. This is the case when the load is a properly terminated transmission line. However, they are designed to drive up 25pF of load capacitance without oscillating, but with reduced AC performance.
Driving large capacitive loads increases the chance of oscillations occurring in most amplifier circuits. This is especially true for circuits with high loop gains, such as voltage followers. The buffer’s output resistance and the load capacitor combine to add a pole and excess phase to the loop response. If the frequency of this pole is low enough to interfere with the loop response and degrade phase margin sufficiently, oscillations can occur.
A second problem when driving capacitive loads results from the amplifier’s output impedance, which looks 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 gain margin.
Figure 6 shows the frequency response of the MAX4014/ MAX4017/MAX4019/MAX4022 under different capacitive loads. To drive loads with greater than 25pF of capaci­tance or to settle out some of the peaking, the output requires an isolation resistor like the one shown in
Figure 5. Input Protection Circuit
Figure 6. Small-Signal Gain vs. Frequency with Load Capacitance and No Isolation Resistor
Figure 7. Driving a Capacitive Load through an Isolation Resistor
MAX4014
IN+
MAX4017 MAX4019 MAX4022
OUT
V
IN
R
TIN
IN-
500500
50
500
500
MAX40_ _
R
ISO
V
OUT
C
L
6
5
4
3
2
1
GIAN (dB)
0
-1
-2
-3
-4 100k 10M 100M1M 1G
CL = 10pF
CL = 5pF
FREQUENCY (Hz)
CL = 15pF
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2
Buffers with Rail-to-Rail Outputs in SOT23
______________________________________________________________________________________ 11
Figure 8. Capacitive Load vs. Isolation Resistance
Figure 9. Small-Signal Gain vs. Frequency with Load Capacitance and 27Isolation Resistor
Figure 7. Figure 8 is a graph of the optimal isolation resis­tor versus load capacitance. Figure 9 shows the frequen­cy response of the MAX4014/MAX4017/MAX4019/ MAX4022 when driving capacitive loads with a 27isola­tion resistor.
Coaxial cables 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 lines’ capacitance.
30
25
()
ISO
20
15
10
ISOLATION RESISTANCE, R
5
0
500 100 200150 250
CAPACITIVE LOAD (pF)
3
2
R
= 27
ISO
1
0
-1
-2
GIAN (dB)
-3
-4
-5
-6
-7 100k 10M 100M1M 1G
CL = 68pF
CL = 120pF
FREQUENCY (Hz)
CL = 47pF
MAX4014/MAX4017/MAX4019/MAX4022
Low-Cost, High-Speed, Single-Supply, Gain of +2 Buffers with Rail-to-Rail Outputs in SOT23
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
© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
__________________________________________________________Pin Configurations
___________________Chip Information
PART NUMBER
NO. OF
TRANSISTORS
MAX4014 95
MAX4017 190
MAX4019 299
MAX4022 362
SUBSTRATE CONNECTED TO V
EE
TOP VIEW
15V
OUT
MAX4014
2
V
EE
34
IN-IN+
SOT23-5
1
ENA OUTC
ENC
2
ENB
3
MAX4019
4
V
CC
INA+
5
INA-
6
OUTA
7
N.C.
8
16
15
14
13
12
11
10
9
QSOP
CC
INC-
INC+
V
EE
INB+
INB-
OUTB
N.C.
OUTA
INA+
OUTA
INA-
INA+
V
INB+
INB-
1
1
2
87V
CC
OUTBINA-
MAX4017
3
4
EE
INB-
6
INB+V
5
SO/µMAX
ENA
ENC
ENB
V
INA+
INA-
2
3
MAX4019
4
CC
5
6
7
OUTC
14
INC-
13
INC+
12
V
11
EE
10
INB+
9
INB-
8
OUTBOUTA
SO
1
2
3
MAX4022
4
CC
5
6
7
OUTD
14
IND-
13
IND+
12
V
11
EE
10
INC+
9
INC-
8
OUTCOUTB
1
OUTA OUTD
INA-
2
INA+
3
MAX4022
4
V
CC
INB+
5
INB-
6
OUTB
7
N.C.
8
16
15
IND-
14
IND+
13
V
EE
INC+
12
INC-
11
10
OUTC
9
N.C.
SO
QSOP
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