MAX4490AXK+T中文资料

General Description
The MAX4490/MAX4491/MAX4492 single/dual/quad,low-cost CMOS op amps feature Rail-to-Rail ®input and output capability from either a single 2.7V to 5.5V sup-ply or dual ±1.35V to ±2.75V supplies. These amplifiers exhibit a high slew rate of 10V/µs and a gain-bandwidth product of 10MHz. They can drive 2k Ωresistive loads to within 55mV of either supply rail and remain unity-gain stable with capacitive loads up to 300pF.
The MAX4490 is offered in the ultra-small, 5-pin SC70package, which is 50% smaller than the standard 5-pin SOT23 package. Specifications for all parts are guaran-teed over the automotive (-40°C to +125°C) tempera-ture range.
Applications
Battery-Powered Instruments Portable Equipment Audio Signal Conditioning
Low-Power/Low-Voltage Applications Sensor Amplifiers
RF Power Amplifier Control
High-Side/Low-Side Current Sensors
Features
o 2.7V to 5.5V Single-Supply Operation
o 10V/µs Slew Rate
o Rail-to-Rail Input Common-Mode Voltage Range o Rail-to-Rail Output Voltage Swing o 10MHz Gain-Bandwidth Product
o Unity-Gain Stable with Capacitive Loads Up to 300pF o 50pA Input Bias Current
o Ultra-Small, 5-Pin SC70 Package (MAX4490)
MAX4490/MAX4491/MAX4492
Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70
________________________________________________________________Maxim Integrated Products
1
19-1525; Rev 2; 4/01
Capacitive-Load Stability
Ordering Information
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
Pin Configurations/Functional Diagrams
For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .
M A X 4490/M A X 4491/M A X 4492
Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC702_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V DD = 5V, V SS = 0, V CM = 0, V OUT = V DD /2, R L = 100k Ωconnected to V DD /2, T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +25°C.) (Note 1)
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.
Supply Voltage (V DD to V SS )....................................................6V All Other Pins...................................(V SS - 0.3V) to (V DD + 0.3V) Output Short-Circuit Duration.................................................10s Continuous Power Dissipation (T A = +70°C)
5-Pin SC70 (derate 2.5mW/°C above +70°C)............200mW 5-Pin SOT23 (derate 7.1mW/°C above +70°C)..........571mW 8-Pin SOT23 (derate 5.26mW/°C above +70°C)........421 mW
8-Pin µMAX (derate 4.1mW/°C above +70°C)...........330mW 14-Pin TSSOP (derate 8.3mW/°C above +70°C).......667mW 14-Pin SO (derate 8.3mW/°C above +70°C)..............667mW Operating Temperature Range ........................-40°C to +125°C Junction Temperature.....................................................+150°C Storage Temperature Range............................-65°C to +150°C Lead Temperature (soldering, 10s)................................+300°C
Note 1:All units production tested at T A = +25°C. Limits over temperature guaranteed by design.Note 2:Guaranteed by the Power-Supply Rejection Ratio (PSRR) test.
Note 3:Input Offset Voltage, Input Bias Current, and Input Offset Current are all tested and guaranteed at both ends of the common-mode range.
MAX4490/MAX4491/MAX4492
Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70
_______________________________________________________________________________________3
500
600550700650800750850-40-10520-253550658095110125
SUPPLY CURRENT PER AMPLIFIER
vs. TEMPERATURE
TEMPERATURE (°C)
S U P P L Y C U R R E N T (µA )
30020010050040090080070060010002.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5SUPPLY CURRENT PER AMPLIFIER
vs. SUPPLY VOLTAGE
M A X 4490t o c 02
SUPPLY VOLTAGE (V)
S U P P L Y C U R R E N T (µA )
-2.0
-1.4-1.6-1.8-1.0-1.2-0.2-0.4-0.6-0.80
-40-25-105203550806595125
110INPUT OFFSET VOLTAGE vs. TEMPERATURE
M A X 4490 t o c 03
TEMPERATURE (°C)
O F F S E T V O L T A G E (m V )
2010306070504080-40-1052035-2550658095110125
OUTPUT SWING HIGH vs. TEMPERATURE
TEMPERATURE (°C)
V D D - V O U T (m V )
2010306070504080-40-1052035-2550658095110125
OUTPUT SWING LOW vs. TEMPERATURE
TEMPERATURE (°C)
V O U T - V S S (m V )
-20
0-101040503020
601001k
10k
100k
1M
10M
OP AMP GAIN AND PHASE
vs. FREQUENCY
FREQUENCY (Hz)
G A I N (d B )
-180-90-135-4590
135450
180P H A S E (D E G R E E S )
-20
0-10104050302060100
1k
10k
100k
1M
10M
GAIN AND PHASE
vs. FREQUENCY (WITH C LOAD )
FREQUENCY (Hz)
G A I N (d B )
-180-90-135
-4590135
450180
P H A S E (D E G R E
E S )
80
90
100
110120
130-40-105-25203550658095110125
LARGE-SIGNAL GAIN vs. TEMPERATURE
TEMPERATURE (°C)
L A R G E -S I G N A L G A I N (d
B )
-100
-70
-60-90
-80-30-40-50-10-200
10
1k
10k
100
100k
1M
10M
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
FREQUENCY (Hz)
P S S R (d B )
Typical Operating Characteristics
(V DD = 5V, V SS = 0, V CM = V DD /2, R L = 100k Ωto V DD /2, T A = +25°C, unless otherwise noted.)
M A X 4490/M A X 4491/M A X 4492
Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC704_______________________________________________________________________________________
Typical Operating Characteristics (continued)
(V DD = 5V, V SS = 0, V CM = V DD /2, R L = 100k Ωto V DD /2, T A = +25°C, unless otherwise noted.)
0.01
1
0.1101001k
1k
10k
100
100k
1M
10M
OUTPUT IMPEDANCE vs. FREQUENCY
FREQUENCY (Hz)
O U T P U T I M P E D A N C E (Ω)
0.040010
100
1k
10k
100k
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
0.005
0.010
FREQUENCY (Hz)
T H D + N O I S E (%)
0.0150.0200.0250.0300.035LARGE-SIGNAL TRANSIENT RESPONSE
(NONINVERTING)
A V = 1
IN OUT 40µs/div
V/div
V/div
M A X 4490t o c 12
LARGE-SIGNAL TRANSIENT RESPONSE
(INVERTING)
A V = -1IN OUT 2V/div
2V/div
40µs/div
M A X 4490t o c 13
SMALL-SIGNAL TRANSIENT RESPONSE
(NONINVERTING)
A V = 1
40µs/div
IN OUT 50mV/div
50mV/div
M A X 4490t o c 14
SMALL-SIGNAL TRANSIENT RESPONSE
(INVERTING)
A V = -1
IN OUT 40µs/div
M A X 4490t o c 15
50mV/div
50mV/div
POWER-UP TRANSIENT RESPONSE
A V = 1, V IN CONNECTED TO V DD /2, R L = 2k Ω
V DD OUT 2V/div
1V/div
M A
X 4490t o c 16
4µs/div
0428610122.5
3.5
4.0
3.0
4.5
5.0
5.5SLEW RATE vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)S L E W R A T E (V /µS )
0-20-40-1200.001
1101000.010.11000
MAX4491/MAX4492CROSSTALK vs. FREQUENCY
-60-80-100M A X 4492t o c 18
FREQUENCY (MHz)
C R O S S T A L K (d B )
MAX4490/MAX4491/MAX4492
Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70
_______________________________________________________________________________________5
Pin Description
Detailed Description
Rail-to-Rail Input Stage
The MAX4490/MAX4491/MAX4492 CMOS operational amplifiers have parallel-connected N- and P-channel differential input stages that combine to accept a com-mon-mode range extending to both supply rails. The N-channel stage is active for common-mode input voltages typically greater than (V SS + 1.2V), and the P-channel stage is active for common-mode input volt-ages typically less than (V DD - 1.2V).
Rail-to-Rail Output Stage
The MAX4490/MAX4491/MAX4492 CMOS operational amplifiers feature class-AB push-pull output stages that can drive a 100k Ωload to within 1.5mV of either supply rail. Short-circuit output current is typically ±50mA.
Figures 1a and 1b show the typical temperature depen-dence of output source and sink currents, respectively,for three fixed values of (V DD - V OH ) and (V OL - V SS ).For example, at V DD = 5.0V, the load currents that main-tain (V DD - V OH ) = 100mV and (V OL - V SS ) = 100mV at T A = +25°C are 2.2mA and 3.3mA, respectively, when
the load is connected to V DD /2. Consistent resistive-drive capability is (2.5 - 0.1) / 2.2 = 1.1k Ω. For the same application, resistive-drive capability is 2.2k Ωwhen the load is connected to V DD or V SS .
Applications Information
Power-Supply Considerations
The MAX4490/MAX4491/MAX4492 operate from a sin-gle 2.7V to 5.5V supply or from dual ±1.35V to ±2.75V supplies with typically 800µA supply current per ampli-fier. A high power-supply rejection ratio of 100dB allows for extended operation from a decaying battery voltage, thereby simplifying designs for portable appli-cations. For single-supply operation, bypass the power supply with a 0.1µF ceramic capacitor placed close to the V DD pin. For dual-supply operation, bypass each supply to ground.
Input Capacitance
One consequence of the parallel-connected differential input stages for rail-to-rail operation is a relatively large input capacitance C IN (typically 5pF). This introduces a
pole at frequency (2πR ′C IN )-1, where R ′is the parallel combination of the gain-setting resistors for the invert-ing or noninverting amplifier configuration (Figure 2). If the pole frequency is less than or comparable to the unity-gain bandwidth (10MHz), the phase margin will be reduced, and the amplifier will exhibit degraded AC performance through either ringing in the step response or sustained oscillations. The pole frequency is 10MHz when R ′= 3.2k Ω. To maximize stability, R ′<3k Ωis recommended.
Applications that require rail-to-rail operation with mini-mal loading (for small V DD - V OH and V OL - V SS ) will typically require R ′values >3k Ω. To improve step response under these conditions, connect a small
capacitor C f between the inverting input and output.Choose C f as follows:
C f = 5(R / R f ) [pf]where R f is the feedback resistor and R is the gain-set-ting resistor (Figure 2).
Figure 3 shows the step response for a noninverting amplifier subject to R ′= 4k Ωwith and without the C f feedback capacitor.
M A X 4490/M A X 4491/M A X 4492
Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC706_______________________________________________________________________________________
Figure 1b. Output Sink Current vs. Temperature
Figure 2. Inverting and Noninverting Amplifier with Feedback Compensation
Driving Capacitive Loads
I n conjunction with op amp output resistance, capaci-tive loads introduce a pole frequency that can reduce phase margin and lead to unstable operation. The MAX4490/MAX4491/MAX4492 drive capacitive loads up to 300pF without significant degradation of step response and slew rate (Figure 4). Capacitive-Load Stability (page 1) shows regions of stable and margin-ally stable (step overshoot <10%) operation for different combinations of capacitive and resistive loads.
I mprove stability for large capacitive loads by adding an isolation resistor (typically 10Ω) in series with the output (Figure 5). Note that the isolation resistor forms a voltage divider with potential for gain error.
Chip Information
MAX4490 TRANSISTOR COUNT: 60MAX4491 TRANSISTOR COUNT: 120MAX4492 TRANSISTOR COUNT: 240SUBSTRATE CONNECTED TO V SS
MAX4490/MAX4491/MAX4492
Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70
_______________________________________________________________________________________7
Figure 4. Step Response With and Without Capacitive Loading
A V = +1, R L = 100k Ω, C L = 0
WITHOUT CAPACITIVE LOADING
WITH CAPACITIVE LOADING
A V = +1, R L = 100k Ω, C L = 300pF
Figure 3. Step Response With and Without Feedback Compensation
A V = -1, R L = 4k Ω, C f = 0WITHOUT FEEDBACK COMPENSATION WITH FEEDBACK COMPENSATION
A V = -1, R L = 4k Ω, C f = 5pF
M A X 4490/M A X 4491/M A X 4492
Low-Cost, High-Slew-Rate,
Rail-to-Rail I/O Op Amps in SC70
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8_____________________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.
Figure 5. Isolation Resistor for Large Capacitive Loads
Package Information
Pin Configurations/
Functional Diagrams (continued)
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