The MAX4230–MAX4234 single/dual/quad, high-outputdrive CMOS op amps feature 200mA of peak output
current, rail-to-rail input, and output capability from a
single 2.7V to 5.5V supply. These amplifiers exhibit a
high slew rate of 10V/µs and a gain-bandwidth product
(GBWP) of 10MHz. The MAX4230–MAX4234 can drive
typical headset levels (32Ω), as well as bias an RF
power amplifier (PA) in wireless handset applications.
The MAX4230 comes in a tiny 5-pin SC70 package and
the MAX4231, single with shutdown, is offered in a
6-pin SC70 package and in 1.5mm x 1.0mm UCSP and
thin µDFN packages. The dual op-amp MAX4233 is
offered in the space-saving 10-bump chip-scale package (UCSP™), providing the smallest footprint area for
a dual op amp with shutdown.
These op amps are designed to be part of the PA control circuitry, biasing RF PAs in wireless headsets. The
MAX4231/MAX4233 offer a SHDN feature that drives
the output low. This ensures that the RF PA is fully disabled when needed, preventing unconverted signals to
the RF antenna.
The MAX4230 family offers low offsets, wide bandwidth,
and high-output drive in a tiny 2.1mm x 2.0mm spacesaving SC70 package. These parts are offered over the
automotive temperature range (-40°C to +125°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.
Supply Voltage (VDDto VSS)....................................................6V
All Other Pins ...................................(V
Note 2: All units 100% tested at +25°C. All temperature limits are guaranteed by design.
Note 3: SHDN logic parameters are for the MAX4231/MAX4233 only.
Note 4: Guaranteed by design.
The MAX4230–MAX4234 CMOS operational amplifiers
have parallel-connected n- and p-channel differential
input stages that combine to accept a common-mode
range extending to both supply rails. The n-channel
stage is active for common-mode input voltages typically greater than (VSS+ 1.2V), and the p-channel
stage is active for common-mode input voltages typically less than (VDD- 1.2V).
Applications Information
Package Power Dissipation
Warning: Due to the high output current drive, this op
amp can exceed the absolute maximum power-dissipation rating. As a general rule, as long as the peak cur-
rent is less than or equal to 40mA, the maximum package
power dissipation is not exceeded for any of the package
types offered. There are some exceptions to this rule,
however. The absolute maximum power-dissipation rating
of each package should always be verified using the following equations. The equation below gives an approximation of the package power dissipation:
where:
V
RMS
= RMS voltage from VDDto V
OUT
when sourcing
current and RMS voltage from V
OUT
to V
SS
when sink-
ing current.
I
RMS
= RMS current flowing out of or into the op amp
and the load.
θ = phase difference between the voltage and the current. For resistive loads, COS θ = 1.
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
——————9, 13IN 3- , IN 4- Inverting Input to Amplifiers 3 and 4
——————8, 14
M AX42 31
SOT 23 /
SC7 0/Th in
µ DF N
11B1————IN+Noninverting Input
22A144B411V
33B2————IN-Inverting Input
44A2————OUTAmplifier Output
56A3810B14V
M A X42 31
U CSP
M AX42 32
SOT 23 /
µ M A X
M A X4 2 3 3
µ M A X
M AX42 33
U CSP
M AX42 34
T SSOP/
SO
NAMEFUNCTION
Negative Supply Input. Connect to
SS
ground for single-supply operation.
Positive Supply Input
DD
SHDN,
SHDN1,
SHDN2
IN3+,
OUT3,
OUT4
Shutdown Control. Tie to high for normal
operation.
Noninverting Input to Amplifiers 3 and 4
Amplifiers 3 and 4 Outputs
P V I COS
IC DISSRMS RMS
()
≅θ
For example, the circuit in Figure 1 has a package
power dissipation of 196mW:
where:
VDC= the DC component of the output voltage.
IDC= the DC component of the output current.
V
PEAK
= the highest positive excursion of the AC com-
ponent of the output voltage.
I
PEAK
= the highest positive excursion of the AC com-
ponent of the output current.
Therefore:
P
IC(DISS)
= V
RMSIRMS
COS θ
= 196mW
Adding a coupling capacitor improves the package
power dissipation because there is no DC current to the
load, as shown in Figure 2:
Therefore:
P
IC(DISS)
= V
RMSIRMS
COS θ
= 15.6mW
If the configuration in Figure 1 were used with all four of
the MAX4234 amplifiers, the absolute maximum powerdissipation rating of this package would be exceeded
(see the
Absolute Maximum Ratings
section).
60mW Single-Supply Stereo
Headphone Driver
Two MAX4230/MAX4231s can be used as a single-supply, stereo headphone driver. The circuit shown in
Figure 2 can deliver 60mW per channel with 1% distortion from a single 5V supply.
The input capacitor (CIN), in conjunction with RIN, forms
a highpass filter that removes the DC bias from the
incoming signal. The -3dB point of the highpass filter is
given by:
Figure 2. Circuit Example: Adding a Coupling Capacitor
Greatly Reduces Power Dissipation of its Package
Figure 1. MAX4230/MAX4231 Used in Single-Supply Operation
Circuit Example
3.6V
R
V
= 2V
IN
C
P-P
MAX4230
R
MAX4231
32Ω
V
V V
≅−
RMSDDDC
. .
I +
RMS
.
()
=−+=
VV
3618
I
DC
mA
PEAK
2
RMS
≅=+
I
=
78 4
PEAK
+
2
.
V
10
.
2 507
2
VV
183210 32
.
Ω
V
RMS
./
2
Ω
R
F
C
IN
R
LEFT
AUDIO INPUT
C
IN
RIGHT
AUDIO INPUT
V
RMS
IN
V
BIAS
R
IN
V
PEAK
≅
2
.
V
10
==
.
0 707
2
I
I +
≅=+
RMS
.
IA
=
22 1
DC
mA
PEAK
2
RMS
MAX4230
R
F
V
RMS
0
C
OUT
C
OUT
./
10 32
HEADPHONE JACK
TO 32Ω STEREO
HEADSET
V
Ω
2
f
dB
−=3
2π
1
RC
IN IN
MAX4230–MAX4234
Choose gain-setting resistors RINand RFaccording to
the amount of desired gain, keeping in mind the maximum output amplitude. The output coupling capacitor,
C
OUT
, blocks the DC component of the amplifier output, preventing DC current flowing to the load. The output capacitor and the load impedance form a highpass
filer with the -3dB point determined by:
For a 32Ω load, a 100µF aluminum electrolytic capacitor gives a low-frequency pole at 50Hz.
Bridge Amplifier
The circuit shown in Figure 3 uses a dual MAX4230 to
implement a 3V, 200mW amplifier suitable for use in
size-constrained applications. This configuration eliminates the need for the large coupling capacitor
required by the single op-amp speaker driver when single-supply operation is necessary. Voltage gain is set
to 10V/V; however, it can be changed by adjusting the
82kΩ resistor value.
Rail-to-Rail Input Stage
The MAX4230–MAX4234 CMOS op amps have parallelconnected n- and p-channel differential input stages
that combine to accept a common-mode range extending to both supply rails. The n-channel stage is active
for common-mode input voltages typically greater than
(VSS+ 1.2V), and the p-channel stage is active for
common-mode input voltages typically less than (VDD-
1.2V).
Rail-to-Rail Output Stage
The minimum output is within millivolts of ground for single-supply operation, where the load is referenced to
ground (VSS). Figure 4 shows the input voltage range
and the output voltage swing of a MAX4230 connected
as a voltage follower. The maximum output voltage
swing is load dependent; however, it is guaranteed to
be within 500mV of the positive rail (VDD= 2.7V) even
with maximum load (32Ω to ground).
Observe the
Absolute Maximum Ratings
for power dissipation and output short-circuit duration (10s, max)
because the output current can exceed 200mA (see
the
Typical Operating Characteristics
.)
Input Capacitance
One consequence of the parallel-connected differential
input stages for rail-to-rail operation is a relatively large
input capacitance CIN(5pF typ). This introduces a pole
at frequency (2πR′CIN)-1, where R′ is the parallel combination of the gain-setting resistors for the inverting or
noninverting amplifier configuration (Figure 5). If the pole
frequency is less than or comparable to the unity-gain
bandwidth (10MHz), the phase margin is reduced, and
the amplifier exhibits degraded AC performance through
either ringing in the step response or sustained oscillations. The pole frequency is 10MHz when R′ = 2kΩ. To
maximize stability, R′ << 2kΩ is recommended.
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
To improve step response when R′ > 2kΩ, connect
small capacitor Cfbetween the inverting input and output. Choose Cfas follows:
Cf= 8(R / Rf) [pf]
where Rfis the feedback resistor and R is the gain-setting resistor (Figure 5).
Driving Capacitive Loads
The MAX4230–MAX4234 have a high tolerance for
capacitive loads. They are stable with capacitive loads
up to 780pF. Figure 6 is a graph of the stable operating
region for various capacitive loads vs. resistive loads.
Figures 7 and 8 show the transient response with
excessive capacitive loads (1500pF), with and without
the addition of an isolation resistor in series with the
output. Figure 9 shows a typical noninverting capacitive-load-driving circuit in the unity-gain configuration.
Figure 5. Inverting and Noninverting Amplifiers with Feedback
Compensation
Figure 6. Capacitive-Load Stability
Figure 8. Small-Signal Transient Response with Excessive
Capacitive Load with Isolation Resistor
Figure 7. Small-Signal Transient Response with Excessive
Capacitive Load
INVERTING
R
V
IN
NONINVERTING
R
C
f
R
f
V
OUT
MAX4230
R′ = R || R
f
RfCf = RC
IN
V
IN
V
OUT
MAX4230
R
f
C
f
R′ = R || R
f
RfCf = RC
IN
2500
2000
1500
1000
CAPACITIVE LOAD (pF)
500
VDD = 5.0V
TO VDD/2
R
L
0
1100101k10k100k
RESISTIVE LOAD (Ω)
20mV/div
UNSTABLE
STABLE
20mV/div
VDD = 3.0V, CL = 1500pF
R
= 100kΩ, R
L
ISO
= 0Ω
1µs/div
20mV/div
20mV/div
VDD = 3.0V, CL = 1500pF
= 100kΩ, R
R
L
ISO
= 39Ω
1µs/div
MAX4230–MAX4234
The resistor improves the circuit’s phase margin by isolating the load capacitor from the op amp’s output.
Power-Up and Shutdown Modes
The MAX4231/MAX4233 have a shutdown option. When
the shutdown pin (SHDN) is pulled low, supply current
drops to 0.5µA per amplifier (VDD= 2.7V), the amplifiers are disabled, and their outputs are driven to VSS.
Since the outputs are actively driven to VSSin shutdown, any pullup resistor on the output causes a current drain from the supply. Pulling SHDN high enables
the amplifier. In the dual MAX4233, the two amplifiers
shut down independently. Figure 10 shows the
MAX4231’s output voltage to a shutdown pulse. The
MAX4231–MAX4234 typically settle within 5µs after
power-up. Figures 11 and 12 show IDDto a shutdown
plus and voltage power-up cycle.
When exiting shutdown, there is a 6µs delay before the
amplifier’s output becomes active (Figure 10).
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
2.7V to 5.5V supply, or from dual ±1.35V to ±2.5V supplies. For single-supply operation, bypass the power
supply with a 0.1µF ceramic capacitor. For dual-supply
operation, bypass each supply to ground. Good layout
improves performance by decreasing the amount of
stray capacitance at the op amps’ inputs and outputs.
Decrease stray capacitance by placing external components close to the op amps’ pins, minimizing trace
and lead lengths.
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX4230–MAX4234
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX4230–MAX4234
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
α
α
MAX4230–MAX4234
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
α
α
MAX4230–MAX4234
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
UCSP.EPS
MAX4230–MAX4234
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX4230–MAX4234
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX4230–MAX4234
High-Output-Drive, 10MHz, 10V/µs,
Rail-to-Rail I/O Op Amps with Shutdown in SC70
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. The parametric values (min and max limits) shown in
the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
28
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