MAX4337EUA Maxim Integrated Products, MAX4337EUA Datasheet - Page 11

• Manufacturer Part Number: MAX4337EUA
• Description: Op Amps 50mA IOUT Rail-Rail w/Shutdown/Mute
• Manufacturer: Maxim Integrated Products

Specifications of MAX4337EUA

• Number Of Channels: 2
• Voltage Gain Db: 95 dB
• Common Mode Rejection Ratio (min): 60 dB
• Input Offset Voltage: 3 mV
• Operating Supply Voltage: 3 V or 5 V
• Maximum Power Dissipation: 362 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: uMAX
• Minimum Operating Temperature: - 40 C

The MAX4335/MAX4336 can be used as a single-sup-
ply speaker driver, as shown in the Typical Operating
Circuit. Capacitor C1 is used for blocking DC (a 0.1µF
ceramic capacitor can be used). When choosing resis-
tors R3 and R4, take into consideration the input bias
current as well as how much supply current can be tol-
erated. Choose resistors R1 and R2 according to the
amount of gain and current desired. Capacitor C3
ensures unity gain for DC. A 10µF electrolytic capacitor
is suitable for most applications. The coupling capaci-
tor C2 sets a low-frequency pole and is fairly large in
value. For a 32
gives a low-frequency pole at 50Hz. The low-frequency
pole can be set according to the following equation:
Devices in the MAX4335–MAX4338 family of high-
output-current amplifiers have rail-to-rail input and output
stages designed for low-voltage, single-supply opera-
tion. The input stage consists of separate NPN and
PNP differential stages that combine to provide an
input common-mode range that extends 0.25V beyond
the supply rails. The PNP stage is active for input volt-
ages close to the negative rail, and the NPN stage is
active for input voltages near the positive rail. The
switchover transition region, which occurs near V
has been extended to minimize the slight degradation
in common-mode rejection ratio caused by mismatch of
the input pairs.
Since the input stage switches between the NPN and
PNP pairs, the input bias current changes polarity as the
input voltage passes through the transition region. Match
the effective impedance seen by each input to reduce the
offset error caused by input bias currents flowing through
external source impedances (Figures 3 and 5).
High source impedances, together with input capaci-
tance, can create a parasitic pole that produces an
underdamped signal response. Reducing the input
impedance or placing a small (2pF to 10pF) capacitor
across the feedback resistor improves response.
The MAX4335–MAX4338’s inputs are protected from large
differential input voltages by 1k
back-to-back double diodes across the inputs (Figure 5).
For differential voltages less than 1.2V, input resistance is
typically 500k . For differential input voltages greater
than 1.2V, input resistance is approximately 8.4k . The
input bias current is given by the following equation:
I
BIAS
SC70/SOT23-8, 50mA I
Single-Supply Speaker Driver
______________________________________________________________________________________
= (V
load, a 100µF coupling capacitor
= 1 / 2 (R
DIFF
Rail-to-Rail Input Stage
- 1.2V) / 8.4k
L
C2)
series resistors and
Op Amps with Shutdown/Mute
CC
/2,
The minimum output is within millivolts of ground for
single-supply operation, where the load is referenced
to ground (GND). Figure 6 shows the input voltage
range and the output voltage swing of a MAX4335 con-
nected as a voltage follower. The maximum output volt-
age swing is load dependent; however, it is guaranteed
to be within 400mV of the positive rail (V
even with maximum load (32 to V
The MAX4335–MAX4338 have a high tolerance for
capacitive loads. They are stable with capacitive loads
up to 200pF. Figure 7 is a graph of the stable operating
region for various capacitive loads vs. resistive loads.
Figure 3. Reducing Offset Error Due to Bias Current
(Noninverting)
Figure 4. Reducing Offset Error Due to Bias Current (Inverting)
R3 = R1
R3 = R1
OUT
R2
R2
R3
R1
R3
R1
, Rail-to-Rail I/O
Driving Capacitive Loads
Rail-to-Rail Output Stage
CC
R2
R2
/2).
MAX4335–MAX4338
MAX4335–MAX4338
CC
= 2.7V)
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