MAX9619 Maxim, MAX9619 Datasheet - Page 7

• Manufacturer Part Number: MAX9619
• Description: The MAX9617–MAX9620 are low-power, zero-drift operational amplifiers available in space-saving SC70 packages
• Manufacturer: Maxim

The MAX9617–MAX9620 are precision, low-power op
amps ideal for signal processing applications. The
MAX9617, MAX9619, and MAX9620 are single-channel
devices. The MAX9618 is a dual-channel device. These
devices use an innovative autozero technique that allows
precision and low noise with a minimum amount of
power. The low input offset voltage, CMOS inputs, and
the absence of 1/f noise allows for optimization of active
filter designs.
The MAX9617–MAX9620 achieve rail-to-rail performance
at the input through the use of a low-noise charge pump.
This ensures a glitch-free, common-mode input voltage
range extending from the negative supply rail up to
the positive supply rail, eliminating crossover distortion
common to traditional n-channel/p-channel CMOS pair
inputs, reducing harmonic distortion at the output.
The MAX9619 features a shutdown mode that greatly reduc-
es quiescent current when the device is not operational.
The MAX9617–MAX9620 feature an autozero circuit that
allows the device to achieve less than 10FV (max) of
input offset voltage and eliminates the 1/f noise.
An internal charge pump provides an internal supply typi-
cally 1V beyond the upper rail. This internal rail allows the
MAX9617–MAX9620 to achieve true rail-to-rail inputs and
outputs, while providing excellent common-mode rejec-
tion, power-supply rejection ratios, and gain linearity.
The charge pump requires no external components, and
in most applications is entirely transparent to the user.
The operating frequency is well beyond the unity-gain
Figure 1. Typical Application Circuit: Sallen-Key Active Lowpass Filter
High-Efficiency, 1.5MHz Op Amps with RRIO
_______________________________________________________________________________________
Detailed Description
V
IN
Internal Charge Pump
Autozero
Single/Dual SC70, Zero-Drift,
MAX9617
+5V
frequency of the amplifier, avoiding aliasing or other sig-
nal integrity issues in sensitive applications.
The MAX9619 features an active-low shutdown mode
that lowers the quiescent current to less than 300nA. In
shutdown mode, the inputs and output are high imped-
ance. This allows multiple devices to be multiplexed
onto a single line without the use of external buffers. Pull
SHDN high for normal operation.
The shutdown high (V
are designed for ease of integration with digital con-
trols like microcontroller outputs. These thresholds are
independent of supply, eliminating the need for external
pulldown circuitry.
The MAX9617–MAX9620 low-power, low-noise, and
precision operational amplifiers are designed for appli-
cations in the portable medical, such as ECG and pulse
oximetry, portable consumer, and industrial markets.
The MAX9617–MAX9620 are also ideal for loop-powered
systems that interface with pressure sensors or strain
gauges.
Driving large capacitive loads can cause instability in
many op amps. The MAX9617–MAX9620 are stable
with capacitive loads up to 400pF. Stability with higher
capacitive loads can be improved by adding an isolation
resistor in series with the op-amp output. This resistor
improves the circuit’s phase margin by isolating the load
capacitor from the amplifier’s output. The graph in the
Typical Operating Characteristics gives the stable oper-
ation region for capacitive load versus isolation resistors.
Applications Information
IH
) and low (V
Capacitive-Load Stability
ADC
Shutdown Operation
IL
) threshold voltages
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