Datasheet MAX44260 (Analog Devices) - 10

link to page 10 link to page 10 MAX44259/MAX44260/ 1.8V, 15MHz Low-Offset, MAX44261/MAX44263 Low-Power, Rail-to-Rail I/O Op Amps
Detailed Description Crossover Distortion
The MAX44259/MAX44260/MAX44261/MAX44263 are These op amps feature a low-noise integrated charge high-speed low-power op amps ideal for signal process- pump that creates an internal voltage rail 1V above ing applications due to the device’s high precision and VDD, which is used to power the input differen- low-noise CMOS inputs. The devices self-calibrate on tial pair of PMOS transistors as shown in Figure 1. power-up to eliminate effects of temperature and power- Such a unique architecture eliminates crossover distor- supply variation. tion common in traditional CMOS input architecture The MAX44260 also features a low-power shutdown (Figure 2), especially when used in a noninverting mode that greatly reduces quiescent current while the configuration, such as for Sallen-Key filters. device is not operational and recovers in 30µs. The charge pump’s operating frequency lies well above the The MAX44261 features a user-selectable self-calibration unity-gain frequency of the amplifier. Thanks to its high- input that shuts down the device and allows it to be reca- frequency operation and ultra-quiet circuitry, the charge librated at any time. The calibration routine takes 10ms. pump generates little noise, does not require external components, and is entirely transparent to the user. Figure 1 INTERNAL CHARGE PUMP STANDARD INPUT STRUCTURE MAX44260 INPUTS STRUCTURE Figure 1. Comparing the Input Structure of the MAX44260 to Standard Op-Amp Inputs Figure 2 CROSSOVER DISTORTION AMPLIFIER OUTPUT MAX44261 TIME Figure 2. Crossover Distortion of Typical Amplifiers www.maximintegrated.com Maxim Integrated │ 10