SLAS536D September 2007 – November 2021 DAC5662A
PRODUCTION DATA
The architecture of the DAC5662A uses a current steering technique to enable fast switching and high update rate. The core element within the monolithic DAC is an array of segmented current sources that are designed to deliver a full-scale output current of up to 20 mA. An internal decoder addresses the differential current switches each time the DAC is updated and a corresponding output current is formed by steering all currents to either output summing node, IOUT1 and IOUT2. The complementary outputs deliver a differential output signal, which improves the dynamic performance through reduction of even-order harmonics, common-mode signals (noise), and double the peak-to-peak output signal swing by a factor of two, compared to single-ended operation.
The segmented architecture results in a significant reduction of the glitch energy, improves the dynamic performance (SFDR), and DNL. The current outputs maintain a high output impedance of greater
than 300 kΩ.
When GSET is high (one resistor mode), the full-scale output current for both DACs is determined by the ratio of the internal reference voltage (1.2 V) and an external resistor RSET connected to BIASJ_A. When GSET is low (two resistor mode), the full-scale output current for each DACs is determined by the ratio of the internal reference voltage (1.2 V) and separate external resistors RSET connected to BIASJ_A and BIASJ_B. The resulting IREF is internally multiplied by a factor of 32 to produce an effective DAC output current that can range from 2 mA to 20 mA, depending on the value of RSET.
The DAC5662A is split into a digital and an analog portion, each of which is powered through its own supply pin. The digital section includes edge-triggered input latches and the decoder logic, while the analog section comprises the current source array with its associated switches, and the reference circuitry.