Product announcements touting enhanced functionality, features, and performance generally get the bulk of the new-product attention, and for good reason: They often make the designer’s challenges anywhere from a little easier to much easier. In contrast, second sources don’t get a lot of new-product attention, but they play an important role in the parts-procurement ecosystem.
What is a second source? In principle, it’s a component that’s form, fit, and functional equivalent to the original primary source. There’s also the “alternative source,” a component similar to the original but it may differ in several aspects such as packaging or performance. Finally, there’s the “improved second source” (ISS), which is just what the name indicates—it’s a second source but has one or more improved specifications.
[Some companies encourage designers to choose as many components for the bill of materials (BOM) as possible having second sources (regular or improved), to reduce supply-chain risk or problems with the original vendor. In general, using an ISS isn’t a problem but it can be, if the improved version changes a specification you were counting on. For example, an ISS op amp with lower bias current (IB) or quiescent current (Iq) should be fine, but what if the improvement is in increased bandwidth or slew rate, and your design relied on the original values for constraining bad behavior? Ooops….]
There’s a clear need and role for second sources, and that’s where a family of four 50-V motor-driver ICs from Toshiba Electronic Devices & Storage Corporation fills a role. Typical applications for these drivers include multifunction printers, automatic teller machines (ATMs), surveillance cameras, factory automation, and robotics.
The series includes a pair of two-phase bipolar stepper-motor-driver ICs and two constant-current dual H-bridge drivers for driving up to two motors each.
The TB67S581FNG and the TB67S580FNG are two-phase bipolar stepper-motor drivers that allow full, half, quarter, 1/8, 1/16, and 1/32 step operation (Fig. 1). Both devices feature a motor output-voltage rating up to 50 V, with the TB67S581FNG having an output current rating up to 2.5 A and the TB67S580FNG up to 1.6 A. They also support mixed, slow, and fast decay modes.
The TB67H481FNG and TB67H480FNG are constant-current dual H-bridge drivers, also featuring a motor output voltage rating up to 50 V and an output current rating up to 2.5 A (Fig. 2). These ICs can be used to power dc-brushed motors or bipolar stepping motors, and support the same decay modes as the stepper-motor ICs. The pair offers a choice between input interfaces, with the TB67H481FNG using a pulse-width-modulated (PWM) input while the TB67H480FNG employs a phase/enable input.
Motor output on-resistance (RDS(ON)) is only 0.4 Ω (typical) for both high-side and low-side, at 24 V with 2-A output current. Safety features include overcurrent, thermal shutdown, and undervoltage-lockout detection.
All four devices support motor power-supply voltages from 8.2 to 44 V and consume less than 10 μA (typical) in sleep mode. They’re housed in 6.4- × 9.7-mm HTSSOP28 packages. The mounting area of this package is approximately 39% smaller compared to the previous generation.
Each motor-driver IC has its own detailed datasheet, and although these are second sources, that doesn’t mean they have no need for user support beyond those datasheets. Created in partnership with MikroElektronika and extending its Click Board series, Toshiba offers compact evaluation boards (Fig. 3).
The Stepper 9 Click (TB67S581FNG), Stepper 20 Click (TB67S580FNG), DC Motor 13 Click (TB67H481FNG), and DC Motor 23 Click (TB67H480FNG) (Fig. 4) are supported by a mikroSDK-compliant library, simplifying software development.
