MAX8520/MAX8521 are designed to drive thermo- electric coolers (TECs) in space-constrained optical modules. Both devices deliver ±1.5A output current and control the TEC current to eliminate harmful current surges. On-chip FETs minimize external components and high switching frequency reduces the size of external components. The MAX8520 and MAX8521 operate from a single supply and bias the TEC between the outputs of two synchro- nous buck regulators. This operation allows for temper- ature control without “dead zones” or other nonlinearities at low current. This arrangement ensures that the control system does not hunt when the set point is very close to the natural operating point, requiring a small amount of heating or cooling. An analog control signal precisely sets the TEC current. Both devices feature accurate, individually adjustable heating current limit and cooling current limit, along with maximum TEC voltage limit to improve the reliability of optical modules. An analog output signal monitors the TEC current. A unique ripple cancellation scheme helps reduce noise. The MAX8520 is available in a 5mm x 5mm thin QFN package and its switching frequency is adjustable up to 1MHz through an external resistor. The MAX8521 is also available in a 5mm x 5mm thin QFN, as well as a space- saving 3mm x 3mm UCSP™, with a pin-selectable switching frequency of 500kHz or 1MHz. Applications SFF/SFP Modules Fiber-Optic Laser Modules Fiber-Optic Network Equipment
The MAX8520 and MAX8521 are ultra‑compact TEC power drivers designed for space‑constrained optical modules. Both devices deliver a bidirectional ±1.5 A TEC current, feature on‑chip MOSFETs to reduce external components, and use a dual synchronous buck regulator architecture to eliminate dead‑zone temperature control.
The drivers support selectable switching frequencies up to 1 MHz, provide precise analog current control, and include ripple‑cancellation circuitry for low‑noise operation. They are offered in 5 mm × 5 mm thin QFN packages (MAX8520) and a 3 mm × 3 mm UCSP package (MAX8521).
| Input Supply Range | 3.0 V – 5.5 V |
|---|---|
| Maximum TEC Current | ±1.5 A |
| Switching Frequency | up to 1 MHz |
| Package (MAX8520) | 5 mm × 5 mm thin QFN |
Both the MAX8520 and MAX8521 can supply a maximum TEC current of ±1.5 A.
The devices operate from 3.0 V to 5.5 V supply voltage.