Analog Devices MAX8521 Product Info

• Circuit Footprint of 0.31in²
• Low-Profile Design
• On-Chip Power MOSFETs
• High-Efficiency Switch-Mode Design
• Ripple Cancellation for Low Noise
• Direct Current Control Prevents TEC Current Surges
• 5% Accurate Adjustable Heating/Cooling Current Limits
• 2% Accurate TEC Voltage Limit
• No Dead Zone or Hunting at Low Output Current
• ITEC Monitors TEC Current
• 1% Accurate Voltage Reference
• Switching Frequency Up to 1MHz
• Synchronization (MAX8521)

The MAX8520/MAX8521 are designed to drive thermoelectric 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/MAX8521 operate from a single supply and bias the TEC between the outputs of two synchronous buck regulators. This operation allows for temperature 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 TQFN package and its switching frequency is adjustable up to 1MHz through an external resistor. The MAX8521 is also available in a 5mm x 5mm TQFN as well as space-saving 3mm x 3mm UCSP™ and 36-bump WLP (3mm x 3mm) packages, with a pin-selectable switching frequency of 500kHz or 1MHz.

Applications

• Automated Test Equipment (ATE)
• Biotech Lab Equipment
• Fiber Optic Network Equipment
• Fiber-Optic Laser Modules
• SFF/SFP Modules