The MAX4670 is an integrated T1/E1/J1 analog protection switch for 1+1 and N+1 line-card redundancy applications. It protects two T1/E1/J1 ports by combining eight SPDT switches in a single package. The switch is optimized for high-return loss and pulse-template performance in T1/E1/J1 long-haul and short-haul applications. The part offers built-in chip-side surge protection capability for short-haul intrabuilding applications.
The MAX4670 replaces two diode arrays or two transient voltage suppressors (TVSs) and four dual-SPDT relays, significantly reducing board space and simplifying PC board routing. The MAX4670 pinout is targeted for T1/E1/J1 applications, resulting in a simplified layout when interfacing with standard line transformers and line interface units (LIUs).
The MAX4670 has four 1.0 (max) on-resistance switches with 60pF/40pF on-/off-capacitances for interfacing to the LIU transmitter outputs. The MAX4670 also includes four 10 (max) on-resistance switches with low 24pF/12pF on-/off-capacitances for interfacing to the LIU receiver inputs. Four logic inputs control the receive/transmit pairs, in addition to a active-low SWITCH input that connects all switches to the system's protection bus.
The MAX4670 operates from a single +2.7V to +3.6V supply and is available in 32-pin thermally enhanced TQFN package. The MAX4670 is specified over the -40°C to +85°C operating temperature range.
Key Features
Single +3.3V Supply Voltage
Quad-DPDT/Octal-SPDT Switches Support Two T1/E1/J1 Ports
Low RON
0.7 (typ) in Transmit Path; 5 (typ) in Receive Path
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(max) on-resistance switches with 60pF/40pF on-/off-capacitances for interfacing to the LIU transmitter outputs. The MAX4670 also includes four 10