Integrated T1/E1/J1 Short-Haul and Long-Haul Protection Switches

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 1.0Ω (max) on-resistance switches with 60pF/40pF on-/off-capacitances for interfacing to the LIU transmitter outputs. The MAX4670 also includes four 10Ω (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.

* Single +3.3V Supply Voltage

* Quad-DPDT/Octal-SPDT Switches Support Two T1/E1/J1 Ports

* Low RON

* 0.7Ω (typ) in Transmit Path; 5Ω (typ) in Receive Path

* Low CON/COFF

* 60pF/40pF (typ) in Transmit Path

* 24pF/12pF (typ) in Receive Path

* Chip Surge Protection

* IEC 61000-4-5 (8µs to 20µs Surge)

* Class 2 (±1kV)

* -70dB (typ) Crosstalk/Off-Isolation (3MHz)

* Small, 32-Pin TQFN Package