Support Mixed-Mode Signal Operation

(5-V Input and Output Voltages With

3.3-V VCC)

Support Unregulated Battery Operation

Down to 2.7 V

Typical VOLP (Output Ground Bounce)

<0.8 V at VCC = 3.3 V, TA = 25°C

Ioff and Power-Up 3-State Support Hot

Insertion

Bus-Hold on Data Inputs Eliminates the

Need for External Pullup/Pulldown

Resistors

Latch-Up Performance Exceeds 500 mA Per

JESD 17

ESD Protection Exceeds JESD 22

− 2000-V Human-Body Model (A114-A)

− 200-V Machine Model (A115-A)

description/ordering information

These octal bus transceivers and registers are designed specifically for low-voltage (3.3-V) VCC operation, but

with the capability to provide a TTL interface to a 5-V system environment.

The ’LVTH2952 devices consist of two 8-bit back-to-back registers that store data flowing in both directions

between two bidirectional buses. Data on the A or B bus is stored in the registers on the low-to-high transition

of the clock (CLKAB or CLKBA) input, provided that the clock-enable (CLKENAB or CLKENBA) input is low.

Taking the output-enable (OEAB or OEBA) input low accesses the data on either port.

Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level. Use of pullup

or pulldown resistors with the bus-hold circuitry is not recommended.

When VCC is between 0 and 1.5 V, the devices are in the high-impedance state during power up or power down.

However, to ensure the high-impedance state above 1.5 V, OE should be tied to VCC through a pullup resistor;

the minimum value of the resistor is determined by the current-sinking capability of the driver.

These devices are fully specified for hot-insertion applications using Ioff and power-up 3-state. The Ioff circuitry

disables the outputs, preventing damaging current backflow through the devices when they are powered down.

The power-up 3-state circuitry places the outputs in the high-impedance state during power up and power down,

which prevents driver conflict.