1FEATURES

2? Member of the Texas Instruments Widebus?

Family

? Output Voltage Translation Tracks VCC

? Supports Mixed-Mode Signal Operation on

All Data I/O Ports

– 5-V Input Down to 3.3-V Output Level

Shift With 3.3-V VCC

– 5-V/3.3-V Input Down to 2.5-V Output

Level Shift With 2.5-V VCC

? 5-V Tolerant I/Os With Device Powered Up

or Powered Down

? Bidirectional Data Flow With Near-Zero

Propagation Delay

? Low ON-State Resistance (ron) Characteristics

(ron = 5 Ω Typ)

? Low Input/Output Capacitance Minimizes

Loading (Cio(OFF) = 5 pF Typ)

? Data and Control Inputs Provide

Undershoot Clamp Diodes

? Low Power Consumption

(ICC = 70 μA Max)

? VCC Operating Range From 2.3 V to 3.6 V

? Data I/Os Support 0- to 5-V Signaling Levels

(0.8 V, 1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V, 5 V)

? Control Inputs Can Be Driven by TTL

or 5-V/3.3-V CMOS Outputs

? Ioff Supports Partial-Power-Down Mode

Operation

? Latch-Up Performance Exceeds 250 mA Per

JESD 17

? ESD Performance Tested Per JESD 22

– 2000-V Human-Body Model

(A114-B, Class II)

– 1000-V Charged-Device Model (C101)

? Supports Digital Applications: Level

Translation, PCI Interface, Bus Isolation

? Ideal for Low-Power Portable Equipment

DESCRIPTION/ORDERING INFORMATION

The SN74CB3T16211 is a high-speed TTL-compatible FET bus switch with low ON-state resistance (ron),

allowing for minimal propagation delay. The device fully supports mixed-mode signal operation on all data I/O

ports by providing voltage translation that tracks VCC. The SN74CB3T16211 supports systems using 5-V TTL,

3.3-V LVTTL, and 2.5-V CMOS switching standards, as well as user-defined switching levels (see Figure 1).

The I/O port of this device has a pullup current source that maintains the output voltage at VCC when the device

is ON, and the input is greater than or equal to VCC – 1. Because of the pullup current source, the output voltage

level may be less than VCC when the operating frequency is low and the I/O port is connected to a pulldown

resistor. In order to maintain the output voltage at VCC, a pullup resistor must be connected to VCC instead of a

pulldown resistor to ground.

The SN74CB3T16211 is organized as two 12-bit bus switches with separate output-enable (1OE, 2OE) inputs. It

can be used as two 12-bit bus switches or as one 24-bit bus switch. When OE is low, the associated 12-bit bus

switch is ON, and the A port is connected to the B port, allowing bidirectional data flow between ports. When OE

is high, the associated 12-bit bus switch is OFF, and a high-impedance state exists between the A and B ports.

This device is fully specified for partial-power-down applications using Ioff. The Ioff feature ensures that damaging

current will not backflow through the device when it is powered down. The device has isolation during power off.

To ensure the high-impedance state during power up or power down, 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.