MCP413X datasheet(39/88 Pages) MICROCHIP

39 / 88 page

DS22060B-page 39

MCP413X/415X/423X/425X

5.3

Shutdown

Shutdown is used to minimize the device’s current

consumption. The MCP4XXX has two methods to

achieve this. These are:

• Hardware Shutdown Pin (SHDN)

• Terminal Control Register (TCON)

The Hardware Shutdown pin is backwards compatible

with the MCP42XXX devices.

5.3.1

HARDWARE SHUTDOWN PIN

(SHDN)

The SHDN pin is available on the dual potentiometer

devices. When the SHDN pin is forced active (VIL):

• The P0A and P1A terminals are disconnected

• The P0W and P1W terminals are simultaneously

connect to the P0B and P1B terminals,

respectively (see Figure 5-2)

• The Serial Interface is NOT disabled, and all

Serial Interface activity is executed

The Hardware Shutdown pin mode does NOT corrupt

the values in the Volatile Wiper Registers nor the

TCON register. When the Shutdown mode is exited

(SHDN pin is inactive (VIH)):

• The device returns to the Wiper setting specified

by the Volatile Wiper value

• The TCON register bits return to controlling the

terminal connection state

FIGURE 5-2:

Hardware Shutdown

Resistor Network Configuration.

5.3.2

TERMINAL CONTROL REGISTER

(TCON)

The Terminal Control (TCON) register is a volatile

resistor network terminal pin (A, B, and W) to the

Resistor

Network.

This

shown

The RxHW bits forces the selected resistor network

into the same state as the SHDN pin. Alternate

low-power configurations may be achieved with the

RxA, RxW, and RxB bits.

5.3.3

INTERACTION OF SHDN PIN AND

TCON REGISTER

Figure 5-3 shows how the SHDN pin signal and the

RxHW bit signal interact to control the hardware

shutdown of each resistor network (independently).

Using the TCON bits allows each resistor network (Pot

0 and Pot 1) to be individually “shutdown” while the

hardware pin forces both resistor networks to be “shut-

down” at the same time.

FIGURE 5-3:

RxHW bit and SHDN pin

Interaction.

Note:

When the RxHW bit forces the resistor

network into the hardware SHDN state,

the state of the TCON register RxA, RxW,

and RxB bits is overridden (ignored).

When the state of the RxHW bit no longer

forces the resistor network into the hard-

ware SHDN state, the TCON register RxA,

RxW, and RxB bits return to controlling the

terminal connection state. In other words,

the RxHW bit does not corrupt the state of

the RxA, RxW, and RxB bits.

SHDN (from pin)

RxHW

(from TCON register)

To Pot x Hardware

Shutdown Control

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