MCP4821 datasheet(15/48 Pages) MICROCHIP

15 / 48 page

 2010 Microchip Technology Inc.

DS22244B-page 15

MCP4801/4811/4821

3.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in Table 3-1.

3.1

Supply Voltage Pins (VDD, VSS)

VDD is the positive supply voltage input pin. The input

supply voltage is relative to VSS and can range from

2.7V to 5.5V. The power supply at the VDD pin should

be as clean as possible for good DAC performance.

Using an appropriate bypass capacitor of about 0.1 µF

(ceramic) to ground is recommended. An additional

10 µF capacitor (tantalum) in parallel is also recom-

mended to further attenuate high-frequency noise

present in application boards.

VSS is the analog ground pin and the current return

path of the device. The user must connect the VSS pin

ground

plane

through

low-impedance

connection. If an analog ground path is available in the

application Printed Circuit Board (PCB), it is highly

recommended that the VSS pin be tied to the analog

ground path or isolated within an analog ground plane

of the circuit board.

3.2

Chip Select (CS)

CS is the Chip Select input pin, which requires an

active low to enable serial clock and data functions.

3.3

Serial Clock Input (SCK)

SCK is the SPI compatible serial clock input pin.

3.4

Serial Data Input (SDI)

SDI is the SPI compatible serial data input pin.

3.5

Latch DAC Input (LDAC)

LDAC (latch DAC synchronization input) pin is used to

transfer the input latch register to the DAC register (out-

put latches, VOUT). When this pin is low, VOUT is

updated with input register content. This pin can be tied

to low (VSS) if the VOUT update is desired at the rising

edge of the CS pin. This pin can be driven by an exter-

nal control device such as an MCU I/O pin.

3.6

Analog Output (VOUT)

VOUT is the DAC analog output pin. The DAC output

has an output amplifier. The full-scale range of the DAC

output is from VSS to G*VREF, where G is the gain

selection option (1x or 2x). The DAC analog output

cannot go higher than the supply voltage (VDD).

3.7

Exposed Thermal Pad (EP)

There is an internal electrical connection between the

exposed thermal pad (EP) and the VSS pin. They must

be connected to the same potential on the PCB.

TABLE 3-1:

PIN FUNCTION TABLE FOR MCP4801/4811/4821

MCP4801/4811/4821

Symbol

Description

MSOP, PDIP,

SOIC, DFN

DFN

VDD

Supply Voltage Input (2.7V to 5.5V)

Chip Select Input

SCK

Serial Clock Input

SDI

Serial Data Input

LDAC

DAC Output Synchronization Input. This pin is used to transfer the input

SHDN

Hardware Shutdown Input

VSS

Ground reference point for all circuitry on the device

VOUT

DAC Analog Output

—

Exposed thermal pad. This pad must be connected to VSS in application

MCP4821 Datasheet(PDF) 15 Page - Microchip Technology

MCP4821 Datasheet(HTML) 15 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

Datasheet Download

Link URL