ADUC814 Analog Devices, ADUC814 Datasheet - Page 36

• Manufacturer Part Number: ADUC814
• Description: Precision Analog Microcontroller: 1.3MIPS 8052 MCU + 8kB Flash + 6-Ch 12-Bit ADC + Dual 12-Bit DAC
• Manufacturer: Analog Devices

Specifications of ADUC814

• Mcu Core: 8052
• Mcu Speed (mips): 1.3
• Sram (bytes): 256Bytes
• Gpio Pins: 17
• Adc # Channels: 6

ADuC814
Figure 40. Source and Sink Current Capability with V
Figure 41. Source and Sink Current Capability with V
4
3
1
0
5
4
3
2
1
0
0
0
DAC LOADED WITH 0FFFH
DAC LOADED WITH 0000H
SOURCE/SINK CURRENT (mA)
SOURCE/SINK CURRENT (mA)
5
5
DAC LOADED WITH 0FFFH
DAC LOADED WITH 0000H
10
10
REF
REF
= V
= V
DD
DD
= 5 V
= 3 V
15
15
Rev. A | Page 36 of 72
For larger loads, the current drive capability may not be sufficient.
To increase the source and sink current capability of the DACs,
an external buffer should be added, as shown in Figure 42.
The DAC output buffer also features a high impedance disable
function. In the chip’s default power-on state, both DACs are
disabled, and their outputs are in a high impedance state (or
three-state) where they remain inactive until enabled in
software. This means that if a zero output is desired during
power-up or power-down transient conditions, then a pull-
down resistor must be added to each DAC output. Assuming
this resistor is in place, the DAC outputs remain at ground
potential whenever the DAC is disabled.
Figure 42. Buffering the DAC Outputs
DAC0
DAC1
ADuC814