HD64F36077GHV Renesas Electronics America, HD64F36077GHV Datasheet - Page 398

• Manufacturer Part Number: HD64F36077GHV
• Description: 16BIT MCU FLASH 56K, SMD, LQFP64
• Manufacturer: Renesas Electronics America

Specifications of HD64F36077GHV

• No. Of I/o's: 47
• Ram Memory Size: 4KB
• Cpu Speed: 20MHz
• No. Of Timers: 4
• Digital Ic Case Style: LQFP
• Supply Voltage Range: 4.5V
• Core Size: 16bit
• Program Memory Size: 56KB
• Oscillator Type: External Only
• Controller Family/series: H8/300H
• Peripherals: ADC
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Section 18 A/D Converter
18.6
18.6.1
This LSI's analog input is designed such that conversion accuracy is guaranteed for an input signal
for which the signal source impedance is 5 kΩ or less. This specification is provided to enable the
A/D converter's sample-and-hold circuit input capacitance to be charged within the sampling time;
if the sensor output impedance exceeds 5 kΩ, charging may be insufficient and it may not be
possible to guarantee A/D conversion accuracy. However, for A/D conversion in single mode with
a large capacitance provided externally, the input load will essentially comprise only the internal
input resistance of 10 kΩ, and the signal source impedance is ignored. However, as a low-pass
filter effect is obtained in this case, it may not be possible to follow an analog signal with a large
differential coefficient (e.g., 5 mV/µs or greater) (see figure 18.6). When converting a high-speed
analog signal or converting in scan mode, a low-impedance buffer should be inserted.
18.6.2
Adding capacitance results in coupling with GND, and therefore noise in GND may adversely
affect absolute accuracy. Be sure to make the connection to an electrically stable GND.
Care is also required to ensure that filter circuits do not interfere with digital signals or act as
antennas on the mounting board.
Rev. 1.00 Sep. 16, 2005 Page 368 of 490
REJ09B0216-0100
Usage Notes
Permissible Signal Source Impedance
Influences on Absolute Accuracy
Sensor input
Figure 18.6 Analog Input Circuit Example
Sensor output
impedance
up to 5 kΩ
Low-pass
filter
C to 0.1 µF
This LSI
C
15 pF
in
=
A/D converter
equivalent circuit
10 kΩ
20 pF