SAM3S4B Atmel Corporation, SAM3S4B Datasheet - Page 1062

• Manufacturer Part Number: SAM3S4B
• Manufacturer: Atmel Corporation

Specifications of SAM3S4B

• Flash (kbytes): 256 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 64 MHz
• Cpu: Cortex-M3
• # Of Touch Channels: 23
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 79
• Ext Interrupts: 79
• Usb Transceiver: 1
• Quadrature Decoder Channels: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 3
• Twi (i2c): 2
• Uart: 4
• Ssc: 1
• Sd / Emmc: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 10
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1000
• Analog Comparators: 1
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 48
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 1.62 to 3.6
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 3
• Output Compare Channels: 3
• Input Capture Channels: 3
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

41.7.0.1
1062
SAM3S
Track and Hold Time versus Source Output Impedance
The following figure gives a simplified acquisition path.
Figure 41-12. Simplified Acquisition Path
During the tracking phase the ADC needs to track the input signal during the tracking time
shown below:
With t
Two cases must be considered:
Set TRANSFER = 1 and TRACTIM = 0.
In this case, the allowed Zsource can be computed versus the ADC frequency with the hypothe-
sis of t
Where t
f
20.00
16.00
10.67
8.00
6.40
5.33
4.57
4.00
3.56
3.20
2.91
2.67
2.46
2.29
2.13
2.00
1.00
• 10-bit mode: t
• 12-bit mode: t
1. The calculated tracking time (t
ADC
TRACK
= ADC clock (MHz)
TRACK
CP_ADC
expressed in ns and Z
= 15 × t
= 1/f
TRACK
TRACK
ADC
CP_ADC
.
Zsource
= 0.042 x Zsource + 160
= 0.054 x Zsource + 205
:
Z
Input
ADC
SOURCE
10
14
22
31
40
48
57
66
74
83
92
100
109
118
126
135
274
SOURCE
TRACK
expressed in Ohms.
(kOhms) for 12 bits
Mux.
Ron
) is lower than 15 t
Sample & Hold
Csample
CP_ADC
Z
14
19
30
41
52
63
74
85
97
108
119
130
141
152
164
175
353
SOURCE
.
12-bit
ADC
Core
(kOhms) for 10 bits
6500C–ATARM–8-Feb-11