U2270B-MFPG3Y Atmel, U2270B-MFPG3Y Datasheet - Page 7

• Manufacturer Part Number: U2270B-MFPG3Y
• Description: IC BASEREADER RFID 125KHZ 16SOIC
• Manufacturer: Atmel
• Series: U2270Br

Specifications of U2270B-MFPG3Y

• Rf Type: Read / Write
• Frequency: 125kHz
• Features: Read/Write Base Station
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Pin Count: 16
• Screening Level: Industrial
• Package Type: SOIC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.4
3.5
4684E–RFID–02/08
Low-pass Filter (LPF)
Amplifier (AMP)
The fully integrated low-pass filter (4th-order Butterworth) removes the remaining carrier signal
and high-frequency disturbances after demodulation. The upper cut-off frequency of the LPF
depends on the selected oscillator frequency. The typical value is f
f
A high-pass characteristic results from the capacitive coupling at the input pin 4 as shown in
ure
impedances of the signal source and LPF input (typical 210 k ) have to be considered. The rec-
ommended values of the input capacitor for selected data rates are given in
“Applications”
Note:
Figure 3-6.
The differential amplifier has a fixed gain, typically 30. The HIPASS pin is used for DC decou-
pling. The lower cut-off frequency of the decoupling circuit can be calculated as follows:
The value of the internal resistor R
Recommended values of C
on
f
Osc
cut
page
=
/ 25 are possible if bi-phase or Manchester encoding is used.
3-6. The input voltage swing is limited to 2 V
--------------------------------------------
2
After switching on the carrier, the DC voltage of the coupling capacitor changes rapidly. When the
antenna voltage is stable, the LPF needs approximately 2 ms to recover full sensitivity.
10.
1
C
, on
Equivalent Circuit of Pin Input
HP
page
R
i
10.
HP
R
for selected data rates can be found in
S
C
i
IN
can be assumed to be 2.5 k .
Input
V
Bias
10 k
- 0.4V
pp
. For frequency response calculation, the
V
Bias
+ 0.4V
210 k
Osc
Section
/ 18, and data rates up to
4.,
“Applications”
U2270B
Section
Fig-
4.,
7
,