T4260-IL Atmel, T4260-IL Datasheet - Page 25

• Manufacturer Part Number: T4260-IL
• Description: IC RECEIVER AM/FM FRONT 44-SSOP
• Manufacturer: Atmel

Specifications of T4260-IL

• Frequency: AM, FM
• Modulation Or Protocol: AM, FM
• Applications: AM/FM Radio Receiver
• Current - Receiving: 85mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 8 V ~ 10 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -
• Sensitivity: -
• Memory Size: -
• Data Rate - Maximum: -

Charge Pump Current
Settings
AM Prescaler (Divider)
Settings
4528J–AUDR–11/04
Bit 62 (0 = 1 mA; 1 = 2 mA) allows to adjust the high current, which is active during a
frequency change (if the delay time of the active HCDEL register is not switched off). A
high charge pump current allows faster frequency changes. After a frequency change,
the current reduction is reduced (in locked mode) to the low current which is set by
bit 63 (0 = 50 µA; 1 = 100 µA). A lower charge pump current guarantees a higher S/N
ratio.
The high current charge pump can be switched off by the active HCDEL register bits. In
this case, when HCDEL 1 is active and the bits 20 and 21 are 0 (HCDEL 1 delay time =
off) or HCDEL 2 is active and the bits 22 and 23 are 0 (HCDEL 2 delay time = off), only
the low current charge pump (current) is active in locked and in the frequency change
mode.
The AM mixer is used for up-conversion of the AM reception frequency to the IF fre-
quency. Therefore, an AM prescaler is implemented to generate the necessary LO from
the VCO frequency. For the reception of the AM band, different prescaler (divider) set-
tings are possible.
Table 28 lists the AM prescaler (divider) settings and the reception frequencies.
f
f
f
f
The following formula can also be useful by AM frequencies higher than 20 MHz:
f
Table 28. AM Prescaler (Divider) Settings and the Reception Frequencies
Note:
VCO
IF
rec
VCO
VCO
= 10.7 MHz
= f
Divider (AM Prescaler)
= 98.2 MHz to 124 MHz
= AM prescaler
= AM prescaler
VCO
The AM Prescaler Divider Settings with f
ple. The tuning range depends on the tuning diode and the inductor in the VCO circuit.
The tank of the VCO should be designed for a maximum range at pin 18 (VTUNE) of
1.5 V to VSPLL - 1 V for a good S/N performance.
Divide by 10
- f
Divide by 2
Divide by 3
Divide by 4
Divide by 5
Divide by 6
Divide by 7
Divide by 8
Divide by 9
No divider
IF
x
x
(f
(f
rec
rec
+ f
- f
IF
IF
)
)
Minimum Reception
Frequency [MHz]
22.033
13.85
5.667
3.329
1.575
0.211
87.5
38.4
8.94
VCO
0
from 98.2 MHz to 124 MHz is only an exam-
Maximum Reception
Frequency [MHz]
30.633
113.3
9.967
7.014
3.078
51.3
20.3
14.1
4.8
1.7
T4260
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