M65850P/FP
3. Input/output LPF
It is necessary to change the LPF setting (signal pass band, fsig) of digital echo according to the clock frequency.
(Refer to the table below)
LPF1
REF
LPF2
REF
+
–
+
–
*
*
*
*
1
2
9
8
C2
C2
* (FP: 2)
* (FP: 3)
* (FP: 10)
* (FP: 9)
R2
R2
R1
R1
R1
R1
C1
C1
1
∴ fsig =
2π C1 • C2 • R1 • R2
(VCC = 5 V, Vi = 100mVrms, f = 1 kHz, Ta = 25°C)
LPF
Distortion
(Reference Value)
(%)
Delay Time
Clock
Frequency (Hz)
Signal Pass
Band (Hz)
(ms)
R1 (Ω)
R2 (Ω)
C1 (F)
C2 (F)
15 to 30
11.0 M to 5.5 M
5.3 M to 1.64 M
1.62 M to 800 k
7 k
5 k
3 k
15 k
15 k
3300 p
680 p
0.2%
(Td = 20 ms)
31 to 100
13 k
16 k
13 k
16 k
4700 p
6800 p
1000 p
1500 p
0.3%
(Td = 50 ms)
101 to 200
1.2%
(Td = 160 ms)
4. Mute
When power is turned on, the mute function works automatically to prevent noise generation.
(Here, however, “mute” means the function which prevents noise generation after the reset time.)
Power on
time
Reset
period
Mute period
(about 260 ms)
Mute off
time
When power is ON (fck = 1 MHz)
REJ03F0171-0201 Rev.2.01 Jan 25, 2008
Page 6 of 11
RENESAS [ RENESAS TECHNOLOGY CORP ]
