CSP1027 Datasheet, PDF (51/64 Pages) Agere Systems – CSP1027 Voice Band Codec for Cellular Handset and Modem Applications

Data Sheet
December 1999
CSP1027 Voice Band Codec for
Cellular Handset and Modem Applications
10 Analog Characteristics and Requirements
The following analog characteristics and requirements are preliminary information and are subject to change. Ana-
log characteristics refer to the behavior of the device under specified conditions. Analog requirements refer to con-
ditions imposed on the user for proper operation of the device. All analog data is valid for the following conditions
unless otherwise specified:
s TA = –40 °C to +85 °C.
s VDDA = 5 V ± 10% (See Section 8.2 on page 47.)
s Sampling frequency = 8 kHz, oversampling clock (CKOS) = 1.0 MHz, input clock (CLK) = 25 MHz.
s 0.22 µF capacitors connected to the REFC pin.
s 0.15 µF coupling capacitors connected to the MICIN and AUXIN pins when EIGS = 0.
s Rfb = Rin = 24 kΩ, Cfb = 270 pF, and Cin = 1 µF when in the external input gain select mode (EIGS = 1).
s 2 kΩ differential output load connected between AOUTP and AOUTN pins.
s 1 µF and 0.1 µF bypass capacitors connected between the VREG and VSSA.
s 0 dBm0 is the level that corresponds to a sine wave that is 3.14 dB below the clipping (overload) level at the out-
put of the A/D or input to the D/A.
s All noise and distortion measurements are flat weighted and integrated over the 300 Hz to 4 kHz frequency band.
10.1 Analog Input and Microphone Regulator
Table 14. Analog Input Characteristics and Requirements
Symbol
Rin
Cin
—
—
—
Parameter
A/D Input Resistance of AUXIN and MICIN:
EIGS = 0
EIGS = 1
A/D Input Capacitance on AUXIN and MICIN
A/D Input Clipping Level at AUXIN or MICIN:
EIGS = 0, cioc0: IRSEL = 0
EIGS = 0, cioc0: IRSEL = 1
A/D Input Clipping Level at AUXIN:
EIGS = 1
Gain Referred to Nominal Clipping Level:
EIGS = 0, cioc0: IRSEL = 0
EIGS = 0, cioc0: IRSEL = 1
EIGS = 1
Note: The input clipping level corresponds to an A/D path output of 3.14 dBm0.
Min
40
1000
—
0.490
0.143
1.49
–0.18
–1.0
–0.5
Typ
—
—
—
0.500
0.160
1.578
0
0
0
Max
—
—
20
0.510
0.180
1.67
0.18
1.0
0.5
Unit
kΩ
kΩ
pF
Vp
Vp
Vp
dB
dB
dB
Table 15. Microphone Regulator Characteristics
Parameter
VREG Output Voltage
VREG Output Current
VREG Output Noise
Min
Typ
Max
Unit
2.7
3.0
3.3
Vrms
—
—
250
µA
—
—
100
µVrms
Note: VREG must be bypassed to analog ground through a 1 µF low ESR capacitor to meet this noise specification. The minimum bypass capac-
itance for stable VREG operation is 0.1 µF, with a maximum noise of 200 µVrms.
Lucent Technologies Inc.
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