CS4205-KQZ Cirrus Logic Inc, CS4205-KQZ Datasheet - Page 62

• Manufacturer Part Number: CS4205-KQZ
• Description: IC CODEC AC97 I2S 48-LQFP
• Manufacturer: Cirrus Logic Inc
• Type: Audio Codec '97r

Specifications of CS4205-KQZ

• Package / Case: 48-LQFP
• Data Interface: Serial
• Resolution (bits): 18, 20 b
• Number Of Adcs / Dacs: 1 / 2
• Sigma Delta: Yes
• Dynamic Range, Adcs / Dacs (db) Typ: 90 / 90
• Voltage - Supply, Analog: 4.75 V ~ 5.25 V
• Voltage - Supply, Digital: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Number Of Adc Inputs: 8
• Number Of Dac Outputs: 3
• Conversion Rate: 48 KSPs
• Interface Type: Serial (5-Wire)
• Resolution: 18 bit, 20 bit
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• Number Of Channels: 1 ADC, 1 DAC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 598-1182

11. CLOCKING
The CS4205 may be operated as a primary or sec-
ondary codec. As a primary codec, the system
clock for the AC-link may be generated from an ex-
ternal 24.576 MHz clock source, a 24.576 MHz
crystal, or the internal Phase Locked Loop (PLL).
The PLL allows the CS4205 to accept external
clock frequencies other than 24.576 MHz. As a
secondary codec, the system clock is derived from
BIT_CLK, which is generated by the primary co-
dec. The CS4205 uses the presence or absence of a
valid clock on the XTL_IN pin in conjunction with
the state of the ID[1:0]# pins to determine the
clocking configuration. See Table 27 for all avail-
able CS4205 clocking modes.
11.1 PLL Operation (External Clock)
The PLL mode is activated if a valid clock is
present on XTL_IN before the rising edge of
RESET#. Once PLL mode is entered, the
XTL_OUT pin is redefined as the PLL loop filter,
as shown in Figure 23. The ID[1:0]# inputs deter-
mine the configuration of the internal divider ratios
required to generate the 12.288 MHz BIT_CLK
output; see Table 27 on page 63 for additional de-
tails. In PLL mode, the CS4205 is configured as a
primary codec independent of the state of the
ID[1:0]# pins. If 24.576 MHz is chosen as the ex-
ternal clock input (ID[1:0]# inputs both pulled high
or left floating), the PLL is disabled and the clock
is used directly. The loop filter is not required and
XTL_OUT is left unconnected. For all other clock
input choices, the loop filter is required. The
ID[1:0] bits of the Extended Audio ID Register
(Index 28h) and the Extended Modem ID Register
(Index 3Ch) will always report ‘00’ in PLL mode.
62
11.2 24.576 MHz Crystal Operation
If a valid clock is not present on XTL_IN during
the rising edge of RESET#, the device disables the
PLL input and latches the state of the ID[1:0]# in-
puts. If the ID[1:0]# inputs are both pulled high or
left floating, the device is configured as a primary
codec. An external 24.576 MHz crystal is used as
the system clock as shown in Figure 24.
11.3 Secondary Codec Operation
If a valid clock is not present on XTL_IN and either
ID[1:0]# input is pulled low during the rising edge
of RESET#, the device is determined to be a sec-
ondary codec. The BIT_CLK pin is configured as
an input and the CS4205 is driven from the
12.288 MHz BIT_CLK of the primary codec. The
ID[1:0] bits of the Extended Audio ID Register
(Index 28h) and the Extended Modem ID Register
(Index 3Ch) will report the state of the ID[1:0]#
inputs.
Clock Source
Figure 23. PLL External Loop Filter
220 pF
DGND
0.022 uF
2.2 kΩ
XTL_IN
XTL_OUT
CS4205
DS489PP4