參數資料
型號: PCM1750P
英文描述: Dual CMOS 18-Bit Monolithic Audio ANALOG-TO-DIGITAL CONVERTER
中文描述: 雙通道CMOS 18位單片音頻模擬數字轉換器
文件頁數: 7/18頁
文件大?。?/td> 240K
代理商: PCM1750P
7
PCM1750
tions of the PCM1750. Two other switched-capacitor TDACs
(trim-DACs, which employ laser-trimmed nichrome resis-
tors) are also used to provide small correction voltages to the
latching comparators. These small correction voltages com-
pensate for ratio matching errors of the binary-weighted
capacitors in the CDAC. The comparators contain autozeroed
preamplifier stages ahead of the latching amplifier stage to
produce a one bit, serial data stream that controls the
successive approximation algorithm for each channel of the
PCM1750.
To simplify user application, the PCM1750 includes an
internal band-gap reference with fast settling buffer amplifi-
ers to drive the CDACs. The dual converters operate syn-
chronously (to minimize digital noise conversion errors)
using an external system clock (normally at 1X, 2X or 4X
the standard 48kHz audio sampling rate). By operating at a
2X or 4X oversampling rate the roll-off requirement for the
input anti-aliasing filters is relaxed. For example, 1X sys-
tems typically use a 9 to 11 pole LPF (low pass filter)
whereas a 4X system can use a 6th (or smaller) order filter
when an appropriate digital filter such as the DF1750 is used
in conjunction with the sampling system. Oversampling also
has the added benefit of improved signal to noise ratio and
total harmonic distortion. Two serial outputs, one for each
input channel, provide binary-two’s-complement coded out-
put to an optional external digital decimation filter when
over sampling operation is desired. The use of the optional
companion digital filter, the DF1750, is described later in
the installation and application sections of this product data
sheet. A separate product data sheet is also available for the
Burr-Brown DF1750 giving all the specifications and per-
formance diagrams associated with this digital filter.
SAMPLE (TRACKING) MODE
After each conversion, the dual ADC returns to the SAMPLE
mode in order to track the input signals. The switches shown
in the simplified circuit diagram of Figure 1 will then be in
the following states: S1 connects V
IN
to C1 ; S2 to S18
connect C2 to C18 to V
REF
; H1 and H2 connect the top
plates of the capacitor arrays to analog common; and the
latching comparator is switched into its auto-zero mode by
closing AZ1 to AZ4. Notice that C1 serves two purposes: it
samples and stores the input signal V
IN
and it is the MSB of
the CDAC. Storing V
REF
on C2 to C18 creates a bipolar
offset, enabling V
IN
to cover a span from –V
REF
to +V
REF
.
The 1/f noise as well as the DC input offset voltage of the
comparator are removed by an autozeroing cycle which
* Clock from optional digital filter chip (DF1750 4x decimation filter).
FIGURE 2. PCM1750 Input/Output Timing Diagram.
P11 (CONVERT)
P4 (EXT CLK IN)
3
4
1
2
18
19
16
17
*Master
System
Clock
64 1 2
3 4 5 6 7 8 9 10 11 12 13 14 15 16
50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 1 2
Bit 1
MSB
Bit 2
Bit 3
Bit 16
Bit 17
Bit 1
MSB
Bit 2
Bit 3
Bit 16
Bit 17
Bit 4
Bit 4
Bit 18
LSB
Bit 18
LSB
INTERNAL
S/H
CONTROL
SR1
SR2
SR3
P3 (SOUT L)
P12 (SOUT R)
Bit 3 test time
Bit 2 test time
Bit 1 test time
HOLD
SAMPLE
相關PDF資料
PDF描述
PCM1750U Dual CMOS 18-Bit Monolithic Audio ANALOG-TO-DIGITAL CONVERTER
PCM1753DBQR 24-BIT, 192 kHz SAMPLING ENHANCED MULTI-LEVEL, DELTA-SIGMA, AUDIO DIGITAL-TO-ANALOG CONVERTER
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PCM1753DBQ 24-BIT, 192 kHz SAMPLING ENHANCED MULTI-LEVEL, DELTA-SIGMA, AUDIO DIGITAL-TO-ANALOG CONVERTER
相關代理商/技術參數
參數描述
PCM1750P/PCM1750U 制造商:BB 制造商全稱:BB 功能描述:PCM1750P. PCM1750U - Dual CMOS 18-Bit Monolithic Audio ANALOG-TO-DIGITAL CONVERTER
PCM1750U 功能描述:音頻模/數轉換器 IC Dual CMOS 18-Bit Mono A/D Converter RoHS:否 制造商:Wolfson Microelectronics 轉換速率: 分辨率: ADC 輸入端數量: 工作電源電壓: 最大工作溫度: 最小工作溫度: 安裝風格: 封裝 / 箱體: 封裝:
PCM1750U/1K 功能描述:音頻模/數轉換器 IC Dual CMOS 18-Bit Mono A/D Converter RoHS:否 制造商:Wolfson Microelectronics 轉換速率: 分辨率: ADC 輸入端數量: 工作電源電壓: 最大工作溫度: 最小工作溫度: 安裝風格: 封裝 / 箱體: 封裝:
PCM1750U/1KG4 功能描述:音頻模/數轉換器 IC Dual CMOS 18-Bit Mono A/D Converter RoHS:否 制造商:Wolfson Microelectronics 轉換速率: 分辨率: ADC 輸入端數量: 工作電源電壓: 最大工作溫度: 最小工作溫度: 安裝風格: 封裝 / 箱體: 封裝:
PCM1750U1K 制造商:TI 制造商全稱:Texas Instruments 功能描述:Dual CMOS 18-Bit Monolithic Audio NALOG-TO-DIGITAL CONVERTER