PCM54KP [TI]
PARALLEL, WORD INPUT LOADING, 3us SETTLING TIME, 16-BIT DAC, PDIP28, PLASTIC, DIP-28;型号: | PCM54KP |
厂家: | TEXAS INSTRUMENTS |
描述: | PARALLEL, WORD INPUT LOADING, 3us SETTLING TIME, 16-BIT DAC, PDIP28, PLASTIC, DIP-28 输入元件 光电二极管 转换器 |
文件: | 总9页 (文件大小:89K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
®
PCM54
PCM55
DESIGNED FOR AUDIO
16-Bit Monolithic
DIGITAL-TO-ANALOG CONVERTERS
FEATURES
● PARALLEL INPUT FORMAT
● 96dB DYNAMIC RANGE
● 16-BIT RESOLUTION
● ±3V or ±1mA AUDIO OUTPUT
● 15-BIT MONOTONICITY (typ)
● OPERATES ON ±5V (PCM55) TO ±12V
(PCM54) SUPPLIES
● –92dB TOTAL HARMONIC DISTORTION
(K Grade)
● 28-PIN DIP (PCM54)
● 3µs SETTLING TIME (Voltage Out)
● 24-LEAD SOIC (PCM55)
DESCRIPTION
The PCM54 and PCM55 family of converters are
parallel input, fully monotonic, 16-bit digital-to-ana-
log converters that are designed and specified for
digital audio applications. These devices employ ul-
tra-stable nichrome (NiCr) thin-film resistors to pro-
vide monotonicity, low distortion, and low differential
linearity error (especially around bipolar zero) over
long periods of time and over the full operating
temperature.
can range from ±5V (PCM55) to ±12V (PCM54).
Power dissipation with ±5V supplies is typically less
than 200mW. Also included is a provision for exter-
nal adjustment of the MSB error (differential linearity
error at bipolar zero, PCM54 only) to further improve
Total Harmonic Distortion (THD) specifications if
desired.
A current output (IOUT) wiring option is provided. This
output typically settles to within ±0.006% of FSR
final value in 350ns (in response to a full-scale change
in the digital input code).
These converters are completely self-contained with a
stable, low noise, internal, zener voltage reference;
high speed current switches; a resistor ladder
network; and a fast settling, low noise output opera-
tional amplifier all on a single monolithic chip. The
converters are operated using two power supplies that
The PCM54 is packaged in 28-pin plastic DIP pack-
age. The PCM55 is available in a 24-lead plastic mini-
flatpak.
Reference
Voltage
RF
16-Bit Ladder
Parallel
Resistor Network
Digital
Input
and
Audio Output
(Voltage)
Current Switches
Output
Operational
Amplifier
International Airport Industrial Park
•
Mailing Address: PO Box 11400, Tucson, AZ 85734
FAXLine: (800) 548-6133 (US/Canada Only)
• Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111
Internet: http://www.burr-brown.com/
•
•
Cable: BBRCORP
•
Telex: 066-6491
•
FAX: (520) 889-1510
•
Immediate Product Info: (800) 548-6132
©1985 Burr-Brown Corporation
PDS-619B
Printed in U.S.A. August, 1998
SBAS146
SPECIFICATIONS
ELECTRICAL
At +25°C and ±VCC = 12V, unless otherwise noted.
PCM54HP, PCM55HP
PCM54JP, PCM55JP
PCM54KP
TYP
PARAMETER
MIN
TYP
MAX
MIN
TYP
MAX
MIN
MAX
UNITS
DIGITAL INPUTS
Resolution
Dynamic Range
16
96
✽
✽
✽
✽
Bits
dB
Logic Levels (TTL/CMOS Compatible):
VIH
VIL
+2.4
0
+5.25
+0.8
+40
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
V
V
µA
mA
I
IH, VIN = +2.7V
IIL, VIN = +0.4V
–0.5
TRANSFER CHARACTERISTICS
ACCURACY
Gain Error
Bipolar Zero Error
Differential Linearity Error at Biploar Zero(1)
Noise (rms) (20Hz to 20kHz) at Bipolar Zero
±2
±30
±0.001
12
✽
✽
✽
✽
✽
✽
✽
✽
%
mV
% FSR(2)
µV
TOTAL HARMONIC DISTORTION(3)
(16-Bit Resolution)
V
V
V
O = ±FS at f = 991Hz
O = –20dB at f = 991Hz
O = –60dB at f = 991Hz
–94
–74
–34
–82
–68
–28
✽
✽
✽
–88
✽
✽
✽
✽
✽
✽
–80
–40
–92
–74
–34
dB
dB
dB
MONOTONICITY
15
✽
✽
Bits
SETTLING TIME (to ±0.006% of FSR)
Voltage Output: 6V Step
1LSB Step
Current Output (1mA Step): 10Ω to 100Ω Load
1kΩ Load(4)
Deglitcher Delay (THD Test)(5)
Slew Rate
3
1
350
350
2.5
10
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
µs
µs
ns
ns
µs
4
✽
✽
V/µs
WARM-UP TIME
1
✽
✽
✽
✽
Min
ANALOG OUTPUT
Voltage Output: Bipolar Range
Output Current
Output Impedance
Short-Circuit Duration
Current Output:(6)
±3
✽
✽
V
mA
Ω
±2
0.1
✽
✽
✽
✽
Indefinite to Common
Bipolar Range (±30%)
Bipolar Output Impedance (±30%)
±1
1.2
✽
✽
✽
✽
mA
kΩ
POWER SUPPLY REQUIREMENTS
Voltage: +VCC (PCM54)
–VCC (PCM54)
+VCC (PCM55)
–VCC (PCM55)
Supply Drain: +VCC
–VCC
+4.75
+12
–12
+5
–5
+13
–16
+15.75
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
✽
V
V
V
V
mA
mA
–4.75
+4.75
–4.75
–15.75
+7.5
–7.5
+20
–25
TEMPERATURE RANGE
Operating
Storage
0
–55
+70
+100
✽
✽
✽
✽
✽
✽
✽
✽
°C
°C
✽ Specifications same as for PCM54HP.
NOTES: (1) Externally adjustable. If external adjustment is not used, connect a 0.01µF capacitor to Common to reduce noise pickup. (2) FSR means Full-Scale Range
and is 6V for ±3V output. (3) The measurement of total harmonic distortion is highly dependent on the characteristics of the measurement circuit. Burr-Brown may
calculate THD from the measured linearity errors using Equation 2 in the section on “Total Harmonic Distortion,” but specifies that the maximum THD measured with
the circuit shown in Figure 2 will be less than the limits indicated. (4) Measured with an active clamp to provide a low impedance for approximately 200ns. (5) Deglitcher
or sample/hold delay used in THD measurement test circuit. See Figures 2 and 3. (6) Output amplifier disconnected.
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN
assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject
to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not
authorize or warrant any BURR-BROWN product for use in life support devices and/or systems.
®
2
PCM54/55
CONNECTION DIAGRAMS
(1)
(Optional)
100kΩ
PCM54
560kΩ
330kΩ
1MΩ
PCM55
–VCC
+VCC
1
2
24
23
22
21
20
19
18
17
16
15
14
13
Zener
Voltage
Reference
1
2
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Zener
Voltage
Reference
–VCC
+VCC
(1)
3
+
1µF
+
1µF
16-Bit
3
4
Ladder
Resistor
Network
and
(2)
4
5
1µF
+
0.1µF
Common
(2)
(2)
5
6
+
1µF
16-Bit
Ladder
Resistor
Network
and
Switches
6
7
Audio
VOUT
7
8
Common
9
8
Switches
(3)
10
11
12
9
Data
Inputs
Audio
10
11
12
13
14
VOUT
Data
Inputs
NOTES: (1) Connect for bipolar operation. (+VCC ≥ 8.5V for unipolar operation.)
(2) Connect for VOUT operation. When VOUT amp is not being used (IOUT mode),
terminatewithanexternal3kΩ feedbackresistorbetweenpin17andpin19, and
a 1kΩ resistor between pin 19 and pin 20 to reduce possible noise effects.
NOTES: (1) MSB error (BPZ differential linearity error) can be adjusted to zero
using this external circuit. (2) Connect to bipolar operation (+VCC ≥ 8.5V for
unipolar operation). (3) Connect for VOUT operation. When VOUT amp is not being
used (IOUT mode), terminate with an external 3kΩ feedback resistor between pin
19 and pin 21, and a 1kΩ resistor between pin 21 and pin 22 to reduce possible
noise effects.
PIN ASSIGNMENTS
PIN ASSIGNMENTS
PIN
PCM54-DIP
PIN
PCM54-DIP
PIN
PCM55-SOIC
PIN
PCM55-SOIC
1
2
Trim
Bit 1 (MSB)
Bit 2
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Bit 13
Bit 14
Bit 15
Bit 16 (LSB)
VOUT
1
2
Bit 1 (MSB)
Bit 2
13
14
15
16
17
18
19
20
21
22
23
24
Bit 13
Bit 14
3
3
Bit 3
Bit 15
4
NC
4
Bit 4
Bit 16
5
Bit 3
5
Bit 5
VOUT
6
Bit 4
RFB
6
Bit 6
Feedback Resistor
Summing Junction
Common
Current Output
Bipolar Offset
+VCC
7
Bit 5
SJ
7
Bit 7
8
Bit 6
Common
IOUT
8
Bit 8
9
Bit 7
9
Bit 9
10
11
12
13
14
Bit 8
NC
10
11
12
Bit 10
Bit 11
Bit 12
Bit 9
IBPO
Bit 10
Bit 11
Bit 12
+VCC
–VCC
MSB Adjust
–VCC
ABSOLUTE MAXIMUM RATINGS
DC Supply Voltage ...................................................................... ±18VDC
Input Logic Voltage ............................................................... –1V to +5.5V
Power Dissipation ..................................PCM54 800mW, PCM55 400mW
Storage Temperature ...................................................... –55°C to +100°C
Lead Temperature, (soldering, 10s) .............................................. +300°C
PACKAGE INFORMATION
PACKAGE DRAWING
NUMBER(1)
PRODUCT
PACKAGE
28-Pin DIP
PCM54HP
PCM54JP
PCM54KP
PCM55HP
PCM55JP
215
215
215
178
178
28-Pin DIP
28-Pin DIP
ORDERING INFORMATION
24-Lead SOIC
24-Lead SOIC
PRODUCT
THD at FS
PACKAGE
PCM54HP
PCM54JP
PCM54KP
0.008
0.004
0.0025
28-Pin DIP
28-Pin DIP
28-Pin DIP
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.
PCM55HP
PCM55JP
0.008
0.004
24-Lead SOIC
24-Lead SOIC
®
3
PCM54/55
the line (Figure 1) about the bipolar zero point and offset
drift shifts the line left or right over the operating tempera-
ture range. Most of the offset and gain drift with temperature
or time is due to the drift of the internal reference zener
diode. The converter is designed so that these drifts are in
opposite directions. This way, the bipolar zero voltage is
virtually unaffected by variations in the reference voltage.
DISCUSSION OF
SPECIFICATIONS
The PCM54 and PCM55 are specified to provide critical
performance criteria for a wide variety of applications. The
most critical specifications for a D/A converter in audio
applications are total harmonic distortion, differential linear-
ity error, bipolar zero error, parameter shifts with time and
temperature, and settling time effects on accuracy.
DIGITAL INPUT CODES
The PCM54 and PCM55 accept complementary digital
input codes in any of three binary formats (CSB, unipolar; or
COB, bipolar; or CTC, Complementary Two’s Comple-
ment, bipolar). See Table II.
The PCM54 and PCM55 are factory-trimmed and tested for
all critical key specifications.
The accuracy of a D/A converter is described by the transfer
function shown in Figure 1. Digital input to analog output
relationship is shown in Table I. The errors in the D/A
converter are combinations of analog errors due to the linear
circuitry, matching and tracking properties of the ladder and
scaling networks, power supply rejection, and reference
errors. In summary, these errors consist of initial errors
including gain, offset, linearity, differential linearity, and
power supply sensitivity. Gain drift over temperature rotates
ANALOG OUTPUT
Digital
Input
Codes
Complementary
Straight Binary
(CSB)
Complementary
Offset Binary
(COB)
Complementary
Two’s Complement
(CTS)(1)
0000H
7FFFH
8000H
+Full Scale
+1/2 Full Scale
+1/2 Full Scale
–1LSB
+Full Scale
Bipolar Zero
–1LSB
–1LSB
–Full Scale
+Full Scale
FFFFH
Zero
–Full Scale
Bipolar Zero
NOTE: (1) Invert the MSB of the COB code with an external inverter to obtain
CTC code.
0000…0000
Gain
TABLE II. Digital Input Codes.
Drift
0000…0001
0111…1101
0111…1110
0111…1111
1000…0000
1000…0001
1111…1110
1111…1111
All Bits
On
BIPOLAR ZERO ERROR
Initial Bipolar Zero (BPZ) error (Bit 1 “ON” and all other
bits “OFF”) is the deviation from 0V out and is factory-
trimmed to typically ±10mV at +25°C.
Bipolar
Zero
Offset
Drift
DIFFERENTIAL LINEARITY ERROR
Differential Linearity Error (DLE) is the deviation from an
ideal 1LSB change from one adjacent output state to the
next. DLE is important in audio applications because exces-
sive DLE at bipolar zero (at the “major carry”) can result in
audible crossover distortion for low level output signals.
Initial DLE on the PCM54 and PCM55 is factory-trimmed
to typically ±0.001% of FSR. This error is adjustable to zero
using the circuit shown in the connection diagram (PCM54
only).
(+FSR/2) –1LSB
Analog Output
* See Table I for digital code definitions.
–FSR/2
FIGURE 1. Input vs Output for an Ideal Bipolar D/A
Converter.
VOLTAGE OUTPUT MODE
Analog Output
Unipolar(1)
Bipolar
15-Bit
Digital Input Code
16-Bit
15-Bit
14-Bit
16-Bit
14-Bit
One LSB
0000H
FFFFH
(µV)
(V)
(V)
91.6
+5.99991
0
183
+5.99982
0
366
+5.99963
0
91.6
+2.99991
–3.0000
183
+2.99982
–3.0000
366
+2.99963
–3.0000
CURRENT OUTPUT MODE
Analog Output
Unipolar
Bipolar
15-Bit
Digital Input Code
16-Bit
15-Bit
14-Bit
16-Bit
14-Bit
One LSB
0000H
FFFFH
(µA)
(mA)
(mA)
0.031
–1.99997
0
0.061
–1.99994
0
0.122
–1.99988
0
0.031
–0.99997
+1.00000
0.061
–0.99994
+1.00000
0.122
–0.99988
+1.00000
NOTE: (1) +VCC must be at least +8.5VDC to allow output to swing to +6.0VDC.
TABLE I. Digital Input to Analog Output Relationship.
®
4
PCM54/55
POWER SUPPLY SENSITIVITY
STABILITY WITH TIME AND TEMPERATURE
Changes in the DC power supplies will affect accuracy.
The parameters of a D/A converter designed for audio
applications should be stable over a relatively wide tempera-
ture range and over long periods of time to avoid undesirable
periodic readjustment. The most important parameters are
bipolar zero, differential linearity error, and total harmonic
distortion. Most of the offset and gain drift with temperature
or time is due to the drift of the internal reference zener
diode. The PCM54 and PCM55 are designed so that these
drifts are in opposite directions so that the bipolar zero
voltage is virtually unaffected by variations in the reference
voltage. Both DLE and THD are dependent upon the match-
ing and tracking of resistor ratios and upon VBE and hFE of
the current-source transistors. The PCM54 and PCM55 were
designed so that any absolute shift in these components has
virtually no effect on DLE or THD. The resistors are made
of identical links of ultra-stable nichrome thin-film. The
current density in these resistors is very low to further
enhance their stability.
The PCM54 and PCM55 power supply sensitivity is shown
by Figure 2. Normally, regulated power supplies with 1% or
less ripple are recommended for use with the DAC. See also
Power Supply Connections paragraph in the Installation and
Operating Instructions section.
10.0
3.0
–60dB
1.0
0.30
0.10
0.03
–20dB
0.01
0.003
0dB
0.001
DYNAMIC RANGE
The dynamic range is a measure of the ratio of the smallest
signals the converter can produce to the full-scale range and
is usually expressed in decibels (dB). The theoretical dy-
namic range of a converter is approximately 6 x n, or about
96dB for a 16-bit converter. The actual, or useful, dynamic
range is limited by noise and linearity errors and is therefore
somewhat less than the theoretical limit. However, this does
point out that a resolution of at least 16 bits is required to
obtain a 90dB minimum dynamic range, regardless of the
accuracy of the converter. Another specification that is
useful for audio applications is total harmonic distortion.
5
10
15
±VCC Supplies (V)
FIGURE 2. Effects of ±VCC on Total Harmonic Distortion
(PCM54JP;VCCswithapproximately2%ripple).
SETTLING TIME
Settling time is the total time (including slew time) required
for the output to settle within an error band around its final
value after a change in input (see Figure 3).
TOTAL HARMONIC DISTORTION
Settling times are specified to ±0.006% of FSR; one for a
large output voltage change of 3V and one for a 1LSB
change. The 1LSB change is measured at the major carry
(0111…11 to 10000.00), the point at which the worst-case
settling time occurs.
THD is useful in audio applications and is a measure of the
magnitude and distribution of the linearity error, differential
linearity error, and noise as well as quantization error. To be
useful, THD should be specified for both high level and low
level input signals. This error is unadjustable and is the most
meaningful indicator of D/A converter accuracy for audio
applications.
1.0
Voltage
The THD is defined as the ratio of the square root of the sum
of the squares of the values of the harmonics to the value of
the fundamental input frequency and is expressed in percent
or dB. The rms value of the PCM54/55 error referred to the
input can be shown to be:
Output
Mode
0.3
0.1
Current
Output
Mode
0.03
0.01
0.003
0.001
(1)
RL = 200Ω
1
n
εrms
=
[ΕL (i) + ΕQ (i)]2
Σ
n
i = 1
0.01
0.1
1.0
Settling Time (µs)
10.0
where n is the number of samples in one cycle of any given
sine wave, EL(i) is the linearity error of the PCM54 or
PCM55 at each sampling point, and EQ(i) is the quantization
FIGURE 3. Full-Scale Range Settling Time vs Accuracy.
®
5
PCM54/55
error at each sampling point. The THD can then be ex-
pressed as:
INSTALLATION AND OPERATING
INSTRUCTIONS
(2)
POWER SUPPLY CONNECTIONS
1
n
[ΕL (i) + ΕQ (i)]2
For optimum performance and noise rejection, power supply
decoupling capacitors should be added as shown in the
connections diagram. These capacitors (1µF tantalum or
electrolytic recommended) should be located close to the
converter.
Σ
n
εrms
i = 1
THD =
=
•100%
Εrms
Εrms
where Erms is the rms signal voltage level.
This expression indicates that, in general, there is a correla-
tion between the THD and the square root of the sum of the
squares of the linearity errors at each digital word of interest.
However, this expression does not mean that the worst-case
linearity error of the D/A is directly correlated to the THD.
MSB ERROR ADJUSTMENT PROCEDURE
(OPTIONAL)
The MSB error of the PCM54 and PCM55 can be adjusted
to make the differential linearity error (DLE) at BPZ essen-
tially zero. This is important when the signal output levels
are very low because zero crossing noise (DLE at BPZ)
becomes very significant when compared to the small code
changes occurring in the LSB portion of the converter.
For PCM54/55 the test period was chosen to be 22.7µs
(44.1kHz) which is compatible with the EIAJ STC-007
specification for PCM audio. The test frequency is 420Hz
and the amplitude of the input signal is 0dB, –20dB, and
–60dB down from full scale.
Differential linearity error at bipolar zero is guaranteed to
meet data sheet specifications without any external adjust-
ment. However, a provision has been made for an optional
adjustment of the MSB linearity point which makes it
possible to eliminate DLE error at BPZ (PCM54 only). Two
procedures are given to allow either static or dynamic
adjustment. The dynamic procedure is preferred because of
the difficulty associated with the static method (accurately
measuring 16-bit LSB steps).
Figure 4 shows the typical THD as a function of output
voltage.
Figure 5 shows typical THD as a function of frequency.
10.0
4.0
2.0
1.0
To statically adjust DLE at BPZ, refer to the circuit shown
in Figure 6 or the PCM54 connection diagram. After allow-
ing ample warm-up time (20-30 minutes) to assure stable
operation of the PCM54, select input code 8000 hexadeci-
mal (all bits off except the MSB). Measure and record it.
Change the digital input code to 7FFF hexadecimal (all bits
off except the MSB). Adjust the 100kΩ potentiometer to
make the audio output read 92µV more than the voltage
reading of the previous code (a ILSB step = 92µV).
0.4
0.2
0.1
14 Bits
0.04
0.02
0.01
0.004
0.002
0.001
16 Bits
–20
–60
–50
–40
–30
–10
0
A much simpler method is to dynamically adjust the DLE at
BPZ. Again, refer to Figure 6 or the PCM54 connection
diagram for circuitry and component values. Assuming the
device has been installed in a digital audio application
circuit, send the appropriate digital input to produce a –60dB
level sinusoidal output. While measuring the THD of the
audio circuit output, adjust the 100kΩ potentiometer until a
minimum level of distortion is observed.
VOUT (dB)
0dB = Full-Scale Range (FSR)
FIGURE 4. Total Harmonic Distortion (THD) vs VOUT
.
0.1
0.05
0.02
560kΩ
1MΩ
100kΩ
330kΩ
0.01
1
–20dB
–VCC
0.005
27
0.002
Full Scale
0.001
100
1k
10k 20k
FIGURE 6. MSB Differential Linearity at Bipolar Zero Ad-
justment Circuit (optional).
Frequency (Hz)
FIGURE 5. Total Harmonic Distortion (THD) vs
Frequency.
®
6
PCM54/55
Due to the fast settling time of the PCM54-V, it is possible
to minimize the delay between the left channel and right
channel outputs when using a single D/A converter for both
channels. This is important because the left and right chan-
nel data is recorded in phase and use of a slower D/A
converter would result in significant phase error at the
higher audio frequencies.
INSTALLATION
CONSIDERATIONS
If the optional external MSB error circuitry is used (PCM54),
a potentiometer with adequate resolution and a TCR of
100ppm/°C or less is required. Also, extra care must be
taken to insure that no leakage path (either AC or DC) exists
to pin 27 (PCM54). If circuit is not used, pin 1 (PCM54)
should be terminated to common with a 0.01µF capacitor.
A low-pass filter is required at the S/H output to remove all
unwanted frequency components caused by the sampling
frequency as well as the discrete nature of the D/A converter
output. The filter must have a flat amplitude response over
the entire audio band (0 to 20kHz) and a very high attenu-
ation above 20kHz. Most previous digital audio circuits used
a high-order (9-13 pole) analog filter. However, the phase
response of an analog filter with these amplitude character-
istics is nonlinear and can disturb the pulse-shaped charac-
teristics of the transients contained in music.
The PCM converter and the wiring to its connectors should
be located to provide the optimum isolation from sources of
RFI and EMI. The important consideration in the elimina-
tion of RF radiation or pickup is loop area; therefore, signal
leads and their return conductors should be kept close
together. This reduces the external magnetic field along with
any radiation. Also, if a signal lead and its return conductor
are wired close together, they represent a small flux-capture
cross section for any external field. This reduces radiation
pickup in the circuit.
R
R
C1
PCM54/55
C
APPLICATIONS
B
Data to
DAC
A sample/hold amplifier, or “deglitcher”, is required at the
output of the D/A converter for both the left and right
channel, as shown in Figure 7. The S/H amplifier for the left
channel is composed of A2, SW1, and associated circuitry. A2
is used as an integrator to hold the analog voltage in C1.
Since the source and drain of the FET switch operates at a
virtual ground when “C” and “B” are closed in the simple
mode, there is no increase in distortion caused by the
modulation effect of RON by the audio signal.
A
A1
SW1
Left Channel
Deglitcher Control
Left Channel Output to LPF
and Other Circuits
R
R
C2
C
B
A
A2
SW2
Right Channel
Deglitcher Control
Right Channel Output to LPF
and Other Circuits
Figure 8 shows the deglitcher control signals for both the left
and right channels which are produced by the timing control
logic. A delay of 2.5µs (tω) is provided to eliminate the
glitch and allow the output of the PCM54-V to settle within
a small error band around its final value before connecting
it to the channel output.
A LOW signal on the
deglitcher control closes switch “A”,
while a HIGH signal closes switch “B”.
A1, A2 ATE
OPA101 or OPA404
FIGURE 7. A Sample/Hold Amplifier (deglitcher) is Re-
quired at the Digital-to-Analog Output for Both
Left and Right Channels.
44.1kHz
Right Channel Data N
Left Channel Data N
tS
Right Channel Data N+1 Left Channel Data N+1
Data for DAC
Right Channel
Deglitcher Control
tW
Left Channel
Deglitcher Control
Delay Between Left and Right Channel
The deglitcher control signals are generated by the timing control logic. The fast settling time of the
PCM54/55 makes it possible to minimize the delay between left and right channels to approximately 4.5µs
which reduces phase error at the higher audio frequencies.
FIGURE 8. Timing Diagram for the Deglitcher Control Signals.
®
7
PCM54/55
PACKAGE OPTION ADDENDUM
www.ti.com
3-Oct-2003
PACKAGING INFORMATION
ORDERABLE DEVICE
STATUS(1)
PACKAGE TYPE
PACKAGE DRAWING
PINS
PACKAGE QTY
PCM54HP
PCM54JP
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
ACTIVE
PDIP
PDIP
PDIP
SOP
SOP
SOP
NTD
NTD
NTD
DVK
DVK
DVK
28
28
28
24
24
24
12
12
PCM54KP
PCM55HP
PCM55HP/1K
PCM55JP
12
30
1000
30
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications,
enhancements, improvements, and other changes to its products and services at any time and to discontinue
any product or service without notice. Customers should obtain the latest relevant information before placing
orders and should verify that such information is current and complete. All products are sold subject to TI’s terms
and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI
deems necessary to support this warranty. Except where mandated by government requirements, testing of all
parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for
their products and applications using TI components. To minimize the risks associated with customer products
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TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right,
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amplifier.ti.com
www.ti.com/audio
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dataconverter.ti.com
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dsp.ti.com
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www.ti.com/military
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Logic
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logic.ti.com
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Copyright 2003, Texas Instruments Incorporated
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