PCM54
PCM55
FEATURES
q
PARALLEL INPUT FORMAT
q
16-BIT RESOLUTION
q
15-BIT MONOTONICITY (typ)
q
92dB TOTAL HARMONIC DISTORTION
(K Grade)
q
3
s SETTLING TIME (Voltage Out)
q
96dB DYNAMIC RANGE
q
3V or
1mA AUDIO OUTPUT
q
OPERATES ON
5V (PCM55) TO
12V
(PCM54) SUPPLIES
q
28-PIN DIP (PCM54)
q
24-LEAD SOIC (PCM55)
16-Bit Monolithic
DIGITAL-TO-ANALOG CONVERTERS
DESIGNED FOR AUDIO
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.
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
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 (I
OUT
) 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).
The PCM54 is packaged in 28-pin plastic DIP pack-
age. The PCM55 is available in a 24-lead plastic mini-
flatpak.
16-Bit Ladder
Resistor Network
and
Current Switches
Reference
Voltage
Parallel
Digital
Input
R
F
Output
Operational
Amplifier
Audio Output
(Voltage)
International Airport Industrial Park Mailing Address: PO Box 11400, Tucson, AZ 85734 Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 Tel: (520) 746-1111 Twx: 910-952-1111
Internet: http://www.burr-brown.com/ FAXLine: (800) 548-6133 (US/Canada Only) 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
PCM54/55
2
SPECIFICATIONS
ELECTRICAL
At +25
C and
V
CC
= 12V, unless otherwise noted.
V
Specifications same as for PCM54HP.
NOTES: (1) Externally adjustable. If external adjustment is not used, connect a 0.01
F 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.
PCM54HP, PCM55HP
PCM54JP, PCM55JP
PCM54KP
PARAMETER
MIN
TYP
MAX
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
DIGITAL INPUTS
Resolution
16
V
V
Bits
Dynamic Range
96
V
V
dB
Logic Levels (TTL/CMOS Compatible):
V
IH
+2.4
+5.25
V
V
V
V
V
V
IL
0
+0.8
V
V
V
V
V
I
IH
, V
IN
= +2.7V
+40
V
V
A
I
IL
, V
IN
= +0.4V
0.5
V
V
mA
TRANSFER CHARACTERISTICS
ACCURACY
Gain Error
2
V
V
%
Bipolar Zero Error
30
V
V
mV
Differential Linearity Error at Biploar Zero
(1)
0.001
V
V
% FSR
(2)
Noise (rms) (20Hz to 20kHz) at Bipolar Zero
12
V
V
V
TOTAL HARMONIC DISTORTION
(3)
(16-Bit Resolution)
V
O
=
FS at f = 991Hz
94
82
V
88
V
V
92
dB
V
O
= 20dB at f = 991Hz
74
68
V
V
V
80
74
dB
V
O
= 60dB at f = 991Hz
34
28
V
V
V
40
34
dB
MONOTONICITY
15
V
V
Bits
SETTLING TIME (to
0.006% of FSR)
Voltage Output: 6V Step
3
V
V
s
1LSB Step
1
V
V
s
Current Output (1mA Step): 10
to 100
Load
350
V
V
ns
1k
Load
(4)
350
V
V
ns
Deglitcher Delay (THD Test)
(5)
2.5
4
V
V
V
V
s
Slew Rate
10
V
V
V/
s
WARM-UP TIME
1
V
V
Min
ANALOG OUTPUT
Voltage Output: Bipolar Range
3
V
V
V
Output Current
2
V
V
mA
Output Impedance
0.1
V
V
Short-Circuit Duration
Indefinite to Common
V
V
Current Output:
(6)
Bipolar Range (
30%)
1
V
V
mA
Bipolar Output Impedance (
30%)
1.2
V
V
k
POWER SUPPLY REQUIREMENTS
Voltage: +V
CC
(PCM54)
+4.75
+12
+15.75
V
V
V
V
V
V
V
V
CC
(PCM54)
4.75
12
15.75
V
V
V
V
V
V
V
+V
CC
(PCM55)
+4.75
+5
+7.5
V
V
V
V
V
V
V
V
CC
(PCM55)
4.75
5
7.5
V
V
V
V
V
V
V
Supply Drain: +V
CC
+13
+20
V
V
V
V
mA
V
CC
16
25
V
V
V
V
mA
TEMPERATURE RANGE
Operating
0
+70
V
V
V
V
C
Storage
55
+100
V
V
V
V
C
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.
PCM54/55
3
CONNECTION DIAGRAMS
PIN
PCM54-DIP
PIN
PCM54-DIP
1
Trim
15
Bit 13
2
Bit 1 (MSB)
16
Bit 14
3
Bit 2
17
Bit 15
4
NC
18
Bit 16 (LSB)
5
Bit 3
19
V
OUT
6
Bit 4
20
R
FB
7
Bit 5
21
SJ
8
Bit 6
22
Common
9
Bit 7
23
I
OUT
10
Bit 8
24
NC
11
Bit 9
25
I
BPO
12
Bit 10
26
+V
CC
13
Bit 11
27
MSB Adjust
14
Bit 12
28
V
CC
PIN ASSIGNMENTS
PIN
PCM55-SOIC
PIN
PCM55-SOIC
1
Bit 1 (MSB)
13
Bit 13
2
Bit 2
14
Bit 14
3
Bit 3
15
Bit 15
4
Bit 4
16
Bit 16
5
Bit 5
17
V
OUT
6
Bit 6
18
Feedback Resistor
7
Bit 7
19
Summing Junction
8
Bit 8
20
Common
9
Bit 9
21
Current Output
10
Bit 10
22
Bipolar Offset
11
Bit 11
23
+V
CC
12
Bit 12
24
V
CC
PIN ASSIGNMENTS
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
ABSOLUTE MAXIMUM RATINGS
ORDERING INFORMATION
PACKAGE INFORMATION
PACKAGE DRAWING
PRODUCT
PACKAGE
NUMBER
(1)
PCM54HP
28-Pin DIP
215
PCM54JP
28-Pin DIP
215
PCM54KP
28-Pin DIP
215
PCM55HP
24-Lead SOIC
178
PCM55JP
24-Lead SOIC
178
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.
PRODUCT
THD at FS
PACKAGE
PCM54HP
0.008
28-Pin DIP
PCM54JP
0.004
28-Pin DIP
PCM54KP
0.0025
28-Pin DIP
PCM55HP
0.008
24-Lead SOIC
PCM55JP
0.004
24-Lead SOIC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
0.1
F
PCM54
16-Bit
Ladder
Resistor
Network
and
Switches
Zener
Voltage
Reference
Data
Inputs
1
F
1
F
(2)
(3)
+
+
Common
+V
CC
Audio
V
OUT
100k
560k
330k
1M
(1)
V
CC
(Optional)
Data Inputs
24
23
22
21
20
19
18
17
16
15
14
13
1F
PCM55
16-Bit
Ladder
Resistor
Network
and
Switches
Zener
Voltage
Reference
Data
Inputs
1F
(2)
+
Common
+V
CC
Audio
V
OUT
(1)
V
CC
Data Inputs
1
2
3
4
5
6
7
8
9
10
11
12
+
(2)
NOTES: (1) MSB error (BPZ differential linearity error) can be adjusted to zero
using this external circuit. (2) Connect to bipolar operation (+V
CC
8.5V for
unipolar operation). (3) Connect for V
OUT
operation. When V
OUT
amp is not being
used (I
OUT
mode), terminate with an external 3k
feedback resistor between pin
19 and pin 21, and a 1k
resistor between pin 21 and pin 22 to reduce possible
noise effects.
NOTES: (1) Connect for bipolar operation. (+V
CC
8.5V for unipolar operation.)
(2) Connect for V
OUT
operation. When V
OUT
amp is not being used (I
OUT
mode),
terminate with an external 3k
feedback resistor between pin 17 and pin 19, and
a 1k
resistor between pin 19 and pin 20 to reduce possible noise effects.
PCM54/55
4
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.
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
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.
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.
Gain
Drift
Offset
Drift
Bipolar
Zero
FSR/2
(+FSR/2) 1LSB
Digital Input
Analog Output
0000...0000
0000...0001
0111...1101
0111...1110
0111...1111
1000...0000
1000...0001
1111...1110
1111...1111
All Bits
On
* See Table I for digital code definitions.
FIGURE 1. Input vs Output for an Ideal Bipolar D/A
Converter.
ANALOG OUTPUT
Digital
Complementary
Complementary
Complementary
Input
Straight Binary
Offset Binary
Two's Complement
Codes
(CSB)
(COB)
(CTS)
(1)
0000
H
+Full Scale
+Full Scale
1LSB
7FFF
H
+1/2 Full Scale
Bipolar Zero
Full Scale
8000
H
+1/2 Full Scale
1LSB
+Full Scale
1LSB
FFFF
H
Zero
Full Scale
Bipolar Zero
NOTE: (1) Invert the MSB of the COB code with an external inverter to obtain
CTC code.
TABLE II. Digital Input Codes.
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.
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).
VOLTAGE OUTPUT MODE
Analog Output
Unipolar
(1)
Bipolar
Digital Input Code
16-Bit
15-Bit
14-Bit
16-Bit
15-Bit
14-Bit
One LSB
(
V)
91.6
183
366
91.6
183
366
0000
H
(V)
+5.99991
+5.99982
+5.99963
+2.99991
+2.99982
+2.99963
FFFF
H
(V)
0
0
0
3.0000
3.0000
3.0000
CURRENT OUTPUT MODE
Analog Output
Unipolar
Bipolar
Digital Input Code
16-Bit
15-Bit
14-Bit
16-Bit
15-Bit
14-Bit
One LSB
(
A)
0.031
0.061
0.122
0.031
0.061
0.122
0000
H
(mA)
1.99997
1.99994
1.99988
0.99997
0.99994
0.99988
FFFF
H
(mA)
0
0
0
+1.00000
+1.00000
+1.00000
NOTE: (1) +V
CC
must be at least +8.5VDC to allow output to swing to +6.0VDC.
TABLE I. Digital Input to Analog Output Relationship.
PCM54/55
5
POWER SUPPLY SENSITIVITY
Changes in the DC power supplies will affect accuracy.
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.
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).
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.
STABILITY WITH TIME AND TEMPERATURE
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 V
BE
and h
FE
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.
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.
TOTAL HARMONIC DISTORTION
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.
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:
(1)
where n is the number of samples in one cycle of any given
sine wave, E
L
(i) is the linearity error of the PCM54 or
PCM55 at each sampling point, and E
Q
(i) is the quantization
10.0
3.0
1.0
0.30
0.10
0.03
0.01
0.003
0.001
5
10
15
V
CC
Supplies (V)
THD (%)
0dB
60dB
20dB
FIGURE 2. Effects of
V
CC
on Total Harmonic Distortion
(PCM54JP; V
CC
s with approximately 2% ripple).
rms
i
n
L
Q
n
i
i
=
+
=
1
1
2
[
( )
( )]
FIGURE 3. Full-Scale Range Settling Time vs Accuracy.
1.0
0.3
0.1
0.03
0.01
0.003
0.001
0.01
0.1
1.0
10.0
Settling Time (
s)
Accuracy Percent Full-Scale Range (%)
R
L
= 200
Current
Output
Mode
Voltage
Output
Mode
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