®
PCM78P
16-Bit Audio
ANALOG-TO-DIGITAL CONVERTER
FEATURES
q
LOW COST/HIGH PERFORMANCE 16-BIT
AUDIO A/D CONVERTER
q
FAST 5
µ
s MAX CONVERSION TIME
(4
µ
s typ)
q
VERY LOW THD+N ( typ –88dB at FS;
max –82dB)
q
±
3V INPUT RANGE
q
TWO SERIAL OUTPUT MODES PROVIDE
VERSATILE INTERFACING
q
COMPLETE WITH INTERNAL REFERENCE
AND CLOCK IN 28-PIN PLASTIC DIP
q
±
5V TO
±
15V SUPPLY RANGE (600mW
Power Dissipation)
APPLICATIONS
q
DSP DATA ACQUISITION
q
TEST INSTRUMENTATION
q
SAMPLING KEYBOARD SYNTHESIZERS
q
DIGITAL AUDIO TAPE
q
BROADCAST AUDIO PROCESSING
q
TELECOMMUNICATIONS
DESCRIPTION
The PCM78P is a low-cost 16-bit analog-to-digital
converter which is specifically designed and tested for
dynamic applications. It features very fast, low
distortion performance (4µs/–88dB THD+N typical)
and is complete with internal clock and reference
circuitry. The PCM78P is packaged in a reliable, low-
cost 28-pin plastic DIP and data output is available in
user-selectable serial output formats. The PCM78P is
ideal for digital audio tape (DAT) recorders. Many
similar applications such as digital signal processing
and telecom applications are equally well served by
the PCM78P.
The PCM78P uses a SAR technique. Analog and
digital portions are efficiently partitioned into a high-
speed, bipolar section and a low-power CMOS
section. The PCM78P has been optimized for excel-
lent dynamic performance and low cost.
Audio Input
16-bit D/A
Converter
–
Comp
+
Convert
Command
16-bit SAR +
Timing Control
Internal
Clock
Circuit
Serial Output 1
Serial Output 2
Clock Output
Status
External Clock
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 • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
©
1989 Burr-Brown Corporation
PDS-989A
Printed in U.S.A. October, 1993
SPECIFICATIONS
ELECTRICAL
At T
C
= +25°C, +V
DD
= +5V, and
±V
CC
=
±12V,
and one minute warm-up in convection environment, unless otherwise noted.
PCM78P
PARAMETER
RESOLUTION
INPUT/OUTPUT
ANALOG INPUT
Input Range
Input Impedance
DIGITAL INPUT/OUTPUT
Logic Family
Logic Level: V
IH
V
IL
V
OH
V
OL
Data Format
Convert Command
Pulse Width
CONVERSION TIME
DYNAMIC CHARACTERISTICS
SIGNAL-TO-NOISE RATIO (SNR)
(2)
f = 1kHz (0dB)
f = 10kHz (0dB)
TOTAL HARMONIC DISTORTION
(5)
f = 1kHz (0dB)
f = 19kHz (0dB)
f = 10kHz (0dB)
f = 90kHz (0dB)
TOTAL HARMONIC DISTORTION + NOISE
(6)
f = 1kHz (0dB)
f = 1kHz (–20dB)
f = 1kHz (–60dB)
f = 19kHz (0dB)
f = 10kHz (0dB)
f = 90kHz (0dB)
TRANSFER CHARACTERISTICS
ACCURACY
Gain Error
Bipolar Zero Error
Differential Linearity Error
Integral Linearity Error
Missing Codes
DRIFT
Gain
Bipolar Zero
POWER SUPPLY SENSITIVITY
+V
CC
–V
CC
+V
DD
POWER SUPPLY REQUIREMENTS
Voltage Range: +V
CC
–V
CC
+V
DD
Current:
+V
CC
–V
CC
+V
DD
Power Dissipation
TEMPERATURE RANGE
Specification
Storage
Operating
0
–50
–25
+70
+100
+85
°C
°C
°C
+4.75
–4.75
+4.75
+V
CC
= +12V
–V
CC
= –12V
+V
DD
= +5V
±V
CC
=
±12V
+15
–21
+7
575
+15.6
–15.6
+5.25
V
V
V
mA
mA
mA
mW
0°C to +70°C
0°C to +70°C
±2
±20
±0.002
±0.003
None
±25
±4
±0.008
±0.003
±0.003
%
mV
% of FSR
(7)
% of FSR
14 Bits
(8)
ppm/°C
ppm of FSR/°C
%FSR/%V
CC
%FSR/%V
CC
%FSR/%V
DD
f
S
= 200kHz/T
CONV
= 4µs
(3)
BW = 20kHz
BW = 100kHz
f
S
= 200kHz/T
CONV
= 4µs
BW = 20kHz
BW = 20kHz
BW = 100kHz
BW = 100kHz
f
S
= 200kHz/T
CONV
= 4µs
BW = 20kHz
BW = 20kHz
BW = 20kHz
BW = 20kHz
BW = 100kHz
BW = 100kHz
90
80
–91
–90
–90
–89
–88
–74
–34
–87
–82
–81
–82
–68
dB
(4)
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
–3
1.5
TTL Compatible CMOS
+2
+5.5
0
+0.8
+2.4
+0.4
Serial BOB or BTC
Negative Edge
(1)
25
50
4
5
+3
V
kΩ
CONDITIONS
MIN
TYP
MAX
16
UNITS
Bits
I
IH
= +40µA
I
IL
= –100µA
I
OH
= 2TTL Loads
I
OL
= 2TTL Loads
V
V
V
V
ns
µs
NOTES: (1) When convert command is high, converter is in a halt/reset mode. Actual conversion begins on negative edge. See detailed text on timing for convert
command description when using external clock. (2) Ratio of Noise rms/Signal rms. (3) f = input frequency; f
S
= sample frequency (PCM78P and SHC702 in
combination); BW = bandwidth of output (based on FFT or actual analog reconstruction using a 20kHz low-pass filter). (4) Referred to input signal level. (5) Ratio
of Distortion rms/Signal rms. (6) Ratio of Distortion rms + Noise rms/Signal rms. (7) FSR: Full-Scale Range = 6Vp-p. (8) Typically no missing Codes at 14-bit
resolution.
®
PCM78
2
PIN ASSIGNMENTS
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
NAME
Analog In
–V
CC
MSB Adjust
+V
DD
No Connection
Comparator Common
MSB
BTC/BOB Select
Status
Clock Out
R
1
C
1
R
2
C
2
S
OUT2
+V
DD
S
OUT1
External Clock
Int/Ext Clock Select
Short Cycle
Convert Command
S
OUT2
Latch
S
OUT2
Clock
Digital Common
+V
CC
V
POT
Reference Decouple
Analog Common
Reference Out
Speed Up
I/O
I
I
I
I
—
I
O
I
O
O
I
I
O
I
O
I
I
I
I
I
I
I
I
O
I
I
O
I
DESCRIPTION
Analog Signal Input (1.5kΩ impedance).
Analog power supply (–5V to –15V).
Internal adjustment point to allow adjustment of MSB major carry.
Power connection for comparator (+5V).
No internal connection.
Comparator common connection. Connect to ground.
Parallel output of bit 1 (MSB) inverted.
Two’s complement (open) or straight binary (grounded) data output format selection.
Output signal held high until conversion is complete.
Internal clock output generated from RC network on pins 11 and 12 (also present when external clock is used lagging
external clock by ~24ns and same duty cycle).
RC connection point used to generate internal clock. Sets clock high time. See text for details.
RC connection point used to generate internal clock. Sets clock low time. See text for details.
Internal shift register containing the previous conversion result. (Alternate latched data output mode).
Power connection for +5V logic supply.
Primary real-time data output synchronized to clock out.
External clock input point (internal clock must be disabled).
Selects either internal or external clock mode (low = internal; open = external).
Terminates conversion at less than 16 bits (open for 16-bit mode). See text for details.
Starts conversion process (can optionally be generated internally).
Latches previous conversion result for readout (must be issued with the S
OUT2
clock to initiate latch and an internal convert
command).
Used to read out internally latched data from previous conversion.
Digital grounding pin.
Analog supply connection (+5V to +15V).
Voltage output (~2.5V) for optional adjustment of MSB transition.
Reference decoupling point.
Analog grounding pin.
2V reference out. Should not be used except as shown in connection diagram.
Connection point for a capacitor to speed reference settling. See text for details.
NOTE: Analog and digital commons are connected internally.
INPUT/OUTPUT RELATIONSHIPS
DIGITAL OUTPUT
ANALOG INPUT
+2.999908V
–3.000000V
0.000000V
–0.000092V
CONDITION
+ Full Scale
–Full Scale
Bipolar Zero
Zero-1 LSB
BTC
7FFF Hex
8000 Hex
0000 Hex
FFFF Hex
BOB
FFFF Hex
0000 Hex
8000 Hex
7FFF Hex
ABSOLUTE MAXIMUM RATINGS
+V
CC
to Analog Common ......................................................... 0 to +16.5V
–V
CC
to Analog Common ......................................................... 0 to –16.5V
–V
DD
to Analog Common .............................................................. 0 to +7V
Analog Common to Digital Common .................................................
±0.5V
Logic Inputs to Digital Common ................................. –0.3V to V
DD
+ 0.5V
Analog Inputs to Analog Common ..................................................
±16.5V
Lead Temperature (soldering, 10s) ................................................ +300°C
Stresses above these ratings may permanently damage the device.
PACKAGE INFORMATION
MODEL
PCM78P
PACKAGE
28-Pin Plastic DIP
PACKAGE DRAWING
NUMBER
(1)
215
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix D of Burr-Brown IC Data Book.
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.
®
3
PCM78
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