TC850 Datasheet, PDF (1/14 Pages) TelCom Semiconductor, Inc – 15-BIT, FAST-INTEGRATING CMOS ANALOG-TO-DIGITAL CONVERTER

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TC850
15-BIT, FAST-INTEGRATING CMOS ANALOG-TO-DIGITAL
CONVERTER
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FEATURES
s 15-bit Resolution Plus Sign Bit
s Up to 40 Conversions per Second
s 12 Conversions per Second Guaranteed
s Integrating ADC Technique
— Monotonic
— High Noise Immunity
— Auto-Zeroed Amplifiers Eliminate Offset
Trimming
s Wide Dynamic Range ...................................... 96dB
s Low Input Bias Current ................................... 30pA
s Low Input Noise ........................................... 30µV_P-P
s Sensitivity ....................................................... 100µV
s Flexible Operational Control
— Continuous or On-Demand Conversions
— Data Valid Output
s Bus Compatible, 3-State Data Outputs
— 8-Bit Data Bus
— Simple µP Interface
— Two Chip Enables
— Read ADC Result Like Memory
s ± 5V Power Supply Operation ...................... 20mW
s 40-Pin Dual-in-Line or 44-Pin PLCC Packages
FUNCTIONAL BLOCK DIAGRAM
REF2 ⁺
REF1 ⁺
REF ^–
39 34 36
IN ⁺
32
IN ^–
31
COMMON
30
ANALOG
MUX
A/D
CONTROL
SEQUENCER
RINT
CINT
BUF INT IN
25
24
–
+
BUFFER
TC850
INT OUT
23
–
+
INTEGRATOR
÷4
CLOCK
OSCILLATOR
BUS INTERFACE
DECODE LOGIC
17
18
5
76 3 412
–5V
+5V
22
40
COMPARATOR
+
–
6-BIT
9-BIT
UP/DOWN UP/DOWN
COUNTER COUNTER
DATA LATCH
OCTAL 2-INPUT MUX
3-STATE DATA BUS
15 . . . . 8
OSC1
OSC2 CONT/ L/H OVR/ WR RD CS CE
DEMAND
POL
DB0
DB7
TELCOM SEMICONDUCTOR, INC.
GENERAL DESCRIPTION
The TC850 is a monolithic CMOS analog-to-digital
converter (ADC) with resolution of 15-bits plus sign. It
combines a chopper-stabilized buffer and integrator with a
3 ^{unique multiple-slope integration technique that increases}
conversion speed. The result is 16 times improvement in
speed over previous 15-bit, monolithic integrating ADCs
(from 2.5 conversions per sec up to 40 per sec). Faster
conversion speed is especially welcome in systems with
human interface, such as digital scales.
The TC850 incorporates an ADC and a µP-compatible
digital interface. Only a voltage reference and a few noncriti-
4 ^{cal passive components are required to form a complete 15-}
bit plus sign ADC.
CMOS processing provides the TC850 with high-
impedance differential inputs. Input bias current is typically
only 30pA, permitting direct interface to sensors. Input
sensitivity of 100µV per least significant bit (LSB) eliminates
the need for precision external amplifiers. The internal
amplifiers are auto-zeroed, guaranteeing a zero digital output
5 ^{with 0V analog input. Zero adjustment potentiometers or}
calibrations are not required.
The TC850 outputs data on an 8-bit, 3-state bus. Digital
inputs are CMOS compatible; outputs are TTL/CMOS com-
patible. Chip-enable and byte-select inputs combined with
an end-of-conversion output ensures easy interfacing to a
wide variety of microprocessors. Conversions can be per-
formed continuously or on command. In continuous mode,
6 ^{data is read as three consecutive bytes and manipulation of}
address lines is not required.
Operating from ±5V supplies, the TC850 dissipates only
20mW. It is packaged in 40-pin plastic or ceramic dual-in-
line packages (DIPs) and in a 44-pin plastic leaded chip
carrier (PLCC), surface-mount package.
ORDERING INFORMATION
Part No.
TC850CLW
Package
44-Pin PLCC
7 Temperature Range
0°C to +70°C
TC850CPL
40-Pin Plastic DIP
0°C to +70°C
TC850IJL
40-Pin CerDIP
– 25°C to +85°C
TC850ILW
44-Pin PLCC
– 25°C to +85°C
TC850-4 11/5/96
3-77
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