TC530 Datasheet, PDF (11/15 Pages) TelCom Semiconductor, Inc – 5V PRECISION DATA ACQUISITION SUBSYSTEMS

5V PRECISION DATA ACQUISITION
SUBSYSTEMS
1
TC530
TC534
Timing
Status
Conversion
Phase
Power-up RESET
AZ
R/W Converter held in AZ
state due to RESET = 1
RESET
D_CLK
Undefined
Write LOAD VALUE to Serial Port
Converter in Normal Service
AZ
R/W brought LOW during AZ
for serial port write cycle
INT
DINT IZ AZ…
Continuous Conversions
R/W = HIGH strobes
LOAD VALUE into
timebase and starts
conversion
2
3
D_IN
EOC
1 1001111
4
MSB
LOAD VALUE
LSB
Figure 4. TC530/534 Initialization and Load Value Write Cycle
verter input. A0 is the least significant address bit (i.e.,
channel 1 is selected when A0 = 1 and A1 = 0). The
multiplexer is designed to be operated in a differential mode.
For single-ended inputs, the CHx^– input for the channel
under selection must be connected to the ground reference
associated with the input signal.
R/W
D_CLK
D_OUT
EOC OVR POL MSB
LSB
Figure 5. Serial Port Data Read Cycle
DC/DC Converter
An on-board, TC7660H-type charge pump supplies
negative bias to the converter circuitry, as well as to external
devices. The charge pump develops a negative output
voltage by moving charge from the power supply to the
reservoir capacitor at V_SS by way of the commutating
capacitor connected to the CAP⁺ and CAP^– inputs.
The charge pump clock operates at a typical frequency
of 100kHz. If lower quiescent current is desired, the charge
5 ^{pump clock can be slowed by connecting an external ca-}
pacitor from the OSC pin to V_DD. Reference typical charac-
teristics curves.
APPLICATIONS
Design Example
Figure 6 shows a typical TC534 interrupt-driven applica-
6 ^{tion. Timing and component values are calculated from}
equations and recommendations made in the Dual Slope
Integrating Converter and Programming the TC530/534
sections of this document. The EOC connection to the
processor INT input is for interrupt-driven applications only.
(In polled systems, the EOC output is available on D_OUT).
GIVEN
7 ^{REQUIRED RESOLUTION: 16 Bits (65,536 counts.)}
MAXIMUM V_IN:
±2V
POWER SUPPLY VOLTAGE: +5V
60Hz SYSTEM
1. Pick Integration time (t_INT)
66msec
2. Estimate crystal frequency
F_IN = 2R/t_INT = 2 x 65536/66 x 10 ^–3 = 1.98MHz
(use 2MHz)
8
TELCOM SEMICONDUCTOR, INC.
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