TC500/A/510/514
Precision Analog Front Ends with Dual Slope ADC
Features:
• Precision (up to 17 bits) A/D Converter “Front
End”
• 3-Pin Control Interface to Microprocessor
• Flexible: User Can Trade-off Conversion Speed
for Resolution
• Single-Supply Operation (TC510/TC514)
• 4 Input, Differential Analog MUX (TC514)
• Automatic Input Voltage Polarity Detection
• Low Power Dissipation:
- (TC500/TC500A): 10 mW
- (TC510/TC514): 18 mW
• Wide Analog Input Range:
- ±4.2V (TC500A/TC510)
• Directly Accepts Bipolar and Differential
Input Signals
General Description:
TheTC500/A/510/514 family are precision analog front
ends that implement dual slope A/D converters having
a maximum resolution of 17 bits plus sign. As a
minimum, each device contains the integrator, zero
crossing comparator and processor interface logic. The
TC500 is the base (16-bit max) device and requires
both positive and negative power supplies. The
TC500A is identical to the TC500 with the exception
that it has improved linearity, allowing it to operate to a
maximum resolution of 17 bits. The TC510 adds an on-
board negative power supply converter for single-
supply operation. The TC514 adds both a negative
power supply converter and a 4-input differential
analog multiplexer.
Each device has the same processor control interface
consisting of 3 wires: control inputs (A and B) and zero-
crossing comparator output (CMPTR). The processor
manipulates A, B to sequence the TC5XX through four
phases of conversion: auto-zero, integrate, de-
integrate and integrator zero. During the auto-zero
phase, offset voltages in the TC5XX are corrected by a
closed loop feedback mechanism. The input voltage is
applied to the integrator during the integrate phase.
This causes an integrator output dv/dt directly
proportional to the magnitude of the input voltage. The
higher the input voltage, the greater the magnitude of
the voltage stored on the integrator during this phase.
At the start of the de-integrate phase, an external
voltage reference is applied to the integrator and, at the
same time, the external host processor starts its on-
board timer. The processor maintains this state until a
transition occurs on the CMPTR output, at which time
the processor halts its timer. The resulting timer count
is the converted analog data. Integrator zero (the final
phase of conversion) removes any residue remaining
in the integrator in preparation for the next conversion.
The TC500/A/510/514 offer high resolution (up to
17 bits), superior 50/60 Hz noise rejection, low-power
operation, minimum I/O connections, low input bias
currents and lower cost compared to other converter
technologies having similar conversion speeds.
Applications:
• Precision Analog Signal Processor
• Precision Sensor Interface
• High Accuracy DC Measurements
©
2008 Microchip Technology Inc.
DS21428E-page 1
TC500/A/510/514
1.0
ELECTRICAL
CHARACTERISTICS
† Notice:
Stresses above those listed under “Absolute
Maximum Ratings” may cause permanent damage to
the device. These are stress ratings only and functional
operation of the device at these or any other conditions
above those indicated in the operation sections of the
specifications is not implied. Exposure to Absolute
Maximum Rating conditions for extended periods may
affect device reliability.
Absolute Maximum Ratings†
TC510/TC514 Positive Supply Voltage
(V
DD
to GND) ......................................... +10.5V
TC500/TC500A Supply Voltage
(V
DD
to V
SS
) .............................................. +18V
TC500/TC500A Positive Supply Voltage
(V
DD
to GND) ............................................ +12V
TC500/TC500A Negative Supply Voltage
(V
SS
to GND)................................................-8V
Analog Input Voltage (V
IN
+ or V
IN
-) ............V
DD
to V
SS
Logic Input Voltage...............V
DD
+0.3V to GND - 0.3V
Voltage on OSC:
........................... -0.3V to (V
DD
+0.3V) for V
DD
< 5.5V
Ambient Operating Temperature Range:
................................................................ 0°C to +70°C
Storage Temperature Range: ............. -65°C to +150°C
DC CHARACTERISTICS
Electrical Specifications:
Unless otherwise specified,
TC510/TC514:
V
DD
= +5V,
TC500/TC500A:
V
SS
= ±5V.
C
AZ
= C
REF
= 0.47
μ
F.
Parameters
Analog
Resolution
Zero-scale Error with
Auto-zero Phase
End Point Linearity
ZSE
ENL
60
—
—
—
—
Best-Case Straight
Line Linearity
Zero-scale Temp.
Coefficient
Full-scale Symmetry
Error (Rollover Error)
Full-scale
Temperature
Coefficient
Input Current
Common Mode
Voltage Range
Integrator Output
Swing
Analog Input Signal
Range
Note 1:
2:
3:
NL
—
—
ZS
TC
SYE
FS
TC
—
—
—
—
—
—
0.005
—
0.003
—
—
0.01
—
—
0.005
0.003
0.015
0.010
0.008
0.005
—
—
—
—
—
—
—
—
—
—
—
—
—
—
0.005
0.003
0.015
0.010
—
—
1
0.03
10
—
0.012
0.009
0.060
0.045
—
—
2
—
—
% F.S.
% F.S.
% F.S.
% F.S.
μ
V/°C
μ
V
Sym
Min.
T
A
= +25°C
Typ.
Max.
T
A
= 0°C to 70°C
Min.
Typ.
Max.
Units
Conditions
Note 1
TC500/TC510/TC514
TC500A
TC500/TC510/TC514
Note 1, Note 2,
TC500A
TC500/TC510/TC514,
Note 1, Note 2
TC500A
Over Operating
Temperature Range
Note 1
% F.S.
% F.S.
ppm/°C Over Operating
Temperature Range;
External Reference
TC = 0 ppm/°C
pA
V
V
V
ACOM = GND = 0V
V
IN
= 0V
I
IN
V
CMR
—
V
SS
+ 1.5
V
SS
+ 0.9
V
SS
+ 1.5
6
—
—
—
—
V
DD
– 1.5
V
DD
– 0.9
—
V
SS
+ 1.5
V
SS
+ 0.9
—
—
—
—
—
V
DD
– 1.5
V
SS
+ 0.9
V
SS
+ 1.5
V
DD
– 1.5 V
SS
+ 1.5
Integrate time
≥
66 ms, auto-zero time
≥
66 ms, V
INT
(peak)
≈
4V.
End point linearity at ±1/4, ±1/2, ±3/4 F.S. after full-scale adjustment.
Rollover error is related to C
INT
, C
REF
, C
AZ
characteristics.
©
2008 Microchip Technology Inc.
DS21428E-page 3
TC500/A/510/514
2.0
Note:
TYPICAL PERFORMANCE CURVES
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
-0
T
A
= +25°C
V+ = 5V
TA = +25°C
5
4
3
Output Voltage (V)
-1
Output Voltage (V)
-2
-3
-4
-5
-6
-7
-8
2
1
0
-1
-2
-3
-4
-5
0
Slope 60Ω
10
20
30
40
60
50
Load Current (mA)
70
80
0
2
4
6
8 10 12 14
Output Current (mA)
16
18 20
FIGURE 2-1:
Current.
200
Output Ripple (mV PK-PK)
175
150
125
100
75
50
25
0
0
1
2
3
Output Voltage vs. Load
FIGURE 2-4:
Current.
100
Output Voltage vs. Output
V+ = 5V, T
A
= +25°C
Osc. Freq. = 100 kHz
Output Source Resistance (Ω)
90
80
70
60
50
40
-50
V+ = 5V
I
OUT
= 10 mA
CAP = 1 µF
CAP = 10 µF
4
5
6
7
Load Current (mA)
8
9 10
-25
0
25
50
Temperature (°C)
75
100
FIGURE 2-2:
Current.
100
Oscillator Frequency (kHz)
Output Ripple vs. Load
FIGURE 2-5:
vs. Temperature.
150
Oscillator Frequency (kHz)
Output Source Resistance
T
A
= +25°C
V+ = 5V
V+ = 5V
125
10
100
75
50
-50
1
1
10
100
Oscillator Capacitance (pF)
1000
-25
0
25
75
50
Temperature (°C)
100
125
FIGURE 2-3:
Capacitance.
Oscillator Frequency vs.
FIGURE 2-6:
Temperature.
Oscillator Frequency vs.
©
2008 Microchip Technology Inc.
DS21428E-page 5
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