Datasheet
Table Of Contents
- 1.0 Electrical Characteristics
- 2.0 Typical Performance Curves
- FIGURE 2-1: INL Error vs. Input Voltage (VDD = 2.7V).
- FIGURE 2-2: INL Error vs. Input Voltage (VDD = 5.0V).
- FIGURE 2-3: INL Error vs. Input Voltage (VDD = 5.0V, VREF = 5V).
- FIGURE 2-4: Maximum INL Error vs. VREF.
- FIGURE 2-5: Maximum INL Error vs. Temperature.
- FIGURE 2-6: Output Noise vs. Input Voltage (VDD = 2.7V).
- FIGURE 2-7: Output Noise vs. Input Voltage (VDD = 5.0V).
- FIGURE 2-8: Output Noise vs. VREF.
- FIGURE 2-9: Output Noise vs.VDD.
- FIGURE 2-10: Output Noise vs. Temperature.
- FIGURE 2-11: Offset Error vs VDD (VCM = 0V).
- FIGURE 2-12: Offset Error vs. Temperature (VREF = 5.0V).
- FIGURE 2-13: Full Scale Error vs. VDD.
- FIGURE 2-14: Full Scale Error vs. Temperature.
- FIGURE 2-15: Full Scale Error vs. Temperature (VREF = 5.0V).
- FIGURE 2-16: MCP3550/1 Output Noise Histogram.
- FIGURE 2-17: MCP3553 Output Noise Histogram.
- FIGURE 2-18: Total Unadjusted Error (TUE) vs. Input Voltage (VDD = 2.7V).
- FIGURE 2-19: Total Unadjusted Error (TUE) vs. Input Voltage.
- FIGURE 2-20: Total Unadjusted Error (TUE) vs. Input Voltage (VREF = 5.0V).
- FIGURE 2-21: Maximum TUE vs. VREF.
- FIGURE 2-22: Maximum TUE vs. Temperature.
- FIGURE 2-23: Maximum TUE vs. VDD.
- FIGURE 2-24: IDDS vs. Temperature.
- FIGURE 2-25: IDD vs. VDD.
- FIGURE 2-26: IDD vs. Temperature.
- 3.0 Pin Descriptions
- 4.0 Device Overview
- FIGURE 4-1: MCP3550/1/3 Functional Block Diagram.
- 4.1 MCP3550/1/3 Delta-Sigma Modulator with Internal Offset and Gain Calibration
- 4.2 Digital Filter
- TABLE 4-1: data rate, output noise and Digital filter specificaTIons by device
- FIGURE 4-2: SINC Filter Response, MCP3550-50 Device.
- FIGURE 4-3: SINC Filter Response, MCP3550-60 Device.
- FIGURE 4-4: SINC Filter Response, MCP3551 Device, Simultaneous 50/60 Hz Rejection.
- FIGURE 4-5: SINC Filter Response at Integer Multiples of the Sampling Frequency (fs).
- 4.3 Internal Oscillator
- 4.4 Differential Analog Inputs
- 4.5 Voltage Reference Input Pin
- 4.6 Power-On Reset (POR)
- 4.7 Shutdown Mode
- 4.8 Sleep Mode
- 5.0 Serial Interface
- 6.0 Packaging Information
© 2009 Microchip Technology Inc. DS21950E-page 13
MCP3550/1/3
3.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1: PIN FUNCTION TABLE
3.1 Voltage Reference (V
REF
)
The MCP3550/1/3 devices accept single-ended
reference voltages from 0.1V to V
DD
. Since the
converter output noise is dominated by thermal noise,
which is independent of the reference voltage, the
output noise is not significantly improved by
diminishing the reference voltage at the V
REF
input pin.
A reduced voltage reference will significantly improve
the INL performance (see Figure 2-4); the INL max
error is proportional to V
REF
2
.
3.2 Analog Inputs (V
IN
+, V
IN
-)
The MCP3550/1/3 devices accept a fully differential
analog input voltage to be connected on the V
IN
+ and
V
IN
- input pins. The differential voltage that is
converted is defined by V
IN
= V
IN
+ – V
IN
-. The
differential voltage range specified for ensured
accuracy is from -V
REF
to +V
REF
. However, the
converter will still output valid and usable codes with
the inputs overranged by up to 12% (see Section 5.0
“Serial Interface”) at room temperature. This
overrange is clearly specified by two overload bits in
the output code.
The absolute voltage range on these input pins extends
from V
SS
– 0.3V to V
DD
+ 0.3V. Any voltage above or
below this range will create leakage currents through
the Electrostatic Discharge (ESD) diodes. This current
will increase exponentially, degrading the accuracy and
noise performance of the device. The common mode of
the analog inputs should be chosen such that both the
differential analog input range and the absolute voltage
range on each pin are within the specified operating
range defined in Section 1.0 “Electrical
Characteristics”.
3.3 Supply Voltage (V
DD
, V
SS
)
V
DD
is the power supply pin for the analog and digital
circuitry within the MCP3550/1/3. This pin requires an
appropriate bypass capacitor of 0.1 µF. The voltage on
this pin should be maintained in the 2.7V to 5.5V range
for specified operation. V
SS
is the ground pin and the
current return path for both analog and digital circuitry
of the MCP3550/1/3. If an analog ground plane is
available, it is recommended that this device be tied to
the analog ground plane of the Printed Circuit Board
(PCB).
3.4 Serial Clock (SCK)
SCK synchronizes data communication with the
device. The device operates in both SPI mode 1,1 and
SPI mode 0,0. Data is shifted out of the device on the
falling edge of SCK. Data is latched in on the rising
edge of SCK. During CS
high times, the SCK pin can
idle either high or low.
3.5 Data Output (SDO/RDY)
SDO/RDY is the output data pin for the device. Once a
conversion is complete, this pin will go active-low,
acting as a ready flag. Subsequent falling clock edges
will then place the 24-bit data word (two overflow bits
and 22 bits of data, see Section 5.0 “Serial
Interface”) on the SPI bus through the SDO pin. Data
is clocked out on the falling edge of SCK.
MCP3550/1/3
Symbol I/O/P Description
MSOP, SOIC
1V
REF
I Reference Voltage Analog Input Pin
2V
IN
+ I Non-inverting Analog Input Pin
3V
IN
- I Inverting Analog Input Pin
4V
SS
P Ground Pin
5 SCK I Serial Clock Digital Input Pin
6 SDO/RDY
O Data/Ready Digital Output Pin
7CS
I Chip Select Digital Input Pin
8V
DD
P Positive Supply Voltage Pin
Type Identification: I = Input; O = Output; P = Power