MCP4921-E/SN Microchip Technology, MCP4921-E/SN Datasheet - Page 20

• Manufacturer Part Number: MCP4921-E/SN
• Description: IC DAC 12BIT SNGL W/SPI 8SOIC
• Manufacturer: Microchip Technology

Specifications of MCP4921-E/SN

• Number Of Converters: 1
• Package / Case: 8-SOIC (3.9mm Width)
• Settling Time: 4.5µs
• Number Of Bits: 12
• Data Interface: Serial, SPI™
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Resolution: 12 bit
• Interface Type: Serial (3-Wire, SPI, Microwire)
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Package: 8SOIC N
• Architecture: Resistor-String
• Digital Interface Type: Serial (3-Wire, SPI, Microwire)
• Number Of Outputs Per Chip: 1
• Output Type: Voltage
• Full Scale Error: 1 %FSR
• Integral Nonlinearity Error: ±12 LSB
• Maximum Settling Time: 4.5(Typ) us
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power Dissipation (max): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP4901/4911/4921
FIGURE 4-2:
4.1.3
An offset error is the deviation from zero voltage output
when the digital input code is zero.
4.1.4
A gain error is the deviation from the ideal output,
V
4.2
4.2.1
The DAC’s output is buffered with a low-power,
precision CMOS amplifier. This amplifier provides low
offset voltage and low noise. The output stage enables
the device to operate with output voltages close to the
power supply rails. Refer to Section 1.0 “Electrical
Characteristics” for the analog output voltage range
and load conditions.
In addition to resistive load driving capability, the
amplifier will also drive high capacitive loads without
oscillation. The amplifier’s strong output allows V
be used as a programmable voltage reference in a
system.
Selecting a gain of 2 reduces the bandwidth of the
amplifier in Multiplying mode. Refer to Section 1.0
“Electrical Characteristics” for the Multiplying mode
bandwidth for given load conditions.
4.2.1.1
The rail-to-rail output amplifier has two configurable
gain options: a gain of 1x (<GA> = 1) or a gain of 2x
(<GA> = 0). The default value is a gain of 2x
(<GA> = 0).
DS22248A-page 20
Digital
Input
Code
REF
– 1 LSB, excluding the effects of offset error.
Circuit Descriptions
111
110
101
100
011
010
001
000
OFFSET ERROR
GAIN ERROR
OUTPUT AMPLIFIER
Programmable Gain Block
Actual
Transfer
Function
DAC Output
Example for DNL Accuracy.
Narrow Code, < 1 LSb
Wide Code, > 1 LSb
Ideal Transfer
Function
OUT
to
4.2.2
The input buffer amplifier for the MCP4901/4911/4921
devices provides low offset voltage and low noise. A
Configuration bit for each DAC allows the V
bypass the V
Buffered or Unbuffered mode. Buffered mode provides
a very high input impedance, with only minor limitations
on the input range and frequency response. Unbuf-
fered mode provides a wide input range (0V to V
with a typical input impedance of 165 k with 7 pF.
Unbuffered mode (<BUF> = 0) is the default
configuration.
4.2.3
The internal Power-on Reset (POR) circuit monitors the
power supply voltage (V
The circuit also ensures that the device powers up with
high output impedance (<SHDN> = 0, typically
500 k. The devices will continue to have a high-
impedance output until a valid write command is
received, and the LDAC pin meets the input low thresh-
old.
If the power supply voltage is less than the POR
threshold (V
in its Reset state. It will remain in that state until
V
received.
Figure 4-3
pulse and the duration required to cause a reset to
occur, as well as the relationship between the duration
and trip voltage. A 0.1 µF decoupling capacitor,
mounted as close as possible to the V
provide additional transient immunity.
FIGURE 4-3:
DD
> V
POR
VOLTAGE REFERENCE AMPLIFIER
POWER-ON RESET CIRCUIT
shows a typical power supply transient
POR
5V
and a subsequent write command is
10
REF
8
6
4
2
0
= 2.0V, typical), the device will be held
Transients
input buffer amplifier, achieving
1
Typical Transient Response.
 2010 Microchip Technology Inc.
V
Transients
Time
DD
DD
T
below
A
2
) during device operation.
– V
Transient Duration
POR
V
DD
the
3
=
above
(V)
- V
POR
4
the
V
POR
DD
5
REF
pin, can
input to
DD
),