MSP430F551X Datasheet, PDF (72/115 Pages) Texas Instruments – MIXED SIGNAL MICROCONTROLLER

MSP430F551x
MSP430F552x
SLAS590D – OCTOBER 2009 – REVISED APRIL 2010
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REF, External Reference
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)⁽¹⁾
V_eREF+
PARAMETER
Positive external reference
voltage input
TEST CONDITIONS
V_eREF+ > V_REF–/V_eREF– ⁽²⁾
V_CC
MIN TYP MAX UNIT
1.4
AV_CC V
V_REF–/V_eREF–
Negative external reference
voltage input
V_eREF+ > V_REF–/V_eREF– ⁽³⁾
0
1.2 V
(V_eREF+ –
V_REF–/V_eREF–)
I_VeREF+,
I_{VREF–/VeREF–}
C_VREF+/-
Differential external reference
voltage input
Static input current
Capacitance at V_REF+/- terminal
V_eREF+ > V_REF–/V_eREF– ⁽⁴⁾
1.4 V ≤ V_eREF+ ≤ V_AVCC , V_eREF– = 0
V, f_ADC12CLK = 5 MHz,
ADC12SHTx = 1h,
Conversion rate 200ksps
1.4 V ≤ V_eREF+ ≤ V_AVCC , V_eREF– = 0
V, f_ADC12CLK = 5 MHz,
ADC12SHTx = 8h,
Conversion rate 20ksps
2.2 V/3 V
2.2 V/3 V
1.4
AV_CC V
±8.5 ±26 µA
(5)₁₀
±1 µA
µF
(1) The external reference is used during ADC conversion to charge and discharge the capacitance array. The input capacitance, C_i, is also
the dynamic load for an external reference during conversion. The dynamic impedance of the reference supply should follow the
recommendations on analog-source impedance to allow the charge to settle for 12-bit accuracy.
(2) The accuracy limits the minimum positive external reference voltage. Lower reference voltage levels may be applied with reduced
accuracy requirements.
(3) The accuracy limits the maximum negative external reference voltage. Higher reference voltage levels may be applied with reduced
accuracy requirements.
(4) The accuracy limits minimum external differential reference voltage. Lower differential reference voltage levels may be applied with
reduced accuracy requirements.
(5) Two decoupling capacitors, 10µF and 100nF, should be connected to VREF to decouple the dynamic current required for an external
reference source if it is used for the ADC12_A. See also the MSP430x5xx Family User's Guide (SLAU208).
REF, Built-In Reference
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)⁽¹⁾
PARAMETER
V_REF+
Positive built-in reference
voltage output
AV_CC(min)
AV_CC minimum voltage,
Positive built-in reference
active
TEST CONDITIONS
REFVSEL = {2} for 2.5 V
REFON = REFOUT = 1
I_VREF+= 0 A
REFVSEL = {1} for 2.0 V
REFON = REFOUT = 1
I_VREF+= 0 A
REFVSEL = {0} for 1.5 V
REFON = REFOUT = 1
I_VREF+= 0 A
REFVSEL = {0} for 1.5 V, reduced
performance
REFVSEL = {0} for 1.5 V
REFVSEL = {1} for 2.0 V
V_CC
MIN TYP
3V
2.50
3V
1.98
2.2 V/ 3 V
1.49
1.8
2.2
2.3
REFVSEL = {2} for 2.5 V
2.8
I_REF+
Operating supply current into ^{REFON = 1, REFOUT = 0, REFBURST = 0}
AV_CC terminal^{(2) (3)}
REFON = 1, REFOUT = 1, REFBURST = 0
3V
3V
100
0.9
MAX
±1.5%
±1.5%
±1.5%
140
1.5
UNIT
V
V
µA
mA
(1) The reference is supplied to the ADC by the REF module and is buffered locally inside the ADC. The ADC uses two internal buffers, one
smaller and one larger for driving the V_REF+ terminal. When REFOUT = 1, the reference is available at the V_REF+ terminal, as well as,
used as the reference for the conversion and utilizes the larger buffer. When REFOUT = 0, the reference is only used as the reference
for the conversion and utilizes the smaller buffer.
(2) The internal reference current is supplied via terminal AV_CC. Consumption is independent of the ADC12ON control bit, unless a
conversion is active. REFOUT = 0 represents the current contribution of the smaller buffer. REFOUT = 1 represents the current
contribution of the larger buffer without external load.
(3) The temperature sensor is provided by the REF module. Its current is supplied via terminal AV_CC and is equivalent to I_REF+ with REFON
=1 and REFOUT = 0.
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