NI-9251 with mini XLR Specifications

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Updated2023-07-06
7 minute(s) read

Definitions

Warranted specifications describe the performance of a model under stated operating conditions and are covered by the model warranty.

Characteristics describe values that are relevant to the use of the model under stated operating conditions but are not covered by the model warranty.

Typical specifications describe the performance met by a majority of models.
Nominal specifications describe an attribute that is based on design, conformance testing, or supplemental testing.

Specifications are Typical unless otherwise noted.

Conditions

Specifications are valid for the range -40 °C to 70 °C unless otherwise noted.

Safety Voltages

Connect only voltages that are within the following limits:

Channel-to-earth ground

±30 V maximum, Measurement Category I

Isolation
Channel-to-channel	None
Channel-to-earth ground	None

Measurement Category I

Warning Do not connect the product to signals or use for measurements within Measurement Categories II, III, or IV, or for measurements on MAINs circuits or on circuits derived from Overvoltage Category II, III, or IV which may have transient overvoltages above what the product can withstand. The product must not be connected to circuits that have a maximum voltage above the continuous working voltage, relative to earth or to other channels, or this could damage and defeat the insulation. The product can only withstand transients up to the transient overvoltage rating without breakdown or damage to the insulation. An analysis of the working voltages, loop impedances, temporary overvoltages, and transient overvoltages in the system must be conducted prior to making measurements.

Mise en garde Ne pas connecter le produit à des signaux dans les catégories de mesure II, III ou IV et ne pas l'utiliser pour des mesures dans ces catégories, ou des mesures sur secteur ou sur des circuits dérivés de surtensions de catégorie II, III ou IV pouvant présenter des surtensions transitoires supérieures à ce que le produit peut supporter. Le produit ne doit pas être raccordé à des circuits ayant une tension maximale supérieure à la tension de fonctionnement continu, par rapport à la terre ou à d'autres voies, sous peine d'endommager et de compromettre l'isolation. Le produit peut tomber en panne et son isolation risque d'être endommagée si les tensions transitoires dépassent la surtension transitoire nominale. Une analyse des tensions de fonctionnement, des impédances de boucle, des surtensions temporaires et des surtensions transitoires dans le système doit être effectuée avant de procéder à des mesures.

Measurement Category I is for measurements performed on circuits not directly connected to the electrical distribution system referred to as MAINS voltage. MAINS is a hazardous live electrical supply system that powers equipment. This category is for measurements of voltages from specially protected secondary circuits. Such voltage measurements include signal levels, special equipment, limited-energy parts of equipment, circuits powered by regulated low-voltage sources, and electronics.

Note Measurement Categories CAT I and CAT O are equivalent. These test and measurement circuits are for other circuits not intended for direct connection to the MAINS building installations of Measurement Categories CAT II, CAT III, or CAT IV.

Power Requirements

Power consumption from chassis
Active mode	0.89 W max
Sleep mode	53 μW max

Thermal dissipation (at 70 °C)
Active mode	1.31 W max
Sleep mode	0.30 W max

Physical Characteristics

Weight	140 g (4.9 oz)
Dimensions	Visit ni.com/dimensions and search by module number.

Environmental Characteristics

Temperature
Operating	-40 °C to 70 °C
Storage	-40 °C to 85 °C

Humidity
Operating	10% RH to 90% RH, noncondensing
Storage	5% RH to 95% RH, noncondensing

Ingress protection (with power plug attached)

IP40

Pollution Degree

Maximum altitude

5,000 m

Shock and Vibration

Operating vibration
Random	5 g RMS, 10 Hz to 500 Hz
Sinusoidal	5 g, 10 Hz to 500 Hz

Operating shock

30 g, 11 ms half sine; 50 g, 3 ms half sine; 18 shocks at 6 orientations

To meet these shock and vibration specifications, you must panel mount the system.

Input Characteristics

Number of channels

2 analog input channels

ADC resolution

24 bits

Type of ADC

Delta-Sigma with analog prefiltering

Sampling mode

Simultaneous

Input coupling

Software-selectable AC/DC

Internal master timebase (f_M)
Frequency	13.1072 MHz
Accuracy	±100 ppm maximum

Data rate range (f_s)

Using internal master timebase
Minimum	267 S/s
Maximum	102.4 kS/s

Using external master timebase
Minimum	244.141 S/s
Maximum	102.734 kS/s

Data rate^[1]¹ The data rate must remain within the appropriate data rate range.

f_{s} = \frac{f_{M}}{4 \times a \times b}

Input delay^[2]² 2.5 μs is applicable for DC to 40 kHz in DC coupling and 50 Hz to 40 kHz in AC coupling.

34/f_s + 2.5 μs

Overvoltage protection

±30 V

Input resistance
Single ended	2 MΩ
Differential	4 MΩ

Input capacitance³ From input pin to ground^[3]

940 pF

Input voltage range (Differential)
Minimum	3.000 Vrms (±4.243 Vpk)
Typical	3.058 Vrms (±4.325 Vpk)
Scaling coefficient	515,589 pV/LSB

Maximum input voltage^[3]

±4.464 Vpk

High pass filter cutoff frequency (AC)
-3 dB	0.4 Hz
-0.1 dB	2.61 Hz

1378 — Figure 1. High Pass Filter Frequency Response

Table 1. Accuracy in DC Coupling
Measurement Conditions	Percent of Reading (Gain Error)	Percent of Range^[4]⁴ Range equals 4.3251 Vpk (Offset Error)
Maximum (-40 °C to 70 °C)	±0.212%	±0.155%
Typical (23 °C, ±5 °C)	±0.056%	±0.023%

Stability of Accuracy
Gain drift	7 ppm/°C
Offset drift	31 μV/°C

Passband, -0.1 dB

Frequency

0.4 * f_s

Flatness (peak-to-peak)^[5]⁵ With 40 Ω source impedance
DC to 20 kHz	0.03 dB maximum
DC to 40 kHz	0.09 dB maximum

Phase linearity

DC coupling
DC to 20 kHz	0.03° maximum
DC to 40 kHz	0.22° maximum

AC coupling
100 Hz to 40 kHz	0.22° maximum

Channel-to-channel mismatch

Gain
DC to 20 kHz	0.075 dB maximum
DC to 40 kHz	0.115 dB maximum

Phase (f_in in kHz)

f _in * 0.03° maximum

Stopband
Frequency	0.499 * f_s
Rejection	105 dB

Alias free bandwidth

0.5 * f_s

Alias rejection @ oversample rate
f _s = 102.4 kS/s	100 dB at 3.2768 MHz
f _s = 267 S/s	78 dB at 273 kHz

Table 2. Idle Channel Noise (AC Coupling and DC Coupling)
Data Rate (S/s)	ADC Decimation Ratio	Noise (μVrms)
102,400	32	8.5
51,200	64	5.9
25,600	128	4.2
12,800	256	3.1
6,400	512	2.3
3,200	1,024	1.8

Note The noise specifications assume the NI-9251 with mini XLR is using the internal master timebase frequency of 13.1072 MHz.

Spectral noise density

\frac{33.3 nV}{\sqrt{Hz}} @ 1 kHz

Table 3. Dynamic Range (1 kHz Input Frequency, -60 dBF amplitude, BW=0.5 * f_s)
Data Rate (S/s)	ADC Decimation Ratio	AC or DC Coupled (dBFS)
102,400	32	111
51,200	64	114
25,600	128	117
12,800	256	120
6,400	512	122
3,200	1,024	124

Crosstalk (CH to CH)
f _in ≤ 1 kHz	-142 dB
f _in ≤ 20 kHz	-118 dB
f _in ≤ 40 kHz	-112 dB

Common mode rejection ratio (CMRR)
f _in = 20 Hz to 1 kHz	49 dB minimum, with AC coupling
f _in = DC to 1 kHz	50 dB minimum, with DC coupling

Intermodulation distortion (IMD)^[6]⁶ Test standards: SMPTE 60 Hz + 7 kHz, amplitude ratio 4:1 with total amplitude at 0dBFS CCIF 14 kHz + 15 kHz, amplitude ratio 1:1 with each tone amplitude at -6 dBFS Up to fifth order harmonic
f _s = 51.2 kS/s	-108 dB
f _s = 102.4 kS/s	-105 dB

Non-harmonic SFDR (f_s = 102.4 kS/s)

135 dBFS

Total Harmonic Distortion (THD)

f _s = 51.2 kS/s
1 kHz	-114 dBc
20 Hz to 22 kHz	-111 dBc

f _s = 102.4 kS/s
8 kHz	-110 dBc
20 Hz to 44 kHz	-108 dBc

Total Harmonic Distortion + Noise (THD+N)

f _s = 51.2 kS/s
1 kHz	-111 dBc
20 Hz to 22 kHz	-109 dBc

f _s = 102.4 kS/s
8 kHz	-107 dBc
20 Hz to 44 kHz	-106 dBc

Calibration

You can obtain the calibration certificate and information about calibration services for the NI-9251 with mini XLR at ni.com/calibration.

Calibration interval

2 years

¹ The data rate must remain within the appropriate data rate range.

² 2.5 μs is applicable for DC to 40 kHz in DC coupling and 50 Hz to 40 kHz in AC coupling.

³ From input pin to ground

⁴ Range equals 4.3251 Vpk

⁵ With 40 Ω source impedance

⁶ Test standards:

SMPTE 60 Hz + 7 kHz, amplitude ratio 4:1 with total amplitude at 0dBFS
CCIF 14 kHz + 15 kHz, amplitude ratio 1:1 with each tone amplitude at -6 dBFS

Up to fifth order harmonic

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