Datasheet

PGA309
www.ti.com
SBOS292C DECEMBER 2003REVISED JANUARY 2011
ELECTRICAL CHARACTERISTICS
Boldface limits apply over the specified temperature range, T
A
= –40°C to +125°C.
At T
A
= +25°C, V
SA
= V
SD
= +5V (V
SA
= V
SUPPLY ANALOG
, V
SD
= V
SUPPLY DIGITAL
; V
SA
must equal V
SD
), GND
D
= GND
A
= 0, and V
REF
= REF
IN
/REF
OUT
= +5V, unless otherwise noted.
PGA309
PARAMETER CONDITIONS MIN TYP MAX UNIT
Front-End PGA + Output Amplifier
V
OUT
/V
IN
Differential Signal Gain Range
(1)
Fine gain adjust = 1 8 to 1152 V/V
Front-End PGA Gains: 4, 8, 16, 23.27, 32, 42.67, 64, 128
Output Amplifier gains: 2, 2.4, 3, 3.6, 4.5, 6, 9
Input Voltage Noise Density f = 1kHz 210 nV/Hz
V
OUT
Slew Rate 0.5 V/ms
V
OUT
Settling Time (0.01%) V
OUT
/V
IN
Differential gain = 8, R
L
= 5kΩ || 200pF 6 ms
V
OUT
Settling Time (0.01%) V
OUT
/V
IN
Differential gain = 191, R
L
= 5kΩ || 200pF 4.1 ms
V
OUT
Nonlinearity 0.002 %FSR
External Sensor Output Sensitivity V
SA
= V
SD
= V
EXC
= +5V 1 to 245 mV/V
Front-End PGA
Auto-Zero Internal Frequency 7 kHz
Offset Voltage (RTI)
(2)
Coarse offset adjust disabled ±3 ±50 mV
vs Temperature ±0.2 mV/°C
vs Supply Voltage, V
SA
±2 mV/V
vs Common-Mode Voltage G
F
= Front-End PGA gain 1500/G
F
6000/G
F
mV/V
Linear Input Voltage Range
(3)
0.2 V
SA
1.5 V
Input Bias Current 0.1 1.5 nA
Input Impedance: Differential 30 || 6 GΩ || pF
Input Impedance: Common-Mode 50 || 20 GΩ || pF
Input Voltage Noise 0.1Hz to 10Hz, G
F
= 128 4 mV
PP
PGA Gain
Gain Range Steps 4, 8, 16, 23.27, 32, 42.67, 64, 128 4 to 128 V/V
Initial Gain Error G
F
= 4 to 42 0.2 ±1 %
G
F
= 64 0.25 ±1.2 %
G
F
= 128 0.3 ±1.6 %
vs Temperature 10 ppm/°C
Output Voltage Range 0.05 to V
SA
0.1 V
Bandwidth Gain = 4 400 kHz
Gain = 128 60 kHz
Coarse Offset Adjust
(RTI of Front-End PGA)
Range ±(14)(V
REF
)(0.00085) ±56 ±59.5 ±64 mV
vs Temperature 0.004 %/°C
Drift ±14 steps, 4-bit + sign 4 mV
Fine Offset Adjust (Zero DAC)
(RTO of the Front-End PGA)
(2)
Programming Range 0 V
REF
V
Output Voltage Range 0.1 V
SA
– 0.1 V
Resolution 65,536 steps, 16-bit DAC 73 mV
Integral Nonlinearity 20 LSB
Differential Nonlinearity 0.5 LSB
Gain Error 0.1 %
Gain Error Drift 10 ppm/°C
Offset 5 mV
Offset Drift 10 mV/°C
(1) PGA309 total differential gain from input (V
IN1
– V
IN2
) to output (V
OUT
). V
OUT
/ (V
IN1
– V
IN2
) = (Front-end PGA gain) × (Output Amplifier
gain) × (Gain DAC).
(2) RTI = Referred-to-input. RTO = referred to output.
(3) Linear input range is the allowed min/max voltage on the V
IN1
and V
IN2
pins for the input PGA to continue to operate in a linear region.
The allowed common-mode and differential voltage depends on gain and offset settings. Refer to the Gain Scaling section for more
information.
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