Datasheet

AFE4490
www.ti.com SBAS602F –DECEMBER 2012–REVISED OCTOBER 2013
ELECTRICAL CHARACTERISTICS (continued)
Minimum and maximum specifications are at T
A
= –40°C to +85°C. Typical specifications are at +25°C.
All specifications are at RX_ANA_SUP = RX_DIG_SUP = 3 V, TX_CTRL_SUP = LED_DRV_SUP = 5 V, stage 2 amplifier
disabled, and f
CLK
= 8 MHz, unless otherwise noted.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
I-V TRANSIMPEDANCE AMPLIFIER
See the Receiver Channel section
G Gain R
F
= 10 kΩ to R
F
= 1 MΩ V/µA
for details
Gain accuracy ±7%
10k, 25k, 50k, 100k, 250k,
Feedback resistance R
F
Ω
500k, and 1M
Feedback resistor tolerance R
F
±7%
Feedback capacitance C
F
5, 10, 25, 50, 100, and 250 pF
Feedback capacitor tolerance C
F
±20%
V
OD(fs)
Full-scale differential output voltage 1 V
Common-mode voltage on input pins Set internally 0.9 V
Includes equivalent capacitance of photodiode,
External differential input capacitance 10 1000 pF
cables, EMI filter, and so forth
With a 1-kΩ series resistor and a 10-nF
V
O(shield)
Shield output voltage, V
CM
0.9 V
decoupling capacitor to ground
AMBIENT CANCELLATION STAGE
G Gain 0, 3.5, 6, 9.5, and 12 dB
Current DAC range 0 10 µA
Current DAC step size 1 µA
LOW-PASS FILTER
Low-pass corner frequency 3-dB attenuation 0.5 and 1 kHz
Duty cycle = 25% 0.004 dB
Pass-band attenuation, 2 Hz to 10 Hz
Duty cycle = 10% 0.041 dB
After diagnostics mode with filter corner = 500 Hz 28 ms
Filter settling time
After diagnostics mode with filter corner =
16 ms
1000 Hz
ADC bypass outputs output impedance RXOUTP and RXOUTN 1 kΩ
ANALOG-TO-DIGITAL CONVERTER
Resolution 22 Bits
See the ADC Operation and Averaging Module
Sample rate 4 × PRF SPS
section
ADC full-scale voltage ±1.2 V
See the ADC Operation and Averaging Module
ADC conversion time 50 PRF / 4 µs
section
ADC reset time 2 t
CLK
TRANSMITTER
0, 50, 75, 100, 150, and 200
Output current range (see the LEDCNTRL: LED Control mA
Register for details)
LED current DAC error ±5%
Output current resolution 8 Bits
0.1-Hz to 20-Hz bandwidth, at 25-mA output
110 dB
current
Transmitter noise dynamic range
0.1-Hz to 20-Hz bandwidth, at 100-mA output
110 dB
current
Minimum sample time of LED1 and LED2
50 µs
pulses
LED_ON = 0 1 µA
LED current DAC leakage current
LED_ON = 1 50 µA
LED current DAC linearity Percent of full-scale current 0.5%
From zero current to 150 mA 7 µs
Output current settling time
(with resistive load)
From 150 mA to zero current 7 µs
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