Datasheet
N = log 2
FB
I
PD
6.6 I´
NOISE
AFE4490
SBAS602F –DECEMBER 2012–REVISED OCTOBER 2013
www.ti.com
ELECTRICAL CHARACTERISTICS
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
PERFORMANCE (Full-Signal Chain)
R
F
= 10 kΩ 50 µA
R
F
= 25 kΩ 20 µA
R
F
= 50 kΩ 10 µA
I
IN_FS
Full-scale input current R
F
= 100 kΩ 5 µA
R
F
= 250 kΩ 2 µA
R
F
= 500 kΩ 1 µA
R
F
= 1 MΩ 0.5 µA
PRF Pulse repetition frequency 62.5 5000 SPS
DC
PRF
PRF duty cycle 25%
f
CM
= 50 Hz and 60 Hz, LED1 and LED2 with
75 dB
R
SERIES
= 500 kΩ, R
F
= 500 kΩ
CMRR Common-mode rejection ratio
f
CM
= 50 Hz and 60 Hz, LED1-AMB and
95 dB
LED2-AMB with R
SERIES
= 500 kΩ, R
F
= 500 kΩ
f
PS
= 50 Hz, 60 Hz at PRF = 200 Hz 100 dB
PSRR Power-supply rejection ratio
f
CM
= 50 Hz, 60 Hz at PRF = 600 Hz 106 dB
PSRR
LED
PSRR, transmit LED driver With respect to ripple on LED_DRV_SUP 75 dB
PSRR
Tx
PSRR, transmit control With respect to ripple on TX_CTRL_SUP 60 dB
With respect to ripple on RX_ANA_SUP and
PSRR
Rx
PSRR, receiver 60 dB
RX_DIG_SUP
R
F
= 100 kΩ with stage 2 gain disabled,
36 pA
RMS
PRF = 1200 Hz, duty cycle = 5%
Total integrated noise current, input-
referred (receiver with transmitter loop
R
F
= 500 kΩ with ambient cancellation enabled
back, 0.1-Hz to 20-Hz bandwidth)
and stage 2 gain = 4, PRF = 1200 Hz, 13 pA
RMS
duty cycle = 25%
R
F
= 100 kΩ, PRF = 1200 Hz, duty cycle = 5% 14.3 Bits
Noise-free bits (receiver with transmitter
N
FB
loop back, 0.1-Hz to 20-Hz bandwidth)
(1)
R
F
= 500 kΩ, PRF = 1200 Hz, duty cycle = 25% 13.5 Bits
RECEIVER FUNCTIONAL BLOCK LEVEL SPECIFICATION
R
F
= 500 kΩ, ambient cancellation enabled,
stage 2 gain = 4, PRF = 1300 Hz, 1.4 pA
RMS
Total integrated noise current,
LED duty cycle = 25%
input-referred (receiver alone) over 0.1-Hz
R
F
= 500 kΩ, ambient cancellation enabled,
to 5-Hz bandwidth
stage 2 gain = 4, PRF = 1300 Hz, 5 pA
RMS
LED duty cycle = 5%
(1) Noise-free bits (N
FB
) are defined as:
where:
I
PD
is the photodiode current, and I
NOISE
is the input-referred RMS noise current.
4 Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated
Product Folder Links: AFE4490