AFE4490 Datasheet, PDF (57/70 Pages) Texas Instruments – Integrated Analog Front-End for Pulse Oximeters

AFE4490
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D23
D22
0
0
D11
D10
TXBRG
MOD
0
SBAS602B – DECEMBER 2012 – REVISED FEBRUARY 2013
CONTROL2: Control Register 2 (Address = 23h, Reset Value = 0000h)
D21
D20
D19
D18
D17
D16
D15
D14
D13
D12
0
0
0
0
TX_SUP_
3V
0
EN_ADC
_BYP
0
0
0
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
XTAL
DIS
EN_
SLOW_
DIAG
0
0
0
0
0
PDNTX PDNRX PDNAFE
This register controls the LED transmitter, crystal, and the AFE, transmitter, and receiver power modes.
Bits D[23:19]
Bits D[18:17]
Bit D16
Bit D15
Bits D[14:12]
Bit D11
Bit D10
Bit D9
Bit D8
Bits D[7:3]
Bit D2
Bit D1
Bit D0
Must be '0'
TX_REF[1:0]: Tx reference voltage
These bits set the transmitter reference voltage. This Tx reference voltage is available on
the device TX_REF pin.
00 = 0.75-V Tx reference voltage (default value after reset)
01 = 0.5-V Tx reference voltage
10 = 1.0-V Tx reference voltage
11 = 0.75-V Tx reference voltage
Must be '0'
EN_ADC_BYP: ADC bypass mode enable
0 = Normal mode, the internal ADC is active (default after reset)
1 = ADC bypass mode, the analog signal is output to the ADC_BYPP and ADC_BYPN pins
Must be '0'
TXBRGMOD: Tx bridge mode
0 = LED driver is configured as an H-bridge (default after reset)
1 = LED driver is configured as a push-pull
Must be '0'
XTALDIS: Crystal disable mode
0 = The crystal module is enabled; the 8-MHz crystal must be connected to the XIN and
XOUT pins
1 = The crystal module is disabled; an external 8-MHz clock must be applied to the XIN pin
EN_SLOW_DIAG: Fast diagnostics mode enable
0 = Fast diagnostics mode, 8 ms (default value after reset)
1 = Slow diagnostics mode, 16 ms
Must be '0'
PDN_TX: Tx power-down
0 = The Tx is powered up (default after reset)
1 = Only the Tx module is powered down
PDN_RX: Rx power-down
0 = The Rx is powered up (default after reset)
1 = Only the Rx module is powered down
PDN_AFE: AFE power-down
0 = The AFE is powered up (default after reset)
1 = The entire AFE is powered down (including the Tx, Rx, and diagnostics blocks)
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