Rainbow Electronics MAX3799 - Manual (Page 25)

Bit 2: IBIASERR. When the bias incremented result is greater than IBIASMAX, then a SOFT FAULT is reported. See
the
Programming Bias Current section.
Bit 1: TXED. This only indicates the absence of an AC signal at the transmit input. This is not an LOS indicator.
Bias Current Setting Register (SET_IBIAS)
Bits 7 to 0: SET_IBIAS[8:1]. The bias current DAC is controlled by a total of 9 bits. The SET_IBIAS[8:1] bits are
used to set the bias current with even denominations from 0 to 510 bits. The LSB (SET_IBIAS[0]) bit is controlled by
the BIASINC register and is used to set the odd denominations in the SET_IBIAS[8:0].
Modulation Current Setting Register (SET_IMOD)
Bits 7 to 0: SET_IMOD[8:1]. The modulation current DAC is controlled by a total of 9 bits. The SET_IMOD[8:1] bits
are used to set the modulation current with even denominations from 0 to 510 bits. The LSB (SET_IMOD[0]) bit is
controlled by the MODINC register and is used to set the odd denominations in the SET_IMOD[8:0].
Maximum Modulation Current Setting Register (IMODMAX)
Bits 7 to 0: IMODMAX[7:0]. The IMODMAX register is an 8-bit register that can be used to limit the maximum modu-
lation current. IMODMAX[7:0] is continuously compared to the SET_IMOD[8:1].
Maximum Bias Current Setting Register (IBIASMAX)
Bits 7 to 0: IBIASMAX[7:0]. The IBIASMAX register is an 8-bit register that can be used to limit the maximum bias
current. IBIASMAX[7:0] is continuously compared to the SET_IBAS[8:1].
MAX3799
1Gbps to 14Gbps, SFP+ Multirate Limiting
Amplifier and VCSEL Driver
______________________________________________________________________________________ 25
Bit # 7 6 5 4 3 2 1 0 ADDRESS
Name
SET_IBIAS
[8] (MSB)
SET_IBIAS
[7]
SET_IBIAS
[6]
SET_IBIAS
[5]
SET_IBIAS
[4]
SET_IBIAS
[3]
SET_IBIAS
[2]
SET_IBIAS
[1]
Default Value 0 0 0 0 0 1 0 0
H0x08
Bit # 7 6 5 4 3 2 1 0 ADDRESS
Name
SET_IMOD
[8] (MSB)
SET_IMOD
[7]
SET_IMOD
[6]
SET_IMOD
[5]
SET_IMOD
[4]
SET_IMOD
[3]
SET_IMOD
[2]
SET_IMOD
[1]
Default Value 0 0 0 1 0 0 1 0
H0x09
Bit # 7 6 5 4 3 2 1 0 ADDRESS
Name
IMODMAX
[7] (MSB)
IMODMAX
[6]
IMODMAX
[5]
IMODMAX
[4]
IMODMAX
[3]
IMODMAX
[2]
IMODMAX
[1]
IMODMAX
[0] (LSB)
Default Value 0 0 1 1 0 0 0 0
H0x0A
Bit # 7 6 5 4 3 2 1 0 ADDRESS
Name
IBIASMAX
[7] (MSB)
IBIASMAX
[6]
IBIASMAX
[5]
IBIASMAX
[4]
IBIASMAX
[3]
IBIASMAX
[2]
IBIASMAX
[1]
IBIASMAX
[0] (LSB)
Default Value 0 0 0 1 0 0 1 0
H0x0B