Rainbow Electronics DS1875 - Manual (Page 13)

DS1875
PON Triplexer and SFP Controller
______________________________________________________________________________________ 13
Pin Description
PIN NAME FUNCTION
1 BEN Burst-Enable Input. Triggers the samples for the APC and quick-trip monitors.
2 SDA I 2 C Serial-Data Input/Output
3 SCL I 2 C Serial-Clock Input
4 TX-F Transmit-Fault Output
5, 7, 11, 20,
36, 37, 38
N.C. No Connection
6 FETG
FET Gate Output. Signals an external n-channel or p-channel MOSFET to enable/disable the
laser’s current.
8 TX-D Transmit-Disable Input. Disables analog outputs.
9, 31, 35 V CC Power-Supply Input (2.85V to 3.9V)
10, 24, 32, 33 GND Ground Connection
12 LOSI
Loss-of-Signal Input. Open-collector buffer for external loss-of-signal input. This input is
accessible in the status register through the I
2 C interface.
13 MON5/D0
External Monitor Input 5 or Digital I/O 0. This signal is the open-collector output driver for IN. It
can also be controlled by the MUX0 and OUT0 bits. The voltage level of this pin can be read at
IN0. In analog input mode, the voltage at this pin is digitized by the internal 13-bit analog-to-
digital converter and can be read through the I
2 C interface. Alarm and warning values can be
assigned to interrupt the processor based on the ADC result.
14, 15, 16
MON6/D1,
MON7/D2,
MON8/D3
External Monitor Inputs 6, 7, and 8 or Digital I/O 1, 2, and 3. In digital mode, these open-collector
outputs are controlled by the OUTx bits, and their voltage levels can be read at the INx bits. In
analog input mode, the voltages at these pins are digitized by the internal 13-bit analog-to-digital
converter and can be read through the I
2 C interface. Alarm and warning values can be assigned
to interrupt the processor based on the ADC result. D2 is configurable as a quick-trip output for
MON3.
17, 18, 19
MON1,
MON2,
MON4
External Monitor Input 1, 2, and 4. The voltage at these pins is digitized by the internal 13-bit
analog-to-digital converter and can be read through the I
2 C interface. Alarm and warning values
can be assigned to interrupt the processor based on the ADC result.
21, 22
MON3N,
MON3P
External Monitor Input 3. This is a differential input that is digitized by the internal 13-bit ADC
and can be read through the I
2 C interface. Alarm and warning values can be assigned to interrupt
the processor based on the ADC result. When used as a single-ended input, connect MON3N to
ground.
23 DAC1 8-Bit DAC Output. Driven either by I 2 C interface or temperature-indexed LUT.
25 M4DAC
8-Bit DAC Output for Generating Analog Voltage. Can be controlled by a LUT indexed by the
voltage applied to MON4.
26 FB
Converter Feedback. Input to error amplifier. The other input to the error amplifier is an 8-bit DAC.
The DAC can be driven by a temperature-indexed LUT. The output of the error amplifier is the
input of the comparator used to create the PWM signal.
27 BIAS Bias-Current Output. This 13-bit current output generates the bias current reference for the MAX3643.
28 MOD
Modulation Output Voltage. This 8-bit voltage output has eight full-scale ranges from 1.25V to
0.3125V. This pin is connected to the MAX3643’s VMSET input to control the modulation current.
29 COMP Compensation for Error Amplifier in PWM Controller
30 BMD Back Monitor Diode Input (Feedback Voltage, Transmit Power Monitor)
34 SW
PWM Output. This is typically the switching node of a PWM converter. In conjunction with FB, a
boost converter, buck converter, or analog 8-bit output can be created.
— EP Exposed Pad