X9523_06 Datasheet, PDF (14/28 Pages) Intersil Corporation – Laser Diode Control for Fiber Optic Modules

X9523
V1 / Vcc
V2, V3
V_TRIPx
V_P
WP
SCL
0 1 23 4 56 7
0 1 23 4 56 7
0 1 23 4 56 7
SDA
S
T
A
R
T
00h
A0h ^†
01h^†
09h^†
0Dh^†
sets
sets
sets
V_TRIP1
V_TRIP2
V_TRIP3
Data Byte ^†
Figure 17. Setting V_TRIPx to a higher level (x = 1,2,3).
† _{All others Reserved.}
V_TRIPX THRESHOLDS (X = 1,2,3)
The X9523 is shipped with pre-programmed threshold
(V_TRIPx) voltages. In applications where the required
thresholds are different from the default values, or if a
higher precision/tolerance is required, the X9523 trip
points may be adjusted by the user, using the steps
detailed below.
Setting a V_TRIPx Voltage (x = 1,2,3)
There are two procedures used to set the threshold
voltages (V_TRIPx), depending if the threshold voltage
to be stored is higher or lower than the present value.
For example, if the present V_TRIPx is 2.9 V and the
new V_TRIPx is 3.2 V, the new voltage can be stored
directly into the V_TRIPx cell. If however, the new setting
is to be lower than the present setting, then it is neces-
sary to “reset” the V_TRIPx voltage before setting the
new value.
Setting a Higher V_TRIPx Voltage (x = 1,2,3)
To set a V_TRIPx threshold to a new voltage which is
higher than the present threshold, the user must apply
the desired V_TRIPx threshold voltage to the corre-
sponding input pin (V1/Vcc, V2 or V3). Then, a pro-
gramming voltage (Vp) must be applied to the WP pin
before a START condition is set up on SDA. Next, issue
on the SDA pin the Slave Address A0h, followed by
the Byte Address 01h for V_TRIP1, 09h for V_TRIP2, and
0Dh for V_TRIP3, and a 00h Data Byte in order to pro-
gram V_TRIPx. The STOP bit following a valid write
operation initiates the programming sequence. Pin WP
must then be brought LOW to complete the operation
(See Figure 18). The user does not have to set the
WEL bit in the CONSTAT register before performing
this write sequence.
V_P
WP
SCL
SDA
0 1 23 4 56 7
0 1 23 4 56 7
0 1 23 4 56 7
00h ^†
A0h^†
03h^† Resets VTRIP1
Data Byte
S
T
0Bh^† Resets VTRIP2
A
R
0Fh^† Resets VTRIP3
T
Figure 18. Resetting the V_TRIPx Level
† _{All others Reserved.}
14
FN8209.1
January 3, 2006