SE98A Datasheet, PDF (27/43 Pages) NXP Semiconductors – DDR memory module temp sensor, 1.7 V to 3.6 V

NXP Semiconductors
SE98A
DDR memory module temp sensor, 1.7 V to 3.6 V
9. Application design-in information
In a typical application, the SE98A behaves as a slave device and interfaces to the master
(or host) via the SCL and SDA lines. The host monitors the EVENT output pin, which is
asserted when the temperature reading exceeds the programmed values in the alarm
registers. The A0, A1 and A2 pins are directly connected to the shared SPD’s A0, A1 and
A2 pins, otherwise they must be pulled HIGH or LOW. The SDA and SCL serial interface
pins are open-drain and require pull-up resistors, and are able to sink a maximum current
of 3 mA with a voltage drop less than 0.4 V. Typical pull-up values for SCL and SDA are
10 kΩ, but the resistor values can be changed in order to meet the rise time requirement if
the capacitance load is too large due to routing, connectors, or multiple components
sharing the same bus.
V_DD
SCL
SPD
SDA
A0
A1
V_SS ^A2
slave
V_DD
SE98A
A0
A1
A2
V_SS
10 kΩ
(3×)
SCL
SDA
EVENT
Fig 13. Typical application
master
HOST
CONTROLLER
002aad900
0.1 µF
V_DD
SE98A
A0
A1
A2 _VSS
3.3 V
10 kΩ
SCL
SDA
EVENT
10 kΩ
mother board
0.1 µF
V_CC(B) V_CC(A) ^{10 kΩ}
B2
A2
PCA9509
B1
A1
10 kΩ
1.1 V
0.1 µF
SCL
SDA
EVENT
HOST
CONTROLLER
EN
Fig 14. SE98A interfacing with 1.1 V host controller
002aad759
SE98A_2
Product data sheet
Rev. 02 — 6 August 2009
© NXP B.V. 2009. All rights reserved.
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