SMM150
Preliminary Information
APPLICATIONS INFORMATION (CONTINUED)
Other codes will enable write protection. For example,
writing 59HEX will allow writes to the configuration
register but not to the memory, while writing 35HEX will
allow writes to the memory but not to the configuration
registers. The SMM150 also features a Write Protect
pin (WP input) which, when asserted, prevents writing
to the configuration registers and EE memory. In
addition to these two forms of write protection there is
Fault Latched by a Fault Condition:
The “Fault Latched by
a
Fault Condition”
programmable option is triggered only on the leading
edge of a Fault. That is, a latched fault can be cleared
while the Fault yet exists.
Fault Latched by Ready I/O Pin:
a
configuration register lock bit which, once
Fault Latched by Ready I/O pin functions on the
margin transitions from Off to Hi/Low/Nominal or from
Nominal to Hi/Low or Hi/Low to Nominal but not from
Hi/Low/Nominal to Off.
programmed, does not allow the configuration
registers to be changed.
A2, A1, A0
The address bits A[2:0] can be hard wired High or Low
or may be left open (High-Z) to allow for a total of 21
distinct device addresses. When floating, the inputs
can tolerate the amount of leakage as described by
the specification IAIT. An external 100k pull-up or pull
down resistor is sufficient to set a High or Low logic
level.
WRITE PROTECTION
Write protection for the SMM150 is located in a volatile
register where the power-on state is defaulted to write
protect. There are separate write protect modes for the
configuration registers and memory. In order to
remove write protection, the code 55HEX is written to
the write protection register.
+VIN - 2.7V to 5.5V
READY
FAULT#
MDN
MUP
DC-DC Converter
Vdd
U2
VOUT = 1.5V
R3
20
C3
10uF
7
8
1
2
4
3
+Vin
+Vout
+Vout
+Vout
Sense
+Vin
11
9
Enable
+Vin
C1
C2
U3
0.01uF
0.1uF
10
Trim
Vdd
J2
C8
C9
25
0.1uF
0.01uF
1
2
MDN
MUP
1
2
24
19
12
14
COMP1
COMP2
VM
D1
DIODE
Programming Supply
J1
1
3
5
7
9
2
1
28
8
SMM150
Gnd
SCL
SDA
MR
SCL
SDA
WP
C10
0.1uF
4
Gnd3
Rsrv5
6
8
20
+10V Rsrv8
+5V Rsrv10
TRIM
10
6
4
2
A0
A1
A2
R4
2.5k
C6
R7
R8
R5
R6
I2C SMX3200 Connector
10
CAP_M
7
GND
C4
0.02uF
C7
0.01uF
0.01uF
C5
1uF
Figure 6 – Typical applications schematic which shows the SMM150 controlling a 3.3V in/1.5V out DC/DC
converter. Care should be taken to filter DC/DC converter noise from the SMM150 VDD supply pin. This is
accomplished with optional components R3, C1, C2, C3 and C10. This example, using a 1.25V VREF, also
shows the COMP1/2 pins monitoring the DC/DC converter VOUT set to an OV of 1.7V on COMP1 and a UV of
1.3V on COMP2, the voltage divider resistors are:
For OV, R5 = 1.37k, 1% R6 = 3.83k, 1%, For UV, R7= 1.02k, 1% R8 = 25.5k, 1%.
The jumper J2 can be used to supply the SMM150 VDD voltage from the SMX3200 programmer when the
device is programmed with board power off and the controlled supply unloaded.
Summit Microelectronics, Inc
2075 2.6 05/13/05
11
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
