XRP7740ILB-0X18-F Exar Corporation, XRP7740ILB-0X18-F Datasheet - Page 15

• Manufacturer Part Number: XRP7740ILB-0X18-F
• Description: IC CTRLR PWM/LDO STP-DWN 40TQFN
• Manufacturer: Exar Corporation
• Series: -r

Specifications of XRP7740ILB-0X18-F

• Topology: Step-Down (Buck) Synchronous (4), Linear (LDO) (1)
• Function: Any Function
• Number Of Outputs: 5
• Frequency - Switching: 1.5MHz
• Voltage/current - Output 1: Controller
• Voltage/current - Output 2: Controller
• Voltage/current - Output 3: Controller
• W/led Driver: No
• W/supervisor: No
• W/sequencer: Yes
• Voltage - Supply: 6.5 V ~ 20 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 1016-1697

There are two locations where the under voltage can be sensed: VIN1 and VIN2. The
SET_UVLO_WARN_VINx register that sets the under voltage warning set point condition at
100mV increments. When the warning threshold is reached, the Host is informed via a GPIO or by
reading the READ_WARN_FLAG register.
The SET_UVLO_TARG_VINx register that controls the under voltage fault set point condition at
100mV increments. This fault condition will be indicated in the READ_FAULT_WARN register.
When an under voltage fault condition occurs (either on VIN1 or VIN2), the fault flag register is set
and all of the XRP7708 outputs are shut down. The measured input voltages can be read back
using the READ_VIN1 or READ_VIN2 register, and both registers have a resolution of 100mV
per LSB. When the UVLO condition clears (voltage rises above the UVLO Warning Threshold), the
chip can be configured to automatically restart.
This is a multi-function pin that provides power to both the Standby Linear Regulator and internal
linear regulators to generate VCCA, VDD, and the Standby LDO (LDOUT).
It is also used as a UVLO detection pin. If Vin1 falls below its user programmed limit, all channels
are shut down.
VIN2 is required to be tied to VIN1 pin. It can be used as a UVLO detection pin. If VIN2 falls below
its user programmed limit, all channels are shut down.
This register allows the user to read back the temperature of the IC. The temperature is expressed
in Kelvin with a maximum range of 520K, a minimum of 200K, and an LSB of 5 degrees K. The
temperature can be accessed by reading the READ_VTJ register.
There are also warning and fault flags that get set in the READ_OVV_UVLO_OVT_FLAG register.
The warning threshold is configurable to 5 or 10 Degrees C below the fault threshold. When the
junction temperature reaches 5 or 10 Degrees C below the user defined set point, the over-
temperature warning bit [OTPW] gets set in the READ_OVV_UVLO_OVT_FLAG register to warn the
user that the IC might go into an over temperature condition (and shutdown all of the regulators).
If the over temperature condition occurs both the OTP and OTPW bits will be set in the
READ_OVV_UVLO_OVT_FLAG register and the IC will shut down all channels (but I
operational). The actual over temperature threshold can be set by the user by using a 7bit
SET_THERMAL_SHDN register with an LSB of 5K.
If the over temperature fault condition clears, then the IC can be set to restart the chip
automatically. The restart temperature threshold can be set by the SET_THERMAL_RESTART
register.
© 2011 Exar Corporation
Under Voltage Lockout (UVLO)
VIN1
VIN2
Temperature Monitoring and Over Temperature Protection (OTP)
•
•
•
•
Over Current Protection (OCP) monitors the current of a channel, and will shutdown the
channel if it surpasses its current threshold.
after a 200ms delay.
Reading the junction temperature
Over Temperature Warning
Over Temperature Fault
Q
Q
u
u
a
a
d
d
C
C
h
h
a
a
n
n
15/28
n
n
e
e
l
l
D
D
i
i
The channel will be automatically restarted
g
g
i
i
t
t
a
a
l
l
P
P
X
X
W
W
R
R
M
M
P
P
S
S
7
7
t
t
7
7
e
e
0
0
p
p
8
8
D
D
o
o
a
a
w
w
n
n
n
d
n
d
C
C
X
2
X
C will remain
o
o
R
R
n
n
P
P
t
t
Rev. 1.2.0
r
r
7
7
o
o
7
7
l
l
l
l
e
e
4
4
r
r
0
0
s
s