LTC2970-1 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC2970-1' PDF : 36 Pages View PDF
LTC2970/LTC2970-1
U
OPERATIO
• Continuously servo one or both supplies to a pro-
grammed voltage.
• Perform a one-time servo of one or both supplies to a
programmed voltage and hold the servo codes in the
controlling IDAC.
• Perform a one time servo of one or both supplies to
a programmed voltage and hold the code(s) in the
controlling IDAC(s) until over/under voltage monitor-
ing detects a fault, at which point a control bit may be
used to allow the LTC2970 to servo back to the initial
voltage target.
• Select any combination of seven possible ADC channels
to be monitored by the ADC.
• Generate instantaneous faults based on user program-
mable over-voltage and under-voltage limits and fixed
IDAC limits. The status of OR’d voltage limit faults and
IDAC faults may be output over GPIO_0 and GPIO_1,
respectively.
• Enable instantaneous faults to set associated latched
faults using the FAULT_EN register. The status of OR’d
latched faults may be signalled using ALERT.
• Configure the GPIO_0 and GPIO_1 pins to act as inputs
or outputs.
2. I2C Serial Digital Interface
The LTC2970 communicates with a host (master) using
the 2-wire, I2C serial bus interface. The Timing Diagram
shows the timing relationship of the signals on the bus.
The two bus lines, SDA and SCL, must be high when the
bus is not in use. External pull-up resistors or current
sources are required on these lines.
The LTC2970 I2C interface is SMBus compatible; it meets
all SMBus setup times, hold times and timeout require-
ments.
The LTC2970 is a receive-only (slave) device. The LTC2970
can signal the host through the SMBALERT protocol that it
wants to talk by asserting ALERT low. The LTC2970 sup-
ports the three I2C protocols summarized in Table 1.
Slave Address
The LTC2970 can respond to one of nine 7-bit addresses.
The two slave address select pins (ASEL1 and ASEL0) are
programmed by the user and determine the slave address,
as shown in Table 2.
The LTC2970 also supports the ARA address and a global
address that allows multiple LTC2970s to be programmed
with the same data simultaneously, as shown in Table 3.
Table 1. Supported I2C Command Types
READ DATA WORD:
S:ADR:W:A:CMD:A:Sr:ADR:R:A:DATA:A:DATA:NACK:P
WRITE DATA WORD:
S:ADR:W:A:CMD:A:DATA:A:DATA:A:P
ALERT RESPONSE
S:ARA:R:A:ADR:NACK:P:
29701fc
14
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