ISL21400USB-EVALZ Intersil, ISL21400USB-EVALZ Datasheet - Page 11

• Manufacturer Part Number: ISL21400USB-EVALZ
• Description: EVAL BOARD FOR ISL21400
• Manufacturer: Intersil

Specifications of ISL21400USB-EVALZ

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DACs Section
The ISL21400 contains two 8-bit DACs whose registers can
be programmed via the I
are non-volatile such that the values are restored during the
V
dedicated to scale the bandgap voltage reference
(Temperature invariant) and the other DAC (V
dedicated to scale the Temperature Sensor. Both of these
DACs can determine the output voltage as defined by
Equation 1 (see “Register Descriptions”).
Output Gain Amplifier Section
The ISL21400 contains an output gain amplifier (A) that is
programmed via the I
last stage before the output and therefore controls the
overall gain for the device. The gain can be programmed for
1x, 2x, or 4x amplification. This gain factor is used to
program the output voltage as determined by Equation 1
(see “Register Descriptions”).
There are 5 registers in the ISL21400 device, all nonvolatile
(see Table 2). All registers are accessible for reading or
writing through the I
Register Descriptions
Register 0: Bandgap Reference Gain (Nonvolatile)
Register 0 sets the output voltage of the bandgap reference
(V
from Register 0 as shown in Equation 2:
This term of Equation 1 can vary from 0V to 1.20V.
V
CC
REF
REG
REF
0
1
2
3
4
Addr
power-up cycle of the device. One DAC (V
•
). Referring to Equation 1, the number “n” is the setting
0
1
2
3
4
--------- -
255
n
NONVOLATILE
, for n = 0 to 255
TABLE 2. REGISTER DESCRIPTIONS
Y
Y
Y
Y
Y
V
(MSB)
TS7
REF
2
D7
D7
D7
D7
C serial bus.
2
C serial bus. The gain amplifier is the
7
2
C serial bus. The DAC registers
Reference setting
Temperature Sensor setting
Gain and storage
Storage
Storage
11
V
TS6
REF
D6
D6
D6
D6
DESCRIPTION
6
TS
TABLE 1. ISL21400 REGISTER BIT MAP
V
REF
) is
TS5
REF
D5
D5
D5
D5
) is
5
(EQ. 2)
ISL21400
V
REF
TS4
D4
D4
D4
D4
4
Register 1: Temperature Slope Gain (Nonvolatile)
Register 1 sets the Temperature Slope (TS) of the
temperature sensor. Referring to Equation 1, the number “m”
is the setting from Register 1 as shown in Equation 3:
V
V
+136mV at -40°C to -126mV at +85°C. The other term varies
from -1 to +1 and scales the temperature term before adding
to the V
Register 2: Device Gain and Storage (nonvolatile)
Register 2 contains 2 bits (2 LSB’s) which control the output
gain of the device. Table 3 shows the state of these two bits
and the resulting output gain. Note that two states produce
the same gain (Gain 1:0 set to 01b and 10b) of x2.
The other 6-bits in the register can be used for general
purpose memory (nonvolatile) or left alone.
Registers 3 and 4: General Purpose Data
(nonvolatile)
These two registers are one byte each and can be used for
general purpose nonvolatile memory.
I
The ISL21400 supports a bidirectional bus oriented protocol.
The protocol defines any device that sends data onto the
bus as a transmitter and the receiving device as the receiver.
The device controlling the transfer is the master and the
device being controlled is the slave. The master always
initiates data transfers and provides the clock for both
transmit and receive operations. Therefore, the ISL21400
operates as a slave device in all applications.
2
TS
TS
C Serial Interface
TABLE 3. REGISTER 2 OUTPUT GAIN (NONVOLATILE):
(
------------------------------- -
2 m
is the temperature dependent term and varies from
GAIN1
•
V
0
0
1
1
255
REF
TS3
REF
D3
D3
D3
D3
) 255
–
3
OUTPUT GAIN
portion.
GAIN0
V
TS2
REF
D2
D2
D2
D2
0
1
0
1
2
V
GAIN1
TS1
REF
D1
D1
D1
OUTPUT GAIN, A
1
x 1
x 2
x 2
x 4
March 31, 2011
V
GAIN0
(LSB)
TS0
REF
D0
D0
D0
FN8091.3
(EQ. 3)
V
0