Dual, 256-Tap, Nonvolatile, I2C-Interface, Digital Poten" />
參數(shù)資料
型號(hào): MAX5477ETE+T
廠商: Maxim Integrated Products
文件頁數(shù): 6/16頁
文件大?。?/td> 0K
描述: IC DGTL POT DUAL 256TAP 16-TQFN
產(chǎn)品培訓(xùn)模塊: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
標(biāo)準(zhǔn)包裝: 2,500
接片: 256
電阻(歐姆): 10k
電路數(shù): 2
溫度系數(shù): 標(biāo)準(zhǔn)值 70 ppm/°C
存儲(chǔ)器類型: 非易失
接口: I²C(設(shè)備位址)
電源電壓: 2.7 V ~ 5.25 V
工作溫度: -40°C ~ 85°C
安裝類型: 表面貼裝
封裝/外殼: 16-WFQFN 裸露焊盤
供應(yīng)商設(shè)備封裝: 16-TQFN(3x3)
包裝: 帶卷 (TR)
MAX5477/MAX5478/MAX5479
Dual, 256-Tap, Nonvolatile, I2C-Interface,
Digital Potentiometers
14
______________________________________________________________________________________
VREGxNVREG: Data transfers from the volatile memory
register into the nonvolatile memory register.
Nonvolatile Memory
The internal EEPROM consists of a 16-bit nonvolatile
register that retains the value written to it prior to power
down. The nonvolatile register is programmed with the
midscale value at the factory. The nonvolatile memory
is guaranteed for 50 years for wiper position retention
and up to 200,000 wiper write cycles. A write-protect
feature prevents accidental overwriting of the EEPROM.
Connect WP to VDD or leave open to enable the write-
protect feature. The wiper position only updates with
the value in the EEPROM when WP = VDD. Connect WP
to GND to allow EEPROM write cycles and to update
the wiper position from nonvolatile memory or directly
from the I2C serial interface.
Power-Up
Upon power-up, the MAX5477/MAX5478/MAX5479
load the data stored in the nonvolatile memory register
into the volatile memory register, updating the wiper
position with the data stored in the nonvolatile memory
register. This initialization period takes 10s.
Standby
The MAX5477/MAX5478/MAX5479 feature a low-power
standby mode. When the device is not being pro-
grammed, it enters into standby mode and supply cur-
rent drops to 500nA (typ).
Applications Information
The MAX5477/MAX5478/MAX5479 are ideal for circuits
requiring digitally controlled adjustable resistance,
such as LCD contrast control (where voltage biasing
adjusts the display contrast), or for programmable fil-
ters with adjustable gain and/or cutoff frequency.
Positive LCD Bias Control
Figures 9 and 10 show an application where the
MAX5477/MAX5478/MAX5479 provide an adjustable,
positive LCD bias voltage. The op amp provides buffer-
ing and gain to the resistor-divider network made by
the potentiometer (Figure 9) or by a fixed resistor and a
variable resistor (see Figure 10).
Programmable Filter
Figure 11 shows the MAX5477/MAX5478/MAX5479 in a
1st-order programmable application filter. Adjust the
gain of the filter with R2, and set the cutoff frequency
with R3. Use the following equations to calculate the
gain (A) and the -3dB cutoff frequency (fC):
Offset Voltage and Gain Adjustment
Connect the high and low terminals of one potentiome-
ter of a MAX5477 between the NULL inputs of a
MAX410 and the wiper to the op amp’s positive supply
to nullify the offset voltage over the operating tempera-
ture range. Install the other potentiometer in the feed-
back path to adjust the gain of the MAX410 (Figure 12).
Adjustable Voltage Reference
Figure 13 shows the MAX5477/MAX5478/MAX5479
used as the feedback resistors in multiple adjustable
voltage reference applications. Independently adjust
the output voltages of the MAX6160 parts from 1.23V to
VIN - 0.2V by changing the wiper positions of the
MAX5477/MAX5478/MAX5479.
A
R
f
RC
C
=+
=
××
1
2
1
2
3
π
VOUT
30V
5V
W_
H_
L_
MAX5477
MAX5478
MAX5479
MAX480
VOUT
30V
5V
W_
H_
L_
MAX5477
MAX5478
MAX5479
MAX480
Figure 9. Positive LCD Bias Control Using a Voltage-Divider
Figure 10. Positive LCD Bias Control Using a Variable Resistor
相關(guān)PDF資料
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MAX5477EUD+T IC POT DGTL DUAL 256-TAP 14TSSOP
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