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LTC1428CS8-50#TRPBF

P1-P3P4-P6P7-P8
1
LTC1428-50
Micropower 8-Bit Current
Sink Output D/A Converter
FEATURES
DESCRIPTION
U
The LTC
®
1428-50 is a micropower 8-bit current sink
output D/A converter (DAC) with an output range of 0µA to
50µA. In 3.3V or 5V systems, the DAC I
OUT
pin can be
biased from 2V to 10V. Supply current is only 130µA.
Shutdown mode drops the supply current to 0.2µA.
The LTC1428-50 communicates with external circuitry by
using one of three interface modes: standard 3-wire serial
mode or one of two pulse modes. Upon power-up, the
internal counter resets to 10000000B, the DAC output
assumes midrange and the chip configures to 3-wire or
pulse mode depending on the CS signal level.
In 3-wire mode, the system MPU can serially transfer
8-bit data to and from the LTC1428-50. In pulse mode, the
upper six bits of the DAC output program for increment-
only (1-wire interface) or increment/decrement (2-wire
interface) operation depending on the D
IN
signal level. In
increment-only mode, the counter rolls over and sets the
DAC to zero if the counter increases beyond full scale. In
increment/decrement mode, the counter stops
incrementing at full scale, stops decrementing at zero
scale and does not roll over.
LTC1428-50 is available in an 8-pin SO package.
APPLICATIONS
U
■
LCD Contrast Control
■
Backlight Brightness Control
■
Power Supply Voltage Adjustment
■
Battery Charger Voltage/Current Adjustment
■
GaAs FET Bias Adjustment
■
Trimmer Pot Elimination
■
Precision Full-Scale DAC Output Current
at 25°C: 50µA ±3%
■
Wide Output Voltage DC Compliance: 2V to 10V
■
Wide Supply Range: 3V ≤ V
CC
≤ 6.5V
■
Supply Current in Shutdown: 0.2µA
■
Low Supply Current: 130µA
■
Available in 8-Pin SO
■
Triple Mode
TM
Interface
1. Standard 3-Wire Mode
2. 1-Wire Pulse Mode Interface: Increment-Only
3. 2-Wire Pulse Mode Interface: Increment/Decrement
■
DAC Value Read Back Capability in 3-Wire Mode
■
DAC Powers Up at Midrange
■
DAC Contents Are Retained in Shutdown
, LTC and LT are registered trademarks of Linear Technology Corporation.
Triple Mode is a trademark of Linear Technology Corporation.
TYPICAL APPLICATION
U
1
2
8
7
D
OUT
D
IN
I
OUT
V
CC
SHDN
CLK
LTC1428-50
GND
CS
1µF
2
CELLS
1428-50 TA01
V
OUT
15.75V TO 27.75V IN STEPS OF 47mV
15mA FROM 2 CELLS
R1
240k
3
4
6
5
C1
0.1µF
LT
®
1307
L1
L1: 4.7µH MURATA-ERIE LQH3C
D1: MBR0530 OR 1N4148
D1
V
IN
FB
V
C
GND
SWSHDN SHDN
R2
22k
R3
22k
100k
MPU
(e.g., 8051)
P1.3
P1.2
P1.1
P1.0
V
CC
5V
4700pF
Digitally Controlled LCD Bias Generator (Standard 3-Wire Mode)
2
LTC1428-50
ABSOLUTE MAXIMUM RATINGS
W
WW
U
PACKAGE/ORDER INFORMATION
W
U
U
(Note 1)
Supply Voltage (V
CC
) ................................................ 7V
Input Voltage (All Inputs)............ –0.3V to (V
CC
+ 0.3V)
Output Voltage
I
OUT
...................................................... –0.3V to 10V
D
OUT
....................................... –0.3V to (V
CC
+ 0.3V)
Short-Circuit Duration (All Outputs) ............... Indefinite
Operating Temperature Range .................... 0°C to 70°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
ORDER PART
NUMBER
V
CC
= 3.3V, T
A
= 25°C, unless otherwise specified.
ELECTRICAL CHARACTERISTICS
LTC1428CS8-50
Consult factory for Industrial and Military grade parts.
14285
S8 PART MARKING
T
JMAX
= 125°C, θ
JA
= 130°C/ W
1
2
3
4
8
7
6
5
TOP VIEW
D
OUT
D
IN
(UP/DN)
GND
CS
I
OUT
V
CC
SHDN
CLK
S8 PACKAGE
8-LEAD PLASTIC SO
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CC
● 3.0 6.5 V
I
CC
Supply Current V
SHDN
= V
DIN
= V
CS
= V
CC
, V
CLK
= 0V, D
OUT
= NC, I
OUT
= NC ● 130 225 µA
Shutdown
● 0.2 10 µA
DAC Resolution 8 Bits
DAC Full-Scale Current I
OUT
Bias Voltage = 2.5V 48.5 50 51.5 µA
● 47.5 50 52.5 µA
DAC Zero-Scale Current I
OUT
Bias Voltage = 2.5V ● 200 nA
DAC Differential Monotonicity Guaranteed, No Missing Codes ● ±0.9 LSB
Nonlinearity
Supply Voltage Rejection V
CC
= 3V to 6.5V, Full Scale Current, I
OUT
Bias Voltage = 2.5V ● ±1 ±4 LSB
Output Voltage Rejection V
CC
= 5V, Full Scale Current, ● ±1 LSB
2V ≤ V(I
OUT
) ≤ 3V
V
CC
= 5V, Full Scale Current, ● ±1 ±4 LSB
3V ≤ V(I
OUT
) ≤ 10V
Logic Input Current 0V ≤ V
IN
≤ V
CC
● ±1 µA
V
IH
High Level Input Voltage V
CC
= 5V ● 2.0 V
V
CC
= 3.3V ● 1.9 V
V
IL
Low Level Input Voltage V
CC
= 5V ● 0.80 V
V
CC
= 3.3V ● 0.45 V
V
OH
High Level Output Voltage V
CC
= 5V, I
O
= 400µA ● 2.4 V
V
CC
= 3.3V, I
O
= 400µA ● 2.1 V
V
OL
Low Level Output Voltage V
CC
= 5V, I
O
= 2mA ● 0.4 V
V
CC
= 3.3V, I
O
= 1mA ● 0.4 V
I
OZ
Three-State Output Leakage V
CS
= V
CC
● ±5 µA
3
LTC1428-50
V
CC
= 5V, unless otherwise specified. (Notes 2, 3)
RECO E DED OPERATI G CO DITIO S
UUUUWW
TYPICAL PERFORMANCE CHARACTERISTICS
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W
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: Timing for all input signals is measured at 0.8V for a High-to-Low
transition and at 2V for a Low-to-High transition.
Note 3: Timing specifications are guaranteed by design but not tested.
Note 4: This is the minimum time required for valid data transfer.
CODE
0
–1.0
DNL (LSB)
–0.8
–0.4
–0.2
0
1.0
0.4
64
128
160
1428-50 G01
–0.6
0.6
0.8
0.2
32 96
192
224
256
V
CC
= 3.3V
V(I
OUT
) = 2.5V
T
A
= 25°C
DNL vs Code
Supply Voltage Rejection
INL vs Code
CODE
0
INL (LSB)
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
64
128
160
1428-50 G02
32 96
192
224
256
V
CC
= 3.3V
V(I
OUT
) = 2.5V
T
A
= 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Serial Interface
f
CLK
Clock Frequency ● 2 MHz
t
CKS
Setup Time, CLK↓ Before CS↓ ● 150 ns
t
CSS
Setup Time, CS↓ Before CLK↑ ● 400 ns
t
DV
CS↓ to D
OUT
Valid See Test Circuits ● 150 ns
t
DS
D
IN
Setup Time Before CLK↑ ● 150 ns
t
DH
D
IN
Hold Time After CLK↑ ● 150 ns
t
DO
CLK↓ to D
OUT
Valid See Test Circuits ● 150 ns
t
CKHI
CLK High Time ● 200 ns
t
CKLO
CLK Low Time ● 250 ns
t
CSH
CLK↓ Before CS↑ ● 150 ns
t
DZ
CS↑ to D
OUT
in Hi-Z See Test Circuits ● 400 ns
t
CKH
CS↑ Before CLK↑ ● 400 ns
t
CSLO
CS Low Time f
CLK
= 2MHz (Note 4) ● 4550 ns
V
CLK
= 0V 400 ns
t
CSHI
CS High Time ● 400 ns
SUPPLY VOLTAGE (V)
1
∆FULL-SCALE OUTPUT CURRENT (LSB)
–0.5
0
0.5
4
6
1428-50 G03
–1.0
–1.5
–2.0
23 5
1.0
1.5
2.0
7
V(I
OUT
) = 2.5V
T
A
= 25°C
P1-P3P4-P6P7-P8

LTC1428CS8-50#TRPBF

Mfr. #:
Buy LTC1428CS8-50#TRPBF
Manufacturer:
Analog Devices Inc.
Description:
Digital to Analog Converters - DAC uP 8-B C Sink Out D/A Conv
Lifecycle:
New from this manufacturer.
Delivery:
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