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Download miễn phí Tài liệu PTN số - Vi xử lý
DAC0808 là một bộ chuyển đổi 8 bit số sang t ương tự đầu ra có đặc tính thời gian đúng
bằng kích th ước của tín hiệu v ào trong kho ảng 150ns với công suất ti êu thụ là 33mW khi đi ện
áp cung cấp là ± 5V. Không c ần phải điềuchỉnh dòng điện I
REF
cho tất cả các ứng dụng, từ đó
đầu ra hiện tại l à ±1LBS c ủa 255(I
REF
/ 256). Ngu ồn cung cấp của DAC0808 độc lập với “bit
code” và đưa ra nh ững đặc điểm nổi bật của thiết bị phụ thộc v ào mức điện áp vào.
Để tải bản Đầy Đủ của tài liệu, xin Trả lời bài viết này, Mods sẽ gửi Link download cho bạn sớm nhất qua hòm tin nhắn.
Ai cần download tài liệu gì mà không tìm thấy ở đây, thì đăng yêu cầu down tại đây nhé:
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Tóm tắt nội dung tài liệu:
DAC08088-Bit D/A Converter
General Description
The DAC0808 is an 8-bit monolithic digital-to-analog con-
verter (DAC) featuring a full scale output current settling time
of 150 ns while dissipating only 33 mW with ±5V supplies.
No reference current (IREF) trimming is required for most
applications since the full scale output current is typically ±1
LSB of 255 IREF/256. Relative accuracies of better than
±0.19% assure 8-bit monotonicity and linearity while zero
level output current of less than 4 µA provides 8-bit zero
accuracy for IREF≥2 mA. The power supply currents of the
DAC0808 is independent of bit codes, and exhibits essen-
tially constant device characteristics over the entire supply
voltage range.
The DAC0808 will interface directly with popular TTL, DTL or
CMOS logic levels, and is a direct replacement for the
MC1508/MC1408. For higher speed applications, see
DAC0800 data sheet.
Features
n Relative accuracy: ±0.19% error maximum
n Full scale current match: ±1 LSB typ
n Fast settling time: 150 ns typ
n Noninverting digital inputs are TTL and CMOS
compatible
n High speed multiplying input slew rate: 8 mA/µs
n Power supply voltage range: ±4.5V to ±18V
n Low power consumption: 33 mW @ ±5V
Block and Connection Diagrams
DS005687-1
Dual-In-Line Package
DS005687-2
Top View
Order Number DAC0808
See NS Package M16A or N16A
May 1999
DAC0808
8-BitD/A
Converter
© 2001 National Semiconductor Corporation DS005687 www.national.com
Block and Connection Diagrams (Continued)
Ordering Information
ACCURACY OPERATING
TEMPERATURE RANGE N PACKAGE (N16A)
(Note 1)
SO PACKAGE
(M16A)
8-bit 0˚C≤TA≤+75˚C DAC0808LCN MC1408P8 DAC0808LCM
Note 1: Devices may be ordered by using either order number.
Small-Outline Package
DS005687-13
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Absolute Maximum Ratings (Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Power Supply Voltage
VCC +18 VDC
VEE −18 VDC
Digital Input Voltage, V5–V12 −10 VDC to +18 VDC
Applied Output Voltage, VO −11 VDC to +18 VDC
Reference Current, I14 5 mA
Reference Amplifier Inputs, V14, V15 VCC, VEE
Power Dissipation (Note 4) 1000 mW
ESD Susceptibility (Note 5) TBD
Storage Temperature Range −65˚C to +150˚C
Lead Temp. (Soldering, 10 seconds)
Dual-In-Line Package (Plastic) 260˚C
Dual-In-Line Package (Ceramic) 300˚C
Surface Mount Package
Vapor Phase (60 seconds) 215˚C
Infrared (15 seconds) 220˚C
Operating Ratings
Temperature Range TMIN ≤ TA ≤ TMAX
DAC0808 0 ≤TA ≤ +75˚C
Electrical Characteristics
(VCC = 5V, VEE = −15 VDC, VREF/R14 = 2 mA, and all digital inputs at high logic level unless otherwise noted.)
Symbol Parameter Conditions Min Typ Max Units
Er Relative Accuracy (Error Relative (Figure 4) %
to Full Scale IO)
DAC0808LC (LM1408-8) ±0.19 %
Settling Time to Within 1⁄2 LSB TA=25˚C (Note 7), 150 ns
(Includes tPLH) (Figure 5)
tPLH, tPHL Propagation Delay Time TA = 25˚C, (Figure 5) 30 100 ns
TCIO Output Full Scale Current Drift ±20 ppm/˚C
MSB Digital Input Logic Levels (Figure 3)
VIH High Level, Logic “1” 2 VDC
VIL Low Level, Logic “0” 0.8 VDC
MSB Digital Input Current (Figure 3)
High Level VIH = 5V 0 0.040 mA
Low Level VIL = 0.8V −0.003 −0.8 mA
I15 Reference Input Bias Current (Figure 3) −1 −3 µA
Output Current Range (Figure 3)
VEE = −5V 0 2.0 2.1 mA
VEE = −15V, TA = 25˚C 0 2.0 4.2 mA
IO Output Current VREF = 2.000V,
R14 = 1000Ω,
(Figure 3) 1.9 1.99 2.1 mA
Output Current, All Bits Low (Figure 3) 0 4 µA
Output Voltage Compliance (Note 3) Er ≤ 0.19%, TA = 25˚C
VEE=−5V, IREF=1 mA −0.55, +0.4 VDC
VEE Below −10V −5.0, +0.4 VDC
SRIREF Reference Current Slew Rate (Figure 6) 4 8 mA/µs
Output Current Power Supply −5V ≤ VEE ≤ −16.5V 0.05 2.7 µA/V
Sensitivity
Power Supply Current (All Bits (Figure 3)
Low)
ICC 2.3 22 mA
IEE −4.3 −13 mA
Power Supply Voltage Range TA = 25˚C, (Figure 3)
VCC 4.5 5.0 5.5 VDC
VEE −4.5 −15 −16.5 VDC
Power Dissipation
DAC0808
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Electrical Characteristics (Continued)
(VCC = 5V, VEE = −15 VDC, VREF/R14 = 2 mA, and all digital inputs at high logic level unless otherwise noted.)
Symbol Parameter Conditions Min Typ Max Units
All Bits Low VCC = 5V, VEE = −5V 33 170 mW
VCC = 5V, VEE = −15V 106 305 mW
All Bits High VCC = 15V, VEE = −5V 90 mW
VCC = 15V, VEE = −15V 160 mW
Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating
the device beyond its specified operating conditions.
Note 3: Range control is not required.
Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, θJA, and the ambient temperature, TA. The maximum
allowable power dissipation at any temperature is PD = (TJMAX − TA)/θJA or the number given in the Absolute Maixmum Ratings, whichever is lower. For this device,
TJMAX = 125˚C, and the typical junction-to-ambient thermal resistance of the dual-in-line J package when the board mounted is 100˚C/W. For the dual-in-line N
package, this number increases to 175˚C/W and for the small outline M package this number is 100˚C/W.
Note 5: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 6: All current switches are tested to guarantee at least 50% of rated current.
Note 7: All bits switched.
Note 8: Pin-out numbers for the DAL080X represent the dual-in-line package. The small outline package pinout differs from the dual-in-line package.
Typical Application
Typical Performance Characteristics VCC = 5V, VEE = −15V, TA = 25˚C, unless otherwise noted
DS005687-3
DS005687-23
FIGURE 1. +10V Output Digital to Analog Converter (Note 8)
Logic Input Current vs
Input Voltage
DS005687-14
Bit Transfer Characteristics
DS005687-15
Logic Threshold Voltage vs
Temperature
DS005687-16
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Typical Performance Characteristics VCC = 5V, VEE = −15V, TA = 25˚C, unless otherwise
noted (Continued)
Unless otherwise specified: R14 = R15 = 1 kΩ, C = 15 pF, pin 16 to VEE; RL = 50Ω, pin 4 to ground.
Curve A: Large Signal Bandwidth Method of Figure 7, VREF = 2 Vp-p offset 1V above ground.
Curve B: Small Signal Bandwidth Method of Figure 7, RL = 250Ω, VREF = 50 mVp-p offset 200 mV above ground.
Curve C: Large and Small Signal Bandwidth Method of Figure 9 (no op amp, RL = 50Ω), RS = 50Ω, VREF = 2V, VS = 100 mVp-p
centered at 0V.
Output Current vs Output
Voltage (Output Voltage
Compliance)
DS005687-17
Output Voltage Compliance
vs Temperature
DS005687-18
Typical Power Supply
Current vs Temperature
DS005687-19
Typical Power Supply
Current vs VEE
DS005687-20
Typical Power Supply
Current vs VCC
DS005687-21
Reference Input
Frequency Response
DS005687-22
DAC0808
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Test Circuits
DS005687-6
VI and I1 apply to inputs A1–A8.
The resistor tied to pin 15 is to temperature compensate the bias current and may not be necessary for all applications.
and AN = “1” if AN is at high level
AN = “0” if AN is at low level
FIGURE 3. Notation Definitions Test Circuit (Note 8)
DS005687-7
FIGURE 4. Relative Accuracy Test Circuit (Note 8)
DAC0808
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Test Circuits (Continued)
DS005687-8
FIGURE 5. Transient Response and Settling Time (Note 8)
DS005687-9
FIGURE 6. Reference Current Slew Rate Measurement (Note 8)
DS005687-10
FIGURE 7. Positive VREF (Note 8)
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Test Circuits (Continued)
Application Hints
REFERENCE AMPLIFIER DRIVE AND COMPENSATION
The reference amplifier provides a voltage at pin 14 for
converting the reference voltage to a current, and a
turn-around circuit or current mirror for feeding the ladder.
The reference amplifier input currrent, I14, must always flow
into pin 14, regardless of the set-up method or reference
voltage polarity.
Connections for a positive voltage are shown in Figure 7.
The reference voltage source supplies the full current I14.
For bipolar reference signals, as in the multiplying mode,
R15 can be tied to a negative voltage corresponding to the
minimum input level. It is possible to eliminate R15 with only
a small sacrifice in accuracy and temperature drift.
The compensation capacitor value must be increased with
increases in R14 to maintain proper phase margin; for R14
values of 1, 2.5 and 5 kΩ, minimum capacitor values are 15,
37 and 75 pF. The capacitor may be tied to either VEE or
ground, but using VEE increases ne...