Texas Instruments TLV5620IN, TLV5620IDR, TLV5620ID, TLV5620CN, TLV5620CDR Datasheet

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TLV5620C, TLV5620I
QUADRUPLE 8-BIT DIGITAL-TO-ANALOG CONVERTERS
SLAS110B – JANUARY 1995 – REVISED APRIL 1997
1
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
D
Four 8-Bit Voltage Output DACs
D
D
Serial Interface
D
High-Impedance Reference Inputs
D
Programmable for 1 or 2 Times Output Range
D
Simultaneous Update Facility
D
Internal Power-On Reset
D
Low-Power Consumption
D
Half-Buffered Output
applications
D
Programmable V oltage Sources
D
Digitally Controlled Amplifiers/Attenuators
D
Mobile Communications
D
Automatic Test Equipment
D
Process Monitoring and Control
D
Signal Synthesis
description
The TLV5620C and TLV5620I are quadruple 8-bit voltage output digital-to-analog converters (DACs) with buffered reference inputs (high impedance). The DACs produce an output voltage that ranges between either one or two times the reference voltages and GND; and, the DACs are monotonic. The device is simple to use, because it runs from a single supply of 3 V to 3.6 V. A power-on reset function is incorporated to ensure repeatable start-up conditions.
Digital control of the TL V5620C and TLV5620I is over a simple three-wire serial bus that is CMOS compatible and easily interfaced to all popular microprocessor and microcontroller devices. The 11-bit command word comprises eight bits of data, two DAC select bits, and a range bit, the latter allowing selection between the times 1 or times 2 output range. The DAC registers are double buffered, allowing a complete set of new values to be written to the device, then all DAC outputs update simultaneously through control of LDAC. The digital inputs feature Schmitt triggers for high noise immunity.
The 14-terminal small-outline (SO) package allows digital control of analog functions in space-critical applications. The TLV5620C is characterized for operation from 0°C to 70°C. The TLV5620I is characterized for operation from –40°C to 85°C. The TLV5620C and TLV5620I do not require external trimming.
AVAILABLE OPTIONS
PACKAGE
T
A
SMALL OUTLINE
(D)
PLASTIC DIP
(N)
0°C to 70°C TLV5620CD TLV5620CN
–40°C to 85°C TLV5620ID TLV5620IN
Copyright 1997, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
1 2 3 4 5 6 7
14 13 12 11 10
9 8
GND REFA REFB
REFC REFD
DATA
CLK
V
DD
LDAC DACA DACB DACC DACD LOAD
D OR N PACKAGE
(TOP VIEW)
TLV5620C, TLV5620I QUADRUPLE 8-BIT DIGITAL-TO-ANALOG CONVERTERS
SLAS110B – JANUARY 1995 – REVISED APRIL 1997
2
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
functional block diagram
Power-On
Reset
Serial
Interface
× 2
DAC
DAC
× 2
× 2
DAC
DAC
× 2
LDAC
REFA
+ –
+ –
+ –
+ –
+ –
+ –
+ –
+ –
REFB
REFC
CLK
REFD
DATA
LOAD
DACA
DACB
DACC
DACD
8 8
8
8
8
8
8
8
LatchLatch
Latch Latch
Latch
Latch
Latch Latch
2
3
4
5
7 6 8
13
12
11
10
9
Terminal Functions
TERMINAL
NAME NO.
I/O
DESCRIPTION
CLK 7 I Serial interface clock. The input digital data is shifted into the serial interface register on the falling edge of the clock
applied to the CLK terminal. DACA 12 O DAC A analog output DACB 11 O DAC B analog output DACC 10 O DAC C analog output DACD 9 O DAC D analog output DATA 6 I Serial interface digital data input. The digital code for the DAC is clocked into the serial interface register serially.
Each data bit is clocked into the register on the falling edge of the clock signal. GND 1 I Ground return and reference terminal LDAC 13 I Load DAC. When this signal is high, no DAC output updates occur when the input digital data is read into the serial
interface. The DAC outputs are only updated when LDAC is taken from high to low. LOAD 8 I Serial interface load control. When the LDAC terminal is low, the falling edge of the LOAD signal latches the digital
data into the output latch and immediately produces the analog voltage at the DAC output terminal. REFA 2 I Reference voltage input to DAC A. This voltage defines the output analog range. REFB 3 I Reference voltage input to DAC B. This voltage defines the analog output range. REFC 4 I Reference voltage input to DAC C. This voltage defines the analog output range. REFD 5 I Reference voltage input to DAC D. This voltage defines the analog output range. V
DD
14 I Positive supply voltage
TLV5620C, TLV5620I
QUADRUPLE 8-BIT DIGITAL-TO-ANALOG CONVERTERS
SLAS110B – JANUARY 1995 – REVISED APRIL 1997
3
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
detailed description
The TLV5620 is implemented using four resistor-string DACs. The core of each DAC is a single resistor with 256 taps, corresponding to the 256 possible codes listed in T able 1. One end of each resistor string is connected to GND and the other end is fed from the output of the reference input buffer . Monotonicity is maintained by use of the resistor strings. Linearity depends upon the matching of the resistor segments and upon the performance of the output buffer. Since the inputs are buffered, the DACs always presents a high-impedance load to the reference source.
Each DAC output is buffered by a configurable-gain output amplifier, which can be programmed to times 1 or times 2 gain.
On power up, the DACs are reset to CODE 0. Each output voltage is given by:
VO(DACA|B|C|D)+REF
CODE
256
(1)
RNG bit value)
where CODE is in the range 0 to 255 and the range (RNG) bit is a 0 or 1 within the serial control word.
Table 1. Ideal Output Transfer
D7 D6 D5 D4 D3 D2 D1 D0 OUTPUT VOLTAGE
0 0 0 0 0 0 0 0 GND 0 0000001 (1/256) × REF (1+RNG)
•••••••
•••••••
0 1111111 (127/256) × REF (1+RNG) 1 0000000 (128/256) × REF (1+RNG)
•••••••
••••••• 1 1 1 1 1 1 1 1 (255/256) × REF (1+RNG)
data interface
With LOAD high, data is clocked into the DATA terminal on each falling edge of CLK. Once all data bits have been clocked in, LOAD is pulsed low to transfer the data from the serial input register to the selected DAC as shown in Figure 1. When LDAC is low, the selected DAC output voltage is updated when LOAD goes low . When LDAC is high during serial programming, the new value is stored within the device and can be transferred to the DAC output at a later time by pulsing LDAC low as shown in Figure 2. Data is entered MSB first. Data transfers using two 8-clock-cycle periods are shown in Figures 3 and 4.
Table 2 lists the A1 and A0 bits and the selection of the updated DACs. The RNG bit controls the DAC output range. When RNG = low, the output range is between the applied reference voltage and GND, and when RNG = high, the range is between twice the applied reference voltage and GND.
Table 2. Serial Input Decode
A1 A0 DAC UPDATED
0 0 DACA 0 1 DACB 1 0 DACC 1 1 DACD
TLV5620C, TLV5620I QUADRUPLE 8-BIT DIGITAL-TO-ANALOG CONVERTERS
SLAS110B – JANUARY 1995 – REVISED APRIL 1997
4
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
A1 A0 RNG D7 D6 D5 D4 D3 D2 D1 D0
DAC Update
CLK
DATA
LOAD
t
su(DATA-CLK)
t
v(DATA-CLK)
t
su(CLK-LOAD)
t
w(LOAD)
t
su(LOAD-CLK)
Figure 1. LOAD-Controlled Update (LDAC = Low)
CLK
DATA
LOAD
LDAC
DAC Update
A1 A0 RNG D7 D6 D5 D4 D3 D2 D1 D0
t
su(DATA-CLK)
t
v(DATA-CLK)
t
w(LDAC)
t
su(LOAD-LDAC)
Figure 2. LDAC-Controlled Update
TLV5620C, TLV5620I
QUADRUPLE 8-DIGITAL-TO-ANALOG CONVERTERS
SLAS110B – JANUARY 1995 – REVISED APRIL 1997
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
5
A1 A0 RNG D7 D6 D5 D4 D3 D2 D1 D0
CLK
DATA
LOAD LDAC
CLK Low
Figure 3. Load Controlled Update Using 8-Bit Serial Word (LDAC = Low)
A1 A0 RNG D7 D6 D5 D4 D3 D2 D1 D0
CLK
DATA
LOAD
LDAC
CLK Low
Figure 4. LDAC Controlled Update Using 8-Bit Serial Word
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