Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsData collecting ICsData acquisition IC - AD converter (ADC) External , Internal SSOP 28

LTC1605-1/LTC1605-2

Single Supply 16-Bit, 100ksps,

Sampling ADCs

The LTC

1605-1/LTC1605-2 are 100ksps, sampling

16-bit A/D converters that draw only 55mW (typical) from

a single 5V supply. These easy-to-use devices include a

sample-and-hold, precision reference, switched capacitor

successive approximation A/D and trimmed internal clock.

The LTC1605-1’s input range is 0V to 4V while the

LTC1605-2’s input range is ±4V. An external reference

can be used if greater accuracy over temperature is

needed.

The ADC has a microprocessor compatible, 16-bit or two

byte parallel output port. A convert start input and a data

ready signal (BUSY) ease connections to FIFOs, DSPs and

microprocessors.

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Sample Rate: 100ksps

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Complete 16-Bit Solution on a Single 5V Supply

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Unipolar Input Range: 0V to 4V (LTC1605-1)

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Bipolar Input Range:

4V (LTC1605-2)

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Power Dissipation: 55mW Typ

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Signal-to-Noise Ratio: 86dB Typ

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Operates with Internal or External Reference

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Internal Synchronized Clock

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28-Pin 0.3" PDIP and SSOP Packages

, LTC and LT are registered trademarks of Linear Technology Corporation.

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Industrial Process Control

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Multiplexed Data Acquisition Systems

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High Speed Data Acquisition for PCs

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Digital Signal Processing

LTC1605-1 Low Power, 100kHz, 16-Bit Sampling ADC on 5V Supply

200Ω

2.5V

REFERENCE

20k 10k

16-BIT

SAMPLING ADC

D15 TO D0

33.2k

2.2µF

2.5V

10µF 0.1µF

2.2µF

0V TO 4V

INPUT

CAP

REF

AGND1

AGND2

DGND

CONTROL

LOGIC AND

TIMING

BUSY

BYTE

R/C

28 27

6 TO 13

15 TO 22

DIGITAL

CONTROL

SIGNALS

1605-1/2 TA01

16-BIT

OR 2 BYTE

PARALLEL

BUS

DIG

ANA

BUFFER

CODE

INL (LSBs)

65535

1605-1/2 TA02/G04

16384

32768

49152

2.0

1.5

1.0

0.5

–0.5

–1.0

–1.5

–2.0

Typical INL Curve

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

Summary of content (20 pages)

PAGE 1
LTC1605-1/LTC1605-2 Single Supply 16-Bit, 100ksps, Sampling ADCs U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO The LTC ®1605-1/LTC1605-2 are 100ksps, sampling 16-bit A/D converters that draw only 55mW (typical) from a single 5V supply. These easy-to-use devices include a sample-and-hold, precision reference, switched capacitor successive approximation A/D and trimmed internal clock.
PAGE 2
LTC1605-1/LTC1605-2 W W U W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Notes 1, 2) VANA .......................................................................... 7V VDIG to VANA ........................................................... 0.3V VDIG ........................................................................... 7V Ground Voltage Difference DGND, AGND1 and AGND2 .............................. ±0.3V Analog Inputs (Note 3) VIN ...................................................
PAGE 3
LTC1605-1/LTC1605-2 W U DY A IC ACCURACY The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
PAGE 4
LTC1605-1/LTC1605-2 UW TI I G CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
PAGE 5
LTC1605-1/LTC1605-2 U W TYPICAL PERFOR A CE CHARACTERISTICS Supply Current vs Supply Voltage 12.5 12.0 fSAMPLE = 100kHz 11.0 10.5 10.0 4.75 5.00 5.25 CHANGE IN CAP VOLTAGE (V) POWER SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 11.5 9.5 4.50 0.04 fSAMPLE = 100kHz 12.0 11.5 11.0 10.5 10.0 –50 5.50 –25 0 25 50 TEMPERATURE (°C) 75 1605-1/2 G01 –0.02 –0.04 LTC1605-2 –0.06 100 2.0 1.5 1.5 1.0 1.0 0.5 0.5 –0.5 –1.0 –20 0 –0.5 –1.5 –2.0 –2.
PAGE 6
LTC1605-1/LTC1605-2 U U U PIN FUNCTIONS VIN (Pin 1): Analog Input. Connect through a 200Ω resistor to the analog input. Full-scale input range is 0V to 4V for the LTC1605-1 and ±4V for the LTC1605-2. being the LSB. With BYTE high the upper eight bits and the lower eight bits will be switched. The MSB is output on Pin 15 and bit 8 is output on Pin 22. Bit 7 is output on Pin 6 and the LSB is output on Pin 13. AGND1 (Pin 2): Analog Ground. Tie to analog ground plane. R/C (Pin 24): Read/Convert Input.
PAGE 7
LTC1605-1/LTC1605-2 TEST CIRCUITS Load Circuit for Output Float Delay Load Circuit for Access Timing 5V 5V 1k DBN 1k DBN 1k DBN DBN CL CL 1k 50pF 1605-1/2 TC02 1605-1/2 TC01 B. HI-Z TO VOL AND VOH TO VOL A. VOH TO HI-Z B. VOL TO HI-Z U A.
PAGE 8
LTC1605-1/LTC1605-2 U W U U APPLICATIONS INFORMATION LT®1007 - Low noise precision amplifier. 2.7mA supply current ±5V to ±15V supplies. Gain bandwidth product 8MHz. DC applications. LT1097 - Low cost, low power precision amplifier. 300µA supply current. ±5V to ±15V supplies. Gain bandwidth product 0.7MHz. DC applications. LT1227 - 140MHz video current feedback amplifier. 10mA supply current. ±5V to ±15V supplies. Low noise and low distortion. LT1360 - 37MHz voltage feedback amplifier. 3.
PAGE 9
LTC1605-1/LTC1605-2 U U W U APPLICATIONS INFORMATION 4k 3 REF (2.5V) 2.2µF 111...110 VANA OUTPUT CODE + – 4 CAP (2.5V) 111...111 BANDGAP REFERENCE S S INTERNAL CAPACITOR DAC 2.2µF UNIPOLAR ZERO 000...001 FS = 4V 1LSB = FS/65536 000...000 1605-1/2 F03 0V 1 LSB FS – 1LSB INPUT VOLTAGE (V) Figure 3. Internal or External Reference Source 1605-1/2 F06a Figure 6a. LTC1605-1 Unipolar Transfer Characteristics 011...111 2 200Ω 1% 33.2k 1% 2.2µF 3 4 + 2.2µF 5 BIPOLAR ZERO 011...
PAGE 10
LTC1605-1/LTC1605-2 U U W U APPLICATIONS INFORMATION DIGITAL INTERFACE Internal Clock The ADC has an internal clock that is trimmed to achieve a typical conversion time of 7µs. No external adjustments are required and, with the typical acquisition time of 1µs, throughput performance of 100ksps is assured. Timing and Control Conversion start and data read are controlled by two digital inputs: CS and R/C.
PAGE 11
LTC1605-1/LTC1605-2 U W U U APPLICATIONS INFORMATION t 10 t 10 t 10 t 10 R/C t1 t1 CS t3 t4 BUSY t6 MODE ACQUIRE CONVERT ACQUIRE t CONV HI-Z DATA BUS DATA VALID t 12 t7 HI-Z 1605-1/2 F09 Figure 9. Using CS to Control Conversion and Read Timing t 10 t 10 R/C CS BYTE PINS 6 TO 13 HI-Z HIGH BYTE t 12 PINS 15 TO 22 HI-Z t 12 LOW BYTE HI-Z LOW BYTE t7 HIGH BYTE HI-Z 1605-1/2 F10 Figure 10.
PAGE 12
LTC1605-1/LTC1605-2 U W U U APPLICATIONS INFORMATION Dynamic Performance FFT (Fast Fourier Transform) test techniques are used to test the ADC’s frequency response, distortion and noise at the rated throughput. By applying a low distortion sine wave and analyzing the digital output using an FFT algorithm, the ADC’s spectral content can be examined for frequencies outside the fundamental. Figure 11 shows a typical LTC1605-2 FFT plot which yields a SINAD of 87dB and THD of –101.1dB.
PAGE 13
LTC1605-1/LTC1605-2 U W U U APPLICATIONS INFORMATION Figure 12. Component Side Silkscreen for the Suggested LTC1605-1/LTC1605-2 Evaluation Circuit ANALOG GROUND PLANE DIGITAL GROUND PLANE Figure 13. Bottom Side Showing Analog Ground Plane ANALOG GROUND PLANE Figure 14.
PAGE 14
2 1 2 1 2 R17 51 GND NA OUT U8 1MHz, OSC EXT_CLK 1 J1 J2 AIN GND E2 3 3 4 3 2 1 2 3 4 5 6 7 10 9 1 8 CLK LOAD ENP ENT A B C OUT TRIM QA QB QC QD RCO 15 14 13 12 11 5 6 7 8 JP1 R18 200Ω 1% VCC R21, 2k 3 15 2 1 JP4 2 CLK 13 CS VCC 3 VCC Q Q JP5 2 C3 0.1µF C4 2.2µF C16 1000pF C9 0.1µF C8 0.1µF C7 10µF VKK C5 0.1µF R19 33.2k 1% C10 0.1µF DIGITAL I.C.
PAGE 15
LTC1605-1/LTC1605-2 U TYPICAL APPLICATIO S The circuit in Figure 16 is an example showing the LTC1605 16-bit A/D converter and LTC1391 8-channel MUX connected to a 68HC11 controller. The LTC1605’s 16-bit data output is read in two 8-bit bytes using Pins 6 (MSB, Bit7) through 13 (Bit8, Bit0), connected to the HC11’s PORTC. The MUX’s 4-bit serial address data is sent using the controller’s SPI. The process to convert a channel’s input signal is shown in sample listing A.
PAGE 16
LTC1605-1/LTC1605-2 U TYPICAL APPLICATIO S ***************************************** * Start GETDATA Routine * ***************************************** * ORG $C000 Program start location INIT1 LDAA #$03 0,0,0,0,0,0,1,1 * “STAF=0,STAI=0,CWOM=0,HNDS=0, OIN=0, PLS=0, EGA=1,INVB=1” STAA PIOC Ensures that the PIOC register’s status is the same * as after a reset, necessary of simple Port D manipulation LDAA #$00 0,0,0,0,0,0,0,0 * “Bits 7 - 0 are used as inputs for the LTC1605’s data STAA DDRC Direction of Por
PAGE 17
LTC1605-1/LTC1605-2 U TYPICAL APPLICATIO S * Retrieve the MUX address from memory * * and send it to the LTC1391 * ***************************************** * LDAA MUX Retrieve the MUX address from memory ORAA #$08 Enable the selected MUX address STAA SPDR Select the MUX channel WAIT1 LDAA SPSR This loop waits for the SPI to complete a serial * transfer/exchange by reading the SPI Status Register BPL WAIT1 The SPIF (SPI transfer complete flag) bit is the SPSR’s * MSB and is set to one at the end of an SPI
PAGE 18
LTC1605-1/LTC1605-2 U TYPICAL APPLICATIO S ************************************************************************* * This routine retrieves the LTC1605’s 16-bit data using two 8-bit * * reads. The BYTE input is manipulated through Port A’s Bit3. During * * the first read when BYTE is low, the upper byte is read and stored in * DIN1.During the second read when BYTE is high, the lower byte is * * read and stored in DIN2.
PAGE 19
LTC1605-1/LTC1605-2 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. G Package 28-Lead Plastic SSOP (0.209) (LTC DWG # 05-08-1640) 10.07 – 10.33* (0.397 – 0.407) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 7.65 – 7.90 (0.301 – 0.311) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 5.20 – 5.38** (0.205 – 0.212) 1.73 – 1.99 (0.068 – 0.078) 0° – 8° 0.65 (0.0256) BSC 0.55 – 0.95 (0.022 – 0.037) 0.13 – 0.22 (0.005 – 0.
PAGE 20
LTC1605-1/LTC1605-2 U TYPICAL APPLICATIO MUX CS MUX DATA CH0 CH1 CH2 R/C BUSY BYTE ADC DATA HI BYTE LO BYTE DATA 0 HI BYTE LO BYTE HI BYTE LO BYTE DATA 1 1605-1/2 F17 Figure 17. This Is the Timing Relationship Between the Selected MUX Channel, Its Conversion Data and the ADC and MUX Control Signals When Using the Sample Program In Listing 1.