AD7495ARZ Datasheet, PDF (1/24 Pages) Analog Devices – 1 MSPS,12-Bit ADCs

FEATURES AND APPLICATIONS
Fast throughput rate: 1 MSPS
Specified for VDD of 2.7 V to 5.25 V
Low power:
4.5 mW max at 1 MSPS with 3 V supplies
10.5 mW max at 1 MSPS with 5 V supplies
Wide input bandwidth:
68 dB SNR at 300 kHz input frequency
Flexible power/serial clock speed management
No pipeline delays
High speed serial interface:
SPI™-/QSPI™-/MICROWIRE™-/DSP-compatible
On-board reference: 2.5 V (AD7495 only)
Standby mode: 1 μA max
8-lead MSOP and SOIC packages
Battery-powered systems
Personal digital assistants
Medical instruments
Mobile communications
Instrumentation and control systems
Data acquisition systems
Optical sensors
GENERAL DESCRIPTION
The AD7475/AD7495¹ are 12-bit, high speed, low power,
successive-approximation ADCs that operate from a single
2.7 V to 5.25 V power supply with throughput rates up to
1 MSPS. They contain a low noise, wide bandwidth track-and-
hold amplifier that can handle input frequencies above 1 MHz.
The conversion process and data acquisition are controlled
using CS and the serial clock, allowing the devices to interface
with microprocessors or DSPs. The input signal is sampled on
the falling edge of CS and conversion is initiated at this point.
The conversion time is determined by the SCLK frequency.
There are no pipeline delays associated with the part.
The AD7475/AD7495 use advanced design techniques to
achieve very low power dissipation at high throughput rates.
With 3 V supplies and a 1 MSPS throughput rate, the AD7475
consumes just 1.5 mA, while the AD7495 consumes 2 mA.
With 5 V supplies and 1 MSPS, the current consumption is
2.1 mA for the AD7475 and 2.6 mA for the AD7495.
The analog input range for the parts is 0 V to REF IN. The 2.5 V
reference for the AD7475 is applied externally to the REF IN
pin, while the AD7495 has an on-board 2.5 V reference.
1_{Protected by U.S. Patent No. 6,681,332}
Rev. B
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1 MSPS,12-Bit ADCs
AD7475/AD7495
FUNCTIONAL BLOCK DIAGRAMS
V_DD
V_IN
REF IN
T/H
12-BIT
SUCCESSIVE
APPROXIMATION
ADC
AD7475
V_DD
CONTROL
LOGIC
GND
SCLK
SDATA
CS
V_DRIVE
V_IN
REF OUT
T/H
BUF
2.5V
REFERENCE
AD7495
12-BIT
SUCCESSIVE
APPROXIMATION
ADC
CONTROL
LOGIC
GND
Figure 1.
SCLK
SDATA
CS
V_DRIVE
PRODUCT HIGHLIGHTS
1. The AD7475 offers 1 MSPS throughput rates with 4.5 mW
power consumption.
2. Single-supply operation with VDRIVE function. The
AD7475/AD7495 operate from a single 2.7 V to 5.25 V
supply. The VDRIVE function allows the serial interface
to connect directly to either 3 V or 5 V processor systems
independent of VDD.
3. Flexible power/serial clock speed management. The con-
version rate is determined by the serial clock, allowing the
conversion time to be reduced through the serial clock
speed increase. The parts also feature shutdown modes to
maximize power efficiency at lower throughput rates. This
allows the average power consumption to be reduced while
not converting. Power consumption is 1 μA when in full
shutdown.
4. No pipeline delay. The parts feature a standard successive
approximation ADC with accurate control of the sampling
instant via a CS input and once-off conversion control.
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