1 MSPS, 12-/10-/8-Bit ADCs
in 6-Lead SOT-23
Fast Throughput Rate: 1 MSPS
Speciﬁed for VDD of 2.35 V to 5.25 V
3.6 mW Typ at 1 MSPS with 3 V Supplies
15 mW Typ at 1 MSPS with 5 V Supplies
Wide Input Bandwidth:
70 dB SNR at 100 kHz Input Frequency
Flexible Power/Serial Clock Speed Management
No Pipeline Delays
High-Speed Serial Interface
Standby Mode: 1 A Max
6-Lead SOT-23 Package
Personal Digital Assistants
Instrumentation and Control Systems
Data Acquisition Systems
The AD7476/AD7477/AD7478 are, respectively, 12-bit, 10-bit,
and 8-bit, high-speed, low-power, successive-approximation
ADCs. The parts operate from a single 2.35 V to 5.25 V power
supply and feature throughput rates up to 1 MSPS. The parts
contain a low-noise, wide bandwidth track/hold ampliﬁer that can
handle input frequencies in excess of 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 the conversion is also initiated at this
point. There are no pipelined delays associated with the part.
The AD7476/AD7477/AD7478 use advanced design techniques
to achieve very low-power dissipation at high throughput rates.
The reference for the part is taken internally from VDD. This
allows the widest dynamic input range to the ADC. Thus the
analog input range for the part is 0 to VDD. The conversion rate
is determined by the SCLK.
FUNCTIONAL BLOCK DIAGRAM
1. First 12-/10-/8-bit ADCs in an SOT-23 package.
2. High Throughput with Low Power Consumption.
3. Flexible Power/Serial Clock Speed Management.
The conversion rate is determined by the serial clock, allowing
the conversion time to be reduced through the serial clock speed
increase. This allows the average power consumption to be
reduced while not converting. The part also features a shut-
down mode to maximize power efﬁciency at lower throughput
rates. Power consumption is 1 µA max when in shutdown.
4. Reference derived from the power supply.
5. 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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