MX7705 16-Bit, Low-Power, 2-Channel, Sigma-Delta ADC

Description

The MX7705 low-power, 2-channel, serial-output analog-to-digital converter (ADC) includes a sigma-delta modulator with a digital filter to achieve 16-bit resolution with no missing codes. This ADC is pin compatible and software compatible with the AD7705. The MX7705 features an on-chip input buffer and programmable-gain amplifier (PGA). The device offers an SPI™-/QSPI™-/MICROWIRE™-compatible serial interface.

The MX7705 operates from a single 2.7V to 5.25V supply. The operating supply current is 320µA (typ) with a 3V supply. Power-down mode reduces the supply current to 2µA (typ).

Self-calibration and system calibration allow the MX7705 to correct for gain and offset errors. Excellent DC performance (±0.003% FSR INL) and low noise (650nV) make the MX7705 ideal for measuring low-frequency signals with a wide dynamic range. The device accepts fully differential bipolar/unipolar inputs. An internal input buffer allows for input signals with high source impedances. An on-chip digital filter, with a programmable cutoff and output data rate, processes the output of the sigma-delta modulator. The first notch frequency of the digital filter is chosen to provide 150dB rejection of common-mode 50Hz or 60Hz noise and 98dB rejection of normal-mode 50Hz or 60Hz noise. A PGA and digital filtering allow signals to be directly acquired with little or no signal-conditioning requirements.

The MX7705 is available in 16-pin PDIP, SO, and TSSOP packages.

Key Features

Applications/Uses

Pin Compatible and Software Compatible with the AD7705
16-Bit Sigma-Delta ADC
Two Fully Differential Input Channels
0.003% Integral Nonlinearity with No Missing Codes
Interface with Schmitt Triggers on Inputs
Internal Analog Input Buffers
PGA from 1 to 128
Single (2.7V to 3.6V) or (4.75V to 5.25V) Supply
Low Power
- 1mW (max), 3V Supply
- 2µA (typ) Power-Down Current
SPI-/QSPI-/MICROWIRE-Compatible 3-Wire Serial Interface
16-Pin PDIP, SO, and TSSOP Packages

	Flow and Gas Meters
	Industrial Instruments
	Loop-Powered Systems
	Medical Instrumentation
	Pressure Transducers
	RTD Measurements
	Strain-Gauge Measurements
	Thermocouple Measurements
	Weigh Scales

Key Specifications: Precision ADCs (< 5Msps)

Part Number

Resolution
(bits)

Input Chan.

Conv. Rate
(ksps)

Conv. Time
(µs)

Data Bus
(bits)

Ref.
(V)

Diff. Inputs

V_SUPPLY
(V)

I_CC
(mA)

Power
(mW)

Standby Mode

Package/Pins

Price

ADC

max

typ

See Notes

MX7705

0.5

2000

Serial

Ext.

Yes

0.32

1.6

Yes

See All Precision ADCs (< 5Msps) (377)

Diagram

Functional Diagram

Application Notes

Application Note 3418: Understanding the Effects of Clock Tolerances on 50/60Hz Noise Rejection in High Performance Sigma Delta ADCs - MX7705
Application Note 4026: Implementing Cold-Junction Compensation in Thermocouple Applications - MX7705

Reliability Reports

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Software/Models

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Ordering Information

Notes:

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
Part number suffixes: T or T&R = tape and reel;+ = RoHS/lead-free;# = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

Devices: 1-10 of 10

MX7705 Free
Sample Buy Status

Package: TYPE PINS FOOTPRINT

DRAWING CODE/VAR *

Temp RoHS/Lead-Free?
Materials Analysis

MX7705EPE

Active PDIP(N);16 pin;158 mm²
Outline Drawing: 21-0043 (PDF)
Land Pattern: Not Applicable
Use pkgcode/variation: P16-1*
-40°C to +85°C RoHS/Lead-Free: No
Materials Analysis

MX7705EPE+

Active PDIP(N);16 pin;158 mm²
Outline Drawing: 21-0043 (PDF)
Land Pattern: Not Applicable
Use pkgcode/variation: P16+1*
-40°C to +85°C RoHS/Lead-Free: Lead Free
Materials Analysis

MX7705EWE

Active SOIC(W);16 pin;112 mm²
Outline Drawing: 21-0042 (PDF)
Land Pattern: 90-0107 (PDF)
Use pkgcode/variation: W16-1*
-40°C to +85°C RoHS/Lead-Free: No
Materials Analysis

MX7705EWE-T

Active

Land Pattern: Not Available

-40°C to +85°C See data sheet

MX7705EWE+

Active SOIC(W);16 pin;112 mm²
Outline Drawing: 21-0042 (PDF)
Land Pattern: 90-0107 (PDF)
Use pkgcode/variation: W16+1*
-40°C to +85°C RoHS/Lead-Free: Lead Free
Materials Analysis

MX7705EWE+T

Active

Land Pattern: Not Available

-40°C to +85°C See data sheet

MX7705EUE

Active TSSOP;16 pin;33 mm²
Outline Drawing: 21-0066 (PDF)
Land Pattern: 90-0117 (PDF)
Use pkgcode/variation: U16-2*
-40°C to +85°C RoHS/Lead-Free: No
Materials Analysis

MX7705EUE-T

Active

Land Pattern: Not Available

-40°C to +85°C See data sheet

MX7705EUE+

Active TSSOP;16 pin;33 mm²
Outline Drawing: 21-0066 (PDF)
Land Pattern: 90-0117 (PDF)
Use pkgcode/variation: U16+2*
-40°C to +85°C RoHS/Lead-Free: Lead Free
Materials Analysis

MX7705EUE+T

Active

Land Pattern: Not Available

-40°C to +85°C See data sheet

More Information

New Product Press Release 2003-11-21

Related Products

MAX1415, MAX1416 16-Bit, Low-Power, 2-Channel, Sigma-Delta ADCs

More Like This: View Product Families for Similar Products

See All Precision ADCs (< 5Msps) (377 Products)

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Document Ref.: 19-3051; Rev 3; 2009-08-07
This page last modified: 2009-08-07