HI7131

Features:

• 120dB CMRR Equal to ±0.01 Count/V of Common Mode Voltage Error
• Fast Recovery from Input Overrange Results "Correct First-Reading" After Overload
• Guaranteed 0000 Reading for 0V Input
• True Polarity at Zero for Precise Null Detection
• 1pA Input Current (Typ)
• True Differential Input and Reference
• Single or Dual Supply Operation Capability
• Direct LCD Display Drive - HI7131
• Direct LED Display Drive - HI7133
• Low Noise, 15mVP-P Without Hysteresis or Overrange Hangover
• Low Power Dissipation, Guaranteed Less Than 1mW, Results 8000 Hours (Typ) 9V Battery Life
• No Additional Active Components Required


Application

• Handheld Instruments
• Basic Measurements: Voltage, Current, Resistance Pressure, Temperature, Fluid Flow and Level, pH, Weight, Light Intensity
• DMMs and DPMs


Pinout




Specifications

Supply Voltage, V+ to V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +15V
Signal Inputs, Pin# 30, 31 (Note 1). . . . . . . . . . . . . . . . . . .  . V+ to V
ReferenceInputs, Pin# 35, 36 . . . . . . . . . .. . . . . . . . . . . V+ to VClock
Input, OSC1, Pin# 40 (Note 2) . . . . . . . . . . .  . . . . . . . TEST pin to V+
All Other Analog Leads, Pin# 27-29, 32-34 . . . . . . . . . . . . . V+ to VAll
Other Digital Leads,
Pin# 2-25, 38, 39 (Note 2). . . . . . . . . . . . . . . . .  . . .. . TEST Pin to V+


Description

The Intersil HI7131 and HI7133 are 31/2 digit, A/D converters that have been optimized for superior DC Common Mode Rejection (CMRR) when used with a split ±5V supply or a single 9V battery. The HI7131 contains all the necessary active components on a single IC to directly interface an LCD (Liquid Crystal Display). The supply current is under 100mA and is ideally suited for battery operation. The HI7133 contains all the necessary active components on a single IC to directly interface an LED (Light Emitting Diode).

The HI7131 and HI7133 feature high accuracy performance like, 120dB of CMRR, auto-zero to less than 10mV of offset, fast recovery from over load, zero drift of less than 1mV/oC, input bias current of 10pA maximum, and rollover error of less than one count. A true differential signal and reference inputs are useful features in all systems, but gives the designer an advantage when measuring load cells, strain gauges and other bridge-type transducers.

The HI7131 and HI7133 are supplied in a 40 lead plastic DIP and a 44 lead metric plastic quad flatpack package.