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Part: E647ATF
Category:
Discrete
Description: Pin Electronics Driver, Window Comparator, And Switch Matrix
Company: Semtech Corporation
Datasheet: Download E647ATF datasheet File size : 96 kB
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Edge647 Pin Electronics Driver, Window Comparator, and Switch Matrix
EDGE HIGH-PERFORMANCE PRODUCTS Description
The Edge647 is an integrated trinary driver, window comparator, and switch matrix pin electronics solution manufactured in a wide voltage CMOS process. It is d e s i g n e d for automatic test equipment and instrumentation where cost, functional density, and power are all at a premium. The tristatable driver is capable of generating 3 levels one for a logic high, one for a logic low, and one for either a termination voltage or a special programming voltage. The on-board window comparator effectively determines whether the DUT is in a high, low, or intermediate state. The switches are included to allow such functions as PMU, pull up, and pull down connections. The Edge647 is intended to offer an extremely low leakage, low cost, low power, small footprint, per pin solution for 100 MHz and below pin electronics applications. It is a higher performance, pin and functionally compatible version of the Edge646.
Applications
· Low Cost Automatic Test Equipment
Functional Block Diagram
VH VTT VL
DATA DATA* DOUT DVR EN DVR EN*
VTT EN VTT EN* SW0
SW0 EN*
Features
SW1 LOAD
· · · · · · · ·
Pin Compatible with the Edge646 100 MHz Operation 12V I/O Range Programmable Output Levels Flex In digital Inputs (Technology Independent) Three Level Driver Extremely Low Leakage Currents (~0 nA) Small Footprint (32 Pin, 7 mm X 7 mm, TQFP Package)
SW1 EN*
SW2
SW2 EN* VBB COMPA HIGH LEVEL VINP LOW LEVEL COMPB CVA
CVB
Revision 2 / October 27, 2000
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Edge647
EDGE HIGH-PERFORMANCE PRODUCTS PIN Description
Pin Name Driver DATA / DATA* DVR EN / DVR EN* VTT EN / VTT EN* DOUT VH, VL, VTT VBB Comparator VINP CVA, CVB COMPA, COMPB LOW LEVEL HIGH LEVEL Switch Matrix SW0 EN*, SW! EN* SW2 EN* SW0 SW1 SW2 LOAD Power Supplies VCC VEE N/C 3, 22, 27 4, 21, 28 9 Positive analog power supply. Negative analog power supply. No Connect pin (leave floating). 11, 13 15 12 14 16 17 TTL compatible inputs that activate switches 0, 1, 2, and 3. Switch 0 Switch 1 Switch 2 Input pin that connects the DUT to the analog switches. 19 20, 18 5, 8 7 6 Analog window comparator input. Analog DC comparator inputs that set the threshold levels for teh window comparator. Digital comparator outputs. Voltage inputs that establish the digital low and high levels of the comparator outputs. 30, 29 32, 31 2, 1 23 24, 25, 26 10 Digital input that determines the high/low status of the driver when it is enabled. Digital input that enables and disables the driver, or places the driver in the VTT state. Digital input that determines whether DVR EN* places the driver in a high impedance state or actively drives to the VTT level. Driver Output. Unbuffered analog inputs that set the voltage level of a logical 1, 0, or VTT at the driver output. Analog input pin which establishes the threshold for all singleended digital input signals. Pin # Description
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Edge647
EDGE HIGH-PERFORMANCE PRODUCTS PIN Description (continued)
32-Pin, 7mm x 7mm TQFP
DVR EN*
DVR EN
DATA*
DATA
VCC
VEE
VTT
25 VTT EN* VTT EN VCC VEE COMPA HIGH LEVEL LOW LEVEL COMPB 9 17 1 VH DOUT VCC VEE CVA VINP CVB LOAD
SW0 EN*
SW1 EN*
SW2 EN*
SW0
SW1
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SW2
VBB
N/C
VL
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Edge647
EDGE HIGH-PERFORMANCE PRODUCTS Circuit Description
Driver Description The Edge647 driver supports three distinct programmable d r i v e r levels; high, low, and termination, and high impedance. There are no restrictions between any of these three levels in that all three may vary independently over the entire operating voltage range between VCC and VEE. The DVR EN*, DATA, and VTT EN pins are digital inputs that control the driver (see Table 1). With DVR EN* low, DATA determines whether the driver will force VH or VL at DOUT. With DVR EN* high, VTT EN* controls whether the driver goes into high impedance or drives VTT.
DVR EN* 1 1 0 0 VTT EN 0 1 X X DATA X X 0 1 DOUT HiZ VTT VL VH
the DUT. In this environment, the driver can withstand a short to any legal DUT voltage for an indefinite period. In a low impedance application with no additional output series resistance, care must be exercised and systems should be designed to check for this condition and tristate the driver if a short is detected. The driver does NOT have on-chip short circuit protection or limitation circuitry. VBB VBB is an analog input which establishes the threshold for all single ended digital input signals. If SW0 EN*, SW1 EN*, or SW2 EN* are more positive than VBB, these inputs are a digital "1". Conversely, if they are more negative than VBB, they are a "0". All digital inputs are wide voltage comparator inputs, so they are technology independent. By establishing the appropriate VBB level for the switch control inputs, and the appropriate differential input levels for the driver digital control inputs, the Edge647 may be driven by TTL, ECL, CMOS, or any custom level circuitry.
SW0 EN*
Table 1. Driver Truth Table
VH, VL, and VTT V H , VL, and VTT define the logical "1", "0", and "termination" levels of the driver and can be adjusted anywhere over the range spanned by VCC to VEE. There is no restriction between VH, VL, and VTT, in that they can all vary independently over the entire voltage range determined by the power supply levels. The VH, VL, and VTT inputs are unbuffered in that they also provide the driver output current, so the sources of these voltages must have ample current drive capability. While VTT is referred to as the termination voltage, it may also be used as a very high "programming" level on many memory devices. Driver Output Protection The Edge647 is designed to operate in a functional testing environment where a controlled impedance (typically 50 ) is maintained between the pin electronics and the DUT. In general, there will be an external resistor at the driver output which series terminates the transmission line to
SW1 EN*
SW2 EN* VBB
Figure 1. Driver Digital Inputs
DATA DATA* DVR EN* DVR EN VTT EN VTT EN*
Figure 2. Driver Differential Digital Inputs
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Edge647
EDGE HIGH-PERFORMANCE PRODUCTS Circuit Description (continued)
Receiver Functionality The Edge647 supports an on-board window comparator. CVB and CVA are high impedance analog inputs which establish the threshold voltages. COMPA and COMPB are the digital outputs which reflect the real time status of VINP Table 2 summarizes the relationship between the . threshold levels, VINP and the output signals. ,
VINP VINP CVA VINP CVB COMPA 1 0 X X COMPB X X 0 1
L oad The Edge647 provides a total of 3 analog switches. Individual switches vary in both their on resistance and their on/off time (see Table 4). Like the driver digital inputs, the switch matrix control inputs S W 0 - 3 EN* are technology independent as VBB determines their threshold level. The switch control is documented in Table 3.
Control Inputs SW0 EN* = 1 SW0 EN* = 0 SW1 EN* = 1 SW1 EN* = 0 Status SW0 disconnected SW0 connected SW1 disconnected SW1 connected SW2 disconnected SW2 connected
Table 2. Comparator Truth Table
SW EN* = 1 SW2 EN* = 0
Comparator Outputs
Table 3. Switch Matrix Truth Table
The comparator outputs are 50 output impedance nont r i s t a t a b l e drivers designed to cleanly drive 50 transmission lines without requiring any external series termination resistors. Input pins LOW LEVEL and HIGH LEVEL establish the logic 0 and 1 levels respectively. In normal operation, LOW LEVEL would be connected to ground and HIGH LEVEL would be connected to a system VDD supply, producing CMOS digital swings at the output. H o w e v e r, the comparator outputs are technology independent in that they can drive PECL, 3V CMOS, ECL, LV CMOS, GTL, and custom levels by varying LOW LEVEL and HIGH LEVEL. For example, should a 3V swing be desired, HIGH LEVEL could be connected to a 3.0V power supply. Notice that HIGH LEVEL and LOW LEVEL provide both the voltage level and the current for the comparator outputs. HIGH LEVEL and LOW LEVEL may be varied between +5V and -2V.
Switch SW0 SW1 SW2
Rout 50 50 50
On/Off Time 100 ns 100 ns 100 ns
Table 4. Switch Matrix Characteristics
Do NOT leave any digital input pins floating.
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