Logic level translators are simple units which are very easy to operate
and translate/convert logic signals from one standard (i.e., NIM or TTL
or ECL) to another one of these standards.
The Model 688AL and the Model 4616 are high performance NIM modules designed
for maximum flexibility.
High Speed - Both modules have greater than 100 MHz capability.
Simple Operation - Both modules easily solve a common problem by
converting logic signals into other standard levels.
High Density - Each unit has 16 separate translator channels.
Maximum Flexibility - NIM modules can be used in NIM bins or in CAMAC
crates with the addition of the Model 4501A NIM-to-CAMAC adapter.
Both LeCroy level translators are NIM modules offering high performance,
speed and maximum flexibility. These units operate by simply connecting
the input and output level desired and easily solve the common problem of
translating between different logic standards.
The Model 688AL Level Adapter provides 8 channels of direct-coupled NIM-to-TTL
and 8 channels of TTL-to-NIM conversion in a single-width NIM module. Standard
negative TTL notation is used to be compatible with unterminated CAMAC and
slow NIM logic levels.
The NIM-to-TTL section accepts either normal or complementary NIM logic
levels (logical "0" = 0 to -2 mA; logical "1" = -12
to -32 mA) at each of its eight 50 ohm inputs. The eight outputs switch
between 0 V and +2.5 V for a time equal to the input signal duration. The
polarity of the outputs is controlled by two front-panel switches common
to two groups of four channels and provides either normal or complementary
operation. Up to 50 mA at +2.5 V is delivered from each output, making the
TTL drive capability compatible with terminated, direct-coupled 50 ohm cable.
The low level clamp capability is 100 mA, or approximately 60 standard TTL
loads. Direct-coupled, the 688AL is free from any rate effects and has no
limitations on duty cycle.
The TTL-to-NIM section accepts standard negative TTL logic levels (logical
"1" = 0 to + .8 V; logical "0" = > 2 V) at each of
its eight inputs. The minimum input duration for a full output is 10 nsec.
The output from each channel is a standard NIM logic level which switches
between 0 V and -16 mA (- 800 mV into 50 ohm) during an output. Rise times
and fall times are < 3 nsec and the output width is approximately equal
to the duration of the input signal. Two front-panel switches common to
two groups of four channels provides either normal operation (TTL logical
"1" IN gives NIM logical "1" OUT) or complementary operation.
The Model 4616 is simultaneously an ECL-to-NIM and NIM-to-ECL converter,
specially designed to fill the gap between ECL circuitry and NIM electronics.
The 4616 is designed so that each channel can be used for both applications.
When ECL complementary pulses have to be converted, the circuit provides
three NIM outputs and an additional ECL output. When a NIM pulse has to
be converted, it is sent in one of the NIM outputs (now used as an input)
while the other two NIM outputs are unconnected. Thus, the circuit provides
a single complementary ECL output. The accompanying diagram shows the basic
circuit configuration of one channel.
The 4616 is a 16 channel ECL/NIM/ECL translator which is fully compatible
with other ECLine circuits. Three NIM outputs and one ECL output per channel
are available and will operate up to 150 MHz. The inputs are direct coupled
and are free from rate effects.
Model 4616 Equivalent Circuit Diagram (one channel)
NIM-TO-TTL SECTION
No. of Channels: 8.
INPUT
Impedance: 50 ohm ±5%; reflections < 10% for rise time >
2 nsec.
Quiescent DC Level: 0 V.
Input Signal: Normal (logical "0" = 0 to -2 mA; logical
"1" = -12 to -32 mA) or complementary fast NIM logic levels.
Input Protection: ±5 V.
Minimum Input Width: < 10 nsec.
OUTPUT
Signal Levels: Standard negative TTL logic levels: logical "1"
<=0.4 V, logical "0" > +2.5 V.
High Level Drive Capability: 50 mA at +2.5 V (compatible with terminated,
direct-coupled 50 ohm cable).
Low Level Clamp Capability: 100 mA at 0 ±500 mV (60 standard
TTL loads, or 50 ohm to +5 V).
Rise Time and Fall Time: < 10 nsec.
Output Duration: Approximately equal to input duration.
Output Impedance: < 5 ohm.
Duty Cycle Limitations: None.
GENERAL
Delay: Approximately 12 nsec.
Logic Polarity: Two front-panel switches, each common to four channels,
provide normal operation (logical "1" IN gives logical "1"
OUT) or complementary operation.
TTL-TO-NIM SECTION
No. of Channels: 8.
INPUT
Input Signal: Standard negative TTL logic levels (logical "1"
= 0 to +0.8 V, requires -1.6 mA maximum; logical "0" = > 2
V, requires +100 µA maximum).
Minimum Input Duration: < 10 nsec.
Input Protection: ±5 A for 0.5 µsec, clamping at +7
V and -1 V.
OUTPUT
Signal Levels: Logical "0", open circuit; logical "1",
-16 mA.
Output Duration: Approximately equal to input duration.
Rise Time and Fall Time: < 3 nsec.
Duty Cycle Limitations: None.
GENERAL
Delay: Approximately 6 nsec.
Logic Polarity: Two front-panel switches, each common to four channels,
provide normal operation (logical "1" IN gives logical "1"
OUT) or complementary operation.
Packaging: NIM single-width module; Lemo connectors.
Power Requirements: 280 mA at +6 V; 30 mA at +12 V; 300 mA at -6
V.
INPUT
ECL Inputs: 16, one per section, in a 2 x 17 pin connector; accepts
complementary ECL levels; typical threshold 200 mV.
NIM Inputs: 16, one per section, Lemo-type connector, to be chosen
out of the three Lemo-type connectors in the channel; the other two have
to be kept unconnected; input impedance 50 ohm ±5%; reflections <
10% for input rise times > 2 nsec.
OUTPUT
ECL Outputs: 16, one per section, in a 2 x 17 pin connector; ECL complementary
levels (-0.8 V and -1.7 V); rise time 2 nsec typical.
NIM Outputs: 48, three bridged outputs per section, Lemo-type connectors;
quiescently at 0 mV, < -700 mV into 3 x 50 ohm loads, maximum -1.2 V
into 1 x 50 ohm load, during output; rise time 2 nsec typical.
GENERAL
Maximum Frequency: 150 MHz.
Minimum Pulse Width: ECL and NIM inputs/outputs 4 nsec.
Transit Times: ECL input to NIM output < 6 nsec. ECL input to
ECL output < 10.5 nsec. NIM input to ECL output < 6.5 nsec.
Power Requirements: -6 V quiescently at 700 mA, with all loads connected
and all channels activated 1.7 A maximum.
SELECTION CHART
Copyright© March 1997. LeCroy is a registered trademark of LeCroy
Corporation. All rights reserved. Information in this publicaction supersedes
all earlier versions.