NTE NTE3882 Datasheet

NTE3882

Integrated Circuit

NMOS, Counter Timer Control (CTC)

Description:

The NTE3882 Counter Timer Circuit (CTC) is a programmable, four channel device in a 28–Lead DIP
type package that provides counting and timing functions for the NTE3880. The NTE3880 configures
the NTE3882’s four independent channels to operate under various modes and conditions as
required.

The internal structure of the NTE3882 consists of an NTE3880 bus interface, internal control logic,
four counter channels, and interrupt control logic. Each channel has an interrupt vector for automatic
interrupt vectoring, and interrupt priority is determined by channel number with channel ∅ having the
highest priority.

The channel logic is composed of 2 registers, 2 counters and control logic. The registers include and
8–bit time constant register and an 8–bit channel control register . The counters include as 8–bit read­able down counter and an 8–bit prescaler. The prescaler may be programmed to divide the system
clock by either 16 or 256.

Structure:

D N–Channel Silicon Gate Depletion Load Technology
D Single 5V Supply
D Single Phase 5V Clock
D Four Independent Programmable 8–Bit Counter/16–Bit Timer Channels

Features:

D Each Channel may be Selected to Operate in Either a Counter Mode or Timer Mode
D Programmable Interrupts on Counter or Timer States
D A Time Constant Register Automatically Reloads, the Down Counter at Zero and the Cycle is

Repeated

D Readable Down Counter Indicates Number of Counts–to–Go until Zero
D Selectable 16 or 256 Clock Prescaler for Each Timer Channel
D Selectable Positive or Negative Trigger may Initiate Timer Operation
D Three Channels have Zero Count/Timeout Outputs capable of Driving Darlington Transistors
D Daisy Chain Priority Interrupt Logic Included to Provide for Automatic Interrupt Vectoring without

External Logic

D All Inputs and Outputs Fully TTL Compatible

Absolute Maximum Ratings:

Temperature Under Bias 0° to +70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Storage Temperature Range –65° to +150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Voltage On Any Pin With Respect to GND –0.3V to +7V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Dissipation 0.8W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Note 1. Stresses above those listed under “Absolute Maximum Ratings” may cause permanent

damage to the device. This is a stress rating only functional operation of the device at these
or any other condition above those indicated in the operational sections of this specification
is not implied. Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.

DC Characteristics

: (TA = 0° to 70°C, VCC = 5V ±5% unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Unit

Clock Input Low Voltage V
Clock Input High Voltage V
Input Low Voltage V
Input High Voltage V
Output Low Voltage V
Output High Voltage V
Power Supply Current I
Input Leakage Current I
Tri–State Output Leakage Current in Float I
Tri–State Output Leakage Current in Float I
Darlington Drive Current I

ILC

IHC

IL

IH

OL

OH

CC

L1

LOH

LOL

OHD

IOL = 2mA – – 0.4 V
IOH = –250µA 2.4 – – V
TC = 250ns – – 120 mA
VIN = 0 to V
V

OUT

V

OUT

VOH = 1.5V, R

CC

= 2.4 to V

CC

= 0.4V – – –10 µA

= 390Ω –1.5 – – mA

EXT

Capacitance: (TA = +25°C, f = 1MHz unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Unit

Clock Capacitance C
Input Capacitance C
Output Capacitance C

OUT

Unmeasured Pins

φ

Returned to GND

IN

–0.3 – 0.45 V

VCC–0.6 – VCC+3 V

–0.3 – 0.8 V

2.0 – V

CC

– – 10 µA
– – 10 µA

– – 20 pF
– – 5 pF
– – 10 pF

V

AC Characteristics: (TA = 0° to 70°C, VCC = 5V ±5% unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Unit

Clock Cycle Time TcC 400 – Note 2 ns
Clock Width (High) T wCH 170 – 2000 ns
Clock Width (Low) TwCL 170 – 2000 ns
Clock Fall Time TfC – – 30 ns
Clock Rise Time TrC – – 30 ns
All Hold Times Th 0 – – ns
CS to Clock ↑ Setup Time TsCS(C) 250 – – ns
CE to Clock ↑ Setup Time TsCE(C) 200 – – ns
IORQ ↓ to Clock ↑ Setup Time TsIO(C) 250 – – ns
RD to Clock ↑ Setup Time TsRD(C) 240 – – ns

Note 2. TcC = TwCH + TwCL + TcC + TrC.