TCF6000

2

MOTOROLA ANALOG IC DEVICE DATA

Rating

Symbol

Value

Unit

Supply Voltage

VCC

6.0

V

Supply Current

Ii

300

mA

Clamping Current

IIK

±50

mA

Junction Temperature

TJ

150

°C

Power Dissipation (TA = + 85°C)

PD

400

m/W

Thermal Resistance (Junction–Ambient)

θJA

100

°C/W

Operating Ambient Temperature Range

TA

–40 to +85

°C

Storage Temperature Range

Tstg

–55 to + 150

°C

NOTE: 1. Values beyond which damage may occur.

Characteristics

Symbol

Min

Max

Unit

Positive Clamping Voltage (Note 2)

(IIK = 10 mA, –40°C ≤ TA ≤ + 85°C)

V(IK)

–

VCC + 1.0

V

Positive Peak Clamping Current

IIK(P)

–

20

mA

Negative Peak Clamping Voltage

(IIK = –10 mA, –40°C ≤ TA ≤ + 85°C)

V(IK)

–0.3

–

V

Negative Peak Clamping Current

IIK(P)

–20

–

mA

Output Leakage Current

(0 V

≤ Vin ≤ VCC)

(0 V

≤ Vin ≤ VCC, –40°C ≤ TA ≤ + 85°C)

IL

ILT

–

–

1.0

5.0

µA

Channel Crosstalk (ACT = 20 log IL/IIK)

ACT

100

–

dB

Quiescent Current (Package)

IB

–

2.0

mA

NOTE: 2. The device might not give 100% protection in CMOS applications.

CIRCUIT DESCRIPTION

To ensure the reliable operation of any integrated circuit

based electronics system, care has been taken that voltage

transients do not reach the device I/O pins. Most NMOS,

HMOS and Bipolar integrated circuits are particularly

sensitive to negative voltage peaks which can provoke

latch–up or otherwise disturb the normal functioning of the

circuit, and in extreme cases may destroy the device.

Generally the maximum rating for a negative voltage

transients on integral circuits is –0.3 V over the whole

temperature range. Classical protection units have consisted

of diode/resistor networks as shown in Figures 2a and 2b.

The arrangement in Figure 2a does not, in general, meet

the specification and is therefore inadequate.

The problem with the solution shown if Figure 2b lies

mainly with the high current drain through the biassing

devices R1 and D3. A second problem exists if the input line

carries an analog signal. When Vin is close to the ground

potential, currents arising from leakage and mismatch

between D3 and D2 can be sourced into the input line, thus

disturbing the reading.

(a)

(b)

Figure 2. Classical Protection Circuits

VCC

D1

Vin

Rin

D2

Cin

Gnd

Gnd

µC

D3

Vin Rin

Cin

R1

VCC

D2

µC

D1

Figure 3 shows the clamping characteristics which

are common to each of the six cells in the Peripheral

Clamping Array.

As with the classical protection circuits, positive voltage

supply line.