LA1781M

No.6038-3/48

Continued from preceding page.

Ratings

Parameter

Symbol

Conditions

min

typ

max

Unit

FM FE Mixer input

N-AGC on input

VNAGC

83MHz, unmodulated.

The input such that the pin 2 voltage is 2.0V or below

81

88

95

dB

μ

W-AGC on input

VWAGC

83MHz, unmodulated. The input such that the pin 2

voltage is 2.0V or below. (When the keyed AGC is set to 4.0V.)

104

110

116

dB

μ

Conversion gain

A. V

83MHz, 80dB

μ, unmodulated. The FE CF output

19

30

48

mVrms

Oscillator buffer output

VOSCBUFF-FM No input

85

110

165

mVrms

NC Block NC input (pin 30)

Gate time

TGATE

f = 1kHz, for a 1

μs, 100-mVp-o pulse

55

μs

Noise sensitivity

SN

The level of a 1kHz, 1

μs pulse input that starts

noise canceller operation. Measured at pin 30.

40

mVp-o

NC effect

SN-NC

The pulse rejection effect provided by the noise canceller.

For a repeated 1

μs wide pulse, frequency = 10kHz,

150mVp-o. The ratio of the FM mode pin 15 output

referenced to the AM mode pin 15 output (effective value)

5

Multipath rejection circuit MRC input (pin 27)

MRC output

VMRC

V24 = 5V

2.2

2.3

2.4

V

MRC operating level

MRC-ON

The pin 32 input level at f = 70kHz such that

pin 24 goes to 5V and pin 27 goes to 2V

10

15

20

mVrms

AM characteristics AM ANT input

Practical sensitivity

S/N-30

1MHz, 30dB

μ, fm = 1kHz, 30% modulation, pin 15

20

dB

Detector output

VO-AM

1MHz, 74dB

μ, fm = 1kHz, 30% modulation, pin 15

130

195

270

mVrms

Pin 31 detector output

VO-AM31

1MHz, 74dB

μ, fm = 1kHz, 30% modulation, pin 31

110

175

230

mVrms

AGC F.O.M.

VAGC-FOM

1MHz, 74dB

μ, referenced to the output, the input amplitude

such that the output falls by 10dB. Pin 15

59

64

69

dB

Signal-to-noise ratio

S/N-AM

1MHz, 74dB

μ, fm = 1kHz, 30% modulation

47

52

dB

Total harmonic distortion

THD-AM

1MHz, 74dB

μ, fm = 1kHz, 80% modulation

0.3

1

%

VSMAM-1

No input

0.0

0.2

0.5

V

Signal meter output

VSMAM-2

1MHz, 130dB

μ, unmodulated

3.5

4.4

6.1

V

Oscillator buffer output

VOSCBUFF-AM1 No input, the pin 15 output

185

230

mVrms

W-AGCsen1

1.4MHz, the input when V46 = 0.7V

92

98

104

dB

μ

Wide band AGC sensitivity

W-AGCsen2

1.4MHz, the input when V46 = 0.7V (seek mode)

83

89

95

dB

μ

SD-sen1AM

1MHz, the ANT input level such that the IF counter output turns

on.

24

30

36

dB

μ

SD sensitivity

SD-sen2AM

1MHz, the ANT input level such that the SD pin goes to the on

state.

24

30

36

dB

μ

IF buffer output

VIFBUFF-AM

1MHz, 74dB

μ, unmodulated. The pin 23 output

200

290

mVrms

Note : These measurements must be made using the either the IC-51-0644-824 or KS8277 IC socket (manufactured by Yamaichi Electronics).

*1. When the resistor between pin 58 and ground is 200k

Ω.

*2. When the resistor between pin 58 and ground is 30k

Ω.