SANYO LA7790M Datasheet

Overview

The LA7790M is a QPSK data transmitter for digital cable TV applications. By integrating the I/Q quadrature modulator, RF amplifier, electronic volume control, mute control, and other functions onto a single chip, parts count is reduced and set size is miniaturized.

Features

• Maximum RF amplifier output level of +10 dBm (75Ω

terminator), suitable for directly driving the cable.

• RF output frequency range of 5 to 70 MHz. Frequency range selection function permits broadband designs.

• Electronic volume control for direct-current control of RF output level.

• Muting ensures ample attenuation during periods with no transmission.

• Support for both internal and external bias for I/Q modulation inputs.

• Support for I/Q modulation frequencies up to 10 MHz. (typ: 500 mVp-p)

Functions

• I/Q quadrature modulator

• I/Q input bias power supply

• RF amplifier

• Varactor diode-based VCO

• Muting

• Electronic volume control

• Power-saving modes

• Switchable output frequency range

• Power supply voltage of 5 V (4.5 to 5.5 V)

Package Dimensions

unit: mm

3108-MFP24D

Monolithic Linear IC

5061998RM (OT) No. 5689-1/14

SANYO: MFP24D

[LA7790M]

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN

QPSK Transmitter for Cable TV

LA7790M

Ordering number : EN5689A

Ambient temperature, Ta (°C)

Allowable power dissipation, Pd

max

(mW)

No. 5689-2/14

LA7790M

Parameter Symbol Conditions Ratings Unit

Maximum power supply voltage V

max Pins 1, 10, and 24 7 V

Circuit voltage Vmax Pins 1, 12, 17, 20, 21, and 23 V

Circuit current

Output lead-in current

1 mA

2 mA Allowable power dissipation Pd max Ta ≤ 54°C 650 mW Operating ambient temperature Topr –20 to +70 °C Storage temperature Tstg –55 to +150 °C

Specifications

Maximum Ratings at Ta = 25°C

Parameter Symbol Conditions

Ratings

Unit

min typ max

Current drain

Circuit current 1 I

With no signal, pin 1 26 33 44 mA

Circuit current 2 I

+ I10With no signal, pins 24 and 10 44 55 73 mA

Modulator fo: f(V19) = 25 MHz

Output frequency range f

(V19)

5 70 MHz

Output signal level V

19(DSB)

Note 1: V20= V23= GND,

–7 –4 –2 dBm

= V17= V21= VCC, S1 = A

Output harmonic distortion

19(HD2)

Note 2: V20= V23= GND, 40 dB

19(HD3)V12

= V17= V21= VCC, S1 = A 35 dB

Output secondary harmonic distortion V

19(2fo)

Note 3: V20= V23= GND,

20 dB

= V17= V21= VCC, S1 = A

Output tertiary harmonic distortion V

19(3fo)

Note 3: V20= V23= GND,

8 dB

= V17= V21= VCC, S1 = A

Carrier suppression ratio V

19(fo)

Note 4: V20= V23= GND,

30 dB

= V17= V21= VCC, S1 = A

Sideband suppression ratio V

19(SSB)

Note 5: V20= V23= GND,

30 dB

= V17= V21= VCC, S1 = A

I input level V

4.5

= |V4— V5| 500 mVp-p

Q input level V

8.9

= |V8— V9| 500 mVp-p

I input DC voltage V

4, 5

External DC bias voltage 1.9 2.1 2.3 V

Q input DC voltage V

8, 9

External DC bias voltage 1.9 2.1 2.3 V

Reference voltage V

Internal DC bias voltage 1.9 2.1 2.3 V

Variable attenuator

Minimum gain control voltage V

V12= V17= VCC, V20= V23= GND, S1 = A 0 0.5 V

Gain range V

19(GR)

Note 6: V20= V23= GND, V12= V17= VCC,

45 dB

S1 = A, V

= VCC→ 0.5 V

Modulator output impedance R

V12= V17= V21= VCC,

80 120 160 Ω

= V23= GND, S1 = A

VCO

Oscillator frequency range f

(osc)

V12= V17= V21= VCC,

20 280 MHz

= V23= GND, S1 = A

VCO output level

11(fo)

V12= V17= V21= VCC,

500 700 900 mVp-p

= V23= GND, S1 = A

VCO output impedance

V12= V17= V21= VCC,

200 300 400 Ω

= V23= GND, S1 = A

Band switch

Band switch 1 “H” level

17H

Note 7: V12= V21= VCC,

4 V

f(V19) = 25 MHz V

= V23= GND, S1 = A

Band switch 1 “L” level

17L

Note 7: V12= V21= VCC,

1 V

f(V19) = 12.5 MHz V

= V23= GND, S1 = A

Operating Characteristics at Ta = 25°C, VCC= 5.0 V

Parameter Symbol Conditions Ratings Unit

Operating power supply voltage V

op Pins 1, 10, and 24 4.5 to 5.5 V

Recommended Conditions at Ta = 25°C

Continued on next page.

No. 5689-3/14

LA7790M

Parameter Symbol Conditions

Ratings

Unit

min typ max

Band switch 2 “H” level

12H

Note 7: V17= V21= VCC,

4 V

f(V

) = 25 MHz V20= V23= GND, S1 = A

Band switch 2 “L” level

12L

Note 7: V17= V21= VCC,

1 V

f(V

) = 12.5 MHz V20= V23= GND, S1 = A

RF output amplifier

Maximum output level V

max

Note 8: V

= V17= V21= VCC,

7 10 13 dBm

= V23= GND, SG3 = –6 dBm, S1 = A

1(HD2)

Note 8: V12= V17= V21= VCC,

40 dBc

Maximum output distortion

= V23= GND, SG3 = –6 dBm, S1 = A

1(HD3)

40 dBc

Muting

Muting on voltage V

23H

V12= V17= V21= VCC,

4 V

= GND, S1 = B

Muting off voltage V

23L

V12= V17= V21= VCC,

1 V

= GND, S1 = B

Muting attenuation V

1(mute)

Note 9: V23= 1 V → 4 V

70 dB

= V17= V21= VCC, V20= GND, S1 = B

Power save function

Power save on voltage V

20H

4 V

Power save off voltage V

20L

1 V

Power save current I

Note 10: V20= 4 V 0 0.1 mA

Continued from preceding page.

Pin Assignment

Note 1 Input: SG1 =1 MHz CW, 500 mVp-p, SG2 = No Signal or

SG2 = 1 MHz CW, 500 mVp-p, SG1 = No Signal

Output:

Note 2 Input: Same as Note 1 Output:

No. 5689-4/14

LA7790M

Note 4 Input: SG1 =SG2 = 1 MHz CW, 500 mVp-p Output:

Note 6 Input: SG1 =1 MHz CW, 500 mVp-p Output:

Note 5 Input: SG1 = 1 MHz CW, 500 mVp-p, 0deg

SG1 = 1 MHz CW, 500 mVp-p, 90deg

Output:

Note 3 Input: Same as Note 1 Output:

No. 5689-5/14

LA7790M

Note 7 Input: SG1 =1 MHz CW, 500 mVp-p Output:

Note 8 Input: SG3 =25 MHz CW, –6 dBm Output:

Note 9 Input: SG1 =1 MHz CW, 500 mVp-p Output:

Note 10 I1= pin 1 current when V20 = 4 V (power save on).

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