lt5558 Linear Technology Corporation, lt5558 Datasheet - Page 7

• Manufacturer Part Number: lt5558
• Description: 600mhz To 1100mhz High Linearity Direct Quadrature Modulator
• Manufacturer: Linear Technology Corporation

PIN FUNCTIONS
TYPICAL PERFORMANCE CHARACTERISTICS
f
shifted, without image or LO feedthrough nulling. f
2-tone measurements), unless otherwise noted. (Note 3)
EN (Pin 1): Enable Input. When the Enable pin voltage is
higher than 1V, the IC is turned on. When the Enable volt-
age is less than 0.5V or if the pin is disconnected, the IC
is turned off. The voltage on the Enable pin should never
exceed V
damage to the chip.
GND (Pins 2, 4, 6, 9, 10, 12, 15, 17): Ground. Pins 6, 9,
15 and the Exposed Pad, Pin 17, are connected to each
RF
= 902MHz, P
30
25
15
20
10
0
5
8
Gain Distribution
–40°C
25°C
85°C
–7.5
CC
–7
by more than 0.5V, in order to avoid possible
LO
–6.5
= 0dBm. BBPI, BBMI, BBPQ, BBMQ CM input voltage = 2.1V
GAIN (dB)
–6
20
15
10
5
5
0
<–66
Image Rejection Distribution
–5.5
V
BB
V
= 400mV
–62
–5 –4.5
BB
= 400mV
IMAGE REJECTION (dBc)
–58
P-P
–4 –3.5
5558 G26
P-P
–54
–50
–46
20
15
10
RF
5
0
–158
–40°C
25°C
85°C
–42
Noise Floor Distribution
= f
5558 G29
–40°C
25°C
85°C
BB
+ f
LO
NOISE FLOOR (dBm/Hz)
–157.5
(upper side-band selection). P
other internally. Pins 2 and 4 are connected to each other
internally and function as the ground return for the LO
signal. Pins 10 and 12 are connected to each other inter-
nally and function as the ground return for the on-chip RF
balun. For best RF performance, Pins 2, 4, 6, 9, 10, 12,
15 and the Exposed Pad, Pin 17, should be connected to
the printed circuit board ground plane.
–157
–40
–50
–60
–70
–80
–90
DC
–40
, baseband input frequency = 2MHz, I and Q 90°
LO Feedthrough and Image
Rejection vs Temperature After
Calibration at 25°C
V
CALIBRATED WITH P
f
f
BBI
BBQ
CC
5558 G27
LO FEEDTHROUGH
= 2MHz, 0°
–20
= 5V, EN = High, T
= 2MHz, 90° + ϕ
TEMPERATURE (°C)
0
RF(OUT)
20
RF
10
CAL
40
30
20
0
= –10dBm
–50
IMAGE REJECTION
LO Leakage Distribution
= –10dBm (–10dBm/tone for
40
–40°C
25°C
85°C
A
–48
= 25°C, f
60
–46
LO LEAKAGE (dBm)
5558 G30
80
–44
LO
= 900MHz,
–42 –40
LT5558
V
BB
= 400mV
–38
5558fa
5558 G28
7
P-P
–36