The LMX2487E device is a low power, high performance delta-sigma fractional-N PLL with an auxiliary integer-N PLL. It is fabricated using TI’s advanced process.
With delta-sigma architecture, fractional spurs at lower offset frequencies are pushed to higher frequencies outside the loop bandwidth. The ability to push close in spur and phase noise energy to higher frequencies is a direct function of the modulator order. Unlike analog compensation, the digital feedback technique used in the LMX2487E is highly resistant to changes in temperature and variations in wafer processing. The LMX2487E delta-sigma modulator is programmable up to fourth order, which allows the designer to select the optimum modulator order to fit the phase noise, spur, and lock time requirements of the system.
Serial data for programming the LMX2487E is transferred through a three-line, high-speed (20-MHz) MICROWIRE interface. The LMX2487E offers fine frequency resolution, low spurs, fast programming speed, and a single-word write to change the frequency. This makes it ideal for direct digital modulation applications, where the N-counter is directly modulated with information. The LMX2487E is available in a 24-lead 4.0 × 4.0 × 0.8 mm WQFN package.
PART NUMBER | PACKAGE | BODY SIZE (NOM) |
---|---|---|
LMX2487E | WQFN (24) | 4.00 mm × 4.00 mm |
Changes from A Revision (March 2013) to B Revision
Changes from * Revision (March 2013) to A Revision
PIN | I/O | DESCRIPTION | |
---|---|---|---|
NO. | NAME | ||
0 | GND | — | Ground Substrate. This is on the bottom of the package and must be grounded. |
1 | CPoutRF | O | RF PLL charge pump output. |
2 | GND | — | RF PLL analog ground. |
3 | VddRF1 | — | RF PLL analog power supply. |
4 | FinRF | I | RF PLL high-frequency input pin. |
5 | FinRF* | I | RF PLL complementary high-frequency input pin. Shunt to ground with a 100-pF capacitor. |
6 | LE | I | MICROWIRE Load Enable. High-impedance CMOS input. Data stored in the shift registers is loaded into the internal latches when LE goes HIGH |
7 | DATA | I | MICROWIRE Data. High-impedance binary serial data input. |
8 | CLK | I | MICROWIRE Clock. High-impedance CMOS Clock input. Data for the various counters is clocked into the 24-bit shift register on the rising edge |
9 | VddRF2 | — | Power supply for RF PLL digital circuitry. |
10 | CE | I | Chip Enable control pin. Must be pulled high for normal operation. |
11 | VddRF5 | I | Power supply for RF PLL digital circuitry. |
12 | Ftest/LD | O | Test frequency output / Lock Detect. |
13 | FinIF | I | IF PLL high-frequency input pin. |
14 | VddIF1 | — | IF PLL analog power supply. |
15 | GND | — | IF PLL digital ground. |
16 | CPoutIF | O | IF PLL charge pump output |
17 | VddIF2 | — | IF PLL power supply. |
18 | OSCout | O | Buffered output of the OSCin signal. |
19 | ENOSC | I | Oscillator enable. When this is set to high, the OSCout pin is enabled regardless of the state of other pins or register bits. |
20 | OSCin | I | Reference Input. |
21 | NC | I | This pin must be left open. |
22 | VddRF3 | — | Power supply for RF PLL digital circuitry. |
23 | FLoutRF | O | RF PLL Fastlock Output. Also functions as Programmable TRI-STATE CMOS output. |
24 | VddRF4 | — | RF PLL analog power supply. |
MIN | MAX | UNIT | ||
---|---|---|---|---|
VCC | Power supply voltage | –0.3 | 4.25 | V |
Vi | Voltage on any pin with GND = 0 V | –0.3 | VCC + 0.3 | V |
TL | Lead temperature (Solder 4 sec.) | 260 | °C | |
Tstg | Storage temperature | –65 | 150 | °C |
VALUE | UNIT | |||
---|---|---|---|---|
V(ESD) | Electrostatic discharge(1) | Human-body model (HBM) | ±2000 | V |
Charged-device model (CDM) | ±750 | |||
Machine model (MM) | ±200 |
MIN | NOM | MAX | UNIT | ||
---|---|---|---|---|---|
VCC | Power supply voltage (1) | 2.5 | 3 | 3.6 | V |
TA | Operating temperature | -40 | 25 | 85 | °C |
THERMAL METRIC(1) | LMX2485, LMX2485E | UNIT | |
---|---|---|---|
RTW (WQFN) | |||
24 PINS | |||
RθJA | Junction-to-ambient thermal resistance | 47.2 | °C/W |
RθJC(top) | Junction-to-case (top) thermal resistance | 43 | °C/W |
RθJB | Junction-to-board thermal resistance | 24 | °C/W |
ψJT | Junction-to-top characterization parameter | 0.8 | °C/W |
ψJB | Junction-to-board characterization parameter | 24 | °C/W |
RθJC(bot) | Junction-to-case (bottom) thermal resistance | 7 | °C/W |
PARAMETER | TEST CONDITIONS | MIN | TYP | MAX | UNIT | |||
---|---|---|---|---|---|---|---|---|
ICC PARAMETERS | ||||||||
ICCRF | Power supply current, RF synthesizer | IF PLL OFF RF PLL ON Charge pump TRI-STATE |
5.7 | mA | ||||
ICCIF | Power supply current, IF synthesizer | IF PLL ON RF PLL OFF Charge pump TRI-STATE |
2.5 | mA | ||||
ICCTOTAL | Power supply current, entire synthesizer | IF PLL ON RF PLL ON Charge pump TRI-STATE |
8.5 | mA | ||||
ICCPD | Power-down current | CE = ENOSC = 0 V CLK, DATA, LE = 0 V |
< 1 | µA | ||||
RF SYNTHESIZER PARAMETERS | ||||||||
fFinRF | Operating frequency | LMX2487E | RF_P = 16 | 3000 | 4000 | MHz | ||
RF_P = 32 | 3000 | 7500 | ||||||
pFinRF | Input sensitivity | 3-6 GHz | -10 | 0 | dBm | |||
6-7.5 GHz | -5 | 5 | ||||||
fCOMP | Phase detector frequency(1) | 50 | MHz | |||||
ICPoutRFSRCE | RF charge pump source current(2) | RF_CPG = 0 VCPoutRF = VCC/2 |
95 | µA | ||||
RF_CPG = 1 VCPoutRF = VCC/2 |
190 | µA | ||||||
... | ... | µA | ||||||
RF_CPG = 15 VCPoutRF = VCC/2 |
1520 | µA | ||||||
ICPoutRFSINK | RF charge pump sink current(2) | RF_CPG = 0 VCPoutRF = VCC/2 |
–95 | µA | ||||
RF_CPG = 1 VCPoutRF = VCC/2 |
–190 | µA | ||||||
... | ... | µA | ||||||
RF_CPG = 15 VCPoutRF = VCC/2 |
–1520 | µA | ||||||
ICPoutRFTRI | RF charge pump TRI-STATE current magnitude | 0.5 ≤ VCPoutRF ≤ VCC -0.5 | 2 | 10 | nA | |||
| ICPoutRF%MIS | | Magnitude of RF CP sink vs CP source mismatch | VCPoutRF = VCC/2 TA = 25°C |
RF_CPG > 2 | 3% | 10% | |||
RF_CPG ≤ 2 | 3% | 13% | ||||||
| ICPoutRF%V | | Magnitude of RF CP current vs CP voltage | 0.5 ≤ VCPoutRF ≤ VCC -0.5 TA = 25°C |
2% | 8% | ||||
| ICPoutRF%T | | Magnitude of RF CP current vs temperature | VCPoutRF = VCC/2 | 4% | |||||
IF SYNTHESIZER PARAMETERS | ||||||||
fFinIF | Operating frequency | IF_P = 8 | 250 | 2000 | MHz | |||
IF_P = 16 | 250 | 3000 | ||||||
pFinIF | IF input sensitivity | –10 | 5 | dBm | ||||
fCOMP | Phase detector frequency | 10 | MHz | |||||
ICPoutIFSRCE | IF charge pump source current | VCPoutIF = VCC/2 | 3.5 | mA | ||||
ICPoutIFSINK | IF charge pump sink current | VCPoutIF = VCC/2 | –3.5 | mA | ||||
ICPoutIFTRI | IF charge pump TRI-STATE current magnitude | 0.5 ≤ VCPoutIF ≤ VCC RF – 0.5 | 2 | 10 | nA | |||
| ICPoutIF%MIS | | Magnitude of IF CP sink vs CP source mismatch | VCPoutIF = VCC/2 TA = 25°C |
1% | 8% | ||||
| ICPoutIF%V | | Magnitude of IF CP current vs CP voltage | 0.5 ≤ VCPoutIF ≤ VCC – 0.5 TA = 25°C |
4% | 10% | ||||
| ICPoutIF%TEMP | Magnitude of IF CP current vs temperature | VCPoutIF = VCC/2 | 4% | |||||
OSCILLATOR PARAMETERS | ||||||||
fOSCin | Oscillator operating frequency | OSC2X = 0 | 5 | 110 | MHz | |||
OSC2X = 1 | 5 | 20 | MHz | |||||
vOSCin | Oscillator input sensitivity | 0.5 | VCC | VP-P | ||||
IOSCin | Oscillator input current | –100 | 100 | µA | ||||
SPURS | ||||||||
Spurs in band(3) | -55 | dBc | ||||||
PHASE NOISE | ||||||||
LF1HzRF | RF synthesizer normalized phase noise contribution(4) | RF_CPG = 0 | –202 | dBc/Hz | ||||
RF_CPG = 1 | –204 | |||||||
RF_CPG = 3 | –206 | |||||||
RF_CPG = 7 | –210 | |||||||
RF_CPG = 15 | –210 | |||||||
LF1HzIF | IF synthesizer normalized phase noise contribution | –209 | dBc/Hz | |||||
DIGITAL INTERFACE (DATA, CLK, LE, ENOSC, CE, Ftest/LD, FLoutRF) | ||||||||
VIH | High-level input voltage | 1.6 | VCC | V | ||||
VIL | Low-level input voltage | 0.4 | V | |||||
IIH | High-level input current | VIH = VCC | –1 | 1 | µA | |||
IIL | Low-level input current | VIL = 0 V | –1 | 1 | µA | |||
VOH | High-level output voltage | IOH = –500 µA | VCC – 0.4 | V | ||||
VOL | Low-level output voltage | IOL = 500 µA | 0.4 | V |
MIN | NOM | MAX | UNIT | |||
---|---|---|---|---|---|---|
MICROWIRE INTERFACE TIMING | ||||||
tCS | Data to clock set-up time | See Figure 1 | 25 | ns | ||
tCH | Data to clock hold time | See Figure 1 | 8 | ns | ||
tCWH | Clock pulse width high | See Figure 1 | 25 | ns | ||
tCWL | Clock pulse width low | See Figure 1 | 25 | ns | ||
tES | Clock to load enable set-up time | See Figure 1 | 25 | ns | ||
tEW | Load enable pulse width | See Figure 1 | 25 | ns |
TA = 25°C, RF_P = 32 |
TA = 25°C, IF_P = 16 |
TA = 25°C, OSC_2X = 0 |
VCC = 3 V, RF_P = 32 |
VCC = 3 V, IF_P = 16 |
VCC = 3 V, OSC_2X = 0 |
FinRF INPUT IMPEDANCE | ||
---|---|---|
FREQUENCY (MHz) | REAL (Ω) | IMAGINARY (Ω) |
3000 | 39 | –94 |
3200 | 37 | –86 |
3400 | 33 | –78 |
3600 | 30 | –72 |
3800 | 28 | –69 |
4000 | 26 | –66 |
4250 | 24 | –63 |
4500 | 23 | –60 |
4750 | 22 | –57 |
5000 | 20 | –54 |
5250 | 19 | –50 |
5500 | 18 | –49 |
5750 | 17 | –47 |
6000 | 17 | –45 |
6250 | 16 | –44 |
6500 | 16 | –42 |
6750 | 16 | –40 |
7000 | 16 | –39 |
7250 | 16 | –37 |
7500 | 16 | –35 |
7750 | 17 | –33 |
8000 | 17 | –30 |
8250 | 16 | –27 |
FinIF INPUT IMPEDANCE | ||
---|---|---|
FREQUENCY (MHz) | REAL (Ω) | IMAGINARY (Ω) |
100 | 508 | –233 |
150 | 456 | –215 |
200 | 420 | –206 |
250 | 403 | –205 |
300 | 370 | –207 |
400 | 344 | –215 |
500 | 207 | –223 |
600 | 274 | –225 |
700 | 242 | –225 |
800 | 242 | –225 |
900 | 214 | –222 |
1000 | 171 | –208 |
1200 | 137 | –191 |
1400 | 112 | –176 |
1600 | 91 | –158 |
1800 | 76 | –139 |
2000 | 62 | –122 |
2200 | 51 | –105 |
2300 | 46 | –96 |
2400 | 42 | –88 |
2600 | 37 | –74 |
2800 | 29 | –63 |
3000 | 25 | –54 |
FREQUENCY (MHz) | POWERED UP | POWERED DOWN | ||||
---|---|---|---|---|---|---|
REAL | IMAGINARY | MAGNITUDE | REAL | IMAGINARY | MAGNITUDE | |
5 | 1730 | –3779 | 4157 | 392 | –8137 | 8146 |
10 | 846 | –2236 | 2391 | 155 | –4487 | 4490 |
20 | 466 | –1196 | 1284 | 107 | –2215 | 2217 |
30 | 351 | –863 | 932 | 166 | –1495 | –1504 |
40 | 316 | –672 | 742 | 182 | –1144 | 1158 |
50 | 278 | –566 | 631 | 155 | –912 | 925 |
60 | 261 | –481 | 547 | 153 | –758 | 774 |
70 | 252 | –425 | 494 | 154 | –652 | 669 |
80 | 239 | –388 | 456 | 147 | –576 | 595 |
90 | 234 | –358 | 428 | 145 | –518 | 538 |
100 | 230 | –337 | 407 | 140 | –471 | 492 |
110 | 225 | –321 | 392 | 138 | –436 | 458 |
120 | 219 | –309 | 379 | 133 | –402 | 123 |
130 | 214 | –295 | 364 | 133 | –374 | 397 |
140 | 208 | –285 | 353 | 132 | –349 | 373 |
150 | 207 | –279 | 348 | 133 | –329 | 355 |
CE = High |
VCC = 3 V |
VCC = 3 V |