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參數(shù)資料
| 型號： | LH79520N0Q000B1 |
| 廠商： | NXP Semiconductors N.V. |
| 元件分類： | 數(shù)學處理器 |
| 英文描述： | System-on-Chip |
| 封裝： | LH79520N0Q000B1<SOT1017-1 (LQFP176)|<<http://www.nxp.com/packages/SOT1017-1.html<1<Always Pb-free,; |
| 文件頁數(shù)： | 50/59頁 |
| 文件大?。?/td> | 666K |
| 代理商： | LH79520N0Q000B1 |
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LH79520
System-on-Chip
50
Rev. 01
—
16 July 2007
Preliminary data sheet
NXP Semiconductors
Printed Circuit Board Layout Practices
LH79520 POWER SUPPLY DECOUPLING
The LH79520 has separate power and ground pins
for different internal circuitry sections. The VDD and
VSS pins supply power to I/O buffers, while VDDC and
VSSC supply power to the core logic.
Each of the VDD and VDDC pins must be provided
with a low impedance path to the corresponding board
power supply. Likewise, the VSS and VSSC pins must be
provided with a low impedance path to the board ground.
Each power supply must be decoupled to ground
using at least one 0.1
μ
F high frequency capacitor
located as close as possible to a VDDx, VSSx pin pair
on each of the four sides of the chip. If room on the cir-
cuit board allows, add one 0.01
μ
F high frequency
capacitor near each VDDx, VSSx pair on the chip.
To be effective, the capacitor leads and associated
circuit board traces connecting to the chip VDDx, VSSx
pins must be kept to less than half an inch (12.7 mm)
per capacitor lead. There must be one bulk 10 μF
capacitor for each power supply placed near one side
of the chip.
REQUIRED LH79520 PLL, VDDA, VSSA FILTER
The VDDA pin supplies power to the chip PLL cir-
cuitry. VSSA is the ground return path for the PLL circuit.
If the internal PLL circuit will be used, these pins must
have a low-pass filter attached as shown in Figure 32.
The Schottky diode shown in the schematic must
have a low forward drop specification, to allow VDDA to
quickly transition through the entire input voltage range.
The power pin VDDA path must be a single wire
from the IC package pin to the high frequency capaci-
tor, then to the low frequency capacitor, and finally
through the series resistor to the board power supply.
The distance from the IC pin to the high frequency
capacitor must be kept as short as possible.
Similarly, the VSSA path is from the IC pin to the
high frequency capacitor, then to the low frequency
capacitor, keeping the distance from the IC pin to the
high frequency cap as short as possible.
UNUSED INPUT SIGNAL CONDITIONING
Floating input signals can cause excessive power
consumption. Unused inputs which do not include inter-
nal pull-up or pull-down resistors should be pulled up or
down externally, to tie the signal to its inactive state.
Some GPIO signals may default to inputs. If the pins
which carry these signals are unused, software can
program these signals as outputs, to eliminate the need
for pull-ups or pull-downs. Power consumption may be
higher than expected until such software executes.
Some LH79520 inputs have internal pull-ups or pull-
downs. If unused, these inputs do not require external
conditioning.
OTHER CIRCUIT BOARD LAYOUT PRACTICES
All output pins on the LH79520 have fast rise and fall
times. Printed circuit trace interconnection length must
therefore be reduced to minimize overshoot, under-
shoot and reflections caused by transmission line
effects of these fast output switching times. This rec-
ommendation particularly applies to the address and
data buses.
When considering capacitance, calculations must
consider all device loads and capacitances due to the
circuit board traces. Capacitance due to the traces will
depend upon a number of factors, including the trace
width, dielectric material the circuit board is made from
and proximity to ground and power planes.
Attention to power supply decoupling and printed cir-
cuit board layout becomes more critical in systems with
higher capacitive loads. As these capacitive loads
increase, transient currents in the power supply and
ground return paths also increase.
Add pull-up resistors to all unused inputs unless
an internal pull-down resistor has been specified;
see Table 3. (All pull-up/pull-down resistors must be
33 K
MAX.) Consider all signals that are Inputs at
Reset time.
Figure 32. VDDA, VSSA Filter Circuit
79520-64
VDDA
VDDC
VSSA
22 μF
100
VDDC
(SOURCE)
0.1 μF
PIN 92
+
PIN 91
LH79520
Note that the VSSA pin specifically does not have a connection to the
circuit board ground. The LH79520 PLL circuit has an internal DC
ground connection to VSS (GND), so the external VSSA pin must
NOT be connected to the circuit board ground, but only to the filter
components.
CAUTION
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LH79520N0Q000B1,55 | 功能描述:IC ARM7 BLUESTREAK MCU 176LQFP RoHS:是 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:BlueStreak ; LH7 標準包裝:250 系列:56F8xxx 核心處理器:56800E 芯體尺寸:16-位 速度:60MHz 連通性:CAN，SCI，SPI 外圍設備:POR，PWM，溫度傳感器，WDT 輸入/輸出數(shù):21 程序存儲器容量:40KB（20K x 16） 程序存儲器類型:閃存 EEPROM 大小:- RAM 容量:6K x 16 電壓 - 電源 (Vcc/Vdd):2.25 V ~ 3.6 V 數(shù)據(jù)轉(zhuǎn)換器:A/D 6x12b 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 125°C 封裝/外殼:48-LQFP 包裝:托盤 配用:MC56F8323EVME-ND - BOARD EVALUATION MC56F8323 |
| LH79520N0Q000B1,551 | 制造商:NXP Semiconductors 功能描述: |
| LH79520N0Q000B1,557 | 制造商:NXP Semiconductors 功能描述:SOC Microcontroller 1.98V 176-Pin LQFP |
| LH79520N0Q000B1;55 | 功能描述:ARM微控制器 - MCU LCD EXT BUS 3 UART RoHS:否 制造商:STMicroelectronics 核心:ARM Cortex M4F 處理器系列:STM32F373xx 數(shù)據(jù)總線寬度:32 bit 最大時鐘頻率:72 MHz 程序存儲器大小:256 KB 數(shù)據(jù) RAM 大小:32 KB 片上 ADC:Yes 工作電源電壓:1.65 V to 3.6 V, 2 V to 3.6 V, 2.2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:LQFP-48 安裝風格:SMD/SMT |
| LH79520N0Q000B155 | 制造商:Rochester Electronics LLC 功能描述: 制造商:NXP 功能描述: 制造商:NXP Semiconductors 功能描述: |
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