参数资料
| 型号： | ISL9443IRZ-T7A |
| 厂商： | Intersil |
| 文件页数： | 19/23页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 32-QFN |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 3 |
| 频率 - 最大： | 1.32MHz |
| 电源电压： | 4.5 V ~ 26 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 32-VFQFN 裸露焊盘 |
| 包装： | 标准包装 |
| 其它名称： | ISL9443IRZ-T7ADKR |
ISL9443
C2
Layout Considerations
R2
C1
1. The input capacitors, upper FET, lower FET, inductor and
CONVERTER
EA
G M = 17.5dB
MODULATOR
R1
TYPE 2 EA
G EA = 18dB
output capacitor should be placed first. Isolate these power
components on the topside of the board with their ground
terminals adjacent to one another. Place the input high
frequency decoupling ceramic capacitors very close to the
MOSFETs.
2. Use separate ground planes for power ground and small
signal ground. Connect the SGND and PGND together close to
F PO
F Z
F C
F P
the IC. Do not connect them together anywhere else.
3. The loop formed by the input capacitor, the top FET and the
bottom FET must be kept as small as possible.
4. Ensure the current paths from the input capacitor to the
MOSFET, to the output inductor and output capacitor are as
short as possible with maximum allowable trace widths.
FIGURE 22. FEEDBACK LOOP COMPENSATION
Conditional stability may occur only when the main load pole is
positioned too much to the left side on the frequency axis due to
excessive output filter capacitance. In this case, the ESR zero
placed within the 1.2kHz to 30kHz range gives some additional
phase ‘boost’. Some phase boost can also be achieved by
connecting capacitor C Z in parallel with the upper resistor R 1 of
the divider that sets the output voltage value. Please refer to
Layout Guidelines
Careful attention to layout requirements is necessary for
successful implementation of an ISL9443 based DC/DC
converter. The ISL9443s switch at a very high frequency and
therefore the switching times are very short. At these switching
frequencies, even the shortest trace has significant impedance.
Also, the peak gate drive current rises significantly in an
extremely short time. Transition speed of the current from one
device to another causes voltage spikes across the
interconnecting impedances and parasitic circuit elements.
These voltage spikes can degrade efficiency, generate EMI,
increase device overvoltage stress and ringing. Careful
component selection and proper PC board layout minimizes the
magnitude of these voltage spikes.
There are three sets of critical components in a DC/DC converter
using the ISL9443: The controller, the switching power
components and the small signal components. The switching
power components are the most critical from a layout point of
view because they switch a large amount of energy, so they tend
to generate a large amount of noise. The critical small signal
components are those connected to sensitive nodes or those
supplying critical bias currents. A multi-layer printed circuit board
is recommended.
19
5. Place The PWM controller IC close to the lower FET. The LGATE
connection should be short and wide. The IC can be best
placed over a quiet ground area. Avoid switching ground loop
currents in this area.
6. Place the VCC_5V bypass capacitor very close to the VCC_5V
pin of the IC and connect its ground to the PGND plane.
7. Place the gate drive components - optional BOOT diode and
BOOT capacitors - together near the controller IC.
8. The output capacitors should be placed as close to the load as
possible. Use short wide copper regions to connect output
capacitors to load to avoid inductance and resistances.
9. Use copper filled polygons or wide but short trace to connect
the junction of the upper FET, Lower FET and output inductor.
Also, keep the PHASE node connection to the IC short. Do not
unnecessarily oversize the copper islands for PHASE node.
Since the phase nodes are subjected to very high dv/dt
voltages, the stray capacitor formed between these islands
and the surrounding circuitry will tend to couple switching
noise.
10. Route all high speed switching nodes away from the control
circuitry.
11. Create a separate small analog ground plane near the IC.
Connect the SGND pin to this plane. All small signal grounding
paths including feedback resistors, current limit setting
resistors, soft-starting capacitors and ENx pull-down resistors
should be connected to this SGND plane.
12. Separate current sensing traces from PHASE node
connections.
13. Ensure the feedback connection to the output capacitor is
short and direct.
FN7663.1
February 24, 2012
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL9443IRZ-T7AS2750 | 制造商:Intersil Corporation 功能描述:ISL9443 TRIPLE, STEP- DOWN PWM CONTROLLER IMVP-6. 32 LD MLFP - Tape and Reel |
| ISL9443IRZ-TS2750 | 制造商:Intersil Corporation 功能描述:PB FREE. ISL9443 TRIPLE, STEP- DOWN PWM CONTROLLER IMVP-6. 3 - Tape and Reel |
| ISL9444CRZ | 制造商:Intersil Corporation 功能描述:PB FREE. ISL9444 TRIPLE, STEP- DOWN PWM CONTROLLER IMVP-6. 4 - Rail/Tube 制造商:Intersil Corporation 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN 制造商:Intersil 功能描述:Pb Free. ISL9444 Tri ple, Step- Down PWM |
| ISL9444CRZ-T | 制造商:Intersil Corporation 功能描述:PB FREE. ISL9444 TRIPLE, STEP- DOWN PWM CONTROLLER IMVP-6. 4 - Tape and Reel 制造商:Intersil Corporation 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN 制造商:Intersil 功能描述:Pb Free. ISL9444 Tri ple, Step- Down PWM |
| ISL9444CRZ-T7A | 制造商:Intersil Corporation 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN 制造商:INTERSIL 功能描述:ISL9444 Series 1.2 Mhz Triple Synchronous Step-Down PWM - QFN-40 制造商:Intersil 功能描述:ISL9444 Triple, Step - Down PWM Controlle 制造商:Intersil 功能描述:ISL9444 Series 1.2 Mhz Triple Synchronous Step-Down PWM - QFN-40 |
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