- 您现在的位置：买卖IC网 > PDF目录1837 > MAX1541ETL+T (Maxim Integrated Products)IC REG CTRLR DIVIDER PWM 40-TQFN PDF资料下载
参数资料
| 型号： | MAX1541ETL+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 25/49页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR DIVIDER PWM 40-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 620kHz |
| 占空比： | 100% |
| 电源电压： | 2 V ~ 28 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 是 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 40-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页当前第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页
Dual Step-Down Controllers with Saturation
Protection, Dynamic Output, and Linear Regulator
Table 3. Approximate K-Factor Errors
CONTROLLER 1 (OUT1)
CONTROLLER 2 (OUT2)
NOMINAL TON
SETTING (kHz)
200kHz (TON = V CC )
300kHz (TON = open)
420kHz (TON = REF)
540kHz (TON = GND)
K-FACTOR
ERROR (%)
±10
±10
±12.5
±12.5
TYPICAL
K-FACTOR
(μs)
4.5 (235kHz)
3.0 (345kHz)
2.2 (485kHz)
1.7 (620kHz)
MINIMUM V IN AT
V OUT1 = 1.8V*
(V)
2.28
2.52
2.91
3.42
TYPICAL
K-FACTOR
(μs)
6.2 (170kHz)
4.1 (255kHz)
3.0 (355kHz)
2.3 (460kHz)
MINIMUM V IN AT
V OUT2 = 2.5V*
(V)
2.96
3.18
3.48
3.87
* See the Step-Down Converter Dropout Performance section (h = 1.5 and worst-case K-factor value used).
Table 4. SKIP Configuration Table
tinuous and discontinuous inductor-current operation
(also known as the “critical-conduction ” point). The
SKIP
V CC
Open
REF
OUT1 MODE
Forced PWM
Forced PWM
Pulse skipping
OUT2 MODE
Forced PWM
Pulse skipping
Forced PWM
load-current level at which PFM/PWM crossover
occurs, I LOAD(SKIP) , is equal to half the peak-to-peak
ripple current, which is a function of the inductor value
(Figure 4). This threshold is relatively constant, with
only a minor dependence on battery voltage:
I LOAD(SKIP) ≈ ? OUT ? ? IN OUT ?
? = 0 . 69 A
? 2 × 4.3 μ H ? ?
? ? ?
GND Pulse skipping Pulse skipping
ing the high-side switch, inductor, and PC board resis-
tances; and t ON is the on-time calculated by the
MAX1540A/MAX1541.
Light-Load Operation ( SKIP )
The four-level SKIP input selects light-load, pulse-skip-
ping operation by independently enabling or disabling
the zero-crossing comparator for each controller (Table
4). When the zero-crossing comparator is enabled, the
controller forces DL_ low when the current-sense inputs
detect zero inductor current. This keeps the inductor
from discharging the output capacitors and forces the
controller to skip pulses under light-load conditions to
avoid overcharging the output. When the zero-crossing
comparator is disabled, the controller maintains PWM
operation under light-load conditions (see the Forced-
PWM Mode section).
Automatic Pulse-Skipping Mode
In skip mode, an inherent automatic switchover to PFM
takes place at light loads (Figure 3). This switchover is
affected by a comparator that truncates the low-side
switch on-time at the inductor current’s zero crossing.
The zero-crossing comparator differentially senses the
inductor current across the current-sense inputs (CSP_
to CSN_). Once V CSP_ - V CSN_ drops below 5% of the
current-limit threshold (2.5mV for the default 50mV cur-
rent-limit threshold), the comparator forces DL_ low
(Figure 3). This mechanism causes the threshold
between pulse-skipping PFM and nonskipping PWM
operation to coincide with the boundary between con-
? V K ? ? V - V ?
? 2L ? ? V IN ?
where K is the on-time scale factor (Table 3). For exam-
ple, in the MAX1541 Standard Application Circuit
(Figure 12) (K = 3.0μs, V OUT2 = 2.5V, V IN = 12V, and L
= 4.3μH), the pulse-skipping switchover occurs at:
? 2.5V × 3 . 0 μ s ? ? 12V - 2.5V ?
12V ?
The crossover point occurs at an even lower value if a
swinging (soft-saturation) inductor is used. The switch-
ing waveforms may appear noisy and asynchronous
when light loading causes pulse-skipping operation,
but this is a normal operating condition that results in
high light-load efficiency. Trade-offs in PFM noise vs.
light-load efficiency are made by varying the inductor
value. Generally, low inductor values produce a broad-
er efficiency vs. load curve, while higher values result in
higher full-load efficiency (assuming that the coil resis-
tance remains fixed) and less output voltage ripple.
Penalties for using higher inductor values include larger
physical size and degraded load-transient response
(especially at low input-voltage levels).
DC-output accuracy specifications refer to the thresh-
old of the error comparator. When the inductor is in
continuous conduction, the MAX1540A/MAX1541 regu-
late the valley of the output ripple, so the actual DC out-
put voltage is higher than the trip level by 50% of the
output ripple voltage. In discontinuous conduction
______________________________________________________________________________________
25
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1542ETP+T | IC DC-DC CONV TFT-LCD 20-TQFN |
| MAX1544ETL+ | IC QUICK-PWM DUAL-PHASE 40-TQFN |
| MAX1545ETL+ | IC QUICK-PWM DUAL-PHASE 40-TQFN |
| MAX1551EZK+T | IC BATT CHRGR LI+ 1CELL SOT23-5 |
| MAX1556ETB/V+T | IC REG BUCK SYNC ADJ 1.2A 10TDFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1541EVKIT | 制造商:Maxim Integrated Products 功能描述:DUAL STEP-DOWN CONTROLLERS W. SATURATION PROT - Bulk |
| MAX15425EVKIT# | 功能描述:显示开发工具 Eval Kit for the MAX15425 (Intel CPU Controller) RoHS:否 制造商:4D Systems 产品:4Display Shields 工具用于评估:?OLED-160-G1, ?OLED-160-G2 接口类型:Serial 工作电源电压:5 V |
| MAX1542ETP | 功能描述:LCD 驱动器 RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX1542ETP+ | 功能描述:LCD 驱动器 TFT LCD DC/DC Conv w/Op Amps RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX1542ETP+T | 功能描述:LCD 驱动器 TFT LCD DC/DC Conv w/Op Amps RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
发布紧急采购，3分钟左右您将得到回复。