- 您现在的位置：买卖IC网 > Sheet目录17351 > AS1329A EB (ams)BOARD EVAL AS1329A
AS1329
Datasheet - D e t a i l e d D e s c r i p t i o n
8.2 Low-Noise Fixed-Frequency Operation
8.2.1
Oscillator
The AS1329 switching frequency is internally fixed at 1.2MHz allowing the use of very small external components.
8.2.2
Error Amplifier
The integrated error amplifier is an internally compensated trans-conductance (g m ) type (current output). The internal 1.23V reference voltage is
compared to the voltage at pin FB to generate an error signal at the output of the error amplifier. A voltage divider from V OUT to GND programs
the output voltage from 2.5 to 5V via pin FB as:
V OUT = 1.23V(1 + (R 1 /R 2 ))
(EQ 1)
8.2.3
Current Sensing
A signal representing the internal NMOS-switch current is summed with the slope compensator. The summed signal is compared to the error
amplifier output to provide a peak current control command for the PWM. Peak switch current is limited to approximately 850mA independent of
V IN or V OUT .
8.2.4
Zero Current Comparator
The zero current comparator monitors the inductor current to the output and shuts off the PMOS synchronous rectifier once this current drops to
20mA (approx.). This prevents the inductor current from reversing polarity and results in improved converter efficiency at light loads.
8.2.5
Anti-Ringing Control
Anti-ringing control circuitry prevents high-frequency ringing on pin SW as the inductor current approaches zero. This is accomplished by
damping the resonant circuit formed by the inductor and the capacitance on pin SW (C SW ).
8.3 Powersave Operation (AS1329A, AS1329B)
In light load conditions, the integrated powersave feature removes power from all circuitry not required to monitor V OUT . When V OUT has
dropped approximately 1% from nominal, the AS1329A & B powers up and begins normal PWM operation.
C OUT (see Figure 19 on page 8) recharges, causing the AS1329A and AS1329B to re-enter powersave mode as long as the output load
remains below the powersave threshold. The frequency of this intermittent PWM is proportional to load current; i.e., as the load current drops
further below the powersave threshold, the AS1329A and AS1329B turns on less frequently. When the load current increases above the
powersave threshold, the AS1329A and AS1329B will resume continuous, seamless PWM operation.
While the AS1329A switches to automatic powersave mode already at medium loads, the AS1329B will do so only at very light loads.
The AS1329C is a continuous switching device, hence the output voltage ripple is very low and no additional frequencies are produced which
may cause interference.
Notes:
1. An optional capacitor (C FF ) between pins V OUT and FB in some applications can reduce V OUTp-p ripple and input quiescent current
during powersave mode. Typical values for C FF range from 15 to 220pF.
2. In powersave mode, the AS1329A and AS1329B draws only 30μA from the output capacitor(s), greatly improving converter efficiency.
8.4 Shutdown
When pin SHDNN is low the AS1329 is switched off and <1μA current is drawn from battery; when pin SHDNN is high the device is switched on.
If SHDNN is driven from a logic-level output, the logic high-level (on) should be referenced to V OUT to avoid intermittently switching the device
on.
Note: If pin SHDNN is not used, it should be connected directly to pin OUT.
In shutdown the battery input is connected to the output through the inductor and the internal synchronous rectifier P-FET. This allows the input
battery to provide backup power for devices such as an idle microcontroller, memory, or real-time-clock, without the usual diode forward drop. In
this way a separate backup battery is not needed.
In cases where there is residual voltage during shutdown, some small amount of energy will be transferred from pin OUT to pin BATT
immediately after shutdown, resulting in a momentary spike of the voltage at pin BATT. The ratio of C IN and C OUT partly determine the size and
duration of this spike, as does the current-sink ability of the input device.
www.ams.com/DC-DC_Step-Up/AS1329
Revision 1.12
9 - 20
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
MC34063SMDBGEVB
BOARD EVALUATION MC34063
HCM06DRYN
CONN EDGECARD 12POS DIP .156 SLD
SJA7501-1-1/2-50-BLACK
LOOP BLACK 1 1/2" X 50YD X 0.12"
EBM11DRYH
CONN EDGECARD 22POS DIP .156 SLD
EEV-HB1C100R
CAP ALUM 10UF 16V 20% SMD
TARQ155K020
CAP TANT 1.5UF 20V 10% AXIAL
RE-243.3S/H
CONV DC/DC 1W 24VIN 3.3VOUT
L-07C4N3SV6T
CER INDUCTOR 4.3NH 0402
相关代理商/技术参数
AS1329ABTTT
制造商:AMS 功能描述:IC, STEP-UP DC/DC CONVERTER, 6-SOT-23; Primary Input Voltage:1.2V; No. of Outputs:1; Output Voltage:5V; Output Current:220mA; No. of Pins:6; Operating Temperature Min:-40C; Operating Temperature Max:85C; Output Current Max:315mA ;RoHS Compliant: Yes
AS1329A-BTTT
功能描述:IC REG BOOST SYNC ADJ TSOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:1,000 系列:- 类型:降压（降压） 输出类型:可调式 输出数:1 输出电压:0.6 V ~ 4.5 V 输入电压:3 V ~ 5.5 V PWM 型:电流模式 频率 - 开关:3MHz 电流 - 输出:1.5A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 供应商设备封装:6-LLP-EP（3x3） 产品目录页面:1300 (CN2011-ZH PDF) 其它名称:LM2831ZSDLM2831ZSDTR
AS1329B
制造商:AMSCO 制造商全称:austriamicrosystems AG 功能描述:Low Voltage, Micropower, DC-DC Step-Up Converters
AS1329B EB
功能描述:BOARD EVAL AS1329B RoHS:否 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969
AS1329BBTTT
制造商:AMS 功能描述:IC STEP-UP DC/DC CONVERTER 6-SOT-23 制造商:AMS 功能描述:IC, STEP-UP DC/DC CONVERTER, 6-SOT-23; Primary Input Voltage:1.2V; No. of Outputs:1; Output Voltage:5V; Output Current:220mA; No. of Pins:6; Operating Temperature Min:-40C; Operating Temperature Max:85C; Output Current Max:315mA ;RoHS Compliant: Yes
AS1329B-BTTT
功能描述:IC REG BOOST SYNC ADJ TSOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:50 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:5 V ~ 25 V 输入电压:2.3 V ~ 5.5 V PWM 型:电流模式 频率 - 开关:600kHz，1.2MHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-TSSOP，8-MSOP（0.118"，3.00mm 宽） 包装:管件 供应商设备封装:8-MSOP
AS1329B-EB
制造商:ams 功能描述:AS1329B Evaluation Board
AS1329B-TT_EK_ST
功能描述:AS1329B - DC/DC, Step Up 1, Non-Isolated Outputs Evaluation Board 制造商:ams 系列:- 零件状态:有效 主要用途:DC/DC，步升 输出和类型:1，非隔离 功率 - 输出:- 电压 - 输出:3.3V 或 5V 电流 - 输出:570mA 电压 - 输入:0.85 V ~ 5 V 稳压器拓扑:升压 频率 - 开关:1.2MHz 板类型:完全填充 所含物品:板 使用的 IC/零件:AS1329B 标准包装:1